Organometallics 1995, 14, 5622-5627
5622
Metallotrihydridosilanes of Molybdenum and Tungsten: Synthesis, Characterization, and Vibrational Studies of (C5R5)(0C)2(Me3P)M-SiH3(M = Mo, W; R = H, Me)1’2 Wolfgang Malisch,*$tReiner Lankat,’ Siegfried Schmitzer,?Ralf Pikl,* Uwe Posset,* and Wolfgang Kiefer*>* Institut f u r Anorganische Chemie, Universitat Wiirzburg, Am Hubland, 0-97074Wurzburg, Germany, and Institut fur Physikalische Chemie, Universitat Wurzburg, Marcusstrasse 9-11,0-97070Wurzburg, Germany Received May 23, 1995@ The lithium metalates Li[M(C0)2(PMe3)CsRs](2a-c), prepared from the corresponding metal hydrides CsRs(OC)z(Me3P)M-H [R = H, M = Mo (la),W (lb);R = Me, M = Mo (IC)] with n-butyllithium, react with HSiCl3 ( 5 ) to give C5R5(0C)2(Me3P)M-Si(H)C12 (6a-c). Compound 6b is additionally obtained, starting with the tetramethylphosphonium metalate [Me4P][W(C0)2(PMe3)C5H51(41, generated from l b with the ylide Me3P=CH2 (3). On treatment with LiAlH4, 6a-c undergo smooth CUI3 exchange a t the silicon to afford the metallotrihydridosilanes C5R5(OC)z(Me3P)M-SiH3 (7a-c). The spectroscopic properties of all the compounds have been extensively studied by NMR and IR spectroscopy. In the case of 78-c, detailed studies of the Raman spectra have been performed as well as force field calculations for the M-SiH3 units, yielding valuable information with respect to Si-H and M-Si force constants.
Introduction Metallohydridosilanes bearing a CsRsL,M fragment ( n = 2, M = Fe, Ru; n = 3, M = Mo, W R = H, Me; L = CO, phosphine) offer a variety of interesting reactivities at the functionalized silicon atom due to the activation of the Si-H unit arising from the pronounced electrondonor capacity of the a-bonded transition metal ligand. In this context, interest is focused on the insertion of oxygen into the Si-H bond offering access to preparatively valuable metall~silanols~ and on the substitution of hydrogen by transition metal groups leading to silicon-bridged dinuclear c~mplexes.~ These reactivities should also be valid for SiH3-metal complexes which offer the possibility to repeat these processes to obtain, e.g., metall~silanetriols~ or metal clusters with the silicon surrounded by the maximum of four transition metal g r ~ u p sbut , ~ evidence has been provided only by an extremely limited number of experiments. In addition, it is of interest to perform these reactions stepwise Institut fur Anorganische Chemie. Institut fur Physikalische Chemie. Abstract published in Advance ACS Abstracts, November 1,1995. (1)Synthesis and Reactivity of Silicon Transition Metal Complexes, Part 27: Malisch, W.; Moller, S.; Lankat, R.; Reising, J.; Schmitzer, S.; Fey, 0. In Orgunosilicon Chemistry: From Molecules to Materials; Auner, N., Weis, J., Eds.; VCH: Weinheim, Germany, 1995; p 575. (2) First results concerning this paper were presented at the 10th International Symposium on Organosilicon Chemistry (Poznan, Poland, 1993; Abstracts of Papers, p 80) and at the 10th FECHEM Conference on Organometallic Chemistry (Crete, 1993; Abstract of Papers, p 59). (3) Malisch, W.; Schmitzer, S.; Kaupp, G.; Hindahl, K.; Ktib, H.; Wachtler, U. In Organosilicon Chemistry; Auner, N., Weis, J., Eds.; VCH: Weinheim, Germany, 1994; p 185. Malisch, W.; Grun, K.; Gunzelmann, N.; Moller, S.; Lankat, R.; Reising, J.; Neumayer, M.; Fey, 0. In Stereoselective Reactions of Metal-Activated Molecules: Werner, H., Sundermeyer, J., Eds.; Vieweg: Braunschweig, Germany, 1995; p 183. Adam, W.; Azzena, U.; Prechtl, F.; Hindahl, K.; Malisch, W. Chem. Ber. 1992,125, 1409. (4) Tobita, H.; Kawano, Y.; Shimoi, M.; Ogino, H. Chem. Lett. 1987, 2247. Malisch, W.; Hindahl, K.; Ktib, H.; Reising, J.; Adam, W.; Prechtl, F. Chem. Ber. 1995,128, 963. +
@
to produce multifunctionalized metal-silicon species of the type L,M-SiH,&-, ( n = 1, 2; X = OH, ML,). Moreover, SiH3-metal complexes have gained increasing interest with respect to the generation of thin-film metal silicides by OMCVD.6 For the preparation of metallosilanes L,M-SiHs the literature mainly offers the reaction of transition metal anions with halosilanes H3SiX (X = h a l ~ g e n ) . ~In, ~ practice, this method creates considerable difficulties concerning the preparation and handling of the silicon component. A more efficient and convenient route has recently been established with the hydrogenation of metal-bound chlorosilyl groups by LiAlH4.9 An essential requirement for this procedure is sufficient metalsilicon bond strength t o prevent heterolytic cleavage by the hydride. It is guaranteed by coordination of ligands with a high a-donorlsc-acceptor ratio (e.g., CsMe5 and PMe3) to the transition metal, demonstrated for the first time in connection with the synthesis of CsMes(OC12(Me3P)W-SiH3.9 As this paper shows, this kind of SiH3 group formation is also possible for the corresponding molybdenum compound as well as for species bearing an “ordinary” cyclopentadienyl ligand in combination with trimethylphosphine. In addition, the normal coordinate analysis of the M-SiH3 moiety in these novel silyl complexes has been established to conform the assignments and to clarify the bond properties. (5) Malisch, W.; Wekel, H.-U.; Grob, I. Z.Naturforsch. 1982,37b, 601. Wekel, H.-U.; Malisch, W. J . Organomet. Chem. 1984,264,C10. Gusbeth, P.; Vahrenkamp. H. Chem. Ber. 1985,118, 1143. (6) Suhr, H. Surf. Coat. Technol. 1991,49,233. Maury, F. Adv. Mater. 1991,3, 542. Kodas, T. T.; Hampden-Smith, M. J. In The Chemistry of Metal CVD; VCH: Weinheim, Germany, 1994. (7) Hagen, A. P.; Higgins, C. R.; Russo, P. J. Inorg. Chem. 1971,10, 1657. (8) Aylett, B. J.; Campbell, J. M. J . Chem. Soc., Chem. Commun. 1966,217. (9) Schmitzer, S.; Weis, U.; Kab, H.; Buchner, W.; Malisch, W.; Polzer, T.; Posset, U.; Kiefer, W. Inorg. Chem. 1993,32,303.
