ARTICLE pubs.acs.org/Organometallics
Metal-Enriched [3]Trochrocenophanes: Bimetallic Metalloarenophanes by Coordination to Chelating Bis(phosphanyls) Holger Braunschweig,* Michael Drisch, Maria Friedrich, Thomas Kupfer, and Krzysztof Radacki Institut f€ur Anorganische Chemie, Julius-Maximilians Universit€at W€urzburg, Am Hubland, D-97074, W€urzburg, Germany
bS Supporting Information ABSTRACT: The first 1,10 -bis(phosphanyl)trochrocene derivatives (13) have been prepared in reasonable isolated yields by salt elimination reactions of monochlorophosphines (ClPPh2, ClPCy2, and ClPMe2) with [Cr(η5-C5H4Li)(η7-C7H6Li)] 3 tmeda. Subsequent treatment with group 6 hexacarbonyls resulted in the formation of the heterobimetallic [3]trochrocenophane species 49, with the novel bisphosphines acting as chelating ligands. The solid-state structures of two bis(phosphanyl) derivatives and four bimetallic species have been studied by X-ray diffraction.
’ INTRODUCTION Initially, we developed a practical protocol for the selective dimetalation of [Cr(η5-C5H5)(η7-C7H7)]1 (trochrocene) to enable the synthesis of strained heteroleptic [n]metalloarenophane species.2 This approach proved highly successful, and we were able to isolate several differently substituted [1]- and [2]trochrocenophanes by simple salt-elimination reactions with appropriate element dihalides. In addition, this strategy has also been applied to other sandwich systems such as [Ti(η5-C5H5)(η7-C7H7)] (troticene) or [V(η5C5H5)(η7-C7H7)] (trovacene), and various strained [n]troticenophanes3 and [n]trovacenophanes4 have appeared in the literature so far. Unlike this direct methodology, the introduction of larger ansa bridges to trochrocene has only been achieved by means of subsequent functionalization reactions based on BB bond1 or SiSi bond5 activation chemistry. In addition, a couple of unstrained 1,10 -disubstituted trochrocene derivatives of the type [Cr(η5C5H4R)(η7-C7H6R)] (R = B(Cl)NiPr2, SiMe3, GeMe3, SnMe3) have been made accessible by applying an excess of the respective element (di)halides.6 Our interest in this kind of research is strongly related to the high potential of the corresponding ferrocene systems in further derivatization reactions, affording novel materials with highly interesting properties.7 Thus, it has been demonstrated for instance that 1,10 -bis(diphenylphosphanyl)ferrocene (dppf)8 is a valuable chelating ligand in catalysis,9 forming heterobimetallic complexes with other transition-metal centers such as PdCl2.10 In contrast, similar 1,10 -disubstituted derivatives derived from heteroleptic [M(η5-C5H5)(η7-C7H7)] systems are considerably less established, even though [Ti(η5-C5H4PR2)(η7-C7H6PR2)] (R = Ph, Me) first appeared in the literature almost two decades ago.11 Interest in this kind of bidentate ligand has reemerged only recently. Thus, Tamm et al. developed an improved experimental protocol for the synthesis of 1,10 -bis(diphenylphosphanyl)troticene (dppti),12 which was successfully converted into a couple of early/late heterobimetallic complexes.12,13 r 2011 American Chemical Society
We are now capable of transferring this approach to the synthesis of the related 1,10 -bis(phosphanyl)trochrocene congeners [Cr(η5-C5H4PR2)(η7-C7H6PR2)] (1, R = Ph; 2, R = Cy; 3, R = Me). Their potential in acting as chelating ligands was unambiguously validated by their reactivity toward group 6 hexacarbonyls, which allowed for the isolation of the first heterobimetallic [3]trochrocenophanes (49) featuring PMP ansa bridges (M = Cr, Mo, W).
’ RESULTS AND DISCUSSION 1,10 -Bis(phosphanyl)trochrocenes. 1,10 -Bis(phosphanyl)tro-
chrocenes 13 are readily available in reasonable isolated yields (6174%) by salt-elimination reactions of [Cr(η5-C5H4Li)(η7C7H6Li)] 3 tmeda with the chlorophosphines ClPPh2, ClPCy2, and ClPMe2 in hexane (Scheme 1). The identities of 13 were fully verified by solution NMR spectroscopy. Consistent with the presence of two chemically inequivalent phosphorus nuclei, each 31P NMR spectrum features two distinct singlet resonances assignable to the phosphine substituents at the seven-membered (1, δ 9.83; 2, δ 18.12; 3, δ 26.73) and five-membered carbocycles (1, δ 17.07; 2, δ 7.97; 3, δ 56.96), respectively. Furthermore, the PR2 substituents at phosphorus show the expected signal patterns in the 1H NMR spectra. Thus, the Ph groups in 1 are detected as three sets of signals (δ 7.04, 7.36, 7.55) with a relative integration ratio of 12:4:4, and the cyclohexyl protons in 2 give rise to the well-known multiplet at δ 1.012.20 integrating to 44 protons, while two doublets are found for the methyl substituents in 3 (C7H6, δ 1.35; C5H4, δ 1.01). In addition, the 1H NMR and 13C NMR signals associated with the trochrocene framework are Received: July 1, 2011 Published: September 08, 2011 5202
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Scheme 1. Synthesis of 1,10 -Bis(phosphanyl)trochrocenes 13
Figure 2. Molecular structure of 2 in the solid state. Hydrogen atoms are omitted for clarity.
