ZrC12{p- [ ( yS-C5H4)SiMe2OSiMe2(y5-C~H4)1} - American

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Organometallics 1995, 14, 177-185

177

New Silyl-SubstitutedCyclopentadienyl Titanium and Zirconium Complexes. X-ray Molecular Structures of [TiC12{p (OSiMe2-y5-C5H4)}12 and [ZrC12{p-[(yS-C5H4)SiMe2OSiMe2(y5-C~H4)1} I

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Santiago Ciruelos, Tomas Cuenca, Pilar Gbmez-Sal,?Antonio Manzanero,? and Pascual Royo* Departamento de Quimica Inorganica, Universidad de Alcala, Campus Universitario, 28871 Alcala de Henares, Spain Received July 28, 1994@ We report the synthesis of 1-(chlorodimethylsily1)-1-(trimethylsilyl)cyclopentadiene,1. The reaction of a toluene solution of 1 with one equivalent of M C 4 (M = Ti, Zr) leads to the mono(cyclopentadieny1) derivatives [MC13(q5-C5H4SiMe2Cl)l[M = Ti (2); M = Zr (311 in 76 and 87% yields, respectively. The same reaction with ZrCl4 in a Zr/Cp molar ratio 1:2 in refluxing methylene dichloride yields the dicyclopentadienylderivative [ZrC12(q5-C5H4SiMe2Cl)zl, 4, whereas the related titanium compound cannot be synthesized by this method. These mono- and bis(cyclopentadieny1)complexes are very moisture sensitive and react with water to give different oxo complexes. Reaction of one equivalent of water with [TiC13(q5-C5H4SiMezCl)] in toluene takes place with elimination of HC1, resulting in formation of the dinuclear titanium methylsiloxane derivative [TiC12Cu-(OSiMe2-q5-C5H4)}12, 5, in a quantitative yield, which by further addition of one equivalent of water gives the mononuclear compound [TiC12{OSiMe20SiMe2(q5-C5H4)}l, 6, in very low yield. However the best procedure to obtain 6 (in 45%yield) is the direct reaction of [TiC13(q5-C5H4SiMe2Cl)lwith two equivalents of water. The analogous reaction of [ZrC12(q5-C5H4SiMe2Cl)21with one equivalent of water 7. Alkylation of [TiC13(q5-C5H4proceeds to give [ZrC12~-[(q5-C5H4)SiMe20SiMe2(q5-C5H4)l}l, SiMezCl)]with Mg(CHzCsH5)2(THF)zleads to the tribenzyl derivative [Ti(CH2C6H5)3(q5-C5H4SiMezCl)],8, and alkylation of [TiC12Cu-(OSiMe2-q5-CsH4))12with MgClMe and Mg(CH$6H5)2(THF)2 allows the isolation of the oxoalkyl complexes [TiR2{p-(OSiMe2-q5-C5H4)}12 [R = Me, 9; R = CH2CsH5,lOI. Reaction of [MC13(q5-C5H4SiMe2C1)1with LiN(SiMe3)z gives the amido complex [TiC12{N(SiMe3)2(q5-C5H4SiMe2C1))l,11,whereas a similar reaction with LiNHtBu takes place with simultaneous elimination of HC1 to give the cyclic amido pendant 12. The molecular structures of cyclopentadienyl complex [TiC12{NtBuSiMe2(q5-C5H4)}l, [TiC12{p-(OSiMe2-q5-C5H4)}12 and [ZrC12{p-[(q5-C5H4)SiMe20SiMe2(q5-C~H4)1}l have been determined by X-ray diffraction methods. Complex 5 is a dimer formed by two [MezSiCpTiClzl fragments bonded by two oxygen bridges, connecting the silicon and titanium atoms from different units. 5 crystallizes in monoclinic space group P2l/n with a = 9.461(7), b = 10.926(1),c = 10.507(3) /3 = 95.20(2)",and V = 1081(1) Hi3 for 2 = 2. The molecular structure of 7 corresponds to a typical bent dicyclopentadienyl system. Complex 7 crystallizes in the space group P21/c with a = 13.479(4),b = 8.654(1),c = 15.343(5) /3 = 97.18(2)",and V = 1775(2) Hi3 for 2 = 4.

A,

A,

Introduction q5-Cyclopentadienylderivatives of group 4 elements play an important role in structural, synthetic, and catalytic organometallic chemistry. Replacement of one or more cyclopentadienyl ring hydrogens has been shown to result in significant changes in both steric and electronic effects at the metal center. Attachment of metal complexes that are homogeneous catalysts to organic polymers and inorganic supports1 is an area of increasing interest in organometallic chemistry, as they combine the most advantageous properties of the homogeneous and heterogeneous catalysis. Polysiloxanes have also been investigated as +X-raydiffraction studies. Abstract published in Advance ACS Abstracts, November 1,1994. @

potential supports for homogeneous catalysts.2 Recently there has been growing interest in the development of catalytic systems based on supported cyclopentadienyl ligands. Cyclopentadienyl ligands are specially attractive as anchoring groups since the metal is strongly bound by the q5-coordination. Good candidates for this (1)(a) Hartley, F. R., Vezez, P. N. Adu. Organomet.Chem., 1977, 15,189.(b)Murre11 in J. J. Burton and R. L. Garten (Eds.), Advanced Materials in Catalysis, Academic Press, New York, 1977. ( c ) F'ruett, R. L. Adu. Organomet. Chem., 1979, 17, 1. (d) James, B. R. Adu. Organomet. Chem., 1979,17, 319.(e) Pittman, C. U.in P. Hodge and D. C. Sherrington (Eds.), Polymer-Supported Reactions in Organic Synthesis, Wiley, New York, 1980.(0 Akelah, A.Synthesis, 1981,413. (g) Bailey, D. C., L a g e r , S. H. Chem. Rev., 1981,81,109.(h) Akelah, A., Sherrington, D. C. Chemt Reu., 1981, 81, 557. (i) Klein, B., Kaziuskas, R. J., Wrighton, M. S. Organometallics, 1982,1 , 1338.(i) Booth, B. L., Ofunne, G. C., Stacey, C., Tait, P. J. T. J. Organomet. Chem., 1986,315,143. (2)Curtis, M. D., D'Errico, J. J., Duffy, D. N., Epstein, P. S., Bell, L. G. Organometallics, 1983,2, 1808.

Q276-7333l95/2314-Q177$Q9,QQlQ0 1995 American Chemical Society

Ciruelos et al.

178 Organometallics, Vol. 14, No. 1, 1995

.('

Scheme 1

a

SiMe3

n-BuLi hexane.O0C

* -SiMe3 Ll

+

( 111 )

proposal could be the silylated cyclopentadienyl derivaFigure 1. Equilibrium between the three possilble isomers ~ this tives, similar t o those previously r e p ~ r t e d .In of 1. paper we report synthetic procedures t o prepare monoScheme 2 and bis(cyclopentadieny1) derivatives of titanium and zirconium with the monosubstituted (chlorodimethylSiMe2C1 sily1)cyclopentadienyl group. The synthesis of the cyclopentadienyl ligand (CsH4)(SiMe2Cl)(SiMe3),1, the mono(cyclopentadieny1)derivatives [MC13(v5-C5H4SiMe2Cl)] (M = Ti, 2; M = Zr, 3)and the bis(cyclopentadieny1) complex [ZrC12(v5-C5H4SiMe2C1)21,4,is described. The M = Ti (a;Zr (3 8 , the alkyl complex [Ti(CH2CsH5)3(v5-C5H4SiMe2Cl)l, amido complexes [TiC12{N(SiMe3)2}(v5-C5H4SiMe2C1)1, Scheme 3 11, and [TiC12{NtBuSiMe2 (v5-C5H4)}l, 12, and the -SiMe,CI 1 + Zrcl, methylsiloxane derivatives [TiC12Cu-(OSiMe2-v5-CsH4))12, CHzCIz 5, [TiCl~{OSiMe2OSiMe2-(~~-CsH4))1, 6, [ZrC1&-[(v5C ! ~ H ~ ) S ~ M ~ ~ O S ~ M ~ ~ ( T ,7,I ~and - C ~[TiR&-(OSiMe2H~)~)I}I, MeM: SI v5-C5H4))12 (R = Me, 9; R = CH2CsH5, 10) are also reported, and the crystal structures of 5 and 7 have been determined by X-ray diffraction methods.