0276-733319512314-5622$09.00/0 0 1995 American Chemical Society
Organometallics, Vol. 14, No. 12, 1995 5623
Metallotrihydridosilanes of Molybdenum and Tungsten
Scheme 1 r + Me3P=CH,
(3)
M
-H
+
n-BuLi
-
n-BuH
~-
1 a-c
4
1-
2a-c
7p M
Mo W M o
Scheme 2
2a-c, 4
+ HSiCl3 (5)
+ LIAIH,
6a-c + .M
7a-c
Mo W Mo
Results and Discussion Synthesis of the Silyl-Metal Complexes 6a-c and 7a-c. For the synthesis of the required carbonyl metalates, CO/Me3P exchange in the known anions [C5R5(OC)3Ml- (M = Mo, W; R = H, Me) can be envisaged. However, this reaction is inhibited by the strong coordination of the carbon monoxide 1igandslO that is derived from the anionic charge. A successful approach is offered via the metal hydrides la-c, which are easily deprotonated to the corresponding anions by n-BuLi. The reaction is conducted in petroleum ether a t 0 "C and leads to the formation of a precipitate of the lithium metalates 2a-c (Scheme 1). Compounds 2a-c are highly pyrophoric beige to yellow powders, which could not be characterized analytically. Spectroscopic data are available due to a reasonable solubility in THF. The anionic character of the transition metal fragment is indicated by extremely low values of the v(CO),, and the v(CO), absorptions in the infrared as well as the low 2J(PCH) coupling in the IH NMR spectra. According to our experience in metalate chemistry,ll exchange of Lif by an [R4Pl+ group significantly increases the solubility of the metalate, a property which is of importance in context with the generation of donor/solvent-labile main group element-transition metal bonds. Simple access to phosphonium metalates is offered by the interaction of a phosphorous ylide with metal hydrides, a process that in the case of highly nucleophilic metalates can create difficulties due to the abstraction of an organic group from the phosphonium unit.ll As the synthesis of 4 demonstrates, the metal hydride l b is cleanly deprotonated by Me3P=CH2 (3)in benzene a t ambient temperature (Scheme 1). The phosphonium metalate 4 spontaneously precipitates and can be directly isolated in the pure state by simple filtration. (10)Malisch, W. Unpublished results. (11)Malisch, W. Angew. Chem. 1973,85, 228;Angew. Chem., Znt. Ed. Engl. 1973, 12, 235. Angerer, W.; Fiederling, N.; Grotsch, G.; Malisch, W. Chem. Ber. 1983,116, 3947.
The reaction of the lithiudtetramethylphosphonium metalates 2a-c and 4 with HSiC13 (5) in cyclohexane results in the formation of the dichlorosilyl metal complexes 6a-c in yields of 60%-90%. Due to the good solubility of 4, the metalation process is complete within less than 1min compared t o 40 h in the case of 2a-c. Compounds 6a-c were obtained as pale yellow crystalline powders, showing high thermal stability and resistance toward air. Metal-silicon bond stabilization by the cyclopentadienyl and the phosphine ligand proves to be high enough to guarantee total CVH exchange at the metalcoordinated SiHC12 group of 6a-c. Thus, treatment with L N H 4 in a mixture of toluene/diethyl ether at -78 "C gives access to the metallotrihydrosilanes 7a-c after an additional period of stirring (4h) at ambient temperature (Scheme 2). Compounds 7a-c, obtained in 74%-80% yield, are yellow solids, which are soluble in aromatic solvents. Increasing stability in solution is found in the order 7a < 7b < 7c, which is in accordance with the increase of the donor character of the metal fragment. Storage of 7a-c under nitrogen at -20 "C is recommended. Under these conditions 7a-c show no decomposition even after a period of months. The resistance to light exposure is high and enables laser spectroscopic investigations. Spectroscopic Characterization of the Silyl Metal Complexes 6a-c and 7a-c. NMR Spectra. The NMR, IR, and Raman spectra of the silyl complexes 6a-c and 7a-c [for comparison, the data of the formerly described complex C5Me5(0C)2(Me3P)W-SiH39 (7d)are included in the following discussion112guaran(12)NMR data of C S M ~ ~ ( ~ C ) ~ ( M ~ ~ P (7d): ) W -'HS NMR ~ H ~ (200 MHz, ds-benzene): 6 1.24 [d, WPCH) = 9.0 Hz, 9 H, (H3C)3Pl, 1.72 [d, 4J(PWCCH) = 0.5 Hz, 15 H, C&H3)61, 4.26 ppm [d, 3J(PWSiH) = 0.4 Hz, 'J(SiH) = 180.2 Hz, 3 H, SiHJ 13C NMR (50 MHz, dsbenzene): 6 10.66 [s, CS(m3)61r20.13 [d, 'J(PC) = 33.2 Hz, (H3ChP1, 100.00 [s, C5(CH&,], 227.34 ppm [d, 2J(PWC) = 18.1Hz, 'J(Wc) = 150.1Hz, CO]. 3lP NMR (36 MHz, de-benzene): 6 -13.92 ppm [s, WWP) = 278.3 Hz]. 29SiN M R (18MHz, &-benzene): 6 -43.18 ppm [d, WPWSi) = 13.2 Hz, lJ(WSi) = 49.8Hzl.