Scheme 2. Preparation of Heterobimetallic [3]Trochrocenophanes 49
Figure 1. Molecular structure of 1 in the solid state. Hydrogen atoms and minor disordered components are omitted for clarity.
comparable for all three species and clearly indicate the absence of any molecular ring strain in 13. Consequently, both the C7H6 protons (1, δ 5.80 (2H), 5.56 (2H), 5.47 (2H); 2, δ 5.93 (2H), 5.72 (4H); 3, δ 5.83 (2H), 5.60 (2H), 5.56 (2H)) and the C5H4 protons (1, δ 4.08 (2H), 3.96 (2H); 2, δ 4.09 (2H), 4.04 (2H); 3, δ 3.93 (2H), 3.92 (2H)) appear considerably deshielded with respect to the parent [Cr(η5C5H5)(η7-C7H7)] molecule (δ 5.45 (7H), 3.66 (5H)), a fact that has already been encountered for other 1,10 -disubstituted trochrocene derivatives.6 The nonstrained character was further validated by X-ray diffraction studies on 1 and 2, and their molecular structures in the solid state are depicted in Figures 1 and 2, respectively. It should be noted that 3 was isolated as a greenish blue oil; for this reason no structural characterization in the crystalline state has been possible so far. Even though the quality of the crystals of 1 was satisfactory, extensive disorder of the π-coordinated carbocycles and the phenyl groups attached to the phosphorus atoms preclude any detailed discussion of its structural parameters. However, X-ray data served to substantiate the unstrained nature of 1 in the solid state, as already deduced from NMR spectroscopy in solution. Due to the presence of a crystallographic inversion center, the phosphine substituents are oriented antiperiplanar to each other, which is highlighted by the torsion angle CpipsoXCpXChtChtipso = 180°.
Table 1. Reaction Times Required for the Syntheses of [3]Trochrocenophanes 49 [Cr(CO)6]
[Mo(CO)6]
[W(CO)6]
1
6 weeks
15 h
8 weeks
2
7 weeks
15 h
8 weeks
As anticipated, the molecular structure of 2 in the solid state strongly resembles that of 1, thus showing the characteristic features of an unstrained sandwich complex. Accordingly, the η5and η7-coordinated rings adopt an almost ideal coplanar arrangement, which is nicely illustrated by the values found for the tilt angle α = 0.4° and the deformation angle δ = 179.9°. Other bond distances and angles are unremarkable and are also comparable to those found in other 1,10 -disubstituted trochrocene derivatives.6 Unlike the antiperiplanar arrangement of the phosphine substituents in 1, the corresponding torsion angle CpipsoXCpXChtChtipso = 34° in 2 indicates a synclinical (staggered) orientation of the PCy2 fragments. [3]Trochrocenophanes. The suitability of 13 to act as chelating ligands was subsequently evaluated by reactivity studies toward group 6 hexacarbonyls. To this end, 1 and 2 were treated with [Cr(CO)6], [Mo(CO)6], and [W(CO)6] in THF at slightly 5203
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Organometallics Table 2.
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P NMR Shifts (ppm) and 2JP,P Coupling Constants (Hz) of [3]Trochrocenophanes 49 (C6D6) 4
5
6
7
8
9
δ(31P)
71.48, 48.21
54.32, 30.04
39.08, 12.92
68.15, 44.57
55.95, 29.41
39.00, 12.74
2
33.5
27.0
25.6
31.2
26.8
26.6
JP,P
1
JP,W
240, 241
Table 3. ν(CO) in THF Solution and in the Solid State for 49 (cm1) 4
5
6
7
8
9
2006 (s)
2017 (s)
2013 (s)
1994 (s)
2008 (s)
2003 (s)
1880 (br)
1901 (br)
1892 (br)
1876 (br)
1882 (br)
1896 (br)
THF Solution
1884 (br)
1874 (br) Solid State
1998 (s)
2013 (br)
2008 (s)
1986 (s)
2007 (br)
2002 (br)
1901 (br) 1863 (br)
1915 (br) 1888 (br)
1903 (br) 1859 (br)
1890 (br) 1863 (br)
1973 (br) 1890 (s)
1957 (br) 1871 (br)
1842 (br)
1855 (s)
1844 (br)
1869 (br)