.e

Results and Discusion Synthesis of Mono- and Bis(cyclopentadieny1) Complexes 1-4. The reaction of a solution of 14trimethylsilyl)cyclopenta-2,4-dienein hexane with n-BuLi at 0 "C permits us to obtain a suspension of the white insoluble lithium salt, which after addition of dichlorodimethylsilane reacted to yield a colorless liquid, soluble in hexane (Scheme l),that could be purified by mmHg) and stored in the distillation (65 "Cll x dark under an inert atmosphere for several months (72% yield). This liquid was identified as 1-(chlorodimethylsily1)1-(trimethylsilyl)cyclopentadiene,1, by NMR spectroscopy. The lH NMR spectrum (CDC13 and CsDs) of the resulting liquid shows resonances assignable to 1(isomer I in Figure 1)(see Experimental Section). Other signals due to trimethylsilyl and chlorodimethylsilyl protons are observed at 6 -0.04 and 6 0.58 (CDC131, respectively, along with other weak and broad signals at ca. Q 3, corresponding t o sp3-C bonded protons. This NMR behavior is indicative of the presence of an equilibrium4 between the three isomers (I, 11, and 111)shown in Figure 1. The relative intensities associated with these resonances allow us to predict that isomer I is present in a ratio of 95%with respect to the other two isomers I1 and 111. Compound 1 reacts with one equivalent of Tic14 at room temperature and ZrCL at 100 "C in toluene to give the mono(cyclopentadieny1)derivatives [MC13(v5-C5H4(3) Winter, C. H., Zhou, X. X., Dobbs, D. A., Heeg, M. J . Organometallics, 1991,10, 210. (4)(a) Jutzi, P., Sauer, R. J. Orgunomet. Chem., 1973,50, C29.(b) Siemeling, U. J . Orgunomet. Chem., 1992,429,C14.

4

I

SiMezCl)] [M = Ti, 2;M = Zr, 31 with elimination of SiMeaCl (Scheme 2). The high selectivity for SiMesCl rather than SiMezClz elimination is probably based on the lower affinity of the silicon bonded ring carbon atom for the attacking electrophile, due to the presence of the more electronegativechloro substituent. Yellow crystals of 2 were isolated in 76% yield by cooling a hexane solution to -30 "C, whereas 3 was isolated as white crystals in 87% yield, after recrystallization from toluene/ hexane of the solid obtained by cooling a hexane solution to -30 "C. The lH and 13C NMR spectra for 2 and 3 show the presence of resonances for two methyl groups bonded to silicon, and an AA'BB spin system is observed for the cyclopentadienyl protons. Broad lH NMR signals observed for 3 are similar to those of (ZrC13Bp)x, indicating that a similar oligomeric or polymeric structure5 can be proposed for this monocyclopentadienyl zirconium derivative. When the same reaction between 1 and ZrCl4 in a Zrl Cp molar ratio of 112 was carried out in refluxing methylene dichloride, the bis(cyclopentadieny1)derivative [ZrC12(v5-C5H4SiMe2C1)21,4, was isolated (Scheme 3). Brown crystals of 4 were formed by cooling a dichloromethane solution to -20 "C and recrystallized from toluenehexane in 74%yield. However, the related bis(cyclopentadieny1) titanium complex could not be (5) Wells, N. J., Huffmann, J . C., Caulton, K. G . J. Organomet. Chem., 1981,213,C17.

Organometallics, Vol. 14, No. 1, 1995 179

Ti and Zr Si-Substituted Cyclopentadienyl Complexes

Scheme 4

A

+A

t n,o +

very slowly

/I

'o-

t

Ti

Si- Me

CI

5

synthesized, as this reaction with Tic4 only affords6the monocyclopentadienyl compound 2. These mono- and bis(cyclopentadieny1) complexes were found to be very moisture sensitive and react inmediately with traces of water; therefore, they have to be stored under rigorously dry conditions. They are soluble in aromatic hydrocarbons, methylene dichloride and chloroform but insoluble in alkanes, with the exception of 2, which is partially soluble in hexane. Synthesis of Oxocomplexes 5-7. Complexes 2-4 have two different types of chlorine bonds that could be involved in hydrolysis, i.e. the chlorine bonded to silicon and those bonded to the metal. We were particularly interested in comparing the reactivity of both M-C1 bonds with water, and the subsequent reactivity of the products, in order to obtain information about the way to achieve selective or simultaneous hydrolysis of these bonds. Selective hydrolysis of the Si-C1 bond would be desirable in order to attach these complexes to acidic inorganic oxides as ~upports,l*~ that can be used as heterogeneous catalysts for the oligo- or polymerization of olefins. Simultaneous hydrolysis of both Si-C1 and M-C1 bonds would lead to complexes with pendant cyclopentadienyl ligands, that combine the stability of the q5-coordinated cyclopentadienyl ligand and the terminal anionic alkoxide coordinated to the high Lewis acidic metal center. Addition of one equivalent of water to a toluene solution of the titanium compound 2 produced the evolution of HC1, and complex 5 was obtained as a yellow crystalline solid in a quantitative yield, by cooling the solution to -20 "C. The same complex 5 was also formed when only I12 equivalent of water was used, leaving l12 equivalent of unreacted starting complex 2, indicating that both Si-C1 and Ti-C1 bonds are simultaneously hydrolyzed. However, the formation of the oxygen bridge is not an intramolecular reaction, as this would lead t o a mononuclear four-membered Cp-Si0-Ti cyclic species. Complex 5 was characterized as the dinuclear titanium compound (Scheme 41, which contains the oxygen atom bridging the silicon and the titanium atoms of two different units to form an eightmembered ring, if the Cp is considered as one member of the titanium-Cp-silicon-oxygen-titanium-Cp(6)(a) Cardoso, A.M., Clark, R. J. H., Moorhouse, S.J. Chem. SOC. Dalton T~czns.,1980,1156.(b)Hidalgo, G.,Mena, M., Palacios, F., Royo, P.,Serrano, R. J. Orgunomet. Chem., 1988,340, 37.

unidentified products

'Me

6 c21

CIlO

Figure 2. Ortep view of molecular structure of 6 with the atom-numbering scheme.

silicon-oxygen ring. This formulation is in agreement with the mass spectrum and the lH NMR (CDC13 and C&) spectrum, which shows one singlet for the methylsilyl protons and two pseudotriplets corresponding to an AA'BB spin system, for the cyclopentadienyl protons. Crystals of 5 suitable for X-ray diffraction were grown by slow cooling of a toluene-hexane solution to -30 "C. The molecular structure of 5, obtained by X-ray diffraction, is shown in Figure 2, with the atomic labeling scheme. Final atomic coordinates and equivalent isotropic thermal parameters for non-hydrogen atoms are displayed in Table 1. Selected bond distances and angles are given in Table 2. The molecular structure consists of a dinuclear compound formed by two fragments related by an inversion center. Dimerization is produced by the interaction of two [MezSiCpTiClzlunits bonded by two oxygen atoms which connect one silicon and one titanium atoms from different units. The coordination around the titanium atom corresponds to a pseudo-three-legged piano-stool structure similar to that found for complexes of the type TiC12Cp(X).' If the centroid of the silyl-substituted ring is (7) (a) Rogers, R. D., Benning, M. M., Kurihara, L. K., Moriaty, K. J., Rausch, M. D. J. Orgunomet. Chem., 1985,293,51. (b) Mena, M., Pellinghelli, M. A., Royo, P., Serrano, R., Tiripicchio, A. J.Chem. Soc., Chem. Commun., 1988,1118.