5624 Organometallics, Vol. 14, No. 12, 1995
Malisch et al.
Table 1. Selected Raman Frequencies and IR Absorptions (in Parentheses) in cm-l, and Force Constants flM-Si) and f(Si-H) in N cm-l of 7a-da
2102 s t (2102 W)b 2082 s t (2075 m)b 1916 m (1910 s)b 1842 m (1842 V S ) ~ 1110 vs, p 732 w 677 st, p 481 sh 463 vs, p 344 m, p 314 vs, p
2102 m (2080 w, sh)b 2074 sh (2068 m)b 1909 m (1915 stJb 1835 m (1833 v d b 1109 vs, p 7341727 w 677 st, p 498 w 479 vs, p 357 m 315 st, p
2089 m, p (2090 wF 2075 m (2075 w)c 1904 m (1915 s t y 1830 m (1842 vsy 592 st, p n.0. n.0. 480 m 454 vs n.0. 335 st, p
2083 st (2075 w ) ~ 2063 s h (2065 m y 1892 m (1903 1814 m (1832 vs)d 593 st, p 727 m 675 st, p 503 m 473 vs, p 359 m 326 st, p
1.433 2.461
1.640 2.470
1.641 2.448
1.778 2.432
a Abbreviations: vs, very strong; st, strong; m, medium; w, weak; sh, shoulder; p, polarized; s, symmetric; as, antisymmetric; d, degenerate; n.o., not observed. Benzene solvent. Pentane solvent. Cyclohexane solvent.
tee unequivocal determination of the stereochemistry at the pseudotetragonal-monopyramidal-coordinated metal center. In all cases the trans-position of the Me3P and the silyl unit is deduced from the appearance of one CO resonance, showing the typical value of 20-30 Hz for the 2J(PMC) coupling to the cis-positioned Me3P ligand. Moreover, the coupling constant lJ(lS3W31P)of 244-278 Hz is characteristic for trans-configurated tungsten complexes C5Rs(OC)2(Me3P)WX(X as a-bonded ligand).13 Consistent with the higher electron-withdrawing character of the dichlorosilyl compared to the trihydridosilyl ligand, the coupling is reduced by ca. 33 Hz on going from 6b to 7b,which is indicative of a decrease of the s-electron density in the P-M bond. For the 31P NMR shift of the Me3P ligand a significant dependence on the metal is observed, with the tungsten species appearing more than 30 ppm upfield from the molybdenum compounds, while the substituents a t the silyl ligand show a minor effect (ca. 1-3 ppm). In connection with the 29SiNMR chemical shifts the following features are notable, which resembles observations made by Berry for the Cp2M(H)(SiR3)(M = Mo, W) systems.14 (1)The metallodichlorosilanes 6a-c and the tungsten compound described above, C5Me5(OC)2(7d),generally show low-field reso(Me~P)w-SiHc12~ nances (60.87-83.81ppm), implying a strong downfield shift by the transition metal fragment [HzSiClz: d(Si) -11.03 ppm1.l5 (2)The metallotrihydridosilanes afford resonances in the negative 8-region 1-30.13 (7c) to -56.87 ppm (7b)l, but a significant transition metal effect is still operating (SiH4: 8 -93.10 ppm).15 It is reduced in comparison to 6a-c. (3)Changing the metal from molybdenum to tungsten effects an upfield shift of about 14 ppm. Introduction of the CsMes ligand instead of a Cp group produces an effect of a similar magnitude but in the opposite direction. (4) The coupling constant 1J(183w29Si) in the 29SiNMR spectra is nearly doubled going from the SiH3 to the SiHC12 species (7b,d, 44.0/49.8Hz; 6b, 82 Hz). C5HdC5Me5 exchange produces an increase of 6 Hz. Due t o the higher electron density caused by electropositive ligands on the metal center or/and on the silicon, the metallo(13)Keiter, R. L.; Verkade, J. G. Inorg. Chem. 1969, 10, 2115. Nixon, J. F.; Pidcock, A. Annu. Reu. NMR Spectrosc. 1969,2, 345. (14)Koloski, T. 5.; Pestana, D. C.; Carroll, P. J.; Berry, D. H. Organometallics 1994, 13, 489. (15) Marsmann, H. 29Si-NMR-Spectroscopic Results. In NMR Basic Principles and Progress; Springer: Berlin 1981; Vol. 17,p 65.
