Organometallics 1995, 14, 3216-3223
3216
Synthesis of a,q2-Alkynyl-BridgedBimetallic Complexes Containing ansa-Metalloceneand Low-Valent Nickel -Monocarbony1 Entities H. Lang,* S. Blau, B. Nuber, and L. Zsolnai Ruprecht-Karls-Universitat Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, 0-69120 Heidelberg, Germany Received February 7, 1995@ The reaction of the ansa-titanocene dichlorides [(q5-C5H3R1)(q5-CgH3R2)SiMeR31TiC12 (la, R1= R2 = H,R3 = Me; lb, R1 = H, R2 = SiMe3, R3 = Me; IC, R1 = R2 = SiMe3, R3 = Ph) with 2 equiv of LiC=CSiMe3 (2) yields the bis( alkynyl) ansa-titanocenes [(q5-C5H3R1)(q5-C5H3R2)SiMeR3]Ti(C=CSiMe& (3a, R1 = R2 = H, R3 = Me; 3b, R1 = H, R2 = SiMe3, R3 = Me; 3c, R1 = R2 = SiMe3, R3 = Ph). These compounds react with Ni(C0)4 (4) to afford {[(q5-C5H3R1)(q5-C5H3R2)SiMeR3]Ti(CrCSiMe3)2}Ni(CO)(Sa, R1 = R2 = H, R3 = Me; 5b, R1 = H, R2 = SiMe3, R3 = Me; 5c, R1 = R2 = SiMe3, R3 = Ph) in high yields. Compounds 5a-c contain a low-valent nickel-monocarbonyl fragment, which is stabilized by the chelating effect of both alkynyl ligands of 3. In contrast, the ansa-zirconocene dichloride [(q5-C5H4)(q5-C5H3SiMe3)SiMezlZrCl2 (6) leads with 2 equiv of LiC=CSiMes (2) to a variety of reaction products, of which the a,q2-doublyalkynyl-bridged dinuclear zirconocene { [(q5-C5H4)(q5-C5H3SiMe3)SiMe21Zr(C=CSiMe3)}2 (7)can be crystallized. Compound 7 can be synthesized in much better yields by reacting 6 first with LiCeCSiMe3 and secondly with n-butyllithium; a possible mechanism for the formation of 7 will be discussed. In 7 the alkynyl ligands act both as uand x-donors. Compound 7 contains two formal Zr"' centers. The X-ray structure analyses of lb, 3a, and 7 are reported. Crystals of l b and 3a are monoclinic space group P21/n ( l b ) and P21/a (3a): lb, cell constants a = 7.516(2) b = 19.862(6) c = 12.2783) ,8 = 91.47(2)", V = 1831.8 A3, and 2 = 4; 3a, cell constants a = 10.786(6) b = 20.01(2) c = 11.88(2) .$, ,8 = 99.86(9)", V = 2526.2 A3, and 2 = 4. Complex 7 crystallizes in the triclinic space group Pi with the cell constants a = 12.354(6) b = 19.15(1) c = 20.28(1) a = 68.59(5)", 3 , = 89.30(5)", y = 86.77(5)", V = 4458.1 Hi3, and 2 = 4. The properties of the MeRSi-bridged titanocenes 3 and 5 in comparison to the appropriate unbridged species are discussed.