180 Organometallics, Vol. 14, No. 1, 1995

Ciruelos et al.

Table 1. Positional Parameters and Their Estimated Standard Deviations for 5 atom

X

Y

Z

Ti( 1) Si(1) Cl(1) Cl(2) 0(1) C(11) C( 12) C(13) C( 14) C(15) C(21) C(22)

0.62148(3) 0.61975(5) 0.84357(5) 0.57657(7) 0.5157(2) 0.7191(2) 0.6644(3) 0.5158(3) 0.4800(2) 0.6068(2) 0.5972(3) 0.7887(3)

0.16861(3) 0.05464(4) 0.10047(6) 0.26053(6) 0.0355(1) 0.2683(2) 0.3607(2) 0.3435(2) 0.2395(2) 0.1889(2) 0.1086(3) -0.0272(2)

0.15 107(3) -0.17760(4) 0.19970(6) 0.33583(5) 0.1538(1) -0.0213(2) 0.0519(2) 0.0485(2) -0.0268(2) -0.0698(2) -0.3452(2) -0.1419(3)

Ba (AZ) 2.217(5) 2.535(8) 4.28(1) 4.32( 1) 3.39(3) 3.01(3) 3.82(4) 4.01(4) 3.33(3) 2.45(3) 4.56(5) 4.39(5)

Isotropic equivalent displacement parameter is defined as (4/3)[azB(l,l) y)B(1,2) ac(cos B)B(1,3) bc(cos a)B(2,3)1.

+ bZB(2,2) + czB(3,3) + &(cos

+

+

Table 2. Selected Bond Distances (A) and Bond Angles (deg) for Compound 5a Ti( 1)-C1( 1) Ti( 1)-O( 1) Ti(1)-C(12) Ti( 1)-C( 14) Si(1)-O(1) Si( 1)-C(21) C(ll)-C(12) C( 12)-C( 13) C( 14)-C( 15) Cl(l)-Ti(l)-Cl(2) C1(2)-Ti(l)-O(l) Si(l)-C(15)-C(ll)

2.244(1) 1.767(1) 2.395(2) 2.330(2) 1.653(1) 1.851(2) 1.396(2) 1.416(4) 1.431(2) 101.36(2) 101.57(5) 127.3(1)

Ti( 1)-C1(2) Ti(1)-C(11) Ti( 1)-C( 13) Ti(1)-C( 15) Si(1)-C(15) Si(1)-C(22) C(11)-C(15) C(13)-C(14) Ti( 1)-Cp( 1) C1( 1)-Ti(1)-O(1) Ti(1)-O(1)-Si(1) Si(l)-C(l5)-C(l4)

2.260( 1) 2.371(2) 2.370(2) 2.323(2) 1.864(2) 1.840(2) 1.430(2) 1.407(3) 2.026 104.09(5) 160.2(1) 126.8(1)

Numbers in parentheses are estimated standard deviations in the least significant digits. Cp(1) is thecentroidofC(ll),C(12). C(13), C(14), C(15). c21 A

Y

[(Me2Si)2(v5-C5H3)21}l(2.004 or [TiC12{O(CH2)3(v5C5Me4))I (2.015 A),g but similar to those found in the fulvalene complex [ ( T ~ C ~ Z ) ~ ~ - O ) ~ - ( ~(2.029 ~-~~-C~OH &.lo Another observed feature is the partial loss of the q5-character of the Cp ligand, as shown by the different Ti-C distances, ranging from the shorter 2.323(2)A for Ti-C15 (bonded to Si) to the larger 2.395(2) A for TiC12. The c-C distances in the Cp ring also show slight differences ranging from 1.396(2) to 1.431(2) A, in contrast with the situation in [(TiCl3)2@-[(MezSi)z(q5C5H3)21)1 and [TiC12{O(CH2)3(~5-CsMe4)}l,9b where the q5-characteris retained. However, the Cp ring is planar and perpendicular to the plane defined by the Ti, C15, and Si atoms, which divides this Cp ring into two symmetrical moieties. The rest of the ligands bonded to Ti and the two chlorine atoms and the oxygen atoms define another plane almost parallel to the Cp plane with an angle of only 3". The Si atom is almost located in the Cp plane, with a distance to this plane of 0.06 A, as expected for a SiCspzbond. The distance from the Si atom to the plane formed by the oxygen and the two chlorine atoms on the same face of the metal, is 2.840 A avoiding the intramolecular interaction that would give a mononuclear species. The Ti-0-Si angle (160.2') is larger than that found in [TiC12{O(CH2)3(v5-C5Me4)}Igb for the C-0-Ti angle (146.1"), corresponding to a more open eight-membered cycle with the cyclopentadienyl alkoxide ligand in comparison with the six-membered ring of the Teuben complex. Another difference between complex 5 and the Teuben complex is the closer linearity of the Ti-0-Si angle due to the stronger Si-0 n bonding with the vacant 3d silicon orbitals, which is absent in the C-0-Ti system. However, the Ti-0 distance, 1.767(1) A, is the same in both compounds, indicating a partial Ti-0 double-bond interaction. It is known that the maximum x interaction in the Ti-0 bond corresponds to angles of 180', but there exist many important examples showing that this relation is not always accomplished." This distance is slightly shorter than that found in the fulvalene complex [(TiC12)&-0)@-(q5:q5-CloH8)}](1.811A, average)l0with a Ti-0-Ti unit. The Si-0 distance (1.653(1)A), is slight1 larger than that found in siloxanes (mean value 1.63 )12 and larger than the Si-0 distance in the zirconium com(1.611 A, average).13 pound [Zr(q5-C5H5)201-OSiPh20)l~ This behavior confirms the competition between silicon and titanium for n-bonding with the bridged oxygen atom, which is more favored for the Ti-0 bond. Therefore, this Ti-0 bond is found to be shorter in the Ti0-Si unit than in the Ti-0-Ti unit.

x

Figure 3. View of central core of 5. C p l and Cp2 are the centroid of cyclopentadienyl rings.

considered as a coordination site bonded to Ti, the central core of the dimeric structure appears as an eightmembered cycle, with a "chair conformation", as shown in Figure 3. The formation of this cycle plays an important role in the disposition of the rest of the molecule. In fact, one of the interesting features is the position of the Ti atom with respect to the Cp-ring. The Ti-Cp(centroid) distance is 2.026 4 larger than those found in [(TiCl&b-

(8)Cano, A., Cuenca, T., G6mez-Sa1, P., Royo, B., Royo, P. Organometallics, 1994, 13,1688. (9)(a) Shapiro, P. J., Bunel, E., Schaefer, W. P., Bercaw, J. E. Organometallics, 1990,9,867. (b) Fandos R., Meetsma, A., Teuben, J. H. organometallics, 1991,10,59. (c) Rieger, B. J.Orgummet. Chem., 1991, 420, C17. (d) Hughes, A. K., Meetsma, A., Teuben, J. H. Organometallics, 1993,12, 1936. (10)Alvaro, L. M., Cuenca, T., Flores, J. C.,Royo, P.,Pellinghelli, M. A., Tiripicchio, A. Organometallics, 1992,11, 3301. (11)Ciruelos, S., Cuenca, T., Flores, J. C., G6mez. R., G6mez-sal, P., Royo, P. Organometallics 1993,12., 944. (12) Wells, A. F. "Structural Inorganic Chemistry", 3rd. ed.; Clarendon Press: Oxford, 1962. (13)Samuel, E.,Harrod, J., McGlinchey, M. J., Cabestaing, C., Robert, F. Inorg. Chem., 1994,33,1292.

