Estimating the Wavenumber of Terminal Metal-Hydride Stretching

Article pubs.acs.org/IC

Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX

Estimating the Wavenumber of Terminal Metal-Hydride Stretching Vibrations of Octahedral d6 Transition Metal Complexes Robert H. Morris* Department of Chemistry, University of Toronto, 80 Saint George St., Toronto, Ontario M5S3H6, Canada

Downloaded via TRINITY COLG DUBLIN on October 23, 2018 at 11:50:26 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

S Supporting Information *

ABSTRACT: The wavenumbers of 774 terminal hydride infrared active stretching modes of 478 distinct classes of structures of d6 octahedral complexes of Mn(I), Re(I), Fe(II), Ru(II), Os(II), Co(III), Rh(III), Ir(III), and Pt(IV) were collected from the literature. A fair correlation (R2 0.95 with standard deviation 31 cm−1) is found for the data with the equation νMHcalc = ν0 + Δνt + Δνn, where ν0 is the base wavenumber for the metal ion in question, Δνt is the parameter of influence of the ligand trans to the hydride, and Δνn is a correction for the charge of the complex [MHL5]n+. The introduction of a cis influence parameter has little effect on the correlation, showing that the trans influence dominates in this case. The equation is useful in identifying anomalous data reported in the literature, validating future assignments of νMH, understanding better metal-hydride bonding, and possibly assisting in identifying superior hydridebased catalysts.

■

A simple equation to estimate νMH is reported here that sheds light on the magnitude of the trans and cis influence of ligands on νMH in d6 octahedral metal ion complexes.

INTRODUCTION We have been interested in additive contributions of ligands to properties of transition metal complexes.1−6 Here, we probe how the terminal metal hydride (deuteride) vibration wavenumbers (νMH) are affected by the nature of the d6 metal ion and the ligands trans- and cis- to the hydride in octahedral complexes. The infrared spectra of transition metal hydrides were highlighted in the reviews of transition metal hydride complexes by Kaesz and Saillant in 1972,7 McCue in 1973,8 and Moore and Robinson in 1983.9 These reviews stressed the important influence of the trans ligand on νMH and provided a qualitative ordering of ligand trans influence, mainly in square planar complexes. Perutz and coworkers measured the Raman and infrared spectra of complexes of the type [MHxCp2]n+, M = Nb, Ta, Mo, W, and discussed how the ν(MHn) band positions changed with previously reported complexes with M = Tc, Re as a function of the formal dn configuration of the metal, the charge of the complex and the row of the periodic table.10 With the advent of more convenient and informative NMR methods in the 1970s, less effort was expended in measuring the vibrational spectra of transition metal hydride complexes, compounds which tend to be oxygen sensitive. More recent reviews about transition metal hydrides11−19 provide little new information on the trends of νMH with respect to changes in molecular structure. With the advent of less expensive spectrometers utilizing attenuated total reflectance (ATR-FTIR) that can even be placed within a glovebox, the acquisition of νMH has become easier, and more data should become available in the future. Therefore, it is of interest to examine the current status of the literature on νMH and look for useful relationships between these data and molecular structure. © XXXX American Chemical Society

■

METHODOLOGY AND RESULTS We gathered together terminal metal-hydride and metaldeuteride vibration wavenumbers of d6 octahedral metal complexes of groups 7, 8, 9, and 10 found scattered in the literature.7,20−228 These are infrared active modes although in a few cases Raman data were also available. In certain cases the mode was verified by preparing the metal deuteride.7,20,26,36,45,

47,52,69,85,88,89,91,104,111,112,121,122,126,132,157,184,201,203,215,217,223

When the hydride is trans to a hydride, usually the antisymmetric H−M−H mode is observed and reported in the region between 1580 and 1900 cm−1 depending on the metal and coligands. The symmetric H−M−H mode at higher wavenumber (1886 cm−1) has been located for trans-RuH2(C6H5P(OC2H5)2)4 by the use of Raman spectroscopy along with the antisymmetric IR-active mode at 1643 cm−1.148 Because in all the other cases only the lower, antisymmetric mode IR-active is reported, this is the one analyzed in this report. Classes of ligands in the octahedral metal hydride complexes were grouped in a similar fashion to that described previously for use in pKa estimations.1,6 For example, all ligands with an imine-type donor such as aldimine, ketimine, imidazole, pyrazole, and one-half of bipyridine, phenanthroline, and diazabutadiene were represented by py. Some of the approximately 774 complexes represented in this data set then are Received: August 17, 2018

A

DOI: 10.1021/acs.inorgchem.8b02314 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry

Table 1. Ligand Contributions (Δνt) to νMH from the Ligands trans to the Hydride in the d6 Octahedral Complex [MHL1L2L3L4L5]n Obtained from the Fit of Eq 1 and Eq 2 to the Data of Table S1a

found to have the same ligand set with the same overall charge and the same metal and so have been grouped into a family, making 478 distinct families of compounds with the same general formula. The νMHobs of the members of each family were averaged so that the large families are not given excessive weight in the regression. Complexes with cyclopentadienide or pentamethylcyclopentadienide ligands along with three other donors are not strictly octahedral but have been included in the analysis. The data set containing the families of complexes with common types of ligands as listed in Table 1 can be found in Table S1, and the actual formula for each member can be found in the spreadsheet (Supporting Information). The fact that νMHobs is dominated by the influence of the trans ligand for the iron group is known from the work of Chatt in the 1960s.20,26,27,220,229 The contribution (Δνt) to the νMH for each class of ligand trans to the hydride in the octahedral complexes was sought by fitting eq 1 and eq 2 (Aw is the atomic weight of the metal) to the set of νMHobs and νMDobs data of Table S1 (see the Supporting Information). Kruck7 showed that the νMnD of the complexes MnH(CO)x(PF3)5−x were invariant at 1290 cm−1, independent of the number and placement of the CO and PF3 ligands; the νMnH mode was mixed with the νCO modes and was not as constant. This suggests that PF3 and CO have the same trans influence on νMnD (see Table S1); therefore, the ligand parameters for CO and PF3 were kept the same. In eq 1, Δνt (Table 1) is the contribution to νMH of the trans ligand; Δνn (Table 2) accounts for the effect of the overall charge n of the complex, and ν0 (Table 3) is the base wavenumber that is characteristic of the metal ion (although cis ligand contributions are also present to a minor extent, see below). An assumption in formulating eq 1 is that νMH responds to Δνt in a linear fashion, which appears to be the case. The harmonic approximation is assumed in eq 2. νMH calc = Δν t + Δν n + ν 0

(1)

νMDcalc = νMH calc/sqrt(2A w /(A w + 2))

(2)

L1 trans to H

Δνt (cm−1)

error (cm−1)

instances

b

−95 −50 −40 −15 −5 −10 −5 5 5 20 40 −290 (−170)l −145 −145 −105 −20 −10 25 30 40 60

12 15 15 15 15 15 15 15 15 15 15 15 15 15 15 10 10 15 15 15 12

64 8 38 15 33 22 40 39, 17 6 96 12 40 10 9 8 98 39 26 20 12 122

PR3 PR2Arc PRAr2d PX3e PAr3f CCg NR3h CO, PF3 H2i pyj OR2k H− CN− Ar− m R− n Cp*− o Cp− p Tp− q OR− r I− Cl− a

See the Supporting Information for the list of the families of complexes in Table S1. bPR3 includes PMe3, PEt3, PiPr3, PCy3, PTA (1,3,5-triaza7-phosphaadamantane), and one-half of dmpm (PMe2CH2PMe2), dmpe (PMe2CH2CH2PMe2), depe (PMe2CH2CH2PMe2), depx (bis(diethylphosphino)xylene), PiPr2CH2CH2PiPr2, and one-third of [PhB(CH2PiPr2)3]− (with n = 1). cPR2Ar includes PMe2Ph and the central donor of linear triphos ligands. dPRAr2 includes PMePh2, PEtPh2, 5-phenyl-5H-dibenzophosphole, a terminal PPh2CH2 group of a triphos (MeCH(CH2PPh2)3), NP3 (N(CH2CH2PPh2)3) or PP3 ligand (P(CH2CH2PPh2)3), one-half of dppe (PPh2CH2CH2PPh2) or dppb (PPh2CH2CH2CH2CH2PPh2), and one-third of [PhB(CH2PPh2)3]− (with n = 1). ePX3 includes P(OMe)3, P(OEt)3, P(OEt)2(Ph), P(OEt)2(OPh), P(OPh)2Ph, and one-half of P(OCH2CF3)2NMeP(OCH2CF3)2. fPAr3 includes PPh3, Ptolyl3, one-half of xantphos ligands, and a P donor of Si(orthoC6H4PPh2)2− = (SiR3−)(PAr3)2. g CC includes C2H4, η2-H2CCH(CN), one-half of allyl, and onethird of η6-cymene, η6-C6H6, η6-C6Me6, η6-C6H3Me3, or η6-C6H5Me. h NR3 includes NH3, NH2CH2 groups, NHMe2, the central donor of NP3 or NH(SiMe2CH2PPh2)2, one-half of 1,2-diaminocyclohexane, one-third of 1,4,7-triazacyclononane (tacn) or 1,4,7-trimethyl-1,4,7triazacyclononane (cn), and one-quarter of [14]aneN4. jpy includes pyridine, MeCN, PhCN, pyrazole, RNCHR, the central donor of PR2CH2pyCH2PR2 pincer ligands, one-half of bipyridine, phenanthroline, diazabutadiene ligands, NH2CMe2CMe2NH2 (tmen), a pyridyl donor of pyOSiMeOPy−, a quinoline donor of bis(8-quinolyl)methylsilyl pincer ligand, and cyclometalated benzoquinolato ligand. kOR2 includes H2O, tBuOH, acetone, urea, acac− = (OR2)(OR−), and central O donor of xantphos pincer ligands. lThe −290 cm−1 value is artificially negative (by about 120 cm−1) compared to the other values in this Table because it refers to the antisymmetric mode of a transHMH structure. The −170 cm−1 value should be used in comparisons with the Δνt of the other anionic ligands. mAr− includes sp2- and sphybridized carbon donors, including Ph−, ortho-tolyl, and alkynyls including CCH−, CCMe−, CCPh−, and CCtBu−. nR− includes Me−, nPr−, CH2Ph−, 2-tetrahydrofuranyl, CH2CN−, and CH2CO(OMe)−. oCp*− is η5-pentamethylcyclopentadienide. pCp− is η5-cyclopentadienide. qTp− includes tris(pyrazolyl)borate and tris3,5-dimethylpyrazolyl)borate (Tp* or Tp′). rOR− includes OPh−, OC 6 H 4 -p-Me − , OC 6 H 4 -p-NO 2 − , OC 6 F 4 -p-Cl − , OC 6 F 4 -p-Me − , OC6H4L− donors, O2PPh2−, O2CH−, OTf−, and central alkoxide of pyCHOpy− tridentate.

Thus, 33 parameters, including those for Δνt (Table 1), charge Δνn (Table 2), and the metal ion ν0 (Table 3) were obtained from an iterative optimization of a least-squares fit regression of eqs 1 and 2 to 478 νMHobs and νMDobs values using Excel spreadsheet methods. The starting guessed values for ν0 for each metal were the average of all of the νMHobs for that metal. The starting Δνt values were obtained by averaging the differences between νMHobs and ν0 for each type of ligand trans to hydride in complexes of ruthenium with the same charge and iridium with the same charge. The charge parameter Δνn developed as the optimization proceeded. The regression of Figure 1 was obtained with R2 0.95 and with a standard deviation between νMHobs and νMHcalc of 31 cm−1. A statistical analysis provides standard deviations of Δνt, Δνn, and ν0 that contribute to the overall standard deviation of νMHcalc; these are listed as errors in Tables 1−3. The Δνt for the frequently occurring PR3, Cp*−, Cp−, and Cl− ligands have standard deviation errors of approximately 10 cm−1, while the rest of have errors of 15 cm−1. The py class of ligands has 103 representatives, but the error is 15 cm−1, probably because the type of ligand assigned to this class is broad (e.g., MeCN, bpy, etc.; see Table 1, footnote j). This class can be broken into more specific types of nitrogen donors as more data become available. The νMHobs values reported in the literature can have significant variation for a variety of reasons. The position of the νMH absorption can be solvent- or crystal structure- dependent B


Article

Inorganic Chemistry Table 2. Effect of the Charge n on the Complex [MHL1L2L3L4L5]n Obtained from the Fit of Eq 1 and Eq 2 to the Data of Table S1 n

Δνn (cm−1)

error (cm−1)

instances

−1 0 1 2

−45 0 25 50

20 5 10 20

22 238 169 14

A combination of 53 parameters, including those for the ligands Δνt′ and Δνc (Table S2), metal ion ν0′ (Table S3), and complex charge Δνn′ (Table S4), were obtained from a best fit regression of eqs 3 and 4 to the 478 νMHobs and νMDobs values. The regression of Figure S1 is obtained with R2 0.96 and with a standard deviation between νMHobs and νMHcalc of 27 cm−1. This correlation is only a marginal improvement from that of Figure 1.