trihydridosilanes 7 exhibit lower 2J(PMSi)values than the metallochlorosilanes 6 (AJ= 2.4-6.2 Hz). Especially useful for the estimation of the electronic properties of the silicon and its ligand sphere is the WSiH) coupling constant, which reflects the s-electron density in the Si-H bond.15 In accordance with Bent's d e l 6the lH NMR spectra reveal a significant decrease of lJ(SiH) when chlorine is substituted by hydrogen [cf.: 6a, lJ(SiH) = 244.9 Hz; 7a, lJ(SiH) = 183.7Hzl. The influence of the metal fragment is less significant, resulting in a variation in lJ(SiH) from 245 to 237 Hz (6a-c) and from 183.7 to 180.2 (7a-d), respectively, which indicates only a small decrease with respect t o metal fragment donor capacity increasing in the series CsHdOC)z(Me3P)Mo .c CsHdOC)z(Me3P)W < CsMes(OCMMe3P)Mo < CsMe5(OC)z(Me3P)W. Vibrational Spectra. The vibrational spectra of some silyl tungsten complexes of the type CsMes(0C)z(Me3P)W-SiR3 (R = H, C1, Me) have already been r e p ~ r t e d .Due ~ to the close similarity to the species presented here, the main features of the vibrational analysis and assignments can be adopted. Therefore, only the most important spectral features are discussed. Spectral data and selected force constants are compiled in Table 1. Both Raman and IR spectra show the expected two (CO)modes of symmetry species A1 B2 (assuming local CzUsymmetry for the M(COI2 oscillators) arising around 1910 (symmetric; IR, s; Raman, m, p) and 1835 cm-l (antisymmetric; IR, vs; Raman, m, dp). The higher electron-releasing character of the CsMe5 ligand compared to C5H5 finds its expression only in the frequency of the v(CO)A1vibration, which is located 5 cm-l higher for the Cp derivatives (7a,b). The v(CO)B2 band remains essentially fmed on going from C5H5 to C5Me5. SiH3 stretching gives rise to two bands of symmetry species A1 E (assuming local 123" symmetry) in the 2100 cm-' spectral region. Whereas IR absorptions are frequently weak, strong features are observed in the Raman spectra. Both the A1 and the E modes are usually superimposed and appear as one strong, broad band which could be deconvoluted by curve-fitting procedures and resolved experimentally in the solid state spectra (Figure 1). Polarization data clearly
+
+
(16)Bent, H. A. Chem. Rev. 1961, 61, 275.
Organometallics, Vol. 14,No. 12, 1995 5625
Metallotrihydridosilanes of Molybdenum a n d Tungsten SiH(sym) SiH(deg)
in benzene
curvefit deconvolution
2100
2000
t-Wovenumbers
1900
1800
[cm-']
250
350
450
t-Wovenumbers
[cm-'
]
Figure 1. Raman spectra of Cp(OC)dMesP)Mo-SiHs (7a)in the v(CO)/v(SiH) and metal-ligand region. Upper trace: in benzene, spectral resolution s = 5 cm-l, temperature T = 300 K. Lower trace: polycrystalline, s = 1 cm-l, T = 20 K. suggest the higher frequency band to be due t o symmetric SiH3 stretching. From force field calculation^^^ the Si-H force constants a r e determined between 2.432
(7d) and 2.470 N cm-l (7b)and hence arise within a narrow range. The force constants correlate well with the lJ(SiH) values of 182.2 (7b)and 180.2 Hz (7d)found in the lH NMR spectra, indicating less Si-H bond strength of 7d (Table 1). A vibration of great interest in silyl complexes is the metal-silicon stretching mode that gives rise t o an intense polarized Raman band in the 300 cm-l region, as previously reported9J8 (see Figure 1). A special feature of this mode is t h e insensitivity of its frequency toward exchange of the metal. This is clearly demonstrated by comparing the v(MSi) frequencies for t h e homologues 7a (314 cm-l) and 7b (315 cm-l) that definitely show no mass effect. On the other hand, on replacing C5Hb with CsMes, one observes a shift of about 20 cm-l to higher wavenumbers, reflecting the increased electron density at the metal. With regard to bond cleavage processes, the strength of the metal-silicon bond is of special Interest. The calculation of M-Si force constants uia a normal coordinate analysis provides a measure for the M-Si bond strengths that can easily be obtained. The results are listed in Table 1. The M-Si force constants increase in the order 7a -= 7b % 7c < 7d. This result is in perfect agreement with the observation that the C5Me5 tungsten complex 7d shows reasonable ~ t a b i l i t ywhereas ,~ the C5Hs molybdenum derivative 7a decomposes in solution and under photolysis with M-Si bond cleavage.
Experimental Section 'H, 13C,31P,and 29SiNMR spectra were obtained on Varian T60, Jeol FX 90 Q, and Bruker AMX 400 spectrometers. 6(31P)/6(29Si) chemical shifts are measured relative to external H3P04(85%)/Si(CH&. 6(lH)/P3C)are reported downfield from Me4Si referenced to the residual proton signal ('H) or natural abundant carbon signal of CD3CN and CsDs. Infrared spectra (17) Pikl, R.; Posset, U.; Moller, S.; Lankat, R.; Malisch, W.; Kiefer, W. Vibr. Spectrosc., in press. (18)Van der Berg, G. C.; Oskam, A. J. J. Organomet. Chem. 1976, 91, 1.