A,
A,
A,
A, A,
/
Introduction Recently, we described the application of l-titanopenta-194-diyne Me3SiC=C-[TiI-C=CSiMea ([Til = (v5-C&I&XMe3)2Ti} as an organometallic chelating ligand (organometallic n-tweezers) for the stabilization of lowvalent M(C0) moieties (M = Ni,1,2Co2r3 ) as well as monomeric Mx (M = Cu, Ag;4-7 X = singly bonded inorganic or organic ligand) and MCl2 (M = Fe, Co, Ni839) entities. In the so-assembled [(v5-C5H4SiMe3)2Ti(C=CSiMe&]ML, species both alkynyl ligands of the (v2-C=CSiMe3)21ML, entity are y2-coordinated to a monomeric ML, building block. Themost striking fea@Abstractpublished in Advance ACS Abstracts, June 1, 1995. (1) (a) Yasufuku, K.; Yamazaki, H. Bull. Chem. SOC. Jpn. 1972,45, 2664. (b) Lang, H.; Herres, M.; Imhof, W. J . Organomet. Chem. 1994, 465, 283. (2) Lang, H.; Imhof, W. Chem. Ber. 1992, 125, 1307. (3) Lang, H.; Herres, M.; Zsolnai, L. Bull. Chem. SOC. Jpn. 1993, 66, 429. (4) Lang, H.; Kohler, K.; Blau, S. Coord. Chem. Rev. 1996, in press, and literature cited therein. (5) Janssen, M. D.; Herres, M.; Dedieu, A,; Spek, A. L.; Grove, D. M.; Lang, H., van Koten, G. J. Chem. SOC., Chem. Commun., in press. (6) Janssen, M. D.; Herres, M.; Zsolnai, L.; Dedieu, A.; Spek, A. L.; Grove, D. M.; Lang, H., van Koten, G. Znorg. Chem., Submitted for publication. (7) Lang, H.; Herres, M.; Zsolnai, L. Organometallics 1993,12,5008. ( 8 ) Lang, H.;Herres, M.; Zsolnai, L.; Imhof, W. J . Organomet. Chem. 1991, 409, C7. (9)Herres, M.; Lang, H. J . Organomet. Chem. 1994, 480, 235.
A, A, A,
Figure 1. Schematic representation of (v5-C5H4SiMe3)2Ti(C=CSiMe& (left)and [(1;15-C5H4SiMe3)2~(C~CSiMe3)21ML, (right). ture about this coordination mode is the decrease of the bite angle 8 (Ca-Ti-Ca,) of the bis(alkyny1) titanocene frag~nent,l-~ which results in a trans-deformation of the Ti-CW-Si unit, due to the tweezers effect of the [Til(C=CSiMe3)2 moiety (Figure l). The bite angle 8, which provides a suitable geometry for the y2-coordination of the Me3SiCsC ligands to monomeric ML, species, should be decisively influenced by changing from unbridged to, e.g., silyl-bridged cyclopentadienyl ligands, a context already established for unbridged metallocene dichlorides and their appropriate bridged derivatives by Brintzinger et a1.l0 (10)Smith, J. A,; v. Seyerl, J.;Huttner, G.; Brintzinger, H. H. J . Organomet. Chem. 1979, 173, 175 and literature cited therein.
0276-733319512314-3216$09.00/00 1995 American Chemical Society
a,$-Alkynyl-Bridged Bimetallic Complexes
Organometallics, Vol. 14, No. 7, 1995 3217
In this respect, we describe the synthesis of bis(alkynyl) ansa-metallocenes and their suitability for the stabilization of low-valent nickel-monocarbonyl building blocks. Results and Discussion Bis(alkyny1) ansa-Titanocenes. [($W5H3R1)(q5C5H3R2)SiMeR3]TiC12(la, R' = R2 = H, R3 = Me; lb, R1 = H, R2 = SiMe3, R3 = Me; IC,R1 = R2 = SiMe3, R3 = Ph)12reacts with 2 equiv of LiC=CSiMea (2) in Et20 a t 25 "C to yield the bis(alkyny1)ansa-titanocenes 3ac, the only isolated products obtained by extraction of the reaction residues with n-pentane, followed by filtration through a pad of Celite.