elevated temperatures (75 °C) (Scheme 2). Reaction times are summarized in Table 1 and strongly depend on the nature of the transition-metal center of the hexacarbonyl species (15 h to 8 weeks). As anticipated, the reactions take advantage of the chelate effect with concomitant loss of 2 equiv of CO, thus affording [3]trochrocenophanes 49, which were isolated as solid materials in moderate yields of 4267%. Similar reaction pathways have already been observed for related systems such as the analogous troticene species,11a dppf,14 or (diphenylphosphino)zirconocene dichloride.15 The transformations are easily monitored by 31P NMR spectrosopy of the reaction mixtures, which revealed the gradual consumption of the 1,10 -bis(phosphanyl) starting materials 1 and 2 and the smooth formation of heterobimetallic 49. Accordingly, the 31P NMR resonances of 1 and 2 are significantly shifted to lower field upon coordination to the transition-metal carbonyl fragments and are each split into a doublet with 2JP,P coupling constants of approximately 30 Hz (Table 2), which lies in the expected range for such species.11a In contrast, 1H NMR data are not well suited for the characterization of 49, due to their strong similarity to the nonbridged precursors 1 and 2. Because of the low solubility of 49 in all common organic solvents, we have not been able to detect any 13C NMR signal of the CO ligands so far. In fact, this solubility issue precluded any meaningful NMR spectroscopic characterization of isolated 7 and 9. Again, 13C NMR resonances of the other [3]trochrocenophanes are unremarkable and strongly resemble those of their respective precursors 1 and 2. Since the presence of CO groups in 49 could not be deduced from NMR spectroscopy, we addressed IR spectroscopy for further characterization. Thus, absorption bands consistent with the presence of terminal CO ligands are found for all species both in THF solution and in the solid state (Table 3). The formulation of 49 as [3]trochrocenophanes is also supported by comparison of the IR data with those of the related Cr- and Mo-bridged troticene congeners, which feature absorption bands in a similar region (Cr, ν(CO) 2010 (s), 1870 (br); Mo, ν(CO) 2020 (s), 1865 (br); KBr).11a
230, 229
X-ray diffraction studies eventually served to determine the molecular compositions of 47 in the solid state. Accordingly, the molecular structures confirm the presence of heterobimetallic [3]trochrocenophanes, in which both phosphorus centers of the bidentate 1,10 -bis(phosphanyl) moieties are coordinated cis to the [M(CO)4] fragments, a structural motif similar to that found for [{Ti(η5-C5H4PPh2)(η7-C7H6PPh2)}M(CO)4] (M = Cr, Mo).11a Relevant structural parameters of 47 are comparable (Table 4); hence, only the molecular structure of 4 is discussed in the following. In addition, only the crystal structures of 4 and 7 are shown in Figures 3 and 4 as representative examples. As expected, the trochrocene backbone in 4 only slightly deviates from the coplanar arrangement observed for its 1,10 bis(phosphanyl) precursor and the parent molecule (α = 2.1°; δ = 179.0°). As a consequence of the chelating cis arrangement, the torsion angle CpipsoXCpXChtChtipso amounts to 41.1°. The PCipso bond lengths in 4 are only marginally affected by the coordination to the [Cr(CO)4] fragment. Thus, the P1Cpipso distance (1.814(3) Å) is slightly shortened with respect to the precursor molecule 1 (1.896(7) Å), while the P2Chtipso distance is somewhat elongated (1.849(3) Å; cf. 1, 1.778(6) Å). The CrP bond lengths within the [P2Cr(CO)4] moiety (Cr2P1 = 2.4184(9) Å; Cr2P2 = 2.4304(9) Å) are found in the same range as those of [{Ti(η5-C5H4PPh2)(η7C7H6PPh2)}Cr(CO)4] (CrP = 2.415(3), 2.445(4) Å),11a just like the CrCO bond distances, which might be separated into two different groups. Those in positions trans to the phosphine ligands (1.851(3) Å for CrCO trans to C5H4PPh2; 1.853(3) Å for CrCO trans to C7H6-PPh2) are considerably shorter that those that are oriented mutually cis (1.882(3), 1.888(3) Å). Bite angles are roughly 100° (4, 98.69(3)°; 5, 97.26(2)°; 6, 97.26(2)°; 7, 102.61(3)°) and are thus similar to that found in [{Ti(η5C5H4PPh2)(η7-C7H6PPh2)}Cr(CO)4] (99.1(1)°).11a