were recorded on a Perkin-Elmer 283 grating spectrometer. The solutions were measured in NaCl cells with 0.1 mm path length with a resolution of about 2 cm-l. Melting points were measured on a Cu block (closed capillary, not corrected). Mass spectra were recorded at 70 eV on a Varian MAT-SM-CH7 mass spectrometer. Elemental analyses were performed in the microanalytical laboratory of the Institut fur Anorganische Chemie der Universitat Wurzburg. Raman spectra were excited with the 647.1 nm line of a krypton ion laser (Spectra Physics model 2025). Spectra were taken from benzene solutions in NMR tubes filled under a dry argon atmosphere. The scattered light was dispersed by means of a Spex model 1404 double monochromator and detected with a CCD (chargecoupled device) camera system (Photometrics model RDS 2000).19 The spectra have been evaluated and fitted with standard software. The spectral resolution was 5 cm-l. Plasma lines from the laser tubes were filtered out by means of a modified Anaspec prism filter. The force field calculations were carried out on personal computers and SUN workstations with the program packages QCMP-067 (modified version)20 and VIA.21 Literature procedures were employed to synthesize M~SP=CH and ~ ~C5R5(0C)2(Me3P)M-H ~ (R = H, Me; M = Mo, W).23 HSiC13, n-BuLi, and LiAlH4 were obtained commercially. All operations were conducted under an atmosphere of purified nitrogen. 1. Lithium [Dicarbonyl(~6-cyclopentadienyl)(trimethylphosphine)molybdenum(0)1 (2a). A solution of 2.56 g O - Hin 40 mL of (8.70 mmol) of C ~ H S ( O C ) ~ ( M ~ ~ P ) M(la) petroleum ether is cooled to 0 "C. A 4.0 mL (10.0 mmol) amount of a 2.5 M solution of n-BuLi in n-hexane is added via syringe, causing the immediate precipitation of 2a,which is filtered off, washed with petroleum ether until the filtrate is colorless, and dried in vacuo. Yield: 2.43 g (93%), beige pyrophoric powder. 'H NMR (400 MHz, ds-THF): 6 1.32 Id, 2J(PCH)= 7.2 Hz, 9 H, (H3C)3Pl,4.79 ppm (5, 5 H, C5H5). 13C NMR (101 MHz, ds-THF): 6 26.50 [d, 'J(PC) = 21.2 Hz, (H3C)3P],84.92 (s, C5H5), 243.45 ppm [d, 2J(PMoC)= 14.1 Hz, CO]. 31PNMR (162 MHz, ds-THF): 6 28.04 ppm. IR (THF): v(C0) = 1786 (vs), 1646 (vs) cm-l. ~~~
~
(19) Deckert, V.; Kiefer, W. Appl. Spectrosc. 1992, 46, 322. (20) McIntosh, D. F.; Peterson, M. R. QCPE 1991,342. (21) Fleischhauer, H. C. Ph.D. Thesis, University of Dusseldorf, Dusseldorf, Germany, 1991. (22) Schmidbauer, H.; Tronich, W. Chem. Ber. 1968,101, 595. (23)Alt, H. G.; Englehardt, H. E.; Klaeui, W.; Muller, A. J . Orgunomet. Chem. 1987,331,317. Bainbridge, A.; Craig, R. J.; Green, M. J. Chem. Soc. A 1968, 2715. Kalck, P.;Pince, R.; Poilblanc, R.; Roussel, J. J.Organomet. Chem. 1970, 24, 445.
5626 Organometallics, Vol. 14, No. 12, 1995 2. Lithium [Dicarbonyl(qs-cyclopentadienyl)(trimethylphosphine)tungsten(O)] (2b). According to the procedure above for 2a,2b is obtained from 5.26 g (13.8 mmol) of C5H5(OC)2(Me3P)W-H (lb)dissolved in 100 mL of petroleum ether and 6.6 mL (16.5 mmol) of a 2.5 M solution of n-BuLi in n-hexane. Yield: 5.09 g (95%), beige pyrophoric powder. 'H NMR (400 MHz, de-THF): 6 1.48 [d, 2J(PCH)= 7.8 Hz, 9 H, (H&)3P], 4.78 ppm (s, 5 H, C5H5). NMR (101 MHz, daTHF): 6 27.69 [d, 'J(PC) = 26.7 Hz, (H3C)3Pl, 82.91 (s,C5H5), 236.63 ppm [d, 2J(PWC) = 5.7 Hz, 'J(WC) = 209.3 Hz, CO]. 31PNMR (162 MHz, da-THF): 6 -12.92 ppm [s, 'J(WP) = 462.9 Hz]. IR (THF): v(C0) = 1782 (vs), 1649 (vs) cm-'. 