Inorg. Chem. 1983, 22, 863-868 tertiary phosphines.12 On the basis of Pt-Pbridge distances (avera e 2.348 A) and Pt-P (terminal) distances (average 2.331 ), they concluded that the two types of phosphorus substituents compete equally. In contrast to the nearly equal M-P bond distances found in the Pt complex, the two types of Rh-P bond distances differ si nificantly in the title compound Rh-P~dge,average 2.359 ;Rh-P-, average 2.256 A. In terms of the relative bond-lengthening influences in the title compound, therefore, the bridging diphenylphosphido group would have to be considered to exert the weaker trans-directing influence. The structural features as reported are fully consistent with predictions based on ,lP (‘HI N M R In sub-
w
w
863
stantiation of this structural report, we suggest that the observed , , a resonance at -104 further demonstrates the lack of significant Rh-Rh bonding in this complex and of the utility of 31PNMR spectroscopy for the structural characterization of transition-metal complexes that contain bridging organophosphido ligands. Registry No. [Rh(pPPh2)(DPPE)]2.C4Hs0, 84332-81-0. Supplementary Material Available: Listings of observed and calculated structure factor amplitudes, atom coordinates and isotropic thermal parameters, bond lengths, bond angles, and anisotropic thermal parameters (28 pages). Ordering information is given on any current masthead page.
Contribution from the Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Y6
Phosphine Complexes of Zirconium(1V) and Hafnium(1V) Obtained through the Use of Hybrid Multidentate Ligands. X-ray Crystal Structure of ZrC12[N(SiMe2CH2PMe2)2]2 MICHAEL D. FRYZUK,* HUGH DAVID WILLIAMS, and STEVEN J. RETTIG Received June 30, I982
The reaction of LiN(SiMe2CHzPR2)zwith either ZrCI, or HfC1, generates new complexes of the formula MClZ[N(SiMe$H2PR2)2]2 (M = Zr or Hf;R = Me or Ph). Both of the potentially tridentate hybrid ligands bind only in a bidentate fashion, generating coordinated and uncoordinated phosphines in the same molecule. The single-crystal X-ray structure of ZrC12[N(SiMe2CH2PMez)2]2 (space group Pbcu; u = 16.8307 (9),b = 18.4663 (8), c = 24.285 (2) A; Z = 8; R = 0.036 ( R , = 0.046)) indicates a distorted-octahedral geometry with trans chloride and cis phosphine ligands. The molecule is chiral both in the solid state and in solution by virtue of a “gear” effect of the two bulky disilylamide ligands.
Introduction The chemistry of the group 4 metals, Ti, Zr, and Hf, is dominated by complexes containing the q5-C5H5-or the $C5Me5-ligand.’ While these derivatives have established the unique reactivity patterns of these metals, new ligands and new combinations of ligands are currently being investigated to extend the potentially rich chemistry of this group.2 One donor type that has only recently been incorporated into complexes of zirconi~m**~,~ and hafnium6 is the soft phosphine ligand, PR3 (R = aryl or alkyl). The evidence so far suggests that monodentate phosphine complexes of Zr(1V) are thermally labile4 and subject to displacement by hard ligands such as NEt, or by chelating ligands. Clearly, mismatching the soft phosphine donors with the hard Zr(1V) and Hf(1V) centers is a major factor in this behavior. To overcome this mismatching of donors and acceptors, we have developed a new series of “hybrid” ligands’ that incorporate the soft phosphine donor into a chelating array (Figure 1) that also contains the hard amido donor, -NR2 (R = alkyl, aryl, or silyl). Since amides of Zr(1V) and Hf(1V) are stable, well-known8-’0 complexes, we anticipated that the amide portion of the chelating ligand would serve as an anchor and reduce the tendency for phosphine dissociation. We present here full (1) (2) (3) (4)
(5) (6) (7) (8) (9) (10)
Labinger, J. A. J. Organomet. Chem. 1982, 227, 341. Reger, D. L.; Tarquini, M. E. Inorg. Chem. 1982, 21, 840. Gell, K. I.; Schwartz, J. J. Chem. SOC.,Chem. Commun. 1979, 245. Wengrovius, J. H.;Schrock, R. R. J. Organomet.Chem. 1981,205,319. Fischer, M. B.; James, E. J.; McNeese, T. J.; Nyburg, S. C.; Posin, B.; Wong-Ng, W.; Wreford, S. S . J. Am. Chem. SOC.1980, 102, 4941. Wreford, S. S.; Whitney, J. F. Inorg. Chem. 1981, 20, 3918. Bertini, I.; Dapporta, P.; Fallani, G.; Sacconi, L. Inorg. Chem. 1971, 10, 1703 and references therein. Andersen, R. A. Inorg. Chem. 1979, 18, 1724, 2928. Lappert, M. F.; Power, P. P.; Sanger, A. R.; Srivastava, R. C. ‘Metal and Metalloid Amides”; Wiley: New York, 1979. Airoldi, C.; Bradley, D. C.; Chudzynska, H.; Hursthouse, M. B.; Malik, K. M. A.; Raithby, P. R. J. Chem. Soc., Dalton Trans. 1980, 2010.