3
5
-50:
R'=@=H,@=Me
R' = H, R1= W e 3 d = ~e 3c, 5c: R' = @ = SiMe3 R3 = Ph
34 5b:
1
3 1430: R ' = @ = H , @ = M e lb,& R'=H,@=SMe3@=Me IC, 3c R' = @ = Ssule3 d = Ph
Complexes 3a and 3c were isolated as orange air stable solids, while 3b was obtained as an oil which decomposes on prolonged exposition to air. Compounds 3a-c are soluble in most polar and nonpolar organic solvents. Treatment of 3a-c with equimolar amounts of Ni(CO)4 at 25 "C in toluene affords in 87%-95% yield the appropriate golden-brown complexes { [(q5-CsH3R1)($C5H3R2)SiMeR3]Ti(C~CSiMe3)2)Ni(CO) (5a,R1 = R2 = H, R3 = Me; 5b, R1 = H, R2 = SiMe3, R3 = Me; 5c, R1 = R2 = SiMe3, R3 = Ph), which are soluble in n-pentane. In 5a-c a low-valent nickel-monocarbonyl building block is stabilized by the y2-coordination of both Me3SiCH! ligands of the bis(alkyny1)ansa-titanocene fragment [(r5-CgH3R1)(7;15-CgH3R2)SiMeR31Ti. Low-valent NiL moieties (L = CO, PMe3) could be independently stabilized by using tripodal ligands of type XM'(OCHZPM~~),(CH~CH~PM~Z)~-, ( M = Si, Ge,n = 0-3)"" and 1,8heptadiyne. lb The 'H NMR and 13C NMR spectra of 1, 3, and 5 consist of sharp and well-resolved signals for each of the organic groupings present. The most informative feature about the 'H NMR spectra is the appearance of ~~~~~~
~
(11)(a)Grobe, J.; Krummen, N.; Wehmschulte, R.; Krebs, B.; LLge,
M. 2.Anorg. Allg. Chem. 1994,620,1645.(b) Proft, B., Porschke, K.R.; Lutz, F., Kriiger, C. Chem. Ber. 1994,127,653. (12)Compounds la-c (Blau, S.; Zsolnai, L.; Neugebauer, U.;Weiss, K.; Lang, H. Manuscript in preparation.) were prepared according to well-established procedures by H. H. Brintzinger and H. K6pf. For detailed information see, for example: (a)Wiesenfeldt, H.; Reinmuth, A.; Barsties, E.; Evertz, K.; Brintzinger, H. H J . Organomet. Chem. 1989,369,359 and literature cited therein. (b)Smith, J. A,; v. Seyerl, J.; Huttner, G.; Brintzinger, H. H. J . Organomet. Chem. 1979,173, 175. (c) Klouras, N.; Kopf, H. Monatsh. Chem. 1981, 112,887 and literature cited therein. (d) Kopf, H.; Kahl, W. J . Organomet. Chem. 1974, 64, C37.
an AAXX' resonance pattern for compounds la, 3a, and Sa, while in lb, 3b, and 5b an ABX (v5-C5H3SiMe3)as well as an ABXY (q5-C5H4)resonance pattern for the cyclopentadienyl protons in the 6 5.1-7.5 region is observed.12 In compounds IC,3c, and 5c, which contain exclusively (q5-C5H3SiMe3)cyclopentadienyl ligands, only ABX resonance patterns appear.12 For the MeRSi links (R = Me, Ph) the lH NMR spectra show the expected simplicity with the resonance signals of the methyl groups at around 6 0.4 and 0.9 as well as of the phenyl protons in the 6 7.3-7.9 region. As expected for the symmetrically substituted compounds la, 3a, and 5a the methyl groups of the MezSi links are equivalent, whereas in the unsymmetrically substituted metallocenes lb, 3b, and 5b two resonance signals are observed. Due to the y2-coordinationof the Me3SiCsC units to the nickel atom in 5a-c the 13CNMR signals of the C, atoms in the Ti(C=CSiMes)z entity (at about 6 170 in 3a,b) shift downfield (at 6 190 in 5b,c),a phenomenon typical for this type of compounds.2-10 The resonance signals for the Cp atoms could not be clearly assigned, since they appear in the cyclopentadienyl and phenyl region. The carbon atom of the nickel-bonded carbonyl ligand in Sa-c shows a resonance signal at 6 200-204. A much better hint for the $-coordination of both Me3Sic%! ligands to the Ni(C0) building block is given by the IR spectra. The C=C stretching vibration a t about 2015 cm-' in 3a-c is shifted to lower wavenumbers in 5 (5a,b, 1834 cm-l; 5c, 1831 cm-l), thus indicating a weakening of the C=C triple bonds of the alkynyl ligands. This observation is generally made by changing from noncoordinating to +coordinating Me3SiCsC ligands and is in agreement with the increasing participation of the back-bonding component in alkyne-tonickel b~ndings.'-~The CO stretching vibration in Sa-c is observed a t 1995 cm-' (5a,b)and 2003 cm-l (5c), respectively (for comparison, the CO-stretching frequency of Ni(C0h is 2052 cm-'). These spectroscopic data, given for the silyl-bridged titanocenes 5a-c, are in agreement with those found for their unbridged equivalents.lV2 However, the latter compounds are stable in the solid state as well as in solution, while compounds Sa-c tend to decompose in solution. This empirical observation has t o be regarded in respect of the different bridging situations that may have an important influence on the specific geometrical properties of the molecules.