■

DISCUSSION We show here that the dominant influence of the trans ligand can be roughly quantified using eq 1 (standard deviation 31 cm−1) for d6 octahedral hydride complexes for typically encountered coligands (Table 1) and metal ions from Mn(I) to Pt(IV) (Table 3). The effect of charge is also quantified for the first time for this class of complexes (Table 2). For the Ru(II) and Os(II) complexes trans-MHX(diphos)2, Chatt reported the order of νMH is I− > Br− > Cl− > SCN− > NO2− > CN− > H− and that the νMH for osmium is 100 cm−1 greater than the one for the corresponding ruthenium complex.26 These observations are consistent with our findings apart from a reversal of the order of chloride and iodide in the ligand order. The ligand order is consistent with other measures of trans influence230 in d6 octahedral complexes. For example, it is interesting to note that the 1H NMR chemical shifts, which are dominated by a spin−orbit coupling effects, of square planar Au(III) complexes are calculated to give an ordering of trans influence: SiH3− > H− > Me− > Ph− > PH3 > CO > CN− > I− > Cl− > NH3 > py > OH2, which is somewhat similar to that of Δνt.231 The hydride ligand has the most negative contribution to νMHcalc with Δνt −290 cm−1. This value is exaggerated compared to the other Δνt in Table 1 as noted in footnote l of this Table because it refers to the antisymmetric vibration of a transHMH unit. The position of this band depends on the magnitude of the coupling between the M−H oscillators (the interaction force constant) in this pseudo triatomic unit.232 However, it is not known yet whether the interaction force constant varies with the nature of the metal or the other ligands. There are two reports where both νHMHasym and νDMDasym were measured for complexes of cobalt and iridium.7,89 For merCoH3(PPh3)3/CoD3(PPh3)3 the ratio of νHMHasym/νDMDasym = 1745/1263 = 1.38 as expected from the effect of the reduced mass of one cobalt and one hydrogen or deuteron. Similarly for IrH3(CO)(PPh3)2/IrD3(CO)(PPh3)2, this ratio is 1745/1263 = 1.40, as expected. Thus, the presence of additional deuterons in the complex does not appear to have a noticeable effect on the position of the bands. If the interaction force constant in transdihydride systems is similar to that of trans-RuH2(C6H5P(OC2H5)2)4 with νHMHsym 1886 and νHMHasym 1643 cm−1,148 then approximately 120 cm−1 should be added to Δνt of the hydride making Δνt −170 cm−1 for comparison with the other ligands in Table 1. This modified Δνt for the hydride ligand still has a more negative contribution to νMHcalc than the cyanide and aryl (−145 cm−1) ligands. An analysis of bond distances of octahedral complexes of Pt(IV), Rh(III), Ir(III), and Ru(II) led to the conclusion that the relative bond order (rbo) of a metal-probe atom bond trans to the following ligands decreases as X2CO = py = NR3 = Cl > SR2 > CO > PPh3 > Ph > CR3 > H.233 There is a fair correlation between the rbo and the Δνt values of Table 1 as long as the effect of charge (25 cm−1) is added to the Δνt of the anions so that the neutral ligand types are comparable (see Figure S2). It is not clear why the order of phenyl and alkyl are reversed when comparing the rbo with Δνt.

6

Table 3. Base Wavenumber for Each Metal in the d Octahedral Hydride Complex Obtained from the Fit of Eq 1 and Eq 2 to the Data of Table S1 metal ion

ν0 (cm−1)

error (cm−1)

instances

Mn(I) Fe(II) Co(III) Ru(II) Rh(III) Re(I) Os(II) Ir(III) Pt(IV)

1780 1895 1980 1940 2030 1875 2045 2130 2260

20 15 20 15 15 20 15 15 20

13 62 24 193 105 7 41 316 13

leading to values which can vary up to at least 30 cm−1.9 The metal hydride vibration often produces a weak absorption peak in the region between 2300 and 1500 cm−1. Ligands with aryl groups have absorptions in this range that can be confused with νMH. We have discovered some incorrect assignments (see below). The M−H mode can be mixed with other modes of similar wavenumber (Fermi Resonance), especially of those of carbonyl and dinitrogen ligands, with vibrations in the same range as νMH. Table S1 contains 28 cis-dihydrides where the ligands trans to the hydrides are the same. The average spacing between the two bands is 49 cm−1 with a standard deviation of 28 cm−1 for values ranging from 0 to 110 cm−1. The wavenumbers of these two bands are averaged when the formulas (which are same) are grouped into the same family. Thus, the deviations will be on average 25 cm−1 or a standard deviation of 14 cm−1, much less than the actual standard deviations of the correlations discussed. In general, the average range of values for a family with more than one member is 38 cm−1; this spread of values is reduced by at least a factor of 2 when the values are averaged. To probe the magnitude of the cis-ligand contributions, additive values making up the νMH for the ligand trans (Δνt′) and cis (Δνc) to the hydride in the octahedral complexes were sought by fitting eq 3 and eq 4 to the set of νMHobs and νMDobs data (Table S5). The primes on these variables indicate that they have values different than those of Δνt, ν0, and Δνn of eq 1. νMH calc ′ = ν 0 ′ + Δν t ′ + Δν c1 + Δν c 2 + Δν c 3 + Δν c 4 + Δν n ′ (3)

νMDcalc ′ = νMH calc ′/sqrt(2A w /(A w + 2))

(4)

In the calculations using eq 3, bidentate ligands such as bipyridine, phenanthroline, and diazabutadiene contribute at two sites of the octahedron (Δνt′ + Δνc or 2Δνc). The tridentate ligands Cp*− (η5-pentamethylcyclopentadienide), Cp − (η 5 -cyclopentadienide), and Tp − (κ 3 -hydridotris(pyrazolyl)borate contribute one Δνt′ and two Δνc to νMHcalc′ (see Table S2). The η6-hexamethylbenzene ligand contributes one Δνt′ (CC) and two Δνc (CC) (Table S2). C


Article

Inorganic Chemistry

Figure 1. Regression of νMHcalc and νMDcalc obtained from eqs 1 and 2 versus νMHobs and νMDobs.

of the formal dn configuration of the metal, the charge of the complex, and the row of the periodic table.10 Although there are changes in coordination number at these early transition metals and the possibility of H···H bonding in certain cases,236,237 similar trends were reported to those noted in the current work. There is a general trend to higher wavenumbers on moving from left to right of the d block elements. The ν(MHn) mode of the 5d metal was on average 59 cm−1 higher than that of the 4d metal (Figure 2), whereas we found a

Chatt also reported that more donating diphos ligands (e.g., depe, dmpe i.e. (PR3)2 donors) in trans-MHX(diphos)2 produced lower νMH than less donating ones (e.g., dppe, dppm i.e. (PRAr2)2 donors). This effect is averaged out in the one ligand parameter (Δνt) approach. However, in the analysis where a cis influence parameter is introduced (Δνc), this trend is reproduced (Table S2) with Δνc(PR3) < Δν c(PRAr2). A major trend apparent from the parameters of Tables 1−3 is that of increasing νMH as the positive charge at the metal center increases. This is most apparent from the charge effect of Table 2 but also from the effect of oxidation state, with νMH increasing on going from M(I) to M(IV) (Table 3). Similarly electronegative atoms in the trans ligand cause an increase in νMH (Table 1). Superimposed on these trends is an increase in ν0 on descending each group with a larger increase on going from the 4d to 5d metal than 3d to 4d. This could be related to relativistic strengthening of the M−H bond in the 5d metals. Overall there is an increase in ν0 diagonally from Mn(I) to Ir(III) or Fe(II) to Pt(IV) from the middle to the right of the d block. A reviewer pointed out that the change in M−H force constant f is even greater because it is roughly proportional to the square of the wavenumber. Thus, ν0(Pt)/ν0(Mn) = 2260/ 1780 = 1.27, while f(Pt)/f(Mn) = 1.61, so the force constant would be 61% bigger for Pt(IV) than that for Mn(I) at first estimate, assuming that the contributions of anharmonicity are similar. No νMHobs appears in Table S1 for Tc(I), Ni(IV), or Pd(IV). The impure complex PdH(Br)2(PPh3)2(CH2Ph) produced a peak at 2190 cm−1.234 If Br− has the same Δνt as Cl−, then ν0 for Pd(IV) is 2130 cm−1, 100 cm−1 greater than the ν0 of 2030 cm−1 for Rh(III). This change in ν0 is somewhat less than the 130 cm−1 increase on going from Ir(III) to Pt(IV). We are not aware of data for Tc(I) or Ni(IV). Of note, the paramagnetic Co(II) complex fac-CoH(PMe3)2(PPh2C6H4NC6H4PPh2) with hydride trans to a PAr3 group has νCoHobs 1894 cm−1.235 If Co(II) has a similar base wavenumber ν0 to that of Fe(II), eq 1 gives νFeHcalc = νCoHcalc = 1880 cm−1. Perutz and coworkers developed an equation that described the ν(MHn) band position of complexes of the type [MHxCp2]n+, M = Nb, Ta, Mo, W, Tc, and Re as a function

Figure 2. Trends in ν(MHn) mode wavenumbers of neutral metal hydride complexes with various d electron configurations using the ν0 of Table 3 and the ν(MHn) values of Perutz and coworkers.10

difference of about 100 cm−1 for the later transition metals. This is likely to be due to a strengthening of the 5d metal bond by relativistic effects. Perutz et al. noted that the order of M−H bond dissociation energies WH2Cp2 > MoH2Cp2 is in the same order as the ν(MHn). The effect of a positive charge for these early transition metal complexes in their protonated forms was on average 24 cm−1, the same as the positive charge effect of our study (Δνn=1 25 cm−1). One difference from the d6 metal results is that the ν(MHn) mode decreases with an increase in formal oxidation state: ν(ReHCp2) > ν(WH2Cp2) > ν(TaH3Cp2). However, it may be that coordination number (CN) is the more important factor with ν(CN7) > ν(CN8) > ν(CN9). The wavenumber of a metal-hydride terminal stretch can be related to the square root of the M−H force constant under the D


Article

Inorganic Chemistry

vibrational wavenumbers is 31, assignments that deviate by more than 100 cm−1 from those expected on the basis of eq 1 are suspect. The νRuH of the trans-dihydride RuH2(PNP)(PPh3) was reported to be 1977 cm−1.46 Eq 1 provides the antisymmetric νRuHcalc 1650 cm−1. Similarly, a vibration at 2035 cm−1 was assigned to the complex IrH2(SiClPh2){xant(PiPr2)2} thought to have trans hydrides,51 but if this were the case, a band at νIrH calc 1840 cm−1 would be expected. The weak band of ReH(PMe3)5 at 1940 cm−1250 is unlikely to be νReH, which is expected on the basis of eq 1 to be 1770 cm−1. The reported band is likely to be due to the νNN of the impurity trans-ReH(N 2)(PMe3) 4 considering that trans-ReH(N2)(PEt2Ph)4 has νNN 1945 cm−1.250 Computational chemistry and DFT methods in particular also allow the calculation of vibrational spectra. We used DFT (Gaussian09,251 PBEBPED3/6-31++G** on all atoms except Re, SDD on Re) and obtained 1778 cm−1 for νReH of ReH(PMe3)5, showing that eq 1 provides a reasonable value.