3. Lithium [Dicarbonyl(qS-pentamethylcyclopentadienyl)(trimethylphosphine)molybdenum(O)](24. According to the procedure above for 2a,2c is obtained from 3.98 g ) Mdissolved O-H in 100 (10.9 mmol) of C ~ M ~ ~ ( O C ) ~ ( M ~ ~ P(IC) mL of petroleum ether and 5.2 mL (13.0 mmol) of a 2.5 M solution of n-BuLi in n-hexane. Yield: 3.85 g (95%), yellow pyrophoric powder. 'H NMR (400 MHz, da-THF): 6 1.27 [d, 2J(PCH)= 6.6 Hz, 9 H, (H&)3P], 1.98 ppm [s, 15 H, C5(CH3)51. NMR (101 MHz, de-THF): 6 12.80 [s, C5(CH3)5], 24.49 [d, WPC) = 20.0 Hz, (H3C)3P], 98.42 [s, C5(CH3)51, 246.62 ppm [d, 'J(PM0C) = 12.8 Hz, CO]. 31PNMR (162 MHz, da-THF): 6 23.15 ppm. IR (THF): v(C0) = 1770 (vs), 1638 (vs) cm-l. 4. Tetramethylphosphonium [(Dicarbonyl)(qs-cyclopentadienyl)(trimethylphosphine)tungsten(O)l(4). To a solution of 578 mg (1.51 mmol) of Cp(OC)z(Me3P)W-H (lb) in 40 mL of benzene is added 136 mg (1.51 mmol) of Me3P=CH2 (3)dissolved in 5 mL of diethyl ether dropwise under vigorous stirring at room temperature within 45 min. The precipitate of 4 that forms is immediately filtered off, washed twice with 20 mL of benzene and 20 mL of pentane, and dried in vacuo. Yield: 663 mg (93%), yellow solid. Mp: 174 "C. 'H NMR (60 MHz, &-acetonitrile): 6 1.55 [d, 2J(PCH) = 7.0 Hz, 9 H, (HsC)3P], 1.83 [d, 2J(PCH) = 15.0 Hz, 12 H, (H&)dP+], 4.80 ppm (bs, 5 H, C5H5). 31PNMR (162 MHz, &-acetonitrile): 6 -15.52 [s, 'J(PW) = 463 Hz, (H3C)3Pl,22.42 ppm [s, (H3C)4P+]. IR (acetonitrile): v(C0) = 1762 (vs), 1681 (vs) cm-'. Anal. Calcd for C1&602P2W (472.2): C, 35.61; H, 5.55. Found: C, 37.42; H, 5.74. 5. Dicarbonyl(dichlorosilyl)(q5-cyclopentadieny1)(trimethylphosphine)molybdenum(II) (6a). A suspension of 2.43 g (8.103 mmol) of 2a in 60 mL of cyclohexane is combined with 3.28 g (24.3 mmol) of HSiC13 (5). Immediately after the addition, the reaction mixture becomes dark brown. After the mixture has been stirred for 40 h, all volatile materials are removed in vacuo, the residue is extracted with 30 mL of toluene, and the extract is filtered over Celite. Solvent is removed in vacuo, and the residue of 6a is washed at -30 "C with 20 mL of pentane to separate oily side products. Yield: 2.39 g (75%), golden yellow crystals. Mp: 143 "C. 'H NMR (60 MHz, ds-benzene): 6 1.00 [d, 2J(PCH)= 10.0 Hz, 9 H, (H3C)3Pl, 4.77 [d, 3J(PM~CH)= 1.0 Hz, 5 H, C5H51, 7.57 ppm [d, 3J(PMoSiH) = 0.3 Hz, 'J(SiH) = 244.9 Hz, 1 H, SiHC121. 13CNMR (101 MHz, &-benzene): 6 20.89 [d, 'J(PC) = 31.8 Hz, (H3C)3PI191.65 (s, C5H5), 230.31 ppm [d, 2J(PMoC) = 25.2 Hz, CO]. 31PNMR (162 MHz, &-benzene): 6 18.22 ppm. 29Si NMR (79 MHz, &-benzene): 6 78.86 ppm [d, 2J(PMoSi)= 21.9 Hzl. IR (benzene): v(SiH) = 2134 (w) cm-I; v(C0) = 1936 (s), 1869 (vs) cm-'. M S (28Si,35C1,98Mo,70 eV, 30 "C): mle = 394 [2, (MI+], 366 [4, (M - CO)'], 338 [8, (M 2CO)+], 296 [49, ( C ~ H ~ ( O C ) ~ ( M ~ ~ P ) M (CbH5(0C)(Me3P)OH)+, MoSiH)+l,274 [60, ( C ~ H ~ ( M ~ ~ P ) M O266 C ~[60, ) + ] (CsH5(OC)2, (Me3P)MoH)+, (C5H5(OC)(MeP)MoSiH)+], 236 [ 100, (C5H5(OC)MoSiHzMe)+],220 [56, (C~H~(OC)ZMOH)+, (C5H5(OC)MoSiH)+l,207 [59, (C5H5(0C)MoHMe)+,(C5H&foSiHMe)+l, 198 [82, (C5H5MoCl)+l, 163 [35, (CsHsMo)+], 118 [8, (C~H~(OC)MOS~H~M 110 ~ )[7, ~ ' I( ,C ~ H ~ ( O C ) ~ M O H 81.5 ) ~ +[4, ], ( C ~ H ~ M O ) ~Anal. + I . Calcd for CloHl&lzMoO2PSi (393.1): C, 30.55; H, 3.85; C1, 18.04. Found: C, 30.21; H, 3.81; C1, 17.83. 6. Dicarbonyl(dichlorosilyl)(q6-cyclopentadienyl)(trimethylphosphine)tungsten(II) (6b). (a) Metalation of
Malisch et al.