’ CONCLUSION In this contribution, we reported on the synthesis of 1,10 bis(phosphanyl)trochrocenes 13. These species have proven to be highly valuable in subsequent reactivity studies toward group 6 hexacarbonyls. Accordingly, 1 and 2 were successfully used as chelating ligands, affording the [3]trochrocenophanes 49 featuring PMP ansa bridges. X-ray diffraction studies on 1, 2, and 47 eventually ascertained the molecular structures of these species in the solid state. Thus, we have demonstrated that 13 show coordination properties similar to those of its wellknown ferrocene-based analogue dppf,14 for which reason we believe that 13 might be of significant relevance as bidentate ligands in homogeneous catalysis, an aspect that is currently being investigated in our laboratories. ’ EXPERIMENTAL SECTION All manipulations were conducted either under an atmosphere of dry argon or in vacuo using standard Schlenk line or glovebox techniques. Solvents were dried according to standard procedures, degassed, and 5204
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Table 4. Bond Distances (Å) and Angles (deg) for 47 compd
δ
α
torsion angle
4
179.0
2.1
5
178.4
1.5
6
178.4
7
177.7
C1P1
C2P2
41.1
1.814(3)
1.849(3)
1.851(3), 1.853(3)
44.7
1.8156(13)
1.8471(13)
1.987(4), 1.993(3)
1.5
44.0
1.8155(16)
1.8506(16)
1.5
32.3
1.816(3)
1.862(3)
Figure 3. Molecular structure of 4 in the solid state. Hydrogen atoms and ellipsoids of the phenyl groups are omitted for clarity. stored under argon over activated molacular sieves. C6D6 was degassed by three freezepumpthaw cycles and stored over molecular sieves. Reagents were dried and purified by standard procedures. NMR spectra were acquired on a Bruker AMX 400 or a Bruker Avance 500 NMR spectrometer. 1H and 13C{1H} NMR spectra were referenced to external TMS via the residual protons of the solvent (1H) or the solvent itself (13C). 31P NMR spectra were referenced to 85% H3PO4. Microanalyses (C, H, N) were performed on a Leco Instruments elemental analyzer, type CHNS 932. IR spectra in THF were acquired on a JASCO FT/IR-6200 spectrometer. Solid measurements were performed in an Innovative Technology PureLab glovebox using a PIKE HWG accessory. [Cr(η5-C5H4Li)(η7-C7H6Li)] 3 tmeda,1 ClPMe2,16 and ClPCy217 were prepared according to published procedures. ClPPh2 was purchased from Sigma-Aldrich and distilled under high vacuum. All other chemicals were obtained commercially, degassed, and used without further purification. The phosphorus atoms are defined as P5 (η5C5H4R) and P7 (η7-C7H6R). [Cr(η5 -C5 H4 PPh2 )(η 7-C7H6PPh2)] (1). [Cr(η5-C5H4Li)(η7C7H 6Li)] 3 tmeda (336 mg, 1.00 mmol) was suspended in hexane (20 mL) and treated dropwise with a solution of ClPPh2 (0.39 mL, 2.20 mmol) in hexane (15 mL). The reaction mixture was stirred for 2 h at ambient temperature. Volatiles were removed under reduced pressure. The resulting residue was washed with hexane (4 15 mL), extracted into toluene (20 mL) and the extract filtered. Concentration of the filtrate (8 mL) and storage at 30 °C afforded 1 as a brown crystalline solid. Crystals suitable for X-ray diffraction were obtained by recrystallization from toluene/hexane (1/1) at ambient temperature. Yield: 415 mg (0.72 mmol, 72%). 1 H NMR (500.1 MHz, C6D6): δ 3.96 (m, 2H, β-C5H4), 4.08 (m, 2H, α-C5H4), 5.47 (m, 2H, β-C7H6), 5.56 (m, 2H, γ-C7H6) 5.80 (pt, 2H, α-
MC1, MC2
MC3, MC4
MP1
MP2
1.888(3), 1.882(3)
2.4184(9)
2.4304(9)
2.045(3), 2.029(3)
2.5590(5)
2.5652(5)
1.9838(17), 1.9907(17)
2.0433(18), 2.0265(17)
2.5454(5)
2.5484(5)
1.847(3), 1.845(3)
1.896(3), 1.857(3)
2.4221(10)
2.4505(9)