harmonic oscillator approximation because the reduced masses for the metal-hydrides in question range from 0.98 to 0.99. A force constant indicates the curvature of the parabolic plot of energy vs M−H displacement and has been thought to reflect the strength of the M−H bond. Thus, M−H with low force constants and weak bonds such those trans to hydride might be particularly reactive. Indeed, certain neutral trans dihydride complexes are particularly active catalysts for the reduction of ketones,42,56,57,59,60,238 imines,239 nitriles,240,241 esters,238 and carbon dioxide.139 The transition state of the attack of transHMH systems on polar bonds often has the character of the antisymmetric stretch.42,57,60,242 Catalyst design in this case should involve trans dihydrides in combination with four ligands of high cis influence (negative Δνc in Table S2). The latter include PR3 (−25), py-type ligands (−30), N-heterocyclic carbene (NHC, −25), amine-type (−20), PR2Ar (−10), and PRAr2 (−15). This has been our and other’s experience with catalysts such as trans-RuH2(binap)(diamine), trans-RuH2(P-NH-NH-P),50,243 trans-FeH2(CO)(P-NH-P),42,238,240−242 trans-OsH2(CO)(P-NH-P),244 mer-IrH3(P−N−P),139 and RuH(NHC-NH2)(Cp*).245,246 A few other νMHobs were collected for d6 octahedral complexes with sets of ligands not covered by Table 1. The data for cis,mer-Ru(H)2(PPh3)3(N2) (νRuHobs 1938, 1960 cm−1) and its dideuteride88 (1400 cm−1) along with that of ReH(N2)(PEt2Ph)4 (νReHobs 1890) provide a Δνt for the η1-N2 ligand of −5 cm−1. This is close to that of the η2-H2 ligand (Δνt 5 cm−1) as might be expected based on the similarity in bonding of the two ligands.2 The complex [IrH(CNtBu)5](PF6)2 has vIrH 2120 cm−1 247 although it may be mixed with vCN. This corresponds to a Δνt of −60 cm−1 (νIrHobs − ν0 − Δν2+) for a CNR ligand. A potentially significant observation is the low νIrHobs of 1778 cm−1 observed for fac-IrH2(PPh3)(NSiN), where NSiN is the tridentate ligand bis(8-quinolyl)methylsilyl.191 With hydride trans to silicon this represents a Δνt for the SiR3− of −355 cm−1 (νIrHobs − ν0) even larger than that of hydride (−290 cm−1). Hydrides positioned trans to carbon and silicon donors in certain pincer Pd(II) complexes react with CO2, while those trans to nitrogen do not;248 the trans influence was attributed to this difference in reactivity although no νPdHobs were reported. Presumably, a low νMH can be used as an indicator of reactivity toward CO2. The very efficient catalyst for CO2 hydrogenation, mer-Ir(H)3(PiPr2CH2pyCH2PiPr2), has trans hydrides and a very low νIrHobs of 1678 cm−1.139 Eq 1 gives 1840 cm−1. This deviation may be due to a cis effect of the ligands or a change in the interaction force constant of the trans-HMH system. However, there is no obvious correlation between reported free energies of hydricity of transition metal hydrides249 and the vibrational parameters reported here. For example, palladium(II) and platinum(II) five coordinate hydride complexes are more hydridic in a thermodynamic sense than analogous nickel(II) ones and rhodium(III) more than cobalt(III).249 This would suggest that complexes with higher νMH would be more hydridic on the basis of the ν0 values of Table 3. On the other hand, neutral complexes are more hydridic than analogous cationic ones;249 this suggests the opposite conclusion: that complexes with lower νMH (on the basis of the lower Δνn value of Table 2) would be more hydridic. Similarly, there is no apparent correlation between νMH obs and the pKaLAC values estimated for the hydride complexes by the methods reported elsewhere.1,5,6 Eq 1 can be used to quickly test the validity of νMH assignments. Because the standard deviation of predicted

■

CONCLUSIONS Eq 1 is useful in assigning the wavenumber of terminal metal hydrides for d6 octahedral metal complexes. Clearly, the nature of the trans ligand, the oxidation state of the metal ion, and the charge on the complex determine the position of this stretch in the infrared spectrum. This equation along with the parameters of Tables 1−3 and additional information provided by the cis influence parameters Δνc found in Table S2 may assist in the design of new reactive hydrides with low νMH. A deeper examination of the trends uncovered here using DFT methods is in progress as well as an analysis of data for square planar complexes.

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.8b02314. Tables S1−S5, Figures S1 and S2, and DFT calculations for the complex ReH(PMe3)5 (PDF) Spreadsheet with the formulas of the complexes and their vibrational data (XLSX)

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Robert H. Morris: 0000-0002-7574-9388 Notes

The author declares no competing financial interest.

■

ACKNOWLEDGMENTS R.H.M. thanks NSERC Canada for a Discovery grant and Compute Canada for a resource allocation grant to access Sharcnet.

■

REFERENCES

(1) Morris, R. H. Brønsted−Lowry Acid Strength of Metal Hydride and Dihydrogen Complexes. Chem. Rev. 2016, 116, 8588−8654. (2) Morris, R. H.; Earl, K. A.; Luck, R. L.; Lazarowych, N. J.; Sella, A. Dihydrogen vs. dihydride. Correlations between electrochemical or UV PES data and force constants for carbonyl or dinitrogen ligands in octahedral, d6 complexes and their use in explaining the behavior of the dihydrogen ligand. Inorg. Chem. 1987, 26, 2674−2683. E


Article

Inorganic Chemistry

tane or (R,R)-1,2-diaminocyclohexane). Organometallics 2006, 25, 5477−5486. (25) Butter, S. A.; Chatt, J. Dihalodi[1,2-bis(dimethylphosphino)ethane]rhodium(III) and related carbonyl- and hydrido-complexes. J. Chem. Soc. A 1970, 1411−1415. (26) Chatt, J.; Hayter, R. G. Hydrido complexes of ruthenium(II) and osmium(II). J. Chem. Soc. 1961, 2605−2611. (27) Chatt, J.; Hayter, R. G. Some hydrido-complexes of iron(II). J. Chem. Soc. 1961, 5507−5511. (28) Esteruelas, M. A.; Werner, H. Five- and six-coordinate hydrido(carbonyl)-ruthenium(II) and -osmium(II) complexes containing triisopropylphosphine as ligand. J. Organomet. Chem. 1986, 303, 221−231. (29) Blum, O.; Milstein, D. Oxidative addition of water and aliphatic alcohols by IrCl(trialkylphosphine)3. J. Am. Chem. Soc. 2002, 124, 11456−11467. (30) Xiong, Z.; Li, X.; Zhang, S.; Shi, Y.; Sun, H. Synthesis and Reactivity of N-Heterocyclic PSiP Pincer Iron and Cobalt Complexes and Catalytic Application of Cobalt Hydride in Kumada Coupling Reactions. Organometallics 2016, 35, 357−363. (31) Kruger, P.; Werner, H. Mono- and dinuclear rhodium and iridium complexes with chiral phospholanes as ligands. Eur. J. Inorg. Chem. 2004, 34, 481−491. (32) Empsall, H. D.; Hyde, E. M.; Mentzer, E.; Shaw, B. L.; Uttely, M. F. Some iridium hydride and tetrahydroborate complexes with bulky tertiary phosphine ligands. J. Chem. Soc., Dalton Trans. 1976, 2069−2074. (33) Rybtchinski, B.; Ben-David, Y.; Milstein, D. Unexpected isomerization of a cis-dihydride into a trans-dihydride complex: a neutral late transition-metal complex as a hydride donor. Organometallics 1997, 16, 3786−3793. (34) Titova, E. M.; Osipova, E. S.; Gulyaeva, E. S.; Torocheshnikov, V. N.; Pavlov, A. A.; Silantyev, G. A.; Filippov, O. A.; Shubina, E. S.; Belkova, N. V. Mild activation of Ir-Cl bond upon the interaction of pincer iridium hydride (tBuPCP)IrH(Cl) with acids and bases. J. Organomet. Chem. 2017, 827, 86−95. (35) Moulton, C. J.; Shaw, B. L. Transition metal−carbon bonds. Part XLII. Complexes of nickel, palladium, platinum, rhodium and iridium with the tridentate ligand 2,6-bis[(di-t-butylphosphino)methyl]phenyl. J. Chem. Soc., Dalton Trans. 1976, 1020−1024. (36) Mediati, M.; Tachibana, G. N.; Jensen, C. M. IrH2Cl(H2)(PiPr3)2 Isolation and Characterization of IrH2Cl(η2-H2)[P(i-Pr)3]2: A Neutral Dihydrogen Complex of Iridium. Inorg. Chem. 1990, 29, 3−4. (37) Anderson, D. W. W.; Ebsworth, E. A. V.; Rankin, D. W. H. Hydride complexes of six-co-ordinate platinum. J. Chem. Soc., Dalton Trans. 1973, 854−858. (38) Chatt, J.; Shaw, B. L. Hydrido-complexes of platinum(II). J. Chem. Soc. 1962, 5075−5084. (39) Aoki, W.; Wattanavinin, N.; Kusumoto, S.; Nozaki, K. Development of Highly Active Ir-PNP Catalysts for Hydrogenation of Carbon Dioxide with Organic Bases. Bull. Chem. Soc. Jpn. 2016, 89, 113−124. (40) Esteruelas, M. A.; Fernandez-Alvarez, F. J.; Olivan, M.; Onate, E. NH-Tautomerization of Quinolines and 2-Methylpyridine Promoted by a Hydride-Iridium(III) Complex: Importance of the Hydride Ligand. Organometallics 2009, 28, 2276−2284. (41) Gusev, D. G. Effect of Weak Interactions on the H···H Distance in Stretched Dihydrogen Complexes. J. Am. Chem. Soc. 2004, 126, 14249−14257. (42) Smith, S. A. M.; Lagaditis, P. O.; Lupke, A.; Lough, A. J.; Morris, R. H. Unsymmetrical Iron P-NH-P′ Catalysts for the Asymmetric Pressure Hydrogenation of Aryl Ketones. Chem. - Eur. J. 2017, 23, 7212−7216. (43) Hara, T.; Yamagata, T.; Mashima, K.; Kataoka, Y. Preferential Geometry and Reactivity of Neutral Iridium(III) and Rhodium(III) Complexes Bearing a Flexible Heterochelate PN Ligand (PN = oPh2PC6H4CH2OCH2C5H4N-2). Organometallics 2007, 26, 110−118. (44) Ortmann, D. A.; Weberndorfer, B.; Ilg, K.; Laubender, M.; Werner, H. Carbene iridium(I) and iridium(III) complexes containing

(3) Morris, R. H. Ligand Additivity Effects and Periodic Trends in the Stability and Acidity of Octahedral η2-Dihydrogen Complexes of d6 Transition Metal Ions. Inorg. Chem. 1992, 31, 1471−1478. (4) Sung, M. M. H.; Morris, R. H. DFT Calculations Support the Additive Nature of Ligand Contributions to the pKa of Iron Hydride Phosphine Carbonyl Complexes. Inorg. Chem. 2016, 55, 9596−9600. (5) Unsleber, J. P.; Neugebauer, J.; Morris, R. H. DFT methods applied to answer the question: how accurate is the Ligand Acidity Constant method for estimating the pKa of transition metal hydride complexes MHXL4 when X is varied? Dalton Trans. 2018, 47, 2739− 2747. (6) Morris, R. H. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants. J. Am. Chem. Soc. 2014, 136, 1948−1959. (7) Kaesz, H. D.; Saillant, R. B. Hydride complexes of the transition metals. Chem. Rev. 1972, 72, 231−281. (8) McCue, J. P. Transition metal hydrides. Coord. Chem. Rev. 1973, 10, 265−333. (9) Moore, D. S.; Robinson, S. D. Hydrido complexes of the transition metals. Chem. Soc. Rev. 1983, 12, 415−452. (10) Girling, R. B.; Grebenik, P.; Perutz, R. N. Vibrational spectra of terminal metal hydrides: solution and matrix-isolation studies of [(ηC5H5)2MHn]x+ (M = Re, Mo, W, Nb, Ta; n = 1−3; x = 0, 1). Inorg. Chem. 1986, 25, 31−36. (11) Hlatky, G. G.; Crabtree, R. H. Transition-metal polyhydride complexes. Coord. Chem. Rev. 1985, 65, 1−48. (12) Puddephatt, R. J. Platinum(IV) hydride chemistry. Coord. Chem. Rev. 2001, 219, 157−185. (13) Jia, G.; Lau, C. P. Structural, acidity and chemical properties of some dihydrogen/hydride complexes of Group 8 metals with cyclopentadienyls and related ligands. Coord. Chem. Rev. 1999, 190− 192, 83−108. (14) McGrady, G. S.; Guilera, G. The multifarious world of transition metal hydrides. Chem. Soc. Rev. 2003, 32, 383−392. (15) Lau, C.; Ng, S.; Jia, G.; Lin, Z. Some ruthenium hydride, dihydrogen, and dihydrogen-bonded complexes in catalytic reactions. Coord. Chem. Rev. 2007, 251, 2223−2237. (16) Belkova, N. V.; Epstein, L. M.; Filippov, O. A.; Shubina, E. S. Hydrogen and Dihydrogen Bonds in the Reactions of Metal Hydrides. Chem. Rev. 2016, 116, 8545−8587. (17) Eberhardt, N. A.; Guan, H. Nickel Hydride Complexes. Chem. Rev. 2016, 116, 8373−8426. (18) Humphries, T. D.; Sheppard, D. A.; Buckley, C. E.; Stralia, V. P. Recent advances in the 18-electron complex transition metal hydrides of Ni, Fe, Co and Ru. Coord. Chem. Rev. 2017, 342, 19−33. (19) Robinson, S. J. C.; Heinekey, D. M. Hydride & dihydrogen complexes of earth abundant metals: structure, reactivity, and applications to catalysis. Chem. Commun. 2017, 53, 669−676. (20) Chatt, J.; Hayter, R. G. Some halido- and hydrido-alkyl and -aryl complexes of ruthenium(II) and osmium(II). J. Chem. Soc. 1963, 6017−6027. (21) Fulton, J. R.; Sklenak, S.; Bouwkamp, M. W.; Bergman, R. G. A Comprehensive Investigation of the Chemistry and Basicity of a Parent Amidoruthenium Complex. J. Am. Chem. Soc. 2002, 124, 4722−4737. (22) Ittel, S. D.; Tolman, C. A.; English, A. D.; Jesson, J. P. The Chemistry of 2-Naphtyl Bis[bis(dimethylphosphino)ethane]Hydride Complexes of Fe, Ru and Os. J. Am. Chem. Soc. 1978, 100, 7577−7585. (23) Basallote, M. G.; Hughes, D. L.; Jimenez-Tenorio, M.; Leigh, G. J.; Vizcaino, M. C. P.; Jimenez, P. V. Chemistry of cobalt complexes with 1,2-bis-(diethylphosphino)ethane: hydrides, carbon disulfide complexes, and C-H cleavage in activated alk-1-ynes. Crystal structure of [CoH(CCCO2Et)(Et2PCH2CH2PEt2)2][BPh4]. J. Chem. Soc., Dalton Trans. 1993, 1841−1847. (24) Clapham, S. E.; Guo, R.; Zimmer-De Iuliis, M.; Rasool, N.; Lough, A.; Morris, R. H. Probing the Effect of the Ligand X on the Properties and Catalytic Activity of the Complexes RuHX(diamine)(PPh3)2 (X = OPh, 4-SC6H4OCH3, OPPh2, OP(OEt)2, CCPh, NCCHCN, CH(COOMe)2; diamine = 2,3-diamino-2,3-dimethylbuF