3218 Organometallics, Vol. 14, No. 7, 1995
Lung et al.
To reinforce this statement, X-ray structure analyses were carried out on single crystals of lb, 3a, and 5c. The structures of lb and 3a are shown in Figure 2; crystallographic parameters and selected geometrical details are listed in Tables 1-5. The needle-like habitus of the crystals of 5c resulted in R-values in the 20% region. For this reason the interatomic bond distances and angles of 5c are only given for comparison.13 Compound lb crystallizes in the monoclinic space group P21/n, whereas 3a crystallizes in the monoclinic space group P21/a. The geometrical environment of the Ti(1) center in lb is fixed by the arrangement of the two chloro groups [C1(1),C1(2)] and the q5-coordinated silyl-bridged cyclopentadienyl ligands. In comparison to their unbridged equivalents, in which the same grouping of ligands is present, different D1-Ti( 1)-D2 (Dl, D2 = centroids of the cyclopentadienyl ligands) and Cl(l)-Ti(l)-Cl(2) angles are found (Table 2). As is typical for these molecules,12the Dl-Ti( 1)-D2 angle decreases slightly by changing from (q5-C5&SiMe3)2TiC1214(131.0') to lb (128.8"),simultaneously increasing the Cl(l)-Ti(l)-Cl(2) angle from 91.63' l4 [in unbridged (q5-Cs&SiMe3)2TiC12J to 97.4(1)' in lb (Table 2). Replacement of the chloro groups in (q5-C5&SiMe3)2Tic12 and [(q5-CsH3R1)(q5-CsH3R2)SiMeR3]TiC12 (1)by alkynyl building blocks leads to the formation of the appropriate bis(alkyny1) titanocenes (q5-CsH4SiMe3)2Ti(c~CSiMe3)2~ and [(q5-CsH3R1)(q5-CsH3R2)SiMeR3]Ti(C=CSiMe& (3).As in compound (q5-C5H&iMe3)2Ti(C~CSiMe3)2,~*l~ the bis(alkyny1) ansa-titanocene 3a exhibits linear Ti-CEC-Si units (Table 3). Compared (13) Compound 5c crystallizes in the monoclinic s ace group P21/n with the cell constants a = 13.480(8)A,6 = 20.29(2) c = 14.52(1) A, fi = 90.78(6Y',V = 39716) A3, and 2 = 4. The structure was determined from single-crystal X-ray diffraction data, which were collected using a Siemens R3mN (Nicolet) diffractometer. At a temperature of 223 K 5208 reflections (4780 independent reflections) were measured in the O = 4 mm-'; graphite monochromator, range 2" 5 2 0 I44", ~ ( MKa) 1 = 0.710 73 A; w-scan with 2.09" min-l I6 I29.3" min-l and Am = 0.75'1. The structure was solved by direct methods (SHELXTL PLUS G. M. Sheldrick, University of Gattingen) and refined by the leastsquares method based on F with all reflections: 2890 observed reflections [ I I2dZ)I were refined to R1 = 0.21 and R, = 0.20 (207 refined parameters).