Figure 4. Molecular structure of 7 in the solid state. Hydrogen atoms and ellipsoids of the cyclohexyl groups are omitted for clarity. C7H6), 7.04 (m, 12H, Ph), 7.36 (m, 4H, Ph), 7.55 (m, 4H, Ph). 13C{1H} NMR (126 MHz, C6D6): δ 79.07 (m, β-C5H4), 81.32 (d, α-C5H4, 2JC,P5 = 14.9 Hz), 84.44 (d, i-C5H4, 1JC,P5 = 10.0 Hz), 88.31 (d, β-C7H6, 3JC,P7 = 8.1 Hz), 88.61 (s, γ-C7H6), 91.70 (d, α-C7H6, 2JC,P7 = 24.4 Hz), 95.71 (d, i-C7H6, 1JC,P7 = 10.4 Hz), 128.53 (d, m-Ph, 3JC,P5 = 6.8 Hz), 128.67 (d, m-Ph, 3JC,P7 = 6.8 Hz), 128.76 (s, p-Ph), 128.95 (s, p-Ph), 134.10 (d, o-Ph, 2JC,P5 = 20.2 Hz), 134.97 (d, o-Ph, 2JC,P7 = 20.3 Hz), 139.89 (d, i-Ph, 1 JC,P5 = 12.2 Hz), 139.95 (d, i-Ph, 1JC,P7 = 14.6 Hz). 31P{1H} NMR (202 MHz, C6D6): δ 17.07 (s, P5), 9.83 (s, P7). Anal. Calcd for C36H30CrP2 (576.57): C, 74.99; H, 5.25. Found: C, 74.68; H, 5.27. [Cr(η5-C5H4PCy2)(η7-C7H6PCy2)] (2). A slurry of [Cr(η5-C5H4Li)7 (η -C7H6Li)] 3 tmeda (336 mg, 1.00 mmol) in hexane (40 mL) was cooled to 0 °C and treated dropwise with a solution of ClPCy2 (0.53 mL, 2.40 mmol) in hexane (20 mL). After complete addition, the reaction mixture was warmed to ambient temperature and was further stirred for 12 h. The reaction mixture was concentrated (5 mL) and subjected to column chromatography (Alox III, hexane). The filtrate was again concentrated to 5 mL, and after storage at 30 °C, 2 could be obtained as a blue crystalline solid. Yield: 444 mg (0.74 mmol, 74%). 1 H NMR (500.1 MHz, C6D6): δ 1.012.20 (m, 44H, C6H11), 4.04 (m, 2H, α-C5H4), 4.09 (m, 2H, β-C5H4), 5.72 (m, 4H, β/γ-C7H6), 5.93 (m, 2H, α-C7H6). 13C{1H} NMR (126 MHz, C6D6): δ 26.79 (s, C6H11), 26.93 (s, C6H11), 27.6327.99 (m, C6H11), 30.4330.59 (m, C6H11), 31.10 (d, C6H11, JC,P = 11.9 Hz), 31.80 (d, C6H11, JC,P = 15.6 Hz), 34.2134.45 (m, C6H11), 78.29 (s, β-C5H4), 80.28 (d, α-C5H4, 2JC,P5 = 11.1 Hz), 86.26 (d, i-C5H4, 1JC,P5 = 20.0 Hz), 88.22 (br, β-C7H6), 88.56 (br, γ-C7H6), 90.42 (br, α-C7H6), 93.78 (br, i-C7H6). 31P{1H} NMR (202 MHz, C6D6): δ 7.97 (s, P5), 18.12 (s, P7). Anal. Calcd for C36H54CrP2 (747.37): C, 71.97; H, 9.06. Found: C, 71.74; H, 9.03. 5205
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Organometallics [Cr(η5-C5H4PMe2)(η7-C7H6PMe2)] (3). A suspension of [Cr(η5-
C5H4Li)(η7-C7H6Li)] 3 tmeda (1.01 g, 3.00 mmol) in hexane (40 mL) was cooled to 30 °C and subsequently treated dropwise with a solution of ClPMe2 (0.57 mL, 7.20 mmol) in hexane (20 mL). After it was warmed to room temperature, the mixture was stirred for an additional 12 h. The reaction mixture was concentrated in volume (3 mL) and subjected to column chromatography (Alox III, hexane). After removal of all volatiles, 3 was isolated as a green oil (603 mg, 1.84 mmol, 61%). 1 H NMR (500.1 MHz, C6D6): δ 1.01 (d, 6H, P5-(CH3)2, 2JH,P5 = 3.6 Hz), 1.35 (d, 6H, P7-(CH3)2, 2JH,P7 = 3.9 Hz), 3.92 (m, 2H, β-C5H4), 3.93 (m, 2H, α-C5H4), 5.56 (m, 2H, β-C7H6), 5.60 (m, 2H, γ-C7H6), 5.83 (m, 2H, α-C7H6). 13C{1H} NMR (126 MHz, C6D6): δ 15.52 (d, P5-(CH3)2, 1JC,P7 = 13.0 Hz), 16.71 (d, P7-(CH3)2, 1JC,P5 = 16.2 Hz), 78.01 (d, β-C5H4, 3JC,P5 = 2.8 Hz), 78.32 (d, α-C5H4, 2JC,P5 = 13.5 Hz), 88.12 (s, γ-C7H6), 88.39 (d, β-C7H6, 3JC,P7 = 7.9 Hz), 89.30 (d, α-C7H6, 2 JC,P7 = 25.0 Hz), 89.36 (d, i-C5H4, 1JC,P5 = 13.3 Hz), 98.62 (d, i-C7H6, 1 JC,P7 = 14.1 Hz). 31P{1H} NMR (202 MHz, C6D6): δ 56.96 (s, P5), 26.73 (s, P7). Anal. Calcd for C16H22CrP2 (328.29): C, 58.54; H, 6.75. Found: C, 58.70; H, 6.77. [{Cr(η5-C5H4PPh2)(η7-C7H6PPh2)}Cr(CO)4] (4). A mixture of 1 (60 mg, 0.10 mmol) and [Cr(CO)6] (23 mg, 0.10 mmol) in THF (0.6 mL) was heated to 75 °C by means of an oil bath over a period of 6 weeks. During this time, brown crystals formed, which were washed with hexane (3 2 mL) and dried in vacuo at 70 °C. Thus, 3 was isolated as a brown solid. Crystals suitable for X-ray analysis were obtained directly from the reaction mixture. Yield: 44 mg (0.06 mmol, 57%). 1 H NMR (500.1 MHz, C6D6): δ 3.69 (m, 2H, C5H4), 4.26 (m, 2H, C5H4), 5.14 (m, 4H, C7H6), 6.10 (m, 2H, C7H6), 6.98 (m, 8H, Ph), 7.09 (m, 4H, Ph), 7.61 (m, 4H, Ph), 8.10 (m, 4H, Ph). 13C{1H} NMR (126 MHz, C6D6): δ 80.91 (br, β-C5H4), 81.75 (d, α-C5H4, 2JC,P5 = 10.9 Hz), 86.31 (br, β-C7H6), 88.68 (br, γ-C7H6), 92.29 (br, α-C7H6), 128.55 (m, m-Ph), 128.65 (d, m-Ph, 3JC,P7 = 8.5 Hz), 130.23 (m, p-Ph), 130.38 (m, p-Ph), 133.60 (d, o-Ph, 2JC,P5 = 11.1 Hz), 134.54 (d, o-Ph, 2JC,P7 = 10.4 Hz), 138.43 (d, i-Ph, 1JC,P5 = 35.1 Hz), 139.50 (br, i-Ph). 