Article

Inorganic Chemistry the metal center in different stereochemical environments. Organometallics 2002, 21, 2369−2381. (45) Maldotti, A.; Sostero, S.; Traverso, O.; Šima, J. Photochemistry of Bis(diphenylphosphino)ethane hydride complexes of iron. Inorg. Chim. Acta 1981, 54, L271−L272. (46) Rahmouni, N.; Osborn, J. A.; Decian, A.; Fischer, J.; Ezzamarty, A. Ruthenium(II) hydride complexes of 2, 6-(diphenylphosphinomethyl)pyridine. Organometallics 1998, 17, 2470−2476. (47) Tiethof, J. A.; Peterson, J. L.; Meek, D. W. Comparison of the properties of cationic alkyl- and hydride-rhodium(III) complexes of the triphosphine bis(3-diphenylphosphinopropyl)phenylphosphine. Inorg. Chem. 1976, 15, 1365−1370. (48) Fryzuk, M. D.; MacNeil, P. A.; Rettig, S. J. Stereoselective formation of rhodium and iridium hydrides via intramolecular hydrogen bonding. J. Am. Chem. Soc. 1987, 109, 2803−2812. (49) Abdur-Rashid, K.; Lough, A. J.; Morris, R. H. RuHCl(diphosphine)(diamine): Catalyst Precursors for the Stereoselective Hydrogenation of Ketones and Imines. Organometallics 2001, 20, 1047−1049. (50) Li, T.; Churlaud, R.; Lough, A. J.; Abdur-Rashid, K.; Morris, R. H. Dihydridoamine and Hydridoamido Complexes of Ruthenium(II) With a Tetradentate P-N-N-P Donor Ligand. Organometallics 2004, 23, 6239−6247. (51) Esteruelas, M. A.; Oliván, M.; Vélez, A. POP-pincer silyl complexes of group 9: Rhodium versus iridium. Inorg. Chem. 2013, 52, 12108−12119. (52) Vaska, L. Hydrido complexes of iridium. J. Am. Chem. Soc. 1961, 83, 756−756. (53) Sung, S.; Boon, J. K.; Lee, J. J. C.; Rajabi, N. A.; Macgregor, S. A.; Kramer, T.; Young, R. D. Convergent (De)Hydrogenative Pathways via a Rhodium alpha-Hydroxylalkyl Complex. Organometallics 2017, 36, 1609−1617. (54) Singer, H.; Wilkinson, G. Oxidative addition of hydrogen cyanide, hydrogen sulphide, and other acids to triphenylphosphine complexes of iridium(I) and rhodium(I). J. Chem. Soc. A 1968, 2516− 2520. (55) Silantyev, G. A.; Titova, E. M.; Filippov, O. A.; Gutsul, E. I.; Gelman, D.; Belkova, N. V. Hydrogen bonds, coordination isomerism, and catalytic dehydrogenation of alcohols with the bifunctional iridium pincer complex (HOCH2)2(PCsp3P) IrHCl. Russ. Chem. Bull. 2015, 64, 2806−2810. (56) Abbel, R.; Abdur-Rashid, K.; Faatz, M.; Hadzovic, A.; Lough, A. J.; Morris, R. H. A Succession of Dihydride Isomers of Ruthenium. Which One is the Ketone Hydrogenation Catalyst? J. Am. Chem. Soc. 2005, 127, 1870−1882. (57) Hadzovic, A.; Song, D.; MacLaughlin, C. M.; Morris, R. H. A Mechanism Displaying Autocatalysis: the Hydrogenation of Acetophenone Catalyzed by RuH(S-binap)(app) Where app is the Amido Ligand Derived from 2-Amino-2-(2-pyridyl)-propane. Organometallics 2007, 26, 5987−5999. (58) Abdur-Rashid, K.; Lough, A. J.; Morris, R. H. Ruthenium dihydride RuH2(PPh3)2(R,R-Cyclohexyldiamine) and Ruthenium Monohydride RuHCl (PPh3)2(R,R-Cyclohexyldiamine): Active Catalyst and Catalyst Precursor for the Hydrogenation of Ketones and Imines. Organometallics 2000, 19, 2655−2657. (59) Abdur-Rashid, K.; Faatz, M.; Lough, A. J.; Morris, R. H. Catalytic Cycle for the Asymmetric Hydrogenation of Prochiral Ketones to Chiral Alcohols: Direct Hydride and Proton Transfer from Chiral Catalysts trans-Ru(H)2(diphosphine)(diamine) to Ketones and Direct Addition of Dihydrogen to the Resulting Hydridoamido Complexes. J. Am. Chem. Soc. 2001, 123, 7473−7474. (60) Abdur-Rashid, K.; Clapham, S. E.; Hadzovic, A.; Harvey, J. N.; Lough, A. J.; Morris, R. H. Mechanism of the Hydrogenation of Ketones Catalyzed by trans-Dihydrido(diamine)ruthenium(II) Complexes. J. Am. Chem. Soc. 2002, 124, 15104−15118. (61) Hallman, P. S.; McGarvey, B. R.; Wilkinson, G. Preparation and reactions of hydridochlorotris(triphenylphosphine)ruthenium(II) including homogeneous catalytic hydrogenation of 1-alkenes. J. Chem. Soc. A 1968, 3143−3150.

(62) Karmel, C.; Li, B.; Hartwig, J. F. Rhodium-Catalyzed Regioselective Silylation of Alkyl C-H Bonds for the Synthesis of 1,4-Diols. J. Am. Chem. Soc. 2018, 140, 1460−1470. (63) Nishihara, Y.; Takemura, M.; Osakada, K. Structure and Properties of Halogeno(hydrido)(triorganosilyl)rhodium(III) Complexes, RhX(H)(SiR1nR23‑n)(PPh3)2 (X = Cl, I; R1 = OSiMe3, OEt, R2 = Me). Influence of the Alkoxy Groups and Halo Ligand on Stability and Reactivity of the Complexes. Organometallics 2002, 21, 825−831. (64) Eiβler, A.; Kläring, P.; Emmerling, F.; Braun, T. α-Dialdimine Complexes of Rhodium(I) and Iridium(I): Their Reactivity with Dioxygen and Dihydrogen. Eur. J. Inorg. Chem. 2013, 2013, 4775− 4788. (65) San Nacianceno, V.; Ibarlucea, L.; Mendicute-Fierro, C.; Rodriguez-Dieguez, A.; Seco, J. M.; Zumeta, I.; Ubide, C.; Garralda, M. A. Hydrido{(acylphosphine)(diphenylphosphinous acid)}rhodium(III) Complexes. Catalysts for the Homogeneous Hydrolysis of Ammonia- or Amine-Boranes under Air. Organometallics 2014, 33, 6044−6052. (66) Smith, S. A.; Blake, D. M.; Kubota, M. Hydridocarboxylato Complexes of Iridium. Inorg. Chem. 1972, 11, 660. (67) Cherry, S. D. T.; Kaminsky, W.; Heinekey, D. M. Structure of a Novel Rhodium Phosphinite Compound: Agostic Interactions as a Model for an Oxidative Addition Intermediate. Organometallics 2016, 35, 2165−2169. (68) He, F.; Braunstein, P.; Wesolek, M.; Danopoulos, A. A. Iminefunctionalised protic NHC complexes of Ir: direct formation by C-H activation. Chem. Commun. 2015, 51, 2814−2817. (69) Bakac, A.; Thomas, L. M. Macrocyclic rhodium(III) hydrides and a monomeric rhodium(II) complex. Inorg. Chem. 1996, 35, 5880− 5884. (70) O, W. W. N.; Lough, A. J.; Morris, R. H. Primary Amine Functionalized N-Heterocyclic Carbene Complexes of Iridium: Synthesis, Structure, and Catalysis. Organometallics 2013, 32, 3808− 3818. (71) Girolami, G. S.; Howard, C. G.; Wilkinson, G.; Dawes, H. M.; Thornton-Pett, M.; Motevalli, M.; Hursthouse, M. B. Alkyl, hydrido, and tetrahydroaluminato complexes of manganese with 1,2-bis(dimethylphosphino)ethane (dmpe). X-Ray crystal structures of Mn 2 (μ-C 6 H 11 ) 2 (C 6 H 11 ) 2 (μ-dmpe), (dmpe) 2 Mn(μ-H) 2 AlH(μH) 2 AlH(μ-H) 2 -Mn(dmpe) 2 , and Li 4 {MnH(C 2 H 4 )[CH 2 (Me)PCH2CH2PMe2]2}2·2Et2O. J. Chem. Soc., Dalton Trans. 1985, 921− 929. (72) Werner, H.; Kletzin, H. Synthese und eigenschaften stabiler hexamethylbenzol(phosphin)dimethyl- und -dihydrido-ruthenium(II)komplexe. J. Organomet. Chem. 1982, 228, 289−300. (73) Werner, H.; Kletzin, H. Basische metalle: XLIII. Synthese kationischer trishydridoruthenium(IV)-komplexe durch protonierung neutraler dihydridoruthenium(II)-verbindungen. J. Organomet. Chem. 1983, 243, C59−C62. (74) Morris, R. H.; Shiralian, M. Benzene carbon-hydrogen bond activation using Ru(C6Me6)[PH(C6H11)2]H2. J. Organomet. Chem. 1984, 260, C47−C51. (75) Conway, C.; Kemmitt, R. D. W.; Platt, A. W. G.; Russell, D. R.; Sherry, L. J. S. Mononuclear η3-allylosmium hydride complexes and the x-ray crystal structure of the solvento complex [OsH(H2O)(CO)2(PPh3)2]BF4 · EtOH. J. Organomet. Chem. 1985, 292, 419−427. (76) Komiya, S.; Yamamoto, A. Reactions of hydrido complexes of ruthenium and rhodium with carbon dioxide involving reversible insertion. J. Organomet. Chem. 1972, 46, C58−C60. (77) Brough, S.-A.; Hall, C.; McCamley, A.; Perutz, R. N.; Stahl, S.; Wecker, U.; Werner, H. Photochemistry of Os(η6-arene) complexes in low-temperature matrixes: an infrared spectroscopic study of C-H bond activation. J. Organomet. Chem. 1995, 504, 33−46. (78) Kaim, W.; Reinhardt, R.; Sieger, M. Chemical and Electrochemical Generation of Hydride-Forming Catalytic Intermediates. Inorg. Chem. 1994, 33, 4453−4459. (79) Currao, A.; Feiken, N.; Macchioni, A.; Nesper, R.; Pregosin, P. S.; Trabesinger, G. An Unexpectedly Stable Chiral Hydrido-Solvent G