I
C11
1,
C
01
Selected bond lengths [AI and angles [degl (avera e values) are as f o l l o ~ Ti-& ~: 2.1 A; Ca-C,,, 1.28 A; Ti-Ni, 2.85 Ni-MP(C%C), 1.89 A(MP = mid-points of the alkynyl ligands Ca-C,,); Ca-Ti-Ca,, 92'; Ti-Ca-Cp, 152"; Ca-C -Si, 145"; D1-Ti-D2, 130.6' ( D l , D2 = centroids of the cyclopentachenyl ligands). (14) Klouras, N.; Nastopoulos, V. Monatsh. Chem. 1991,122,551. (15) Lang, H.; Seyferth, D. 2. Nuturforsch. 1990,456, 212.
X;
Figure 2. ORTEP drawings (drawn at 50% probability level) of lb (top) and 3a (bottom) (with exclusion of the hydrogen atoms) with the atom numbering schemes.
to the titanocene dichlorides (q5-Cs&SiMe3)2TiC1214and [(q5-C5H4)(q5-CsH3SiMe3) SiMe21TiC12 (lb)the angle Dl-Ti-D2 (Dl, D2 = centroids of the cyclopentadienyl ligands) in the bis(alkyny1) compounds is even more reduced in size (Tables 2 and 3). However, the angle C,-Ti- C,. (Figure 1)does not depend on the bridging situation of the cyclopentadienyl ligands. The interatomic distances of the C=C moieties in 3a [C(13)-C(14), 1.20(2) A; C(15)-C(16), 1.21(2) A] correspond to typical CH! separations found in organic as well as organometallic alkynes (e.g., HCECH 1.21 A;16 MezInCWMe, 1.207(2) A;17 [(q5-CsMe5)2SmC~CtBu12, 1.209(8) A;18 [(Me3N)(MeCsC)Be@-C=CMe)l2, 1.198( 5 ) A;19 (q5-CsH5)2ZrCu-q1-q2-MeC~CC~H11)@-C~CC6H11)AMe2, 1.195(6) A;2o (q5-CsH4SiMe3)2Ti(C~CSiMe&, 120.3(9)A, 121.4(6)A7 (Table 3)). The Ti(1)C(13) and Ti(1)-C( 15)distances at 2.08(1)and 2.08(2) A in 3a are similar to those found in (q5-C5&SiMe3)2(16) Dale, J. Properties of Acetylenic Compounds. In Chemistry of Acetylenes; Viehe, H. G., Ed.; Marcel Dekker: New York, 1969; p 53. (17) Fries, W.; Schwarz, W.; Hausen, H.-D.; Weidlein, J. J. Organomet. Chem. 1978,159,373. See also: Stucky, G. D.; McPherson, A. M.; Rhine, W. E.; Eisch, J. J.; Considine, J. L. J.Am. Chem. Soc. 1974, 96, 1941. (18) Evans, W. J.; Keyer, R.A.; Ziller, J. W. Organometallics 1993, 12, 2618. (19) Bell, N. A.; Nowell, J. W.; Coates, G. E.; Shearer, H. M. M. J. Organomet. Chem. 1984,273, 179. (20)Erker, G.; Albrecht, M.; Krilger, C.; Nolte, M.; Werner, S . Organometallics 1993, 12, 4979.
a,$-Alkynyl-Bridged Bimetallic Complexes
Organometallics, Vol. 14,No. 7,1995 3219
Table 1. Crystallographic Parameters for lb, 3a, and 7 lb formula fw cryst syst space group a,A b,A C,
A
a , deg A deg Y! deg
v, A3
ecalcd.