31P{1H} NMR (162 MHz, C6D6): δ 48.21 (d, P5, 2JP5,P7 = 33.5 Hz), 71.48 (d, P7, 2 JP7,P5 = 33.5 Hz). IR (THF): 2006 (s), 1880 (br) cm1, ν(CO). IR (solid): 1998 (s), 1901 (br), 1863 (br) cm1, ν(CO). Anal. Calcd for C40H30Cr2P2O4 (740.60): C, 64.87; H, 4.08. Found: C, 64.78; H, 4.23. [{Cr(η5-C5H4PPh2)(η7-C7H6PPh2)}Mo(CO)4] (5). 5 was prepared similarly to 4 using a mixture of 1 (60 mg, 0.10 mmol) and [Mo(CO)6] (28 mg, 0.10 mmol) in THF (0.6 mL; 75 °C; 15 h). Brown crystals suitable for X-ray analysis were obtained by recrystallization from toluene at ambient temperature. Yield: 55 mg (0.07 mmol, 67%). 1 H NMR (500.1 MHz, C6D6): δ 3.70 (m, 2H, C5H4), 4.16 (m, 2H, C5H4), 5.10 (m, 4H, C7H6), 6.04 (m, 2H, C7H6), 7.00 (m, 8H, Ph), 7.09 (m, 4H, Ph), 7.56 (m, 4H, Ph), 8.04 (m, 4H, Ph). 13C{1H} NMR (126 MHz, C6D6): δ 80.96 (m, β-C5H4), 81.97 (d, α-C5H4, 2JC,P5 = 11.2 Hz), 86.72 (br, β-C7H6), 88.53 (br, γ-C7H6), 92.30 (br, α-C7H6), 128.35 (m, m-Ph), 128.72 (d, m-Ph, 3JC,P7 = 8.8 Hz), 129.81 (m, p-Ph), 130.07 (m, p-Ph), 133.38 (d, o-Ph, 2JC,P5 = 12.7 Hz), 134.65 (d, o-Ph, 2JC,P7 = 12.2 Hz), 138.38 (d, i-Ph, 1JC,P5 = 34.5 Hz), 139.30 (br, i-Ph). 31P{1H} NMR (202 MHz, C6D6): δ 30.04 (d, P5, 2JP5,P7 = 27.0 Hz), 54.32 (d, P7, 2 JP7,P5 = 27.0 Hz). IR (THF): 2017 (s), 1901 (br), 1884 (br) cm1, ν(CO). IR (solid): 2013 (br), 1915 (br), 1888 (br), 1869 (br) cm1, ν(CO). Anal. Calcd for C40H30CrP2O4Mo (784.55): C, 61.24; H, 3.85. Found: C, 61.37; H, 4.02. [{Cr(η5-C5H4PPh2)(η7-C7H6PPh2)}W(CO)4] (6). 6 was prepared similarly to 4 using a mixture of 1 (60 mg, 0.10 mmol) and [W(CO)6] (37 mg, 0.10 mmol) in THF (0.6 mL; 75 °C; 8 weeks). Brown crystals suitable for X-ray analysis were obtained by recrystallization from toluene at ambient temperature. Yield: 49 mg (0.06 mmol, 54%). 1 H NMR (500.1 MHz, C6D6): δ 3.69 (m, 2H, β-C5H4), 4.16 (m, 2H, α-C5H4), 5.05 (m, 2H, β-C7H6), 5.08 (m, 2H, γ-C7H6), 6.06 (m, 2H, α-
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C7H6), 6.99 (m, 8H, Ph), 7.08 (m, 4H, Ph), 7.54 (m, 4H, Ph), 8.04 (m, 4H, Ph). 13C{1H} NMR (126 MHz, C6D6): δ 80.99 (d, β-C5H4, 3JC,P5 = 5.7 Hz), 81.92 (d, α-C5H4, 2JC,P5 = 11.2 Hz), 86.46 (d, β-C7H6, 3JC,P7 = 10.0 Hz), 88.66 (s, γ-C7H6), 92.28 (d, α-C7H6, 2JC,P7 = 16.7 Hz), 128.32 (m, m-Ph), 128.72 (d, m-Ph, 3JC,P7 = 9.2 Hz), 129.99 (m, p-Ph), 130.23 (m, p-Ph), 133.46 (m, o-Ph, 2JC,P5 = 12.0 Hz), 134.82 (d, o-Ph, 2JC,P7 = 11.5 Hz), 138.21 (d, i-Ph, 1JC,P5 = 40.7 Hz), 139.26 (d, i-Ph, 1JC,P7 = 37.1 Hz). 31P{1H} NMR (202 MHz, C6D6): δ 12.92 (d, P5, 2JP5,P7 = 25.6 Hz, 1 JP5,W= 241 Hz), 39.08 (d, P7, 2JP7,P5 = 25.6 Hz, 1JP7,W= 240 Hz). IR (THF): 2013 (s), 1892 (br) cm1, ν(CO). IR (solid): 2008 (s), 1903 (br), 1859 (br) cm1, ν(CO). Anal. Calcd for C40H30CrP2O4W (872.45): C, 55.07; H, 3.47. Found: C, 55.47; H, 3.75. [{Cr(η5-C5H4PCy2)(η7-C7H6PCy2)}Cr(CO)4] (7). 7 was prepared similarly to 4 using a mixture of 2 (60 mg, 0.10 mmol) and [Cr(CO)6] (22 mg, 0.10 mmol) in THF (0.6 mL; 75 °C; 7 weeks). Green crystals suitable for X-ray analysis were obtained by recrystallization from toluene at ambient temperature. Yield: 39 mg (0.05 mmol, 51%). 31 P NMR (162 MHz, C6D6): δ 44.57 (d, P5, 2JP5,P7 = 31.2 Hz), 68.15 (d, P7, 2JP7,P5 = 31.2 Hz). IR (THF): 1994 (s), 1876 (br) cm1, ν(CO). IR (solid): 1986 (br), 1890 (br), 1863 (br), 1842 (br) cm1, ν(CO). Anal. Calcd for C40H54Cr2P2O4 (764.79): C, 62.82; H, 7.12. Found: C, 62.85; H, 7.41. [{Cr(η5-C5H4PCy2)(η7-C7H6PCy2)}Mo(CO)4] (8). 8 was prepared similarly to 4 using a mixture of 2 (60 mg, 0.10 mmol) and [Mo(CO)6] (26 mg, 0.10 mmol) in THF (0.6 mL; 75 °C; 15 h). Yield: 35 mg (0.04 mmol, 44%) as a green solid. 1 H NMR (500.1 MHz, C6D6): δ 1.091.94 (m, 36H, C6H11), 2.322.62 (m, 8H, C6H11), 3.83 (m, 2H, C5H4), 3.95 (m, 2H, C5H4), 5.43 (m, 4H, C7H6), 5.90 (m, 2H, C7H6). 13C{1H} NMR (126 MHz, C6D6): δ 26.50 (m, C6H11), 27.6728.12 (m, C6H11), 28.87 (m, C6H11), 29.60 (m, C6H11), 30.53 (s, C6H11), 39.95 (br, C6H11), 40.60 (br, C6H11), 78.67 (m, β-C5H4), 81.20 (d, α-C5H4, 2JC,P5 = 8.8 Hz), 87.15 (br, β-C7H6), 88.00 (br, γ-C7H6), 90.81 (br, α-C7H6). 