Ti and Zr Si-Substituted Cyclopentadienyl Complexes The Ti-Cl distances are 2.244(1) and 2.260(1) A, in the range of mono(cyclopentadieny1)derivatives,1°slightly larger than that found in [(TiC13)2[~-[(MezSi)2(y5C5H3)21}]but slightly shorter than in [TiC12[O(CH2)3(y5C5Me4)}1, due probably to the oxygen competition. The disposition of these ligands is alternated with respect to the Cp ring. Addition of an excess of water to a toluene solution of 2 led to a solution which contained a mixture of different compounds, as shown by its IH N M R spectrum. However, complex 6 could be easily separated from this mixture in a 45% yield, as a yellow crystalline solid, because it is the only component that crystallizes on cooling a toluene-hexane solution of this mixture to -20 “C. Very low yields of complex 6 are also obtained together with other unidentified products, when a toluene solution of 5 is left to the open air for a period of time, by addition of a second equivalent of water or by reaction of a toluene solution of 5 with aqueous HC1. Therefore, complex 5 is resistant to hydrolysis, that takes place very slowly leading to complex 6, which is the main product when an excess of water is added to complex 2, preventing the formation of 5. This behavior can be explained (see Scheme 4) by assuming that simultaneous hydrolysis of both Si-C1 and Ti-C1 bonds in complex 2 takes place with elimination of HCl, leading to an intermediate fragment, which in the presence of an excess of water liberates the -SiMez-O- fragment that couples to give 6, whereas in the absence of water it dimerizes to give 5. Complex 6 was characterized by its elemental analysis, mass spectrum, and lH, 13C,and 29SiNMR spectroscopy. The mass spectrum agrees with the formulation of 6 as a mononuclear compound, [TiC12[ OSiMe20SiMe2(y5C5H4)}1, formed by a new six membered ring system (Ti-Cp-Si-0-Si-0) if Cp is considered as one of the members. In agreement with this formulation, the cyclopentadienyl protons appear as two pseudotriplets, whereas two singlets at 6 0.18 and 6 0.42 (CDC13) are observed for the methyl-silyl protons with an intesity ratio of 3:3:1:1 with respect t o the cyclopentadienyl signals. Two resonances are also observed for the methyl-silyl carbon atoms in the 13C and for the two silicon atoms in the 29SiNMR spectra, respectively. The relative stability of the cycle could explain why 5 prefers a dinuclear disposition whereas 6 presents a mononuclear structure. As shown by the X-ray molecular structure of complex 5, the long distance between the Ti center and the oxygen bonded to the silicon atom, coplanar with the cyclopentadienyl ring, prevents the formation of a mononuclear species, which would give a too greatly constrained four-membered ring, less stable than the eight-membered ring that leads to the prefered dinuclear disposition. However, 6 prefers a mononuclear disposition by formation of a stable sixmembered ring. Teuben et al. have observed the stability of the six-membered ring Ti-Cp-C-C-C-0 in the titanium cyclopentadienyl alkoxide [TiC12[O(CH2)3(y5-C5Me4)}l,9b in which the bidentate ligand is flexible enough to produce little steric constraint. The reaction of complex 3 with one equivalent of water under the same conditions described for the titanium compound gave a white solid, insoluble in all the common solvents indicating its polymeric nature.

Organometallics, Vol. 14, No. 1, 1995 181

-C13

Figure 4. Ortep view of molecular structure of 7 with the atom numbering scheme. Its analytical composition corresponds to the expected oxo compound [ZrC12(y5-C5H4SiMe20)lz,which could not be structurally characterized due to its lack of solubility. The results observed in the reactions of 2 and 3 with water allow us to conclude that the reactivity of the SiC1 bond, in this type of mono(cyclopentadieny1)complex, is very similar t o the reactivity of one of the M-C1 bonds, so that the selective hydrolysis of one of these bonds is not possible in these compounds. However, this selectivity could probably be easier for bis(cyclopentadieny1)-type complexes. The reaction of the bis(cyclopentadieny1) zirconium compound 4 with one equivalent of water gave a colorless crystalline solid (Scheme 3). The proton NMR spectra (CDC13and CsDs) show the expected singlet for the methyl protons and two pseudotriplets for the cyclopentadienyl protons with an intensity ratio of 6:2:2, respectively. The infrared spectrum clearly shows the unit “ZrClz”. These data together with the elemental analysis and the mass spectrum are in agreement with the formulation proposed for compound 7 (Scheme 3) as a tetramethyldisiloxane-bridged bis(cyclopentadieny1)dichloride complex. Single crystals of this compound have been obtained, and the X-ray diffraction study confirmed the proposed structure. Similar bis(cyclopentadieny1)titanium and -zirconium complexes have been obtained by reacting the lithium or sodium salt of 1,3-bis(cyclopentadienyl)tetramethyldisiloxane and poly(cyclopentadieny1methylsiloxane) with MC14.2,14 The X-ray crystal structure of compound 7 is shown in Figure 4 with the atomic labeling scheme. Final atomic parameters for non-hydrogen atoms are displayed in Table 3. Selected bond distances and bond angles are given in Table 4. The molecular structure of 7 is a typical bent bis(cyclopentadienyl) system, similar to that reported previously for compounds with free or bridged cyclopentadienyl rings.15J6 The structure of this zirconium (14)(a) Wang, Y, Zhon, X., Wang, H., Yas, X. Huaxue Xuebao 1991, 49(11), 1107.(Chem. Abst., 1991,116,129129s).(b) Wang, Y., Zhon, X. Youji Huaxue 1992,12(3), 286. (Chem. Abst., 1992,117,171616~). (15)(a) Prout, K.,Cameron, T. S., Forder, R. A., Critchley, S. R., Denton, B., Rees, G . V. Acta Crystallogr., 1974, B30, 2290. (b) Clearfield, A.,Warner, D. K., Saldarriaga-Molina, C. H., Ropal, R., Bernal I. Can.J. Chem., 1975,53,1622.

182 Organometallics, Vol. 14, No. 1, 1995

Ciruelos et al.

Table 3. Positional Parameters and Their Estimated Standard Deviations for 7 atom

X

Y

Z

Ea (A2)

Zr( 1) Si(1) Si(2) Cl(1) Cl(2) O(1) C(11) C(12) C(13) C(14) C(15) C(21) C(22) C(23) C(24) C(25) C(111) C(112) C(211) C(212)

0.1985 1(1) 0.37998(4) 0.23196(5) 0.33396(5) 0.12819(5) 0.3064(1) 0.3102(1) 0.3459(1) 0.2740(2) 0.1919(2) 0.2145(2) 0.1481(2) 0.0750(2) 0.0223(2) 0.0581(2) 0.1338(2) 0.4938(2) 0.4116(2) 0.3036(3) 0.1522(3)

-0.09717(2) -0.15768(6) 0.1 1286(7) 0.07341(7) -0.1467(1) -0.0325(2) -0.2474(2) -0.2755(2) -0.3568(3) -0.3829(2) -0.3201(2) 0.0701(2) -0.0479(3) -0.0333(3) 0.0989(3) 0.1624(2) -0.0630(3) -0.3102(3) 0.2889(3) 0.1389(4)

0.17960( 1) 0.38917(4) 0.40237(5) 0.15212(5) 0.02752(4) 0.4286(1) 0.2892(2) 0.2077(2) 0.1523(2) 0.1996(2) 0.2832(2) 0.29960(2) 0.2855(2) 0.2018(2) 0.1624(2) 0.221 8(2) 0.3592(2) 0.4715(2) 0.3862(3) 0.4910(2)

2.15 l(4) 2.37(1) 3.16(1) 4.05(1) 4.56(1) 3.15(3) 2.43(4) 2.77(4) 3.23(4) 3.33(5) 2.74(4) 2.62(4) 3.15(4) 3.92(5) 3.89(5) 3.12(4) 4.23(6) 3.64(5) 6.22(8) 6.09(7)

-c1c2,

Figure 6. Alternative view of molecular structure of 7, showing the disposition of the ligand.