0020-1669/83/1322-0863$01.50/0
details of our initial work in this area, which has provided a new entry into phosphine derivatives of group 4B,specifically zirconium and hafnium. Experimental Section General Information. All manipulations were performed under prepurified nitrogen in a Vacuum Atmospheres HE-553-2 glovebox equipped with a MO-40-2H purification system or in standard Schlenk-type glassware. ZrC1, and HfCI, were obtained from Alfa and sublimed prior to use. Methylene chloride (CH2C12)was purified by distillation from CaH2 under argon. Toluene, hexanes, and diethyl ether (Et20) were distilled from sodium-benzophenone ketyl under argon. Melting points were determined on a Mel-Temp apparatus in sealed capillaries under nitrogen and are uncorrected. Carbon, hydrogen, and nitrogen analyses were performed by Mr. P. Borda of this department. ‘H NMR spectra were recorded on one of the following instruments, depending on the complexity of the particular spectrum: Varian EM-360L, Bruker WP-80, Varian XL-100, or Bruker WH-400. ’lP(’HJ spectra were run at 32.442 MHz on the Bruker WP-80 in 10-mm tubes fitted with inserts for the internal standard P(OMe), (set at +141.0 ppm relative to 85% H,P04). Deuterated benzene (C&) and deuterated toluene (Cy&) were purchased from Aldrich, dried over activated 4-A molecular sieves, and vacuum transferred prior to use. The starting ligand precursors LiN(SiMQCH2PR2)2(R = Philb or MeIZ)were prepared as described elsewhere. Z K C I ~ [ N ( S ~ M ~ ~ C HA~solution P P ~ ~of)LiN(SiMezCHzPPh2)2 ~]~ (8.56 g, 16.0 mmol) in Et20 (150 mL) was added dropwise to a cold (-4 “C) suspension of ZrC14 (1.86 g, 8.0 mmol) in E t 2 0 (100 mL). The mixture was warmed to room temperature and stirred for 3 h. After the Et20 was removed in vacuo, the residue was extracted with hexanes (2 X 20 mL) to remove the lemon yellow, “tris” derivative, ZrCl[N(SiMe2CHzPPh2)2]3. Although this material was never ob(11) (a) Fryzuk, M. D.; MacNeil, P. A. J. Am. Chem. Soc. 1981,103, 3492. (b) Fryzuk, M. D.; MacNeil, P. A,; Secco, A. S.; Rettig, S. J.; Trotter, J. Organometallics 1982, 1 , 918. (12) Fryzuk, M. D.; Brzezowski, C.; MacNeil, P. A,; Williams, H. D.,
manuscript in preparation.