Article

Inorganic Chemistry Complex of RuII: A Mechanistic Link in the Enantioselective Hydrogenation of Pyrones. Helv. Chim. Acta 1996, 79, 1587−1591. (80) Albertin, G.; Antoniutti, S.; Botter, A.; Castro, J. Preparation of Hydride-Ethylene Complexes of Osmium. Z. Anorg. Allg. Chem. 2016, 642, 250−254. (81) Holah, D. G.; Hughes, A. N.; Hui, B. C. Reactions of sodium tetrahydroborate and cyanotrihydroborate with ruthenium(II) and (III) systems in the presence of tertiary phosphines. Can. J. Chem. 1976, 54, 320−328. (82) Liu, X.; Bouherour, S.; Jacobsen, H.; Schmalle, H.; Berke, H. The interaction of Lewis acidic boron derivatives with Re(CO)5‑nH(PMe3)n complexes. Inorg. Chim. Acta 2002, 330, 250−267. (83) Vogt, M.; Nerush, A.; Diskin-Posner, Y.; Ben-David, Y.; Milstein, D. Reversible CO2 binding triggered by metal-ligand cooperation in a rhenium(i) PNP pincer-type complex and the reaction with dihydrogen. Chem. Sci. 2014, 5, 2043−2051. (84) Rocchini, E.; Rigo, P.; Mezzetti, A.; Stephan, T.; Morris, R. H.; Lough, A. J.; Forde, C. E.; Fong, T. P.; Drouin, S. D. Synthesis and properties of iron-group hydrido-cyano complexes trans-[MH(CN)(L)2], M = Fe, Ru or Os, L = diphosphine, and their hydrogen, trifluoroboron and triphenylboron isocyanide derivatives of the type trans-[MH(CNH)(L)2]O3SCF3, trans-[MH(CNBX3)(L)2], X = F or Ph, and trans-[M(H 2 )(CNBF 3 )(dppp) 2 ]BF 4 [dppp = Ph 2 P(CH2)3PPh2]. J. Chem. Soc., Dalton Trans. 2000, 3591−3602. (85) Gerlach, D. H.; Peet, W. G.; Muetterties, E. L. Preparations and reactions of tetrakis(organophosphorus)metal dihydride complexes. J. Am. Chem. Soc. 1972, 94, 4545−4549. (86) Sherlock, S. J.; Boyd, D. C.; Moasser, B.; Gladfelter, W. L. Homogeneous catalytic carbonylation of nitroaromatics. 4. Preparation and characterization of ruthenium radical cations. Inorg. Chem. 1991, 30, 3626−3632. (87) Letts, J. B.; Mazanec, T. J.; Meek, D. W. The synthesis, characterization, and reactivity of an unusual, amphoteric (tetrahydroborato)ruthenium hydride complex of a chelating triphosphine, Ru(H)(η2-BH4)(ttp). J. Am. Chem. Soc. 1982, 104, 3898−3905. (88) Harris, R. O.; Hota, N. K.; Sadavoy, L.; Yuen, J. M. C. Preparation and reactions of tetrahydridotris(triphenylphosphine)ruthenium(IV). J. Organomet. Chem. 1973, 54, 259−264. (89) Malatesta, L.; Caglio, G.; Angoletta, M. 1288. New triphenylphosphine-iridium compounds. J. Chem. Soc. 1965, 6974− 6983. (90) Carter, W. J.; Kelland, J. W.; Okrasinski, S. J.; Warner, K. E.; Norton, J. R. Mononuclear hydrido alkyl carbonyl complexes of osmium and their polynuclear derivatives. Inorg. Chem. 1982, 21, 3955−3960. (91) Braterman, P. S.; Harrill, R. W.; Kaesz, H. D. Spectroscopic studies of isotopically substituted metal carbonyls. II. Assignment of carbonyl stretching absorptions and their interaction with metalhydrogen stretching modes in pentacarbonyl hydrides. J. Am. Chem. Soc. 1967, 89, 2851−2855. (92) Jazzar, R. F. R.; Bhatia, P. H.; Mahon, M. F.; Whittlesey, M. K. N-heterocyclic carbene stabilized trans-dihydrido aqua and ethanol complexes of ruthenium: Precursors to complexes with Ru-heteroatom bonds. Organometallics 2003, 22, 670−683. (93) Suárez, E.; Plou, P.; Gusev, D. G.; Martín, M.; Sola, E. Cationic, Neutral, and Anionic Hydrides of Iridium with PSiP Pincers. Inorg. Chem. 2017, 56, 7190−7199. (94) Jia, G.; Drouin, S. D.; Jessop, P. G.; Lough, A. J.; Morris, R. H. Use of the New Ligand P(CH2CH2PCy2)3 in the Synthesis of Dihydrogen Complexes of Iron(II) and Ruthenium(II). Organometallics 1993, 12, 906−916. (95) Amendola, P.; Antoniutti, S.; Albertin, G.; Bordignon, E. Molecular Hydrogen Complexes - Preparation and Reactivity of New Ruthenium(II) and Osmium(II) Derivatives and a Comparison Along the Iron Triad. Inorg. Chem. 1990, 29, 318−324. (96) Geier, S.; Goddard, R.; Holle, S.; Jolly, P. W.; Kruger, C.; Lutz, F. Reaction of Unconjugated Dienes. Organometallics 1997, 16, 1612− 1620.

(97) Jungbauer, A.; Behrens, H. Zur Kenntnis der Chemie der Metallcarbonyle und der Cyano-Komplexe in flüssigem ammoniak: XXXIX. Ü ber die Reaktionen von ein - und zweikernigen, kationischen η5-Cyclopentadienyl-carbonyl-Komplexen des Eisens, Rutheniums und Osmiums mit flüssigem Ammoniak oberhalb 10°C. J. Organomet. Chem. 1980, 186, 361−370. (98) Esteruelas, M. A.; Gomez, A. V.; Lopez, A. M.; Oro, L. A. New cyclopentadienylosmium derivatives prepared from the 5-coordinate complex [OsHCl(CO)(PPri3)2]. Organometallics 1996, 15, 878−881. (99) Kusumoto, S.; Akiyama, M.; Nozaki, K. Acceptorless Dehydrogenation of C-C Single Bonds Adjacent to Functional Groups by Metal-Ligand Cooperation. J. Am. Chem. Soc. 2013, 135, 18726− 18729. (100) Freeman, S. T. N.; Lemke, F. R.; Haar, C. M.; Nolan, S. P.; Petersen, J. L. Effect of Ancillary Ligation on the Relative Bond Disruption Enthalpies of Ru-H and Ru-Cl Bonds in Cp(PR3)2RuX (PR3 = PMe3, PMe2Ph, PMePh2, PPh3; X = H, Cl). Organometallics 2000, 19, 4828−4833. (101) Bruce, M. I.; Humphrey, M. G.; Swincer, A. G.; Wallis, R. C. Cyclopentadienyl-ruthenium and -osmium chemistry. XXIII. Synthesis and reactions of some hydrido complexes containing ruthenium or osmium, and related chemistry. Aust. J. Chem. 1984, 37, 1747−1755. (102) Devies, S. G.; Hibberd, J.; Simpson, S. J.; Thomas, S. E.; Watts, O. Carbon monoxide reduction. [Fe(η5-C5H5)(Ph2PCH2CH2PPh2)(CO)H]: reactions and formation by reduction of the complex [Fe(η5C5H5)(Ph2PCH2CH2PPh2)(CO)]PF6. J. Chem. Soc., Dalton Trans. 1984, 701−709. (103) Ostapowicz, T. G.; Merkens, C.; Hoelscher, M.; Klankermayer, J.; Leitner, W. Bifunctional Ruthenium(II) Hydride Complexes with Pendant Strong Lewis Acid Moieties: Structure, Dynamics, and Cooperativity. J. Am. Chem. Soc. 2013, 135, 2104−2107. (104) Davison, A.; McCleverty, J. A.; Wilkinson, G. Spectroscopic studies on alkyl and hydrido transition metal carbonyls and πcyclopentadienyl carbonyls. J. Chem. Soc. 1963, 0, 1133−1138. (105) Estes, D. P.; Vannucci, A. K.; Hall, A. R.; Lichtenberger, D. L.; Norton, J. R. Thermodynamics of the Metal−Hydrogen Bonds in (η5C5H5)M(CO)2H (M = Fe, Ru, Os). Organometallics 2011, 30, 3444− 3447. (106) Kruck, T.; Knoll, L. Ü ber Metalltrifluorphosphin-Komplexe, XXXIV π-Cyclopentadien-tris(trifluorphosphin)-eisen(0) und π-Cyclopentadienyl-bis(trifluorphosphin)-eisenhydrid. Chem. Ber. 1972, 105, 3783−3788. (107) Hoyano, J. K.; May, C. J.; Graham, W. A. G. Cyclopentadienylosmium and (pentamethylcyclopentadienyl)osmium compounds. Synthesis and reactions of (η-C5H5)Os(CO)2H, (η-C5Me5)Os(CO)2H, and some of their derivatives. Inorg. Chem. 1982, 21, 3095−3099. (108) Rausch, M. D.; Gastinger, R. G.; Gardner, S. A.; Brown, R. K.; Wood, J. S. Isolation and structural characterization of bis(η5cyclopentadienyl)bis(carbonyl)-μ-(o-phenylene)-diiridium (Ir-Ir), (C5H5)2(CO)2Ir2(C6H4): a product formally derived from the double oxidative addition of benzene to iridium. J. Am. Chem. Soc. 1977, 99, 7870−7876. (109) Pons, V.; Heinekey, D. M. An Elongated Dihydrogen Complex of Iridium. J. Am. Chem. Soc. 2003, 125, 8428−8429. (110) Janowicz, A. H.; Bergman, R. G. Activation of carbon-hydrogen bonds in saturated hydrocarbons on photolysis of (η5-C5Me5)(PMe3)IrH2. Relative rates of reaction of the intermediate with different types of carbon-hydrogen bonds and functionalization of the metal-bound alkyl groups. J. Am. Chem. Soc. 1983, 105, 3929−3939. (111) Iimura, M.; Evans, D. R.; Flood, T. C. Synthesis and Characterization of Triazacyclononane-Ligated Iridium Dihydride Complexes. Organometallics 2003, 22, 5370−5373. (112) Partridge, M. G.; McCamley, A.; Perutz, R. N. Photochemical generation of 16-electron [Rh(η5-C5H5)(PMe3)] and [Ir(η5-C5H5)(PMe3)] in low-temperature matrices: evidence for methane activation. J. Chem. Soc., Dalton Trans. 1994, 3519−3526. (113) Hughes, R. P.; Kovacik, I.; Lindner, D. C.; Smith, J. M.; Willemsen, S.; Zhang, D.; Guzei, I. A.; Rheingold, A. L. Unusual H


Article

Inorganic Chemistry

1,10-phenanthroline; X = Cl or H. Single crystal structures of [(η5Me5C5)Ir(bpy)Cl]Cl and [(η5-Me5C5)Rh(phen)Cl]ClO4. J. Organomet. Chem. 1989, 363, 197−208. (130) Creutz, C.; Chou, M. H.; Hou, H.; Muckerman, J. T. Hydride Ion Transfer from Ruthenium(II) Complexes in Water: Kinetics and Mechanism. Inorg. Chem. 2010, 49, 9809−9822. (131) Greulich, S.; Klein, A.; Knödler, A.; Kaim, W. Qualitatively Different Reactivities of Hydride Reagents toward [(α-diimine)(η5C5Me5)ClIr]+ Cations: Substitution, Electron Transfer (Reduction), or Stepwise Hydrogenation. Organometallics 2002, 21, 765−769. (132) Hu, Y.; Norton, J. R. Kinetics and Thermodynamics of H−/H /H+ Transfer from a Rhodium(III) Hydride. J. Am. Chem. Soc. 2014, 136, 5938−5948. (133) Arita, S.; Koike, T.; Kayaki, Y.; Ikariya, T. Synthesis and reactivities of Cp*Ir amide and hydride complexes bearing C-N chelate ligands. Organometallics 2008, 27, 2795−2802. (134) Rodriguez, V.; Atheaux, I.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B. Ruthenium Dihydridobis(pyrazolyl)borate Complexes Adopting a κ3 N,N,H, κ2 N,H, or κ2 N,N Bonding Mode. Organometallics 2000, 19, 2916−2926. (135) Goldberg, J. M.; Cherry, S. D. T.; Guard, L. M.; Kaminsky, W.; Goldberg, K. I.; Heinekey, D. M. Hydrogen Addition to (pincer)IrI(CO) Complexes: The Importance of Steric and Electronic Factors. Organometallics 2016, 35, 3546−3556. (136) Gusev, D. G.; Lough, A. J.; Morris, R. H. New Polyhydride Anions and Proton-Hydride Hydrogen Bonding in Their Ion Pairs. J. Am. Chem. Soc. 1998, 120, 13138−13147. (137) Landau, S. E.; Groh, K. E.; Lough, A. J.; Morris, R. H. Large Effects of Ion Pairing and Protonic-Hydridic Bonding on the Stereochemistry and Basicity of Crown-, Azacrown-, and Cryptand222-potassium Salts of Anionic Tetrahydride Complexes of Iridium(III). Inorg. Chem. 2002, 41, 2995−3007. (138) Abdur-Rashid, K.; Gusev, D. G.; Landau, S. E.; Lough, A. J.; Morris, R. H. Organizing Chain Structures by Use of Proton-hydride Bonding. The Single Crystal X-ray Diffraction Structures of [K(Q)][Os(H)5(PiPr3)2] and [K(Q)][Ir(H)4(PiPr3)2], Q= 18-crown-6 and 1,10-diaza-18-crown-6. J. Am. Chem. Soc. 1998, 120, 11826−11827. (139) Tanaka, R.; Yamashita, M.; Nozaki, K. Catalytic Hydrogenation of Carbon Dioxide Using Ir(III)−Pincer Complexes. J. Am. Chem. Soc. 2009, 131, 14168−14169. (140) Abdur-Rashid, K.; Gusev, D.; Lough, A. J.; Morris, R. H. Intermolecular Proton-Hydride Bonding in Ion Pairs: Synthesis and Structural Properties of [K(Q)][MH5(PiPr3)2] (M = Os, Ru; Q = 18crown-6, 1-aza-18-crown-6, 1,10-diaza-18-crown-6). Organometallics 2000, 19, 834−843. (141) Hill, A. F.; Ma, C. X.; McQueen, C. M. A.; Ward, J. S. Iridium complexes of perimidine-based N-heterocyclic carbene pincer ligands via aminal C-H activation. Dalton Trans. 2018, 47, 1577−1587. (142) Harding, P. A.; Robinson, S. D. Synthesis and chemistry of some iridium sulfonate derivatives. J. Chem. Soc., Dalton Trans. 1987, 947−952. (143) Guilera, G.; McGrady, G. S.; Steed, J. W.; Burchell, R. P. L.; Sirsch, P.; Deeming, A. J. Synthesis and characterisation of [(triphos)Fe(CO)H2] and its protonation to a dihydrogen complex via an unconventional hydrogen-bonded intermediate. New J. Chem. 2008, 32, 1573−1581. (144) Fryzuk, M. D.; MacNeil, P. A. Stereoselective formation of iridium(III) amides and ligand-assisted heterolytic splitting of dihydrogen. Organometallics 1983, 2, 682−684. (145) Bautista, M. T.; Earl, K. A.; Maltby, P. A.; Morris, R. H. Stereochemical control of the exchange of hydrogen atoms between hydride and dihydrogen ligands in the complexes [M(η2-H2)(H)(meso- or rac-tetraphos-1)]+, M = Fe, Os. J. Am. Chem. Soc. 1988, 110, 4056−4057. (146) Guilera, G.; McGrady, G. S.; Steed, J. W.; Jones, A. L. Complex Formation and Rearrangement Reactions of the Phosphine Hydride Anions [OsH3(PPh3)3]− and [IrH2(PPh3)3]−. Organometallics 2006, 25, 122−127.