HSiCls (5)with [Me4Pl[W(CO)z(PMes)Cp] (4). To a suspension of 390 mg (0.83 mmol) of 4 in 25 mL of benzene is added 279 mg (2.06 mmol) of HSiC13 (5) in 5 mL of benzene dropwise under vigorous stirring within 30 s at room temperature. Subsequently [Me4PlC1(65 mg, 93%)is separated, and the filtrate is evaporated to dryness. The residue is dissolved in 5 mL of pentane, and 6b crystallizes on cooling to -78 "C. Yield: 359 mg (go%),yellow crystalline powder. Mp: 137 "C. (b) Metalation of HSiC13 (5)with Li[W(CO)n(PMes)Cpl (2b). According to section 5 above, 6b is obtained from 563 mg (1.60 mmol) of Li[W(CO)z(PMe3)Cp](2b)and 0.30 mL (0.30 mmol) of HSiC13 (5) in 20 mL of cyclohexane. Yield: 515 mg (67%). 'H NMR (60 MHz, &-benzene): 6 1.15 [d, 2J(PCH)= 9.4 Hz, 9 H, (H3C)3Pl,4.82 [d, 3J(PWCH)= 1.3 Hz, 5 H, C5H51, 7.94 ppm [d, 3J(PWSiH) = 0.3 Hz, 'J(SiH) = 248.1 Hz, 1 H, SiHC121. I3C NMR (101 MHz, ds-benzene): 6 20.68 [d, IJ(PC) = 35.5 Hz, (H3C)3Pl, 89.94 (9, C5H5), 222.30 ppm [d, 2J(PWC) = 20.1 Hz, 'J(WC) = 134.4 Hz, CO]. 31P NMR (162 MHz, &-benzene): 6 -18.30 ppm ['J(PW) = 244 Hz]. 29SiNMR (79 MHz, &-benzene): 6 52.58 ppm [d, 2J(PWSi) = 21.3 Hz, 'J(WSi) = 82 Hzl. IR (cyclohexane): v(SiH) = 2137 (w) cm-'; v(C0) = 1942 (SI, 1863 (m) (cis);1935 (m), 1855 (vs) (trans) cm-'. MS (28Si,35Cl,la4W,70 eV, 70 "C): mle = 480 [2, (MI+], 452 [3, (M - CO)+l, 422 13, (C5H5(0C)(MeP)WSiC12H)+l,382 [52, (C~H~(OC)Z(M~~P)WH)+I, 352 [59, (C5HdOC)dMeP)WH)+I, 322 [loo, (C5H5(0C)WSiMeH2)+],306 [50, (C5H5(0C)2WH)+, (C5H5(0C)WSiH)+l, 292 [31, (C5H5(OC)zWMe)+], 277 [13, (CsHb(OC)WH)+,(C5H5WSi)+l,160 [12, (C5H5(OC)2WSiMe)2+l, 153 [13, (C5H5(OC)WSiH)2+,(C5H5(OC)2WH)2+l.Anal. Calcd for CloH15C12P02SiW (481.1): C, 24.97; H, 3.14; C1, 14.74. Found: C, 24.49; H, 3.18; C1, 14.39. 7. Dicarbonyl(dichlorosilyl)(q6-pentamethylcyclopentadienyl)(trimethylphosphine)molybdenum(II)(6c). According to the procedure above for 6a,6c is obtained from 1.20 g (3.24 mmol) of Li[Mo(CO)z(PMe3)C5Me5](2c)and 805 mg (5.94 mmol) of HSiC13 (5) in 50 mL of cyclohexane. Yield: 839 mg (56), beige crystalline powder. Mp: 86 "C. 'H NMR (400 MHz, &-benzene): 6 1.05 [d, %7(PCH) = 8.9 Hz, 9 H, (H3C)3P], 1.62 [s, 15 H, C5(CH3)5], 7.20 ppm [d, 3J(PMoSiH) = 2.0 Hz, NMR (101 MHz, d6lJ(SiH) = 236.9 Hz, 1 H, SiHC121. benzene): 6 10.87 [s, C5(CH3)5I119.23 [d, 'J(PC) = 30.7 Hz, (H3C)3PIr103.15 [s, C5(CH3)51,236.11ppm [d, 2J(PMoC)= 29.1 Hz, CO]. 31PNMR (162 MHz, &-benzene): 6 19.06 ppm. 29Si NMR (79 MHz, &-benzene): 6 83.81 ppm [d, 2J(PMoSi)= 15.7 Hz]. IR (toluene): v(SiH) = 2093 (w) cm-'; v(C0) = 1930 (s), 1855 (vs) cm-'. Anal. Calcd for C15H25Cl2MoOzPSi (463.3): C, 38.89; H, 5.44; Found: C, 37.33; H, 6.06. 8. Dicarbonyl(q5-cyclopentadienyl)(trimethylphosphine)(silyl)molybdenum(II) (7a). To a solution of 354 mg (0.90 mmol) of Cp(OC)z(MesP)Mo-SiHClz (6a)in 20 mL of diethyl etherltoluene (4:l) is added 105 mg (2.76 mmol) of LiAlH4 at -78 "C. After being stirred for 2 h at this temperature, the mixture is warmed up to room temperature and stirred for another 4 h. Volatile materials are removed in vacuo, and the remaining residue is repeatedly extracted with 20 mL of benzene. After filtration over Celite, the solvent is evaporated and the residual 6a washed at -78 "C with 20 mL of pentane. Yield: 225 mg (77%), pale yellow solid. Mp: 148 "C. 