8, for both Cp), and for the normal to the Cp plane (2.194

and 2.208 A). Thus, the Zr-C(Cp) distances are very similar, with a maximum difference of 0.04 keeping + + + the y5-coordination. Table 4. Selected Bond Distances (A) and Bond Angles The Si-0-Si bond angle of 143.5 (1)"and the Si-0 (deg) for Compound 7 bond distances (1.635(1) and 1.627(2)A) are similar to Zr( I)-Cl( 1) 2.4256(7) Zr(1)-Cl(2) 2.4443(7) those observed in hexamethyldisiloxane." Another zr(1)-C(11) 2.480(2) Zr(1)-C(12) 2.51 l(2) important structural feature to notice is the conformaZr(l)-C(13) 2.523(2) Zr(1)-C(14) 2.495(2) tion of the bridge that, as in the related titanium Zr( 1)-C( 15) 2.492(2) Zr( 1)-C(2 1) 2.495(2) compound,2is not symmetrically placed with respect t o Zr(1)-C(22) 2.504(2) Zr( 1)-C(23) 2.504(2) Zr(l)-C(24) 2.531(2) Zr( 1)-C(25) 2.523(2) the C1-Zr-C1 angle but shows instead the disposition Si(1)-O(1) 1.635(1) Si(1)-C( 11) 1.865(2) presented in Figure 5. Due to this wedging of the ring, Si(1)-C(111) 1.847(3) Si(1)-C(112) 1.839(2) the minimum C-C distance between the rings corSi(2)-0(1) 1.627(2) Si(2)-C(21) 1.866(2) responds to C22-Cl5, whereas the distance Cll-C21 Si(2)-C(211) 1.837(3) Si(2)-C(212) 1.850(3) is 3.526 A. Zr(l)-Cp( 1) Zr(l)-Cp(2) 2.208 2.202 This lack of symmetry affects the Zr-C1 distances, Cl(l)-zr(l)-C1(2) 98.71(3) Si(l)-O(l)-Si(2) 143.5(1) which are slightly different (Zr-Cll, 2.4256(7) A,and O(l)-Si(l)-C(ll) 108.24(8) O(l)-Si(2)-C(21) 110.24(9) Cl(1)-Zr(1)-Cp(1) 106.7 Cl(1)-Zr(1)-Cp(2) 106.2 Zr-C12, 2.4443(7) A) due t o the different effect of the Cl(2)-Zr(l)-Cp(l) 104.9 C1(2)-Zr(l)-Cp(2) 105.0 siloxo group. Both rings are located in an eclipsed Cp(1)-Zr(1)-Cp(2) 130.9 configuration. a Numbers in parentheses are estimated standard deviations in the least Synthesis of Alkyl Complexes. Reaction of comsignificant digits. Cp(1) is the centroid of C(11), C(12), C(13),C(14), C(15), 2 with 1.5 equivalents of Mg(CHzCsH&(THF)2 in plex and Cp(2) is the centroid of C(21), C(22), C(23), C(24), C(25). hexane at room temperature led to the tribenzyl deriva8, which was isotive [Ti(CH2CsH5)3(r5-C5H4SiMe2Cl)l, compound is comparable with that previously reported lated as red crystals in 86% yield from diethyl ether a t for the similar titanium derivativeU2 -40 "C. The same compound was also obtained when The two cyclopentadienyl rings are bonded by the Sian excess of the alkylating agent was used. The same 0-Si chain. The oxygen atom is out of the reflection reaction with 3 equivalents of MgClMe led t o a yellow plane defined by the zirconium and chlorine atoms, with oil that spontaneously decomposed with evolution of a distance to the plane of 0.052(2) A. methane to give a dark paramagnetic unidentified The most important feature in this structure is the residue. The thermal decomposition was monitored by disposition of the Si-0-Si bridge, which is long enough lH NMR spectroscopy in a sealed tube in the presence t o allow the Cp rings to be located with an angle of ethyl benzoate and the formation of a-ethoxystyrene between the Cp planes of 51.1", smaller than that found was detected, indicating the intermediate formation of in the double-ansa-bridged complex [ZrC12{(r5-C5H3)a methylidenetitanium compound. The same behavior (SiMe2)2(r5-C5H3)}1(69.6(1)")*and in the mono-ansabridged derivative [ZrC12[(r5-C5H4)SiMe2(r5-C5H4)ll6 was also observed for complex 8 when heated to 80 "C with evolution of toluene and transfer of the benzylidene (56.8'1, but comparable to those reported for other group to ethyl benzoate. compounds containing free cyclopentadienyl rings. AcAlkylation of 6 with 4 equivalents of MgClMe or 2 cordingly, the Cp(centroid1-Zr-Cp(centroid) angle is equivalents of Mg(CH2CsH&(THF)z produced the tetmore open, 130.9", than those in the examples menramethyl and tetrabenzyl derivatives 9 and 10,respectioned above. In this way, it is possible to introduce tively (Scheme 5 ) . The same alkylations of complex 6 the Zr atom between the Cp rings and maintain the led to yellow and red oils, which could not be isolated same distances for the Zr-Cp(centroid) (2.202 and 2.208 Anisotropically refined atoms are given in the form of the isotropic equivalent displacement parameter refined as (4/3)[a2B(l,l) b2B(2,2) c2B(3,3) nb(cos y)B(1,2) ac(cos /3)B(1,3) bc(cos a)B(2,3)].

+

+

(16) Bajgur, C. S., Tikkanen, W. R., Petersen, J. Znorg.Chem., 1986, 24, 2539.

A,

(17) Glidewell, C., Rankin, D. W. H., Robiette, A. G., Sheldrick, G. M. J. Chem. Soc. A 1970, 318.

Ti and Zr Si-Substituted Cyclopentadienyl Complexes

Organometallics, Vol. 14, No. 1, 1995 183

Scheme 5 SiMczCl

e

SiMe2Cl

Me

Me

MgCIMeor Mg(CH2Ph),(THF), -MgCI,

R= Me 2 R= CHzPh lQ

as solids, that contained the expected methyl and benzyl complexes respectively, according to their lH NMR spectra. Compounds 8-10 were characterized by elemental analyses, mass spectrometry, and NMR spectroscopy. The 'H NMR spectrum of 8 in C& shows a singlet at 6 3.05 for the six equivalent protons of the benzyl = 10 Hz) methylene groups, whereas two doublets (JH-H are observed for the diastereotopic protons of the methylene groups bonded to the prochiral metal center in complex 10 and one singlet is observed at 6 0.75 due t o the equivalent methyl groups in complex 9. Synthesis of Amido Complexes. As we have discussed above, both Si-C1 and M-C1 bonds are simultaneously involved in reactions with protic reagents such as water, whereas reactions with nucleophilic Grignard reagents take place selectively at the M-C1 bonds. In order to obtain additional information about this different reactivity, we decided to study the reactions of complex 2 with tertiary and secondary lithium amides. Reaction of 2 with 1 equivalent of LiN(SiMe& in hexane a t room temperature led to the amido complex [TiC12{N(SiMe&}(q5-C5H~SiMe2C1)1, 11, which was isolated as orange crystals aRer cooling a hexane solution to -40 "C. An analogous reaction of 2 with LiNHtBu took place with elimination of HC1 and LiCl t o give the constrained monomeric cyclic species ['l'iC12{NtBuSiMe2(q5-C5H4)}1,'* 12, containing the amido pendant cyclopentadienyl ligand in high yield (Scheme 5). Both

complexes were characterized by mass spectrometry and NMR spectroscopy (see Experimental Section).