Reactivity of Proton Sponge as a Hydride Donor to Transition Metals: Synthesis and Structural Characterization of Fluoroalkyl(hydrido) Complexes of Iridium(III) and Rhodium(III). Organometallics 2001, 20, 3190−3197. (114) Acha, F.; Ciganda, R.; Garralda, M. A.; Hernandez, R.; Ibarlucea, L.; Pinilla, E.; Torres, M. R. Reactivity of hydridoirida-betadiketones with bases: the selective formation of new di-mu-acyl-muhydridodiiridium(III) or dihydridoirida-beta-diketone complexes and heterometallic Ir(III)-Rh(I) derivatives. Dalton Trans. 2008, 4602− 4611. (115) Paisner, S. N.; Burger, P.; Bergman, R. G. Mechanistic Investigation of the Reaction of Iridium Dihydride Complexes with Organic Acid Chlorides. Organometallics 2000, 19, 2073−2083. (116) Argouarch, G.; Hamon, P.; Toupet, L.; Hamon, J.-R.; Lapinte, C. [(η5-C5Me5)Fe(Ph2PCH2CH2CH2PPh2)][SO3CF3], a Stable 16Electron Complex with a Coordinating Counteranion and without Agostic Interaction: The Dramatic Role of a Trivial Methylene Group. Organometallics 2002, 21, 1341−1348. (117) Tilset, M. Theoretical, Thermodynamic, Spectroscopic, and Structural Studies of the Consequences of One-Electron Oxidation on the Fe-X Bonds in 17- and 18-Electron Cp*Fe(dppe)X Complexes (X) F, Cl, Br, I, H, CH3). J. Am. Chem. Soc. 2001, 123, 9984−10000. (118) Glueck, D. S.; Winslow, L. J. N.; Bergman, R. G. Iridium alkoxide and amide hydride complexes. Synthesis, reactivity, and the mechanism of oxygen-hydrogen and nitrogen-hydrogen reductive elimination. Organometallics 1991, 10, 1462−1479. (119) Grotjahn, D. B.; Kraus, J. E.; Amouri, H.; Rager, M. N.; Cooksy, A. L.; Arita, A. J.; Cortes-Llamas, S. A.; Mallari, A. A.; DiPasquale, A. G.; Moore, C. E.; Liable-Sands, L. M.; Golen, J. D.; Zakharov, L. N.; Rheingold, A. L. Multimodal Study of Secondary Interactions in CpIr* Complexes of Imidazolylphosphines Bearing an NH Group. J. Am. Chem. Soc. 2010, 132, 7919−7934. (120) Sowa, J. R., Jr.; Zanotti, V.; Facchin, G.; Angelici, R. J. Heats of protonation of transition-metal complexes: the effect of phosphine basicity on metal basicity in CpIr(CO)(PR3) and Fe(CO)3(PR3)2. J. Am. Chem. Soc. 1991, 113, 9185−9192. (121) Bloyce, P. E.; Rest, A. J.; Whitwell, I. Photochemistry of carbonyl(η5-cyclopentadienyl)dihydridoiridium in frozen gas matrices at ca. 12 K: infrared evidence relating to C-H activation. J. Chem. Soc., Dalton Trans. 1990, 813−821. (122) Hoyano, J. K.; Graham, W. A. G. Oxidative addition of the carbon-hydrogen bonds of neopentane and cyclohexane to a photochemically generated iridium(I) complex. J. Am. Chem. Soc. 1982, 104, 3723−3725. (123) Hoyano, J. K.; McMaster, A. D.; Graham, W. A. G. Activation of methane by iridium complexes. J. Am. Chem. Soc. 1983, 105, 7190− 7191. (124) Peterson, T. H.; Golden, J. T.; Bergman, R. G. Deprotonation of the Transition Metal Hydride (η5-C5Me5)(PMe3)IrH2. Synthesis and Chemistry of the Strongly Basic Lithium Iridate (η5-C5Me5)(PMe3)Ir(H)(Li). Organometallics 1999, 18, 2005−2020. (125) Gilbert, T. M.; Hollander, F. J.; Bergman, R. G. (Pentamethylcyclopentadienyl)iridium polyhydride complexes: synthesis of intermediates in the mechanism of formation of (pentamethylcyclopentadienyl)iridium tetrahydride and the preparation of several iridium(V) compounds. J. Am. Chem. Soc. 1985, 107, 3508−3516. (126) Gilbert, T. M.; Bergman, R. G. Preparation and reactions of tetrahydrido(pentamethylcyclopentadienyl)iridium: a novel iridium(V) polyhydride. Organometallics 1983, 2, 1458−1460. (127) Jungton, A.-K.; Herwig, C.; Braun, T.; Limberg, C. Activation and Coordination of Ammonia at [Cp*Ir(H)2]: NMR and Matrix Isolation Studies. Chem. - Eur. J. 2012, 18, 10009−10013. (128) Drover, M. W.; Schafer, L. L.; Love, J. A. Dehydrogenation of cyclic amines by a coordinatively unsaturated Cp*Ir(III) phosphoramidate complex. Dalton Trans. 2017, 46, 8621−8625. (129) Youinou, M.-T.; Ziessel, R. Synthesis and molecular structure of a new family of iridium(III) and rhodium(III) complexes: [(η5Me5C5)Ir(LL)X]+ and (η5-Me5C5)Rh(LL)Cl]+; LL= 2,2′-bipyridine or I


Article

Inorganic Chemistry (147) Romero, P. E.; Whited, M. T.; Grubbs, R. H. Multiple C−H Activations of Methyl tert-Butyl Ether at Pincer Iridium Complexes: Synthesis and Thermolysis of Ir(I) Fischer Carbenes. Organometallics 2008, 27, 3422−3429. (148) Schweizer, A.; Titus, D. D.; Gray, H. B. Spectral studies of the isomerization of dihydridotetrakis (diethyl phenylphosphonite)metal(II) complexes in solution. J. Am. Chem. Soc. 1973, 95, 4552−4554. (149) Fox, D. J.; Bergman, R. G. Synthesis of a First-Row Transition Metal Parent Amido Complex and Carbon Monoxide Insertion into the Amide N-H Bond. J. Am. Chem. Soc. 2003, 125, 8984−8985. (150) Fulton, J. R.; Bouwkamp, M. W.; Bergman, R. G. Reactivity of a Parent Amidoruthenium Complex: A Transition Metal Amide of Exceptionally High Basicity. J. Am. Chem. Soc. 2000, 122, 8799−8800. (151) Wang, C.; Ziller, J. W.; Flood, T. C. Preparation of [(1,4,7Trimethyl-1,4,7-triazacyclononane)Rh(PR3)(H)(CH3)]+ and Its Carbon-Hydrogen Reductive-Elimination and Oxidative-Addition Chemistry. J. Am. Chem. Soc. 1995, 117, 1647−1648. (152) Rossin, A.; Rossi, A.; Peruzzini, M.; Zanobini, F. Chemical hydrogen storage: Ammonia borane dehydrogenation catalyzed by NP3 ruthenium hydrides (NP3N(CH2CH2PPh2)3). ChemPlusChem 2014, 79, 1316−1325. (153) Bianchini, C.; Masi, D.; Meli, A.; Peruzzini, M.; Sabat, M.; Zanobini, F. Intra- and intermolecular activation of sp2 carbonhydrogen bonds at rhodium(I) and iridium(I) metal centers. X-ray structure of the cis.sigma.-cyclooctadienyl hydride [{N(CH2CH2PPh2)3}IrH(σ-C8H11)]BPh4.CH3COCH3. Organometallics 1986, 5, 2557−2559. (154) Ciganda, R.; Garralda, M. A.; Ibarlucea, L.; Mendicute-Fierro, C.; Torralba, M. C.; Torres, M. R. Reactions of hydridoirida-betadiketones with amines or with 2-aminopyridines: formation of hydridoirida-beta-ketoimines, PCN terdentate ligands, and acyl decarbonylation. Inorg. Chem. 2012, 51, 1760−1768. (155) Blake, A. J.; Hyde, T. I.; Schroder, M. Hydrido platinum metal macrocyclic complexes: the synthesis and single-crystal X-ray structure of cis-[IrCl(H)L1]PF6{L1=7-methyl-3,7,11,17-tetrazabicyclo[11.3.1]heptadeca-1(17),13,15-triene}. J. Chem. Soc., Dalton Trans. 1988, 1165−1168. (156) Malan, F. P.; Ali, A.; Singleton, E.; Meijboom, R. The dominant steric effect in the synthesis of ammine hydrido- and chlorido-Ru(II)-N,N-dimethylhydrazine and mixed alkyl-aryl phosphine complexes: Novel methyldiazene reduction intermediates. Inorg. Chim. Acta 2015, 437, 133−142. (157) Prokopchuk, E. M.; Jenkins, H. A.; Puddephatt, R. J. Stable Cationic Dimethyl(hydrido)platinum(IV) Complex. Organometallics 1999, 18, 2861−2866. (158) Carmona, D.; Ferrer, J.; García, N.; Ramírez, P.; Lahoz, F. J.; García-Orduña, P.; Oro, L. A. Chiral Octahedral Phosphano− Oxazoline Iridium(III) Complexes as Catalysts in Asymmetric Cycloaddition Reactions. Organometallics 2013, 32, 1609−1619. (159) Dahlenburg, L.; Herbst, K. Ligand vs. metal basicity: reactions of 2-(diphenylphosphanyl)anilido and 2-(diphenylphosphanyl)phenolato complexes of rhodium(I) and iridium(I) with HBF4. Z. Naturforsch., B: J. Chem. Sci. 2010, 65, 376−382. (160) Lee, J. C., Jr; Rheingold, A. L.; Muller, B.; Pregosin, P. S.; Crabtree, R. H. Complexation of an amide to iridium via an iminol tautomer and evidence for an Ir-H···HO Hydrogen bond. J. Chem. Soc., Chem. Commun. 1994, 1021−1022. (161) Crabtree, R. H.; Demou, P. C.; Eden, D.; Mihelcic, J. M.; Parnell, C. A.; Quirk, J. M.; Morris, G. E. Dihydrido olefin and solvento complexes of iridium and the mechanisms of olefin hydrogenation and alkane dehydrogenation. J. Am. Chem. Soc. 1982, 104, 6994−7001. (162) Ezhova, M. B.; Patrick, B. O.; Sereviratne, K. N.; James, B. R.; Waller, F. J.; Ford, M. E. Interactions of Rh(III)−Dihydrido− Bis(phosphine) Complexes with Semicarbazones. Inorg. Chem. 2005, 44, 1482−1491. (163) Burn, M. J.; Fickes, M. G.; Hollander, F. J.; Bergman, R. G. Reactions of (PMe3)4Ru(C2H4) and (DMPE)2Ru(C2H4) with Weak Proton-Donating Electrophiles HX (X = OAr, SAr, NHPh, PHPh).