31 1 P{ H} NMR (202 MHz, C6D6): δ 29.41 (d, P5, 2JP5,P7 = 26.8 Hz), 55.95 (d, P7, 2JP7,P5 = 26.78). IR (THF): 2008 (s), 1882 (br) cm1, ν(CO). IR (solid): 2007 (br), 1973 (br), 1890 (s), 1855 (s) cm1, ν(CO). Anal. Calcd for C40H54CrP2O4Mo (808.74): C, 59.41; H, 6.73. Found: C, 59.06; H, 6.71. [{Cr(η5-C5H4PCy2)(η7-C7H6PCy2)}W(CO)4] (9). 9 was prepared similarly to 4 using a mixture of 2 (60 mg, 0.10 mmol) and [W(CO)6] (25 mg, 0.10 mmol) in THF (0.6 mL; 75 °C; 8 weeks). Yield: 37 mg (0.04 mmol, 42%) as a green solid. 31 P NMR (162 MHz, C6D6): δ 12.74 (d, P5, 2JP5,P7 = 26.6 Hz, 1JP5,W = 229 Hz), 39.00 (d, P7, 2JP7,P5 = 26.6 Hz, 1JP7,W = 230 Hz). IR (THF): 2003 (s), 1896 (br), 1874 (br) cm1, ν(CO). IR (solid): 2002 (br), 1957 (br), 1871 (br), 1844 (br) cm1, ν(CO). Anal. Calcd for C40H54CrP2O4W (896.64): C, 53.58; H, 6.07. Found: C, 53.30; H, 5.90. Crystal Structure Determinations. The crystal data of 1, 2, and 47 were collected on a Bruker X8 Apex diffractometer with a CCD area detector and multilayer mirror or graphite-monochromated Mo Kα radiation. The structures were solved using direct methods, refined with the Shelx software package,18 and expanded using Fourier techniques. All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were assigned idealized positions and were included in structure factor calculations. Crystallographic data have been deposited with the Cambridge Crystallographic Data Center as Supplementary Publication Nos. CCDC-832102 (1), CCDC-832103 (2), CCDC-832104 (4), CCDC832105 (5), CCDC-832106 (6), and CCDC-832107 (7). These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. Crystal Data for 1: C36H30CrP2, Mr = 576.54, brown block, 0.18 0.05 0.05 mm3, monoclinic, space group P21/c, a = 8.6348(2) Å, b = 18.6822(5) Å, c = 8.9345(2) Å, β = 99.7020(10)°, V = 1420.67(6) Å3, Z = 2, Fcalcd = 1.348 g cm3, μ = 0.540 mm1, F(000) = 600, T = 100(2) 5206
dx.doi.org/10.1021/om200577b |Organometallics 2011, 30, 5202–5207
Organometallics K, R1 = 0.0559, wR2 = 0.1122, 3960 independent reflections (2θ e 61.02°) and 272 parameters. Crystal Data for 2: C36H54CrP2, Mr = 600.73, blue block, 0.17 0.11 0.10 mm3, monoclinic, space group P21/c, a = 14.067(3) Å, b = 19.872(4) Å, c = 11.342(2) Å, β = 91.392(8)°, V = 3169.5(10) Å3, Z = 4, Fcalcd = 1.259 g cm3, μ = 0.486 mm1, F(000) = 1296, T = 100(2) K, R1 = 0.0434, wR2 = 0.0947, 8108 independent reflections (2θ e 56.74°) and 353 parameters. Crystal Data for 4: C44H38Cr2O5P2, Mr = 812.68, colorless plate, 0.05 0.04 0.015 mm3, triclinic, space group P1, a = 10.4357(6) Å, b = 10.9398(7) Å, c = 17.5197(11) Å, α = 82.997(3)°, β = 78.777(3)°, γ = 84.337(3)°, V = 1941.5(2) Å3, Z = 2, Fcalcd = 1.390 g cm3, μ = 0.687 mm1, F(000) = 840, T = 100(2) K, R1 = 0.0685, wR2 = 0.1686, 9420 independent reflections (2θ e 57°) and 451 parameters. Crystal Data for 5: C40H30CrMoO4P2, Mr = 784.52, brown plate, 0.31 0.13 0.09 mm3, triclinic, space group P1, a = 10.537(2) Å, b = 10.998(2) Å, c = 17.697(4) Å, α = 82.334(9)°, β = 78.593(9)°, γ = 85.707(8)°, V = 1990.0(7) Å3, Z = 2, Fcalcd = 1.309 g cm3, μ = 0.704 mm1, F(000) = 796, T = 100(2) K, R1 = 0.0223, wR2 = 0.0584, 9749 independent reflections (2θ e 56.58°) and 433 parameters. Crystal Data for 6: C80H60Cr2O8P4W2, Mr = 1744.86, colorless block, 0.21 0.16 0.12 mm3, triclinic, space group P1, a = 10.5147(16) Å, b = 11.0026(15) Å, c = 17.662(3) Å, α = 82.539(6)°, β = 78.703(7)°, γ = 85.626(6)°, V = 1984.1(5) Å3, Z = 1, Fcalcd = 1.460 g cm3, μ = 3.287 mm1, F(000) = 860, T = 100(2) K, R1 = 0.0192, wR2 = 0.0475, 12 020 independent reflections (2θ e 61.26°) and 433 parameters. Crystal Data for 7: 2(C40H54Cr2O4P2), 3(C7H8), Mr = 1805.95, colorless plate, 0.26 0.07 0.03 mm3, triclinic, space group P1, a = 10.7619(8) Å, b = 14.9029(11) Å, c = 15.0545(11) Å, α = 84.561(4)°, β = 76.001(4)°, γ = 73.667(4)°, V = 2247.3(3) Å3, Z = 1, Fcalcd = 1.334 g cm3, μ = 0.599 mm1, F(000) = 958, T = 100(2) K, R1 = 0.0926, wR2 = 0.1345, 10 797 independent reflections (2θ e 56.78°) and 555 parameters.