0 1983 American Chemical Society
864 Inorganic Chemistry, Vol. 22, No. 6,1983
Fryzuk, Williams, and Rettig Table 11. Final Positional (Fractional X lo5,C X lo4) and Isotropic Thermal Parameters (UX l o 3 A') with Estimated Standard Deviations in Parentheses
1
2
Figure 1. Hybrid tridentate (1) and bidentate (2) ligands (M is a transition metal). Table I. Crystal Data and Experimental Conditions for Data Collection C,, H,,C1, N,P, Si,Zr a = 16.8307 (9) A b = 18.4663 (8) A c = 24.285 (2) A p = 6.68 cm-'
fw 723.05 space group Pbca Z=8 V = 7547.8 (8) A' D, = 1.273 g cmV3
radiation: Mo Ka, graphite monochromator, 26 = 12.2", h=0.71073 A scan: w-20, range (0.65 + 0.35 tan 0)" in w , extended 25% on each side for bkgds, speed 0.7-10.1" min-l to give Ilo(I) 2 28.6 aperture: (2.0 + tan 8 ) X 4 mm, 173 mm from cryst stds: reflectns 0,12,5, 587, 10,8,1 monitored every hour of exposure time, random intens fluctuations of +2% (three reflctns recentered every 150 reflctns for orientation control) data collected: h,k,l for 0 < 20 < 55" o*(n: S t 2B+ [0.04(S-B)I2 ( S = s c a n c o u n t , B = b k g d c o u n t ) boundary planes: 6 faces; {OOl}, ( l l l ) , (-l,-l,l), (-l,l,l), (1 1 7 1 ) transmission factors: 0.675-0.889 cryst size: ca. 0.48 X 0.50 X 0.50 mm temp: 21 t 1 "C 3-
55039 (2) 67 135 (6) 45781 (7) 54661 (8) 54013 (9) 66742 (7) 30772 (10) 40059 (7) 48337 (8) 66447 (8) 48820 (8) 47205 (19) 56929 (19) 4415 (3) 5396 (3) 7288 (3) 3948 (3) 5700 (4) 5943 (3) 6129 (4) 4503 (4) 7356 (4) 6383 (4) 2268 (5) 2997 (9) 3754 (3) 3054 (3) 5420 (3) 3851 (3) 6714 (4) 7106 (3) 4660 (4) 5078 (4)
10231 (2) 9029 (6) 7014 (6) -4906 (6) 11672 (8) 8282 (7) 29293 (11) 1608 (7) 13489 (7) 23983 (7) 26480 (7) 8514 (18) 20814 (18) -607 (2) 809 (3) 1602 (3) 2365 (3) -1158 (3) -863 (3) 566 (4) 738 (4) 70 (4) 994 (3) 2369 (6) 3425 (9) -250 (3) 476 (3) 2203 (3) 1671 (3) 3029 (3) 2862 (3) 2636 (3) 3598 (3)
63998 (2) 69600(5) 56544(5) 64806 (5) 89018(6) 55977 (6) 61396 (9) 70427 (6) 76674(6) 59653(6) 59573(6) 70577 (15) 61166 (15) 6614(2) 8195 (2) 5765 (2) 6317 (3) 5950(2) 7091 (2) 9219(2) 9179 (3) 5533 (3) 4896 (2) 6311 (7) 6705 (6) 7724(2) 6737 (2) 7569(2) 7935 (2) 5365 (3) 6566(3) 5206(3) 6187 (3)
42 60 60 55 71 59 102 54 54 60 62 47 48 63 60 60 76 81 72 90 89 110 93 256 286 82 72 72 75 99 78 86 99
tained analytically pure, its spectral proper tie^'^ are consistent with this formulation. The hexanes-insolubleresidue was extracted with toluene (3 X 30 mL); the toluene solution was filtered through Celite and concentrated to -30 mL and hexanes was added to give the product as colorless crystals, yield 5.8 g (60%). Recrystallization from in the structure solution and refinement. The computer programs CH2ClZand hexanes gave colorless prisms that contain '/2 equiv of employed have been described previo~sly.'~ CH2C12of crystallization (confirmed by 'H NMR); mp 228-230 'C. The coordinatesof the Zr, C1, and P, and Si atom were determined Anal. Calcd for C60,5H73C13N2P4Si4Zr: C, 57.60; H, 5.83; N, 2.22. from the Patterson function and those of the remaining non-hydrogen Found: C, 57.87; H, 5.96; N, 2.26. atoms from a subsequent difference map. Refinement was full-matrix HfC12[N(SiMezCHzPPh2)2]2. The procedure follows that of the where w = least squares, with minimization of Cw(lFol zirconium derivative except that the initial Et20 solution was stirred 1/u2(F). Neutral-atom scattering factors and anomalous dispersion for 4 h at room temperature to give the product in 50% yield. Recorrections (employed for Zr, C1, P, and Si atoms) were taken from crystallization from CH2C12and hexanes gave colorless crystals that ref 15. Refinement of the non-hydrogen atoms with anisotropic contain one CH2C12of crystallization (confirmed by 'H NMR); mp thermal parameters resulted in R = C(IIF,,l-IF,II)/CIFol = 0.052 238-243 OC. Anal. Calcd for C61H&14Hfl\12P.