'H NMR (60 MHz, ds-benzene): 6 1.07 [d, 2J(PCH)= 9.0 Hz, 9 H, (H3C)3Pl, 4.50 [d, 3J(PMoSiH) = 0.4 Hz, 'J(SiH) = 183.7 Hz, 3 H, SiH31, 4.64 ppm [d, 3J(PMoCH) = 1.0 Hz, 5 H, C5H51. I3C NMR (101 MHz, ds-benzene): d 21.20 [d, 'J(PC) = 30.4 Hz, (H3C)3Pl, 89.47 (9, C5H5), 230.42 ppm [d, 2J(PMoC) = 24.1 Hz, CO]. 31PNMR (162 MHz, &-benzene): 6 16.21 ppm. 29Si NMR (79 MHz, &-benzene): 6 -42.65 ppm [d, 2J(PMoSi)= 15.9 Hz]. MS (28Si,98Mo, 70 eV, 35 "C): mle = 326 [21%, (MI+], 311 [12, (CsHs(OC)z(MezP)MoH)+,295 [31, (C~H~(OC)~(M~~P)M 281 O ) [21, + I , (C5HdOC)dMe2P)MoH)+, (CsH5(OC)(MezP)MoSiH)+], 252 [21, (C5Hs(OC)(MezP)Mo)+, (C5H5(MezP)MoSi)+],235 [15, (C5H5(OC)MoMeSiH)+l,220 [ll, (C~H~(OC)~MOH)+], 191 [18, (CsH5(OC)Mo)+,(C6H5MoSi)+l,163 [32, (C5HsMo)+],61 [loo, (MezP)+]. Anal. Calcd for C10H17-
Metallotrihydridosilanes of Molybdenum and Tungsten MoOzPSi (324.3): C, 37.04; H, 5.28; Mo, 29.60. Found: C, 36.29; H, 4.91; Mo, 28.42. 9. Dicarbonyl(qs-cyclopentadienyl)(trimethylphosphine)(silyl)tungsten(II) (7b). According t o the procedure above for 7a,7b is obtained from 478 mg (0.99 mmol) of Cp(OC)2(Me3P)W-SiHC12 (6b)and 132 mg (3.48 mmol) of LiAlH4 in 20 mL of diethyl etherkoluene (4:l). Yield: 325 mg (80%), pale yellow solid. Mp: 162 "C. 'H NMR (60 MHz, d6benzene): 6 1.05 [d, 2J(PCH)= 9.4 Hz, 9 H, (H3C)3PI14.48 [d, V(PWCH) = 1.1Hz, 5 H, C5H51,4.52 ppm [s, WSiH) = 182.8 Hz, 3 H, SiH31. I3C NMR (101 MHz, &-benzene): 6 21.53 [d, V(PC) = 34.8 Hz, (H3C)3P], 87.72 (s, C5H5), 221.59 ppm [d, 2J(PWC)= 18.1 Hz, 'J(WC) = 151.8 Hz, CO]. 31PNMR (162 MHz, &-benzene): 6 -16.75 ppm ['J(WP) = 277 Hzl. 29Si NMR (79 MHz, &-benzene): 6 -56.87 ppm [d, 2J(PWSi)= 15.1 , Hz, 'J(WSi) = 44.0 Hz]. MS (28Si,184W,70 eV, 60 "C): mle = 412 [30, (MI+], 381 [47, (M - SiH3)+],351 [60, (C~KS(OC)~(MeP)W)+, (C5H5(0C)(MeP)WSi)+l, 322 [60, C5H5(0C)WMeSiH2)+], 334 [18, (C5H5(0C)2WSiH3)+],320 [60, (C5H5(OC)WSiMe)+,(C5Hs(OC)zWMe)+],306 [33, (C&(OC)WSiH)+, (C5HdOC)zWH)+I,305 [32, (C5HdOC)zW)+,(C5HdOC)WSi)+I, 292 (17, (CbHbWSiMe)+, (C5Hs(OC)WMe)+],277 [9, (C5H5WSi)+,(C5Hs(OC)W)+l,191 [3, (C5H5(OC)2(Me3P)WH)2+l, 160 [8, C5H5(OC)2WMe)2+],153 [ 8 , (C5H5(OC)2WH)2+l,61 [loo, (MezP)+l. Anal. Calcd for C10H1702PSiW (412.2): C, 29.14; H, 4.16; W, 44.61. Found: C, 29.07; H, 4.11; W, 43.82.
Organometallics, Vol. 14, No. 12, 1995 5627 10. Dicarbonyl(q6-pentamethylcyclopentadienyl)(trimethylphosphine)(silyl)molybdenum(II)(7c). According to the procedure above for 7a,7c is obtained from 565 mg (1.22 mmol) of C ~ M ~ ~ ( O C ) ~ ( M ~ ~ P ) M(6c) O - and S ~ H125 C ~mg ~ (3.29 mmol) of LiAlH4 in 50 mL of diethyl ethedtoluene (4:l). Yield: 354 mg (74%),yellow solid. Mp: 54 "C. 'H NMR (400 MHz, &-benzene): 6 1.12 [d, 2J(PCH)= 8.6 Hz, 9 H, (H3C)3Pl, 1.66 [s, 15 H, C5(CH3)51,4.19 ppm Is, 'J(SiH) = 180.9 Hz, 3 H, SiH31. I3C NMR (101 MHz, &-benzene): 6 10.60 [s, C5(CH3)51, 19.78 [d, 'J(PC) = 29.4 Hz, (H3C)3Pl, 101.25 [s, C5(CH3)51, 234.58 ppm [d, 2J(PMoC)= 26.6 Hz, CO]. 31PNMR (162 MHz, ds-benzene): 6 22.22 ppm. 29SiNMR (18 MHz, &-benzene): 6 -30.13 ppm [d, 2J(PMoSi) = 13.3 Hzl. Anal. Calcd for C15H27Mo02PSi (394.4): C, 45.68; H, 6.90. Found: C, 45.57; H, 7.27.
Acknowledgment. We gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 347, "Selektive Reaktionen Metall-aktivierter Molekule", Projects B-2 and C-2) as well as from the Fonds der Chemischen Industrie. We also thank R. Schedl, U. Neumann, and C. P. Kneis for the elemental analyses and Dr. W. Buchner and M. L. Schkifer for recording part of the NMR-spectra. OM950380A