All manipulations were performed under an inert atmosphere (dinitrogen or argon) using Schlenk and high vacuum line techniques or a VAC glove box Model HE 63P. Solvents were purified by distillation from a n appropriate drying/ deoxygenating agent (phosphorus pentoxide for dichloromethane, sodium for toluene and sodiudpotassium alloy for hexane). C&I&Me3,19Mg(CHzPh)z(THF)2,20and LiN(SiMe3)Zz1 were prepared according to literature procedures. n-BuLi, L BuNH2, MgClMe, SiMezClz, TiC4, and ZrCld (Aldrich) were obtained commercially. NMR spectra were recorded on a Varian Unity FT-300 and a Varian FT-500Unity Plus instruments (lH and 13C chemical shifts were referenced t o MerSi, 6 0 ppm, and 29Si chemical shifts were referenced to TMS external reference). IR spectra were performed (Nujol mulls) on a 883 Perkin-Elmer spectrophotometer. Mass spectra were recorded on a Hewlett-Packard 5890 spectrometer. Elemental C, H analyses were carried out on a Perkin-Elmer 240B microanalyzer. Synthesis of (C&)(SiMe&l)(SiMe& 1. A 1.6 M solution of n-BuLi in hexane/3.75 mL, 6.00 mmol) was added dropwise, at 0 "C, to a solution of freshly distilled C5H5SiMe3 (1.00 mL, 0.83 g, 6.0 mmol) in 50 mL of hexane. The reaction mixture was slowly warmed to room temperature and stirred for 3 h. A white precipitate was formed which after filtration was washed with hexane (3 x 20 mL). To a suspension of this white solid in 50 mL of hexane was inmediately added SiMe,Clz (0.73 mL, 0.78 g, 6.02 mmol) at -10 "C, and the reaction mixture was stirred for 5 h and warmed t o room temperature. After filtration, the resulting solution was evaporated under

(18) (a) Stevens, J. C., Timmers, F. J., Wilson, D. R., Schmidt, G. F., Nickias, P. N., Rose, R. K., Knight, G. W.,Lai, S., Eur. Pat. Appl. EP 416,815,1991. (Chem. Abst., 1991, 115, 93163m).(b) Okuda, J. Chem. Ber., 1990,123,1649.

(19)Abel, E.W., Dunster, M. 0.J.Orgunomet.Chem.,1971,33,161. (20)Schrock R.R., J. Orgunomet. Chem., 1976,122, 209. (21)Amonoo-Neizer, E. H.,Shaw, R. A,, Skovlin, D. O.,Smith, B. C . , Inorg. Synth., 1966,8, 19.

Experimental Section

184 Organometallics, Vol. 14,No. 1, 1995 vacuum to give a yellow-orange oil. Distillation at 65 "C/1 x mmHg gave a colorless liquid which was characterized as 1(1.00 g, 1.14 mL, 4.33 mmol, 72% yield) (d = 0.876 g/mL). lH NMR (300 MHz, CDCb, 25 "C): 6 0.00 (s,9H, SiMed, 0.22 (s,6H, SiMezCl), 6.54 (m, 2H, C5H4), 6.78 (m, 2H, CsH4). (300 MHz, C6&, 25°C): 6 0.01 (s, 9H, SiMes), 0.12 (s, 6H, SiMezCl), 6.42 (m, 2H, C5&), 6.65 (m, 2H, C5&). 13CNMR (75 MHz, CDC13, 25 "C): 6 -0.9 (9, 'Jc-H = 119 Hz, SiMed, 1.6 (9,'Jc.H = 121 Hz, SiMezCl),58.2 [s, Clpso(CsH4)1, 132.5,134.7 [d, 'JC-H = 165-169 Hz, CZ-c5 (CsH4)I. MS(E1) m / z : 230 (M+) (3%); 122 (M+-SiMe&I) (100%) Synthesis of WCl&1~-C&Sillle2Cl),2. (CsH4)(SiMezCl)(SiMe3),l ( l . l lmL, 0.97 g, 4.21 mmol), was added dropwise to a solution of TiC14 (0.46 mL, 0.79 g, 4.19 mmol) in toluene (40 mL). The reaction mixture was stirred for 2 days at room temperature. A change of color from orange to dark red was gradually observed. After evaporation under vacuum t o dryness, an oil was obtained which was disolved in hexane (60 mL). The resulting solution was concentrated and cooled to -30 "C t o give a microcrystalline yellow solid which was characterized as 2. (1.00 g, 3.21 mmol, 76% yield). Anal. Cald. for C7HloC14SiTi: C, 26.95; H, 3.23. Found: C, 27.34; H, 3.39. 'H NMR (300 MHz, CDC13, 25°C): 6 0.80 (s, 6H, SiMezCl), 7.10 (m, 2H, C5H4), 7.30 (m, 2H, C5H4). (300 MHz, C&, 25 "C): 6 0.47 (s, 6H, SiMezCl), 6.05 (m, 2H, C5H4), 6.45 (m, 2H, = C5H4). 13C NMR (75 MHz, CDC13, 25 "C): 6 2.4 (4, 'Jc.H 122 Hz., SiMezCl), 126.3, 129.1 [d, 'Jc.H = 178-179 Hz, CZ-c5 (C5H4)], 135.1 [s, Cipso(CsHd)]. MS(E1) m l z : 312 (M+) (7%); 242 (M+-2C1)(35%). Synthesis of ZrCls (qs-C&SiMe2C1), 3. (CaH4)(SiMezCl)(SiMes), 1 (0.85 mL, 0.74 g, 3.23 mmol), was added t o a suspension of ZrC4 (0.75g, 3.22 mmol) in 15 mL of toluene. The Schlenk was connected to a bubbler and the reaction mixture was warmed slowly to 100 "C with vigorous stirring. As the temperature was raised the ZrCl4 reacted and the formation of a brown solution was observed. The solution was filtered and cooled to -30 "C to give a white solid which was washed with cold hexane (2 x 20 mL). Recrystallization from toluenehexane gave a microcrystalline white solid which was characterized as 3. (1.00 g, 2.81 mmol,87% yield). Anal. Cald. for C~H10C14SiZr: C, 23.67; H, 2.84. Found: C, 24.02; H, 3.06. lH NMR (300 MHz, CDC13, 25 "C): 6 0.79 (s, 6H, SiMezCl), 6.99 (m, 2H, C5H4), 7.09 (m, 2H, C5H4). (300 MHz, CsDs, 25 "C): 6 0.50 (s, 6H, SiMezCI),6.12 (m, 2H, C5H4), 6.39 (m, 2H, C5H4). 13C{lH} NMR (75 MHz, C6D6, 25 "C): 6 124.0, 126.1 [C,-C5 (C5H4)1, (Clpso(C5H4) not observed).MS(EI) n / z : 354 (M+)(2%); 319 (Mf-C1)(28%). Synthesis of ZrCl2 (q5-C&SiMe2Cl)2, 4. (CsHJ(SiMe2Cl)(SiMes) 1 (1.49 mL, 1.31 g, 5.67 mmol) was added to a suspension of ZrC14 (0.66g, 2.83 mmol) in 50 mL of dichloromethane. The reaction mixture was refluxed with stirring for 4 days. ZrC14 gradually reacted and the formation of a brown solution was observed. After filtration the resulting solution was concentrated (10 mL) and cooled to -20 "C t o give a brown solid which was washed with cold hexane (3 x 20 mL). Recrystallization from toluenehexane gave a pale brown microcrystalline solid characterized as 4. (l.OOg, 2.09 mmol, 74% yield). Anal. Cald. for C~HzoC14SizZr:C, 35.21; H, 4.22. F o n d : C, 35.60; H, 4.57. 'H NMR (300 MHz, CDCl3, 25 "C): 6 0.73 (s, 12H, SiMezCl), 6.59 (m, 4H, C5H4), 6.79 (m, 4H, C5H4). (300 MHz, CsDs, 25 "C): 6 0.67 (s, 12H, SiMezCl), 5.82 (m, 4H, C5H4), 6.37 (m, 4H, C5H4). l3C(lH} NMR (75 MHz, C6D6, 25 "C): 6 116.8 [Cipso (CEH~)], 122.9, 127.0 [Cz-cS (CsH4)I. MS(E1) m l z : 477 (M+) (5%),407 (M+-2C1)(94%). Synthesis of [TiC12(q5:q1-CsH4SiMez)Ol-O)12,5. Deoxygenated water (73 pL, 4.06 mmol) was added t o a solution of TiC4(y5-CsH4SiMezC1) 2 (1.26g, 4.04 mmol) in 50 mL of toluene. The reaction mixture was stirred for 15 h. The color of the solution changed to yellow orange. After filtration the resulting solution was concentrated (10 mL) and cooled t o -20 "C t o give a pale yellow microcrystalline solid which was characterized as 5. Recrystallization from toluenehexane at