z
g ~ m - ~
cryst size, mm3 diff model P,mm-' radiation (1,A) temp, K scan mode scan range Am, deg scan speed, deg min-l 28 range, deg index ranges no. of unique data no. obsd no. refined params R1° R w wRzb 3
7
3a
C15HzzClzSizTi 377.30 monoclinic P2dn (No. 14) 7.516(2) 19.862(6) 12.275(3)
CzzH32Si3Ti 428.63 monoclinic P2da (No. 14) 10.786(6) 20.01(2) 11.88(2)
91.47(2)
99.86(9)
1831.8 1.1 4 0.30 x 0.25 x 0.25 Siemens R3mN 0.04 Mo Ka (0.710 73) 198 tu-scan 0.75 2.4-29.3 2.0-45.0
2526.2 1.13 4 0.25 x 0.30 x 0.50 Siemens R3mN 0.48 MoKa (0.710 73) 276 w-scan 1.2 3-29.3 3.0-48 O5h513 O5k523 -14 5 1 5 14 4109 1631 [Zt 2.5dZ)l 236 0.097 0.076
O5h58
O5k521 -13 5 1 5 13 2369 2128 [I t 2.OdZ)l 185 0.027 0.025
C40H6zSi6Zrz 893.89 triclinic P1 (No. 2) 12.354(6) 19.15(1) 20.28(1) 68.59(5) 89.30(5) 86.77(5) 4458.1 1.33 4 0.3 x 0.3 x 0.25 Siemens R3mN 0.04 MoKa (0.710 73) 190 w-scan 0.65 7-29.3 2.5-42.1 -12 5 h 5 12 -19 5 k 5 19 -20 5 1 5 20 9555 7270 [I t 2.0dZ)l 975 0.041 0.124
for all reflections.
Table 2. Selected Bond Lengths (A)and Angles (deg) for [(@-CsH4)(tls-CsH3SiMe3)SiMezlnC12(lb) and Its Unbridged Equivalent, (qS-C&SiMes)2TiC1214
Ti(l)-Cl(l) Ti(l)-C1(2) C(2)-Si(2) C(lO)-Si(B) D1-Ti( 1P D2-Ti(lP Cl(l)-Ti(l)-Cl(2) C(2)-Si(2)-C(lO) D1-Ti(l)-D2a a
lb (q5-C5H4SiMe3)~TiC1~14 Bond Lengths 2.345( 1) 2.367(1) 2.362( 1) 2.344( 1) 1.859(3) 1.863(3) 2.078 2.063 2.068 2.061 Angles 97.4(1) 91.63 90.1(1) 128.8 131.0
D1, D2 = centroids of the cyclopentadienyl ligands
Ti(C=CSiMe3)z7(Table 3) but are remarkably shorter than those titanium-to-carbon bonds involving sp3hybridized carbon atoms, as found in, eg., (q5-C5Hs)zTi(CHzPh)z,2.239(6) and 2.210(5)A;21 (v5-C5H&TiMez, 2.170(2) and 2.181(2) A;22 (y5-CsH4SiMe3)Ti(C1)(CHzSiMes), 2.209(6) A;23and (q5-CsH7)zTiMe2,2.21(2) Asz4 These data indicate some n-conjugation between the do-configurated 16-valence electron titanocene fragment and the n-system of the organic alkynyl ligands C=CSiMe3 in 3a due to a conjugative interaction of a vacant orbital available at the metallocene fragmentz5 with the n-systems of the adjacently bonded alkynyl (21)Scholz, J.; Rehbaum, F.; Thiele, K.-H.; Goddard, R.; Betz, P.; Kriiger, K.-H. J. Organomet. Chem. 1993,443, 93. (22) Thewalt, U.;Wohrle, T. J. Organomet. Chem. 1994,464, C17. (23) Lang, H.; Blau, S.; Nuber, B. Manuscript in preparation. (24) Atwood, J. L.; Hunter, W. E.; Hrncir, D. C.; Samuel, E.; A t , H.; Rausch, M. D. Inorg. Chem. 1975, 14, 1757. ( 2 5 )Erker, G.; Fromberg, W.; Benn, R.; Mynott, R.; Angermund, K.;Krtiger, C. Organometallics 1989, 8 , 911.