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(9) (a) Fihri, A.; Meunier, P.; Hierso, J.-C. Coord. Chem. Rev. 2007, 251, 2017. (b) Colacot, T. J. Platinum Met. Rev. 2001, 45, 22. (10) Hayashi, T.; Konishi, M.; Kumada, M. Tetrahedron Lett. 1979, 20, 1871. (11) (a) Kool, L. B.; Ogasa, M.; Rausch, M. D.; Rogers, R. D. Organometallics 1989, 8, 1785. (b) Ogasa, M.; Rausch, M. D.; Rogers, R. D. J. Organomet. Chem. 1991, 403, 279. (12) Mohapatra, S.; B€uschel, S.; Daniliuc, C.; Jones, P. G.; Tamm, M. J. Am. Chem. Soc. 2009, 131, 17014. (13) Rausch, M. D.; Ogasa, M.; Ayers, M. A.; Rogers, R. D.; Rollins, A. N. Organometallics 1991, 10, 2481. (14) Rudie, A. W.; Lichtenberg, D. W.; Katcher, M. L.; Davison, A. Inorg. Chem. 1978, 17, 2859. (15) Tikkanen, W.; Fujita, Y.; Peterson, J. L. Organometallics 1986, 5, 888. (16) Wolfsberger, W. J. Organomet. Chem. 1986, 317, 167. (17) Issleib, K.; Seidel, W. Chem. Ber. 1959, 92, 2681. (18) Sheldrick, G. Acta Crystallogr., Sect. A 2008, 64, 112.
’ ASSOCIATED CONTENT
bS
Supporting Information. CIF files giving crystallographic data for 1, 2, and 47. This material is available free of charge via the Internet at http://pubs.acs.org.
’ REFERENCES (1) (a) Braunschweig, H.; Lutz, M.; Radacki, K. Angew. Chem. 2005, 117, 5792. Angew. Chem., Int. Ed. 2005, 44, 5647. (b) Braunschweig, H.; Friedrich, M.; Kupfer, T.; Radacki, K. Chem. Commun. 2011, 47, 3998. (2) See the review: Braunschweig, H.; Kupfer, T. Acc. Chem. Rev. 2010, 3, 455. (3) (a) Tamm, M. Chem. Commun. 2008, 3089. (b) Braunschweig, H.; Fuss, M.; Mohapatra, S. K.; Kraft, K.; Kupfer, T.; Lang, M.; Radacki, K.; Daniliuc, C. G.; Jones, P. G.; Tamm, M. Chem. Eur. J. 2010, 16, 11732. (4) (a) Elschenbroich, C.; Paganelli, F.; Nowotny, M.; Neum€uller, B.; Burghaus, O. Z. Anorg. Allg. Chem. 2004, 630, 1599. (b) Tamm, M.; Kunst, A.; Herdtweck, E. Chem. Commun. 2005, 1729. (c) Braunschweig, H.; Lutz, M.; Radacki, K.; Schauml€offel, A.; Seeler, F.; Unkelbach, C. Organometallics 2006, 25, 4433. (5) Braunschweig, H.; Kupfer, T. Organometallics 2007, 26, 4634. (6) Braunschweig, H.; Kupfer, T.; Lutz, M.; Radacki, K. J. Am. Chem. Soc. 2007, 129, 8893. (7) Ferrocenes; Togni, A., Hayashi, T., Eds.; Wiley-VCH: Weinheim, Germany, 1995. (8) (a) Sollot, G. P.; Snead, J. L.; Portnoy, S.; Peterson, W. R., Jr.; Mertwoy, H. E. Chem. Abstr. 1965, 63, 1847b. (b) Marr, G.; Hunt, T. J. Chem. Soc. C 1969, 7, 1070. (c) Bishop, J. J.; Davison, A.; Katcher, M. L.; Lichtenberg, D. W.; Merrill, R. E.; Smart, J. C. J. Organomet. Chem. 1971, 27, 241. 5207
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