Synthesis of Complexes with Metal-Heteroatom Single Bonds. Organometallics 1995, 14, 137−150. (164) Caballero, A. n.; Carmen Carrión, M.; Espino, G.; Jalón, F. A.; Manzano, B. R. Ruthenium hydride complexes with a heteroscorpionate ligand derived from methane: 2-phenoxy-bis(pyrazol-1-yl)methane. The hemilabile role of the ligand in substitution and proton transfer reactions. Polyhedron 2004, 23, 361−371. (165) Hartwig, J. F.; Andersen, R. A.; Bergman, R. G. Synthesis and Chemistry of Ruthenium Hydrido Aryloxides and Arylamides. An Investigation of Structure, N-H and O-H Elimination Processes, Proton-Catalyzed Exchange Reactions, and Relative Ru-X Bond Strengths. Organometallics 1991, 10, 1875−1887. (166) Iglesias, M.; Del Pino, C.; Nieto, J. L. Synthesis and characterization of new cationic hydride complexes of rhodium(III). Inorg. Chim. Acta 1986, 119, 7−12. (167) Albertin, G.; Amendola, P.; Antoniutti, S.; Bordignon, E. Reactivity of the Hydride [CoH(P(OEt)2Ph)4] with Aryl-N2+, NO+, and H+ Cations - Preparation and Properties of New Cobalt Complexes - Measurements of T1 for [CoH(P(OEt)2Ph)4] and [CoH2(P(OEt)2Ph)4]BPh4. J. Chem. Soc., Dalton Trans. 1990, 2979− 2984. (168) Almeida Leñero, K.; Kranenburg, M.; Guari, Y.; Kamer, P.C. J.; van Leeuwen, P. W. N. M; Sabo-Etienne, S.; Chaudret, B. Ruthenium Dihydrogen Complexes with Wide Bite Angle Diphosphines. Inorg. Chem. 2003, 42, 2859−2866. (169) Drago, R. S.; Miller, J. G.; Hoselton, M. A.; Farris, R. D. An NMR and thermodynamic investigation of the reaction of squareplanar rhodium(I) compounds with hydrogen. J. Am. Chem. Soc. 1983, 105, 444−449. (170) Zhang, P.; Xu, S.; Li, X.; Qi, X.; Sun, H.; Fuhr, O.; Fenske, D. Synthesis and reactivity of silyl cobalt complexes bearing a tetradentate phosphino silyl ligand via Si−H bond activation. Polyhedron 2018, 143, 165−170. (171) Cariati, F.; Ugo, R.; Bonati, F. Reactions of Inorganic Acids with Zerovalent Platinum, Palladium, and Nickel Compounds Having Triphenylphosphine or 1,2-Bis(diphenylphosphino)ethane as Ligands. Inorg. Chem. 1966, 5, 1128−1132. (172) Zumeta, I.; Mendicute-Fierro, C.; Rodriguez-Dieguez, A.; Seco, J. M.; Garralda, M. A. On the Reactivity of Dihydridoirida-betadiketones with 2-Aminopyridines. Formation of Acylhydrido Complexes with New PCN Terdentate Ligands. Organometallics 2015, 34, 348−354. (173) Bianchini, C.; Jimenez, M. V.; Meli, A.; Moneti, S.; Vizza, F.; Herrera, V.; Sanchez-Delgado, R. A. Hydrodesulfurization (HDS) Model Systems. Opening, Hydrogenation, and Hydrodesulfurization of Dibenzothiophene (DBT) at Iridium. First Case of Catalytic HDS of DBT in Homogeneous Phase. Organometallics 1995, 14, 2342− 2352. (174) Thoreson, K. A.; Follett, A. D.; McNeill, K. Synthesis and Characterization of Pentaphosphino Zero-Valent Iron Complexes and Their Corresponding Iron(II)-Chloride and -Hydride Complexes. Inorg. Chem. 2010, 49, 3942−3949. (175) Turculet, L.; Feldman, J. D.; Tilley, T. D. Coordination Chemistry and Reactivity of New Zwitterionic Rhodium and Iridium Complexes Featuring the Tripodal Phosphine Ligand [PhB(CH2PiPr2)3]−. Activation of H-H, Si-H, and Ligand B-C Bonds. Organometallics 2004, 23, 2488−2502. (176) Raebiger, J. W.; DuBois, D. L. Thermodynamic Studies of HRh(depx)2 and [(H)2Rh(depx)2](CF3SO3): Relationships between Five-Coordinate Monohydrides and Six-Coordinate Dihydrides. Organometallics 2005, 24, 110−118. (177) Mock, M. T.; Potter, R. G.; O’Hagan, M. J.; Camaioni, D. M.; Dougherty, W. G.; Kassel, W. S.; DuBois, D. L. Synthesis and hydride transfer reactions of cobalt and nickel hydride complexes to BX3 compounds. Inorg. Chem. 2011, 50, 11914−11928. (178) Peres, Y.; Dartiguenave, M.; Dartiguenave, Y.; Britten, J. F.; Beauchamp, A. L. Reaction of formaldehyde with [Co(PMe3)4]X (X = PF6 and BPh4). Structural characterization of [Co(CO)(PMe3)4]PF6 J


Article

Inorganic Chemistry

Performance in Kumada Coupling Reactions. Chem. - Asian J. 2017, 12, 1234−1239. (195) Babbini, D. C.; Iluc, V. M. Iridium PCsp3P-type Complexes with a Hemilabile Anisole Tether. Organometallics 2015, 34, 3141− 3151. (196) Bellachioma, G.; Cardaci, G.; Macchioni, A.; Zuccaccia, C. Preparation of methyl hydride and dimethyl complexes of osmium and iron. J. Organomet. Chem. 2001, 628, 255−261. (197) Tokmic, K.; Markus, C. R.; Zhu, L.; Fout, A. R. Well-Defined Cobalt(I) Dihydrogen Catalyst: Experimental Evidence for a Co(I)/ Co(III) Redox Process in Olefin Hydrogenation. J. Am. Chem. Soc. 2016, 138, 11907−11913. (198) Bianchini, C.; Mealli, C.; Peruzzini, M.; Zanobini, F. Evidence for a Molecular Hydrogen Complex of Rhodium. Some Factors Affecting cis-Dihydride < -> η2-Dihydrogen Exchange. J. Am. Chem. Soc. 1987, 109, 5548−5549. (199) Bianchini, C.; Peruzzini, M.; Vacca, A.; Zanobini, F. Metalhydride alkynyl.fwdarw. metal-vinylidene rearrangements occurring in both solid state and solution. Role of the 1-alkyne substituent in determining the relative stability of π-alkyne, hydride alkynyl, and vinylidene forms at cobalt. Organometallics 1991, 10, 3697−3707. (200) Price, A. J.; Ciancanelli, R.; Noll, B. C.; Curtis, C. J.; DuBois, D. L.; DuBois, M. R. HRh(dppb)2, a Powerful Hydride Donor. Organometallics 2002, 21, 4833−4839. (201) Bianchini, C.; Marchi, A.; Marvelli, L.; Peruzzini, M.; Romerosa, A.; Rossi, R.; Vacca, A. Reactions of the rhenium(I) fragment [{MeC(CH2PPh2)3}Re(CO)2]+.Synthesis and characterization of a stable cationic η2-H2 complex of rhenium. Organometallics 1995, 14, 3203−3215. (202) Rossin, A.; Gutsul, E. I.; Belkova, N. V.; Epstein, L. M.; Gonsalvi, L.; Lledos, A.; Lyssenko, K. A.; Peruzzini, M.; Shubina, E. S.; Zanobini, F. Mechanistic Studies on the Interaction of (κ3-P,P,PNP3)IrH3 NP3 = N(CH2CH2PPh2)3 with HBF4 and Fluorinated Alcohols by Combined NMR, IR, and DFT Techniques. Inorg. Chem. 2010, 49, 4343−4354. (203) Bianchini, C.; Moneti, S.; Peruzzini, M.; Vizza, F. Synthesis and reactivity of the labile dihydrogen complex [(MeC(CH2PPh2)3)Ir(H2)(H)2]BPh4. Inorg. Chem. 1997, 36, 5818−5825. (204) Gray, T. G.; Veige, A. S.; Nocera, D. G. Cooperative bimetallic reactivity: Hydrogen activation in two-electron mixed-valence compounds. J. Am. Chem. Soc. 2004, 126, 9760−9768. (205) Henry, R. M.; Shoemaker, R. K.; Newell, R. H.; Jacobsen, G. M.; DuBois, D. L.; Rakowski DuBois, M. Stereochemical Control of Iron(II) Complexes Containing a Diphosphine Ligand with a Pendant Nitrogen Base. Organometallics 2005, 24, 2481−2491. (206) Henry, R. M.; Shoemaker, R. K.; DuBois, D. L.; DuBois, M. R. Pendant bases as proton relays in iron hydride and dihydrogen complexes. J. Am. Chem. Soc. 2006, 128, 3002−3010. (207) Iglesias, M.; del Pino, C.; Nieto, J. L.; García Blanco, S.; Martínez Carrera, S. Synthesis, characterization and structure of cationic hydrides of rhodium(III). Part II. Crystal structure of dihydride(1,4-biscyclohexyl-diaza-1,3-butadiene)-bis(4-fluortristriphenylphosphine)rhodium(III) perchlorate. Inorg. Chim. Acta 1988, 145, 91−98. (208) Elliott, P. I. P.; Haslam, C. E.; Spey, S. E.; Haynes, A. Formation and reactivity of Ir(III) hydroxycarbonyl complexes. Inorg. Chem. 2006, 45, 6269−6275. (209) Ciancanelli, R.; Noll, B. C.; DuBois, D. L.; Rakowski-DuBois, M. Comprehensive thermodynamic characterization of the metalhydrogen bond in a series of cobalt-hydride complexes. J. Am. Chem. Soc. 2002, 124, 2984−2992. (210) Giannoccaro, P.; Rossi, M.; Sacco, A. New cationic hydrido and hydrido-dinitrogen complexes of iron. Coord. Chem. Rev. 1972, 8, 77−79. (211) Macchioni, A.; Zuccaccia, C.; Clot, E.; Gruet, K.; Crabtree, R. H. Selective Ion Pairing in [Ir(bipy)H2(PRPh2)2]A (A = PF6, BF4, CF3SO3, BPh4, R = Me, Ph): Experimental Identification and Theoretical Understanding. Organometallics 2001, 20, 2367−2373.

and the nonstoichiometric complex [CoH2−2x(CO)x(PMe3)4]BPh4. Organometallics 1990, 9, 1041−1047. (179) Chatt, J.; Davidson, J. M. The tautomerism of arene and ditertiary phosphine complexes of ruthenium(0), and the preparation of new types of hydrido-complexes of ruthenium(II). J. Chem. Soc. 1965, 843−855. (180) Dioumaev, V. K.; Procopio, L. J.; Carroll, P. J.; Berry, D. H. Synthesis and Reactivity of Silyl Ruthenium Complexes: The Importance of Trans Effects in C-H Activation, Si-C Bond Formation, and Dehydrogenative Coupling of Silanes. J. Am. Chem. Soc. 2003, 125, 8043−8058. (181) Klein, H.-F. Tetrakis(trimethylphosphane)hydridocobalt(I) and -dihydridoiron(II). Angew. Chem., Int. Ed. Engl. 1970, 9, 904−904. (182) Hermes, A. R.; Warren, T. H.; Girolami, G. S. Iron(0) Arene and Iron(II) Hydride Complexes from the Hydrogenation or Thermolysis of High-spin lron(II) Alkyls. J. Chem. Soc., Dalton Trans. 1995, 301−305. (183) Ittel, S. D.; Tolman, C. A.; English, A. D.; Jesson, J. P. Novel carbon-hydrogen bond cleavage by bis(dimethylphosphino)ethane complexes of iron, ruthenium, and osmium. J. Am. Chem. Soc. 1976, 98, 6073−6075. (184) Krogstad, D. A.; Halfen, J. A.; Terry, T. J.; Young, V. G. Synthesis and Characterization of Iridium 1,3,5-Triaza-7-phosphaadamantane (PTA) Complexes. Inorg. Chem. 2001, 40, 463−471. (185) Pang, M.; Wu, C.; Zhuang, X.; Zhang, F.; Su, M.; Tong, Q.; Tung, C. H.; Wang, W. Addition of a B-H Bond across an AmidoCobalt Bond: CoII-H-Catalyzed Hydroboration of Olefins. Organometallics 2018, 37, 1462−1467. (186) Milstein, D.; Calabrese, J. C.; Williams, I. D. Formation, structures, and reactivity of cis-hydroxy-, cis-methoxy-, and cismercaptoiridium hydrides. Oxidative addition of water to Ir(I). J. Am. Chem. Soc. 1986, 108, 6387−6389. (187) Wong, W.-K.; Chiu, K. W.; Statler, J. A.; Wilkinson, G.; Montevalli, M.; Hursthouse, M. B. Alkyl, hydrido and related compounds of ruthenium with trimethylphosphine and bis(1,2dimethylphosphino)ethane. X-ray crystal structures of cishydridoethyltetrakis(trimethylphosphine)-ruthenium(II) and ethylene tetrakis-(trimethylphosphine)ruthenium(0). Polyhedron 1984, 3, 1255−1265. (188) Statler, J. A.; Wilkinson, G.; Thornton-Pett, M.; Hursthouse, M. B. Alkyl, hydrido-, and related compounds of ruthenium(II) with trimethylphosphine. X-ray crystal structures of hydrido(tetrahydroborato- HH′)tris(trimethylphosphine)ruthenium(II), triμ-chloro- bis[tris(trimethylphosphine)ruthenium(II)] tetrafluoroborate, and bis[cis-methyltetrakis(trimethylphosphine)ruthenio]mercury(II) -tetrahydrofuran(1/1). J. Chem. Soc., Dalton Trans. 1984, 1731−1738. (189) Feldman, J. D.; Peters, J. C.; Tilley, T. D. Structural and Chemical Properties of Zwitterionic Iridium Complexes Featuring the Tripodal Phosphine Ligand [PhB(CH2PPh2)3]−. Organometallics 2002, 21, 4050−4064. (190) Baker, R. T.; Ovenall, D. W.; Calabrese, J. C.; Westcott, S. A.; Taylor, N. J.; Williams, I. D.; Marder, T. B. Boryliridium and boraethyliridium complexes fac-[IrH2(PMe3)3(BRR′)] and fac-[IrH(PMe3)3(eta-2-CH2BHRR′)]. J. Am. Chem. Soc. 1990, 112, 9399− 9400. (191) Sangtrirutnugul, P.; Tilley, T. D. Silyl Derivatives of [Bis(8quinolyl)methylsilyl]iridium(III) Complexes: Catalytic Redistribution of Arylsilanes and Dehydrogenative Arene Silylation. Organometallics 2007, 26, 5557−5568. (192) Tejel, C.; Geer, A. M.; Jimenez, S.; Lopez, J. A.; Ciriano, M. A. Easy Access to Hydride Chemistry on a Tripodal P-Based Rhodium Scaffold. Organometallics 2012, 31, 2895−2906. (193) Dong, Y.; Shi, Y.; Geng, Y.; Zheng, T.; Li, X.; Sun, H.; Fuhr, O.; Fenske, D. Synthesis and characterization of bissilyl cobalt and iron hydrides bearing disilazane ligands via Si-H bond activation. Inorg. Chim. Acta 2018, 471, 99−103. (194) Xu, S. L.; Zhang, P.; Li, X. Y.; Xue, B. J.; Sun, H. J.; Fuhr, O.; Fenske, D. Synthesis of a Silyl Cobalt Hydride and Its Catalytic K