Ciruelos et al. -30 "C gave single crystals for X-ray diffraction. (1.00 g, 1.95 mmol, 96%yield). Anal. Cald. for C ~ ~ H Z O C ~ O Z C, S ~32.71; ZT~Z: H, 3.92. Found: C, 32.74; H, 4.04. 'H NMR (300 MHz, CDC13, 25 "C): 6 0.55 (s, 12H, SiMez), 6.99 (m, 4H, C5H4), 7.05 (m, 4H, C5H4). (300 MHz, 25 "C): 6 0.39 (s, 12H, SiMez), 6.36 (m, 4H, C5H4), 6.64 (m, 4H, C5H4). 13C{lH} NMR (75 MHz, CDCl3,25 "C): 6 0.3 (SiMez),124.6,126.5 [c& (C5H4)1, 131.6 [Ci,., (C5&)]. MS(E1) m l z : 499 (M+-CH3)(36%). synthesis O f WCl~[~s~'-C~SiM~-O-SiM~Ol, 6. Deoxygenated water (242 pL, 13.9 mmol) was added, at room temperature, to a solution of TiC13(q5-C5H4SiMezC1),3 (2.09g, 6.70 mmol), in 50 mL of toluene. The reaction mixture was stirred for 24 h. After filtration the resulting solution was concentrated (10 mL) and cooled to -20 "C to give a pale greenyellow solid which was recrystallized from toluenehexane at -20 "C giving a crystalline solid characterized as 6 (LOOg,3.02 mmol,-45%yield). Anal. Cald. for c&I&1~0~SizTi:C, 32.64; H, 4.87. F o n d : C, 32.95; H, 4.68. 'H NMR (300 MHz, CDC13, 25 "C,): 6 0.18 (s, 6H, SiMez), 0.42 (s, 6H, SiMez), 6.76 (m, 2H, C5H4), 7.12 (m, 2H, C5H4). (300 MHz, C&, 25 "c): 6 0.03 (s, 6H, SiMez), 0.12 (s, 6H, SiMez), 6.26 (m, 2H, C5H4), 6.58 (m, 2H, C5H4). 13C{lH} NMR (75 MHz, CDCl3, 25 "C): 6 -0.2 (SiMez), 0.0 (SiMez), 128.4 [Ci,., (C5H4)1, 125.2, 125.1 [CZ-CS (CsH4)I. l3C NMR (75 MHz, CeD6,25 "c): 6 -0.4 (SiMez), -0.3 (SiMez), 128.9 [Ci,,, (C5H4)1, 125.2, 125.1 [c2-c5(C5HdI. 29Si NMR (75 MHz, C6D6, 25 "c): 6 -4.9 (SiMez), -3.1 (SiMez). MS(E1) mlz: 330 (M+) (3%), 315 (M+-CH3)(100%). Synthesis of Zr Cl2 [(qs:qs:-C~H4)~Ol-Me2SiOSiMe2)l, 7. Deoxygenated water (47 pL, 2.61 mmol) was added t o a solution of ZrC12(y5-C5H4SiMe&l)z,4 (1.25g, 2.62 mmol), in 50 mL of toluene. The reaction mixture was stirred at room temperature for 15 h. After filtration the resulting solution was concentrated (10 mL) and cooled t o -20 "C to give a colorless solid. Recrystallization from toluenehexane at -20 "C gave a white microcrystalline solid which was characterized as 7 (l.OOg, 2.37 mmol, 91% yield). Anal. Cald. for C14HzoClzOSizZr: C, 39.79; H, 4.77. Found: C, 39.59; H, 4.75. lH NMR (300 MHz, CDCl3, 25 "C): 6 0.37 (s, 12H, SiMez), 6.54 (m, 4H, C5H4),6.84 (m, 4H, C5H4). (300 MHz, CsD6,25 "C): 6 0.23 ( 8 , 12H, SiMez), 6.27 (m, 4H, C5H4), 6.42 (m, 4H, C5H4). 13C{lH}NMR (75 MHz, CDCl3, 25 "C): 6 0.8 (SiMez), 117.1 [Ci,,, (CSH~)], 121.3, 125.5 [CZ-CS (C5H4)I. MS(E1) mlz: 422 (M+) (6%), 417 (M+-CH3)(90%). Synthesis of W(CH2CsHs)s(qS-CsH4SiMe~Cl), 8. To a suspension of TiC13(v5-C5H4SiMezC1),2 (0.76g, 2.43 mmol), in 75 mL of hexane cooled to -60 "C was added dropwise a solution of Mg(CHzPh)Z(THF)z(2.568, 7.30 mmol) in 30 mL of toluene. The reaction mixture was allowed to stir at room temperature for 3h, over which time it turned from yellow to dark red. After filtration the resulting solution was concentrated to 20 mL and cooled t o -40 "C t o give a dark red microcrystalline solid which was characterized as 8 (l.OOg,2.09 mmol, 86% yield). Anal. Cald. for CzsH31ClSiTi: C, 70.21; H, 6.52. Found: C, 70.56; H, 6.66. 'H NMR (300 MHz, C6D6, 25 "C): 6 0.36 (s,6H, SiMezCl), 3.05 (s, 6H, CHZPh), 5.72 (m, 2H, C5H4), 6.10 (m, 2H, C5H4), 6.85-7.15 (m, Ph). 13C NMR (75 MHz, C&, 25 "c): 6 3.0 (9, 'Jc.H = 119 Hz, SiMez), 94.7 (t, 'Jc.H= 125 Hz, CHzPh), 121.6, 121.9 Ed, 'Jc.H = 173 Hz, CzC5, (C5H4)1, 123.4, 127.2, 128.9 (d, 'Jc.H = 153-159 Hz, Ph), 148.6 (s, Ci,,,, Ph). (Cipsoof C5H4 not observed). MS(E1) mlz: 91 (C,H7+, 100%). Synthesis of [TiMe2(qs:q1-C5~SiMe~)(Ir-0)la, 9. To a suspension of [TiCl~(y~-vl-C5HaSiMe~)~-O)l~, 5 (1.67g, 3.25 mmol), in 100 mL of hexane, cooled to -60 "C, was added 4.33 mL of a 3M solution of MgClMe in THF (13.00 mmol) via syringe. After warming to 25 "C, the reaction mixture was allowed to stand for 5 h. The MgClz formed was removed by filtration and the volume of the filtrate was reduced in vacuum to 20 mL and cooled to -60 "C. Yellow microcrystals were obtained and were characterized as 9 (LOOg, 2.31 mmol, 71% yield). Anal. Cald. for C18H320~SizTi2: C, 50.00; H, 7.46. Found: C, 49.53; H, 7.21. 'H NMR (300 MHz, CaD6,25"C): 6

Ti and Zr Si-Substituted Cyclopentadienyl Complexes Table 5. Crystal and Experimental Data and Structure Refinement Procedures for Compounds 5 and 7