$i4: c , 52.05; H, and R, = [xw(lFol- IFc1)2/~w(F,)2]1/2 = 0.080. A difference map 5.30; N, 1.99; C1, 10.07. Found: C, 51.76; H, 5.33; N, 1.85; C1, 10.03. ZrClJN(Sie2CH2PMe2),h. A solution of L ~ N ( S ~ M Q C H ~ P M ~ ~at)this ~ point revealed 50 of the 56 hydrogen atoms, those not located being associated with C( 11) and C( 12), which, in view of their large (1.04 g, 3.62 mmol) in hexanes (30 mL) was added dropwise to a thermal parameters, are probably disordered. No attempt to resolve cold (-4 "C) suspension of ZrC1, (0.421, 1.81 mmol) in Et20 (50 this rotational disorder about the P(4)-C(4) bond was made, the mL). The reaction mixture was warmed to room temperature and uncoordinated P(4)Mez moiety not being an important part of the stirred for 2.5 h, at which time the E t 2 0 was removed in vacuo. structure; the ordered model was retained. Contributions to the Extraction with hexanes (4 X 20 mL) followed by filtration and structure factors of the 56 H atoms were included in the calculations concentration gave the product as a white solid. Recrystallization with use of 'ideal" positional parameters (C-H = 0.98 A) and isotropic from minimum hexanes gave colorless prisms: yield 0.790 g (60%); thermal parameters (U, = U, + 0.01 1 A2), recalculated after each mp 134-136 OC. Anal. Calcd for C20H56C12N2P4Si4Zr: C, 33.22; cycle of refinement. H, 7.81; N, 3.87. Found: C, 33.67; H, 8.18; N, 3.20. Convergence was reached at R = 0.036 and R, = 0.046 for 4069 HfCldN(SiezCH2PMe2)2]2The compound was prepared by the reflections and 298 variables. The mean error in an observation of exact procedure used for the zirconium analogue: yield 65%; mp unit weight was 1.807 e. The mean and maximum parameter shifts 137-138 OC. Anal. Calcd for C2&6C12Hfl\12P4Si4: c , 29.64; H, on the final cycle of refinement corresponded to 0 . 0 5 ~and 0.85~,the 6.96; N, 3.46. Found: C, 29.90; H, 6.84; N, 3.59. largest shift being associated with the U2,parameter of C(12). A X-ray Crystallographic Analysis of ZrC12[N(Sie2CH2PMe2)21z final differencemap revealed, not unexpectedly, four peaks in the range (4b). A colorless crystal of 4 b was sealed under dry nitrogen in a 0.5-0.75 e A-3 in the vicinity of the P(4)Me2 group, indicating that Lindemann glass capillary tube and mounted on an Enraf-Nonius the ordered model is not ideal but satisfactorily accounts for the CAD4-F diffractometer in a nonspecific orientation. Final unit cell electron density in this region. No other unusual features were noted; parameters were determined by least squares on 2 (sin @)/Avalues the largest residual peaks on the remainder of the difference map were for 25 reflections (with 35 < 28 < 43') measured with Mo K q 0.35 e A-3 near the Zr and C1 atoms. Final positional and equivalent radiation (A = 0.709 30 A). Crystal data and conditions for data collection are summarized in Table I. Of 8615 independent reflections (with 28 I55") measured, 4069 had Z > 3 4 0 and were employed (14) Ball, R.G.;Hames, B. W.;Legzdins, P.; Trotter, J. Inorg. Chem. 1980, 19, 3626. (1 5 ) "International Tables for X-Ray Crystallography"; Kynoch Press: (1 3) ZrCl[N(SiMe2CH*PPh2)2J~ 'H NMR (C,D6, ppm): Si(CH>),,0.02 (s); Birmingham, England, 1974; Vol. IV, pp 99, 149. PCH,Si, 1.27 (br s); P(C&)2, 7.10 (m, meta/para), 7.50 (m. ortho).
Inorganic Chemistry, Vol. 22, No. 6, 1983 865
Phosphine Complexes of Zr(1V) and Hf(1V) Table VI. Bond Lengths (A) with Estimated Standard Deviations in Parentheses atoms length atoms length 2.4585 (11) 2.4613 (12) 2.8028 (12) 2.7936 (13) 2.096 (4) 2.096 (3) 1.811 (5) 1.826 (5) 1.821 (5) 1.839 (5) 1.823 (6) 1.835 (6) 1.809 (5) 1.817 (6) 1.799 (6) 1.849 (5) 1.761 (10)
P(4)-C( 12) Si( 1)-N( 1) Si(l)-C( 1) Si(l)-C(13) Si(1)-C( 14) Si(Z)-N(l) Si(2)-C(2) Si(2)-C( 15) Si(2)-C( 16) Si(3)-N(2) Si(3)-C(3) Si(3)-C( 17) Si(3)