Article

Inorganic Chemistry (212) Luther, T. A.; Heinekey, D. M. Synthesis, characterization, and reactivity of dicationic dihydrogen complexes of osmium and ruthenium. Inorg. Chem. 1998, 37, 127−132. (213) Dubé, T.; Faller, J. W.; Crabtree, R. H. A cis-IrL(CO) Group Responds to Increasing Steric Bulk of L by M−L Stretching, Not M− C−O Tilting or Bending. Inorg. Chem. 2002, 41, 5561−5565. (214) San Nacianceno, V.; Azpeitia, S.; Ibarlucea, L.; MendicuteFierro, C.; Rodriguez-Dieguez, A.; Seco, J. M.; San Sebastian, E.; Garralda, M. A. Stereoselective formation and catalytic activity of hydrido(acylphosphane)(chlorido)(pyrazole)-rhodium(III) complexes. Experimental and DFT studies. Dalton Trans. 2015, 44, 13141−13155. (215) Taliaferro, C. M.; Danilov, E. O.; Castellano, F. N. Ultrafast Dynamics of the Metal-to-Ligand Charge Transfer Excited States of Ir(III) Proteo and Deutero Dihydrides. J. Phys. Chem. A 2018, 122, 4430−4436. (216) Sangtrirutnugul, P.; Tilley, T. D. Alkyl and hydrido complexes of platinum(IV) supported by the bis(8-quinolyl)methylsilyl ligand. Organometallics 2008, 27, 2223−2230. (217) Creutz, C.; Chou, M. H. Rapid transfer of hydride ion from a ruthenium complex to C-1 species in water. J. Am. Chem. Soc. 2007, 129, 10108−10109. (218) Garcés, K.; Lalrempuia, R.; Polo, V.; Fernández-Alvarez, F. J.; García-Orduña, P.; Lahoz, F. J.; Pérez-Torrente, J. J.; Oro, L. A. Rhodium-Catalyzed Dehydrogenative Silylation of Acetophenone Derivatives: Formation of Silyl Enol Ethers versus Silyl Ethers. Chem. - Eur. J. 2016, 22, 14717−14729. (219) Gruet, K.; Clot, E.; Eisenstein, O.; Lee, D. H.; Patel, B.; Macchioni, A.; Crabtree, R. H. Ion pairing effects in intramolecular heterolytic H2 activation in an Ir(III) complex: a combined theoretical/experimental study. New J. Chem. 2003, 27, 80−87. (220) Chatt, J.; Hayter, R. G. Complex hydrides and alkyls of ruthenium, and a hydride of osmium. Proc. Chem. Soc. 1959, 153. (221) Wiley, J. S.; Heinekey, D. M. Novel intramolecular C-H bond activation in an iridium dppm complex. Inorg. Chem. 2002, 41, 4961− 4966. (222) Oldham, W. J.; Hinkle, A. S.; Heinekey, D. M. Synthesis and characterization of hydrotris(pyrazolyl)borate dihydrogen/hydride complexes of rhodium and iridium. J. Am. Chem. Soc. 1997, 119, 11028−11036. (223) Reinartz, S.; White, P. S.; Brookhart, M.; Templeton, J. L. Tp′PtH3: A Stable Platinum(IV) Trihydride. Organometallics 2000, 19, 3748−3750. (224) Jiao, Y. Z.; Brennessel, W. W.; Jones, W. D. Synthesis and energetics of Tp′RhP(OMe)3(R)H: a systematic investigation of ligand effects on C-H activation at rhodium. Chem. Sci. 2014, 5, 804− 812. (225) Cristóbal, C.; Santos, L. L.; Gutiérrez-González, R.; Á lvarez, E.; Paneque, M.; Poveda, M. L. Allylic C-H Activation of Olefins by a TpMe2IrIII Compound. Eur. J. Inorg. Chem. 2016, 2016, 2534−2542. (226) Canty, A. J.; Fritsche, S. D.; Jin, H.; Patel, J.; Skelton, B. W.; White, A. H. Water and Protic Acids as Oxidants for Platinum(II): Diorgano(hydrido)platinum(IV) and Diorgano(hydroxo)platinum(IV) Chemistry, Including Structural Studies of Poly(pyrazol-1yl)borate Complexes Pt(OH)R2{(pz)3BH} (R = Methyl, p-Tolyl) and Pt(OH)Me2{(pz)4B}·H2O. Organometallics 1997, 16, 2175−2182. (227) Canty, A. J.; Dedieu, A.; Jin, H.; Milet, A.; Richmond, M. K. Synthesis and Theoretical Studies of a Diorganohydridoplatinum(IV) Complex, PtHMe2{(pz)3BH-N,N′,N″} ([(pz)3BH]− = Tris(pyrazol-1yl)borate). Organometallics 1996, 15, 2845−2847. (228) Reinartz, S.; Brookhart, M.; Templeton, J. L. Platinum(II) and Platinum(IV) Acyl and Formyl Complexes. Organometallics 2002, 21, 247−249. (229) Chatt, J.; Hart, F. A.; Rosevear, D. T. The reaction of metals with o-phenylenebis(diethylphosphine). J. Chem. Soc. 1961, 5504− 5507. (230) Appleton, T. G.; Clark, H. C.; Manzer, L. E. Trans influence. Coord. Chem. Rev. 1973, 10, 335−422.

(231) Rocchigiani, L.; Fernandez-Cestau, J.; Chambrier, I.; Hrobarik, P.; Bochmann, M. Unlocking Structural Diversity in Gold(III) Hydrides: Unexpected Interplay of cis/trans-Influence on Stability, Insertion Chemistry, and NMR Chemical Shifts. J. Am. Chem. Soc. 2018, 140, 8287−8302. (232) Nakamoto, K. Infrared Spectra of Inorganic and Coordination Compounds, 2nd ed.; Wiley-Interscience: New York, 1970. (233) See, R. F.; Kozina, D. Quantification of the trans influence in d8 square planar and d6 octahedral complexes: a database study. J. Coord. Chem. 2013, 66, 490−500. (234) Vedernikov, A. N.; Kuramshin, A. I.; Solomonov, B. N. Reversible thermal carbon−hydrogen bond cleavage in alkanes and arenes with dihalogenobis(triphenylphosphine)palladium(II) complexes. J. Chem. Soc., Chem. Commun. 1994, 0, 121−122. (235) Zhao, H.; Li, X.; Zhang, S.; Sun, H. Synthesis and Characterization of Iron, Cobalt, and Nickel [PNP] Pincer Amido Complexes by N-H Activation. Z. Anorg. Allg. Chem. 2015, 641, 2435− 2439. (236) Besora, M.; Lledos, A.; Maseras, F. Protonation of transitionmetal hydrides: a not so simple process. Chem. Soc. Rev. 2009, 38, 957−966. (237) Antinolo, A.; Carrillo-Hermosilla, F.; Fajardo, M.; GarciaYuste, S.; Otero, A.; Camanyes, S.; Maseras, F.; Moreno, M.; Lledos, A.; Lluch, J. M. Synthesis and spectroscopic properties of dihydrogen isocyanide niobocene [Nb(eta-5-C5H4SiMe3)2(eta-2-H2)(CNR)]+ complexes: experimental and theoretical-study of the blocked rotation of a coordinated dihydrogen. J. Am. Chem. Soc. 1997, 119, 6107−6114. (238) Chakraborty, S.; Dai, H.; Bhattacharya, P.; Fairweather, N. T.; Gibson, M. S.; Krause, J. A.; Guan, H. Iron-Based Catalysts for the Hydrogenation of Esters to Alcohols. J. Am. Chem. Soc. 2014, 136, 7869−7872. (239) Chakraborty, S.; Brennessel, W. W.; Jones, W. D. A molecular iron catalyst for the acceptorless dehydrogenation and hydrogenation of N-heterocycles. J. Am. Chem. Soc. 2014, 136, 8564−8567. (240) Bornschein, C.; Werkmeister, S.; Wendt, B.; Jiao, H.; Alberico, E.; Baumann, W.; Junge, H.; Junge, K.; Beller, M. Mild and selective hydrogenation of aromatic and aliphatic (di) nitriles with a welldefined iron pincer complex. Nat. Commun. 2014, 5, 1. (241) Chakraborty, S.; Milstein, D. Selective Hydrogenation of Nitriles to Secondary Imines Catalyzed by an Iron Pincer Complex. ACS Catal. 2017, 7, 3968−3972. (242) Sonnenberg, J. F.; Wan, K. Y.; Sues, P. E.; Morris, R. H. Ketone Asymmetric Hydrogenation Catalyzed by P-NH-P′ Pincer Iron Catalysts: An Experimental and Computational Study. ACS Catal. 2017, 7, 316−326. (243) Rautenstrauch, V.; Hoang-Cong, X.; Churlaud, R.; AbdurRashid, K.; Morris, R. H. Hydrogenation versus Transfer Hydrogenation of Ketones: Two Established Ruthenium Systems Catalyze Both. Chem. - Eur. J. 2003, 9, 4954−4967. (244) Bertoli, M.; Choualeb, A.; Lough, A. J.; Moore, B.; Spasyuk, D.; Gusev, D. G. Osmium and Ruthenium Catalysts for Dehydrogenation of Alcohols. Organometallics 2011, 30, 3479−3482. (245) O, W. W. N.; Morris, R. H. Ester Hydrogenation Catalyzed by a Ruthenium(II) Complex Bearing an N-heterocyclic Carbene Tethered with an ″NH2″ Group and a DFT Study of the Mechanism. ACS Catal. 2013, 3, 32−40. (246) Wan, K. Y.; Sung, M. M. H.; Lough, A. J.; Morris, R. H. HalfSandwich Ruthenium Catalyst Bearing an Enantiopure Primary Amine Tethered to an N-heterocyclic Carbene for Ketone Hydrogenation. ACS Catal. 2017, 7, 6827−6842. (247) Lacey, P.; Sykes, A. G. Isolation and X-ray Structure of [Ir(CNBut)5H](PF6)2. J. Coord. Chem. 2003, 56, 141−145. (248) Suh, H. W.; Schmeier, T. J.; Hazari, N.; Kemp, R. A.; Takase, M. K. Experimental and Computational Studies of the Reaction of Carbon Dioxide with Pincer-Supported Nickel and Palladium Hydrides. Organometallics 2012, 31, 8225−8236. (249) Wiedner, E. S.; Chambers, M. B.; Pitman, C. L.; Bullock, R. M.; Miller, A. J. M.; Appel, A. M. Thermodynamic Hydricity of Transition Metal Hydrides. Chem. Rev. 2016, 116, 8655−8692. L


Article

Inorganic Chemistry (250) Kwok W, C.; Howard, C. G.; Rzepa, H. S.; Sheppard, R. N.; Wilkinson, G.; Galas, A. M. R.; Hursthouse, M. B. Trimethyl and diethylphenylphosphine complexes of rhenium(I, III, IV, V) and their reactions. X-ray crystal structures of a bis(η5-cyclopentadienyl)ethane-bridged dirhenium(I) complex obtained from phenylacetylene, tetrakis-(diethylphenylphosphine) (dinitrogen) hydridorhenium (I), tetrakis(trimethyl-phosphine) (η2-dimethylphosphinomethyl) rhenium(I) and tetrakis(trimethylphosphine) (iodo)methyl rhenium(III) iodide-tetramethylphosphonium iodide. Polyhedron 1982, 1, 441−451. (251) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, Ö .; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J.Gaussian 09, Revision D.01; Gaussian, Inc.: Wallingford, CT, 2009.

M


Estimating the Wavenumber of Terminal Metal-Hydride Stretching

Recommend Documents