Organometallics, Vol. 14, No. 1, 1995 185

(LOOg, 2.29 mmol, 73% yield). Anal. Cald. for C13HzsC13NSi3Ti: C, 35.74; H, 6.46; N, 3.21. Found: C, 36.06; H, 6.67; N, 3.29. 'H NMR (300 MHz, C&6, 25 "C): 6 0.25 (8, 18H, 5 7 NSiMed, 0.73 (9, 6H, SiMezCl), 6.21 (m, 2H, C5H4), 6.62 (m, formula C ~ ~ H ~ O O ~ S ~ ~ CC L ~+ JT-~I Z ~ O O S ~ ~ C ~ ~ Z I 2H, C5&). I3C{'H} NMR (75 MHz, &De, 25 "C): 6 2.4 (SiMezcrystal habit prismatic prismatic Cl), 5.5 (NSiMes), 118.9 [CZ-CS, (CsH4)I. (Cips0and another color yellow yellow CZ-5 not observed). MS(E1) mlz: 437 (M+,l%);422 (M+-CH3, crystal size 0.20 x 0.12 x 0.15 0.3 x 0.20 x 0.15 6%), 262 [M+-CH3-NSi(Me&,51%1. monoclinic P21In monoclinic P21Ic symmetry Synthesis of Ti Clz (q6-Cs&SiMez-NtBu),12. A mixture unit cell determination least-squares fit from 25 reflns of TiC13(q5-C5H4SiMezC1),2 (1.89g, 6.06 mmol), and LiNHtBu unit cell dimensions 9.461(7), 10.926(1), 13.479(4),8.654(1), (0.48g, 6.06 mmol) in 60 mL of hexane was stirred at room a, b, c, 8, 10.507(3) 15.343(5) temperature overnight and then filtered. The filtrate was 95.20(2) 97.18(2) B, deg concentrated under reduced pressure and cooled to -30 "C to v. A3 1081.8(6) 1775(1) give an orange-brown solid. Recrystallization from toluene4 2 hexane gave a microcrystalline solid whose analytical composi1.578 1.581 tion and NMR spectra were coincident with data reported18" 5 14.1 422.6 for complex 12 (l.OOg, 3.20 mmol, 53% yield). 520 856 Crystal Structuresof [TiCl2(tl6:~'-Cs&SiMe2)(Ir-0)I2,5, 13.443 10.386 w128 scans; w128 scans; and ZrC12[(tlS-CaH4)2Gu-Me2SiOSiMe2)l, 7. Crystallographic , ,e = 30" 8, = 30" and experimental details of X-ray crystal structure determinano. of reflections tion are given in Table 5. Suitable crystals of 5 and 7 were measured 3465 5666 mounted on an Enraf-Nonius CAD-4 automatic four-circle independent observed 2803 I > 2u(4 4139 I > 20(4 diffractometer with bisecting geometric and using graphitecriterion criterion o = oriented monochromator with Mo Ka radiation ( ~ ( M Ka) range of hkl h-l3to13;kOt015; h-l9to19;kOto12; 0.710 73 A). Data were collected at room temperature. InlOto14 lOto21 tensities were corrected for Lorenz and polarisation effects in 2 reflections every 120 min, no variation standard reflections the usual manner. No absorption or extinction corrections R 0.036 0.029 0.065 0.054 were made. The structures were solved by a combination of Rw 0.866 0.317 m a peak in final direct methods and Fourier synthesis and refined (on F)by diff map, e1A3 full matrix least-squares calculations. All the non hydrogen min peak in final -0.544 -0.493 atoms were refined anisotropically. In the last cycle of diff map e/A3 refinement the hydrogen atoms were introduced from geometgoodness of fit indicator 1.633 2.249 ric calculation refined one cycle isotropically and then fured. largest param shift/error 0.02 0.02 Final values of R = 0.036 and R, = 0.065 were obtained for compound 5 and R = 0.029 and R , = 0.054 for compound 7 , 0.41 ( 6 , 12H, SiMez), 0.75 (s, 12H, TiMe), 6.13 (m, 4H, C5H4), with R , = [xwllFol - ~ F c ~ ~ 2 / w ~and Fo~ w 2=]4Foz/talFo1]2. uz 6.56 (m, 4H, C5&). 13C{lH} NMR (75 MHz, CsD6, 25 "c): 6 Anomalous dispersion corrections and atomic scattering 1.3 (SiMez),52.7 ( W e ) , 118.7,119.2 [CZ-CS (c~&)],122.9 [Ci,, factors were taken from ref 22. Calculations were performed (C5H4)I. MS(E1)m l z 417 (M+-CH3,4%),387 (Mf-3CH3, 15%). with the SDP package,23 and the programs MultanZ4 and Synthesisof [T~(CH~C~HS)~(~~:~'-C~H~S~M~~)G~-O)I~, 10. DirdiP5 on a Microvax I1 computer. To a suspension of [TiCl~(r~-r~-CsH4SiMe~)O1-0)12, 5 (0.90g, 1.75 mmol), in 100 mL of hexane, cooled to -60 "C, was added Acknowledgment. We are grateful to the DGICYT dropwise a solution of Mg(CHZPh)z(THF)z (2.46g, 7.01 mmol) (Project PB-92-0178-C)for financial support. S.C. in 30 mL of toluene. The reaction mixture was allowed to stir acknowledges the MEC, and A.M. acknowledges Uniat room temperature for 4h, turning from orange to dark red. versidad de Alcala for fellowships. After filtration over celite the resulting solution was concentrated t o 20 mL and cooled to -40 "C t o give a dark red SupplementaryMaterial Available: Tables of hydrogen microcrystalline solid which was characterized as 10 (1.OOg, atom positional and isotropic thermal parameters, non1.36 mmol, 78% yield). Anal. Cald. for C42H402Si~Tiz:C, hydrogen atom anisotropic thermal parameters, and all bond 68.47; H, 6.57. Found: C, 67.92; H, 6.88. 'H NMR (300 MHz, distances and angles for 5 and 7 (14 pages). Ordering CsDs, 25 "C): 6 0.31 (s, 12H, SiMez), 2,54 (d, 'JH.H = 10 Hz, information is given on any current masthead page. 4H, CHZPh), 2,74 (d, 'JH.H= 10 Hz, 4H, CHzPh), 5.79 (m, 4H, C5H4), 6.58 (m, 4H, C5H4), 6.93-7.18 (m, Ph). NMR (75 OM940607M MHz, C&, 25 "C): 6 2.0 (9, 'Jc.H= 119 Hz, SiMez), 82.7 (t, 'Jc.H= 125 Hz, CHZPh), 121.7,123.3[d, 'Jc.H = 173 Hz, Cz-Cs (22)International Tables for X-Ray Crystallography; Kynoch Press: Birminghan, U. IC, 1974 Vol. IV. (C5H4)], 124.2 (s, Cipso,C5H4), 122.7, 126.8, 128.6, (d, 'Jc-H= (23)B. A. Frenz and Associates, Inc. S D P Texas A&M and Enraf 153-159 Hz, Ph), 149.0 (s, Cipso,Ph). MS(E1) m l z 91 (C7H7+, Nonius: College Station, TX 77840,and Delft, Holland, 1986. 100%). (24)Main, P.;Fiske S. E.; Hull, S. L.; Lessinger, L.; Germain, C.; Synthesis of TiClz[N(SiMes)21(tlS-CaHaSiMe2C1), 11. A Declerq, J. P.; Woolfson, M. M. MULTAN. Universities of York and Louvain, 1980. mixture of TiC13(~,-~-C5H4SiMezCl), 2 (0.98g, 3.14 mmol), and Bossman, W. P.; Doesburg, H. M.; Could, R. (25)Beurkens, P .T.; LiN(SiMe3)z (0.53g, 3.14 mmol) in 50 mL of hexane was stirred 0.: van der Hark. T. E. M.: Prick. P. A. J.: Noordik. J. H.: Beurkens, at room temperature for 10h and then filtered. The filtrate G.; Parthasarathu, V. DIRDIF Manual 82.Technical Report 1981was concentrated under reduced pressure and cooled to -40 82;Crystallographic Laboratory : Toemooiveld, The Netherlands, 1981. "C to give orange crystals which were characterized as 11