Table 3. Selected Bond Lengths (A)and Angles (3a) and (deg) for [(q5- CaI4)2SiMealTi(C~CSie3)~ Its Unbridged Equivalent, (~S-C~14SiMe3)2Ti(C=CSiMe3)27 3a (q5-CsH4SiMe3)2Ti(C~CSiMe3)z7 Ti( 1)-C( 13) Ti( 1)-C(15) C(13)-C( 14) C(15)-C( 16) C(Psi(1) C(G)-Si(l) D1-Ti( 1P DP-Ti( 1P C(l3)-Ti(l)-C(l5) Ti(l)-C(l3)-C(14) Si(2)-C(14)-C(13) Ti(l)-C(l5)-C(l6) Si(3)-C(16)-C(15) C(l)-Si(l)-C(6) Dl-Ti(l)-D2"
Bond Lengths 2.08(2) 2.08(1) 1.20(2) 1.21(2) 1.87(1) 1.83(2) 2.03 2.04 Angles 100.8(5) 176(1) 176(1) 177(1) 178(1) 91.9(7) 128.8
2.124(5) 2.103(5) 1.214(6) 1.203(9) 2.06 2.05 102.8(2) 178.2(5) 178.3(5) 175.8(4) 174.8(4) 134.7
D1, D2 = centroids of the cyclopentadienyl ligands.
ligands. As a consequence the bite angles C(131-Ti(1)-C(15) in 3a (100.8(5)")as well as in ($-C5H4SiMe3)~Ti(C=CSiMe3)z7(102.8(2)")are significantly larger than those found in complexes containing Ti-C(sp3)a-bonds, e.g., ($-CsH&TiMez, 91.2(1)0;22 (~5-C5H4SiMe3)~Ti(C1)(CHzSiMes),92.8(2Y';23 (q5-CsH7)2TiMez,93.5(2)",24(q5C~jH5)zTi(CHzPh)z, 91.0(2)0.21 As is typical for [(y5-C5H4SiMe~)~Ti(C=CSiMe3klML, compounds it is found that the Ni(C0) entity in Sa-c is stabilized by the +coordination of both alkynyl ligands in 3a-c.13 As result, the linear Ti-C=C-SiMes units in 3a are deformed. The tweezers effect of the bis(alkyny1) ansa-titanocene induces a trans-deformation of the Ti-CmC-Si moieties (for comparison, see
Lang et al.
3220 Organometallics, Vol. 14, No. 7, 1995
Table 4. Atomic Coordinates and E uivalent Isotropic Displacement Parameters for lba
(I2)
atom Ti(1) C1(1) Cl(2) Si(1) Si(2) C(1) c2 C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14) C( 15) a
xla
Y'!b
2fc
0.12119(6) 0.2569(1) -0.17094(9) 0.2650(1) 0 . 3 4 6 1) ~ 0.3521(4) 0.2767(4) 0.0984(4) 0.0744(4) 0.2301(4) 0.2851(4) 0.1416(4) -0.0125(4) 0.0327(4) 0.2221(3) 0.0767(4) 0.4860(4) 0.2591(4) 0.5878(4) 0.2518(4)
0.74463(3) 0.67239(4) 0.70555(4) 0.56430(4) 0.85839(4) 0.7108(1) 0.7699(1) 0.7518(1) 0.6827(1) 0.6559(1) 0.8297(1) 0.8162(2) 0.8344(2) 0.8583(1) 0.8583(1) 0.5307(2) 0.5508(2) 0.5226(2) 0.8667(2) 0.9173(2)
0.74416(4) 0.87249(6) 0.76172(7) 0.65426(7) 0.60931(6) 0.6296(2) 0.5832(2) 0.5530(2) 0.5756(2) 0.6238(2) 0.8382(2) 0.9061(2) 0.8496(3) 0.7461(3) 0.7388(2) 0.7332(2) 0.7232(2) 0.5180(2) 0.6375(2) 0.5069(2)
U(eqP 0.023 0.039 0.041 0.028 0.026 0.024 0.026 0.031 0.029 0.023 0.029 0.037 0.042 0.034 0.025 0.038 0.040 0.040 0.037 0.049
U(eq) is defined as one-third of the trace of the orthogonalized
Vu tensor. Table 5. Atomic Coordinates (~104)and Equivalent Isotropic Displacement Parameters (A2 x 103) for 3aa atom Ti(1) Si(1) Si(2) Si(3) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) (312) C(13) C(14) C(15) C(16) C(17) C(18) C(19) C(20) C(21) C(22)
X
204 l(2) 1790(4) 2974(5) 1923(4) 651(10) 240(111 -183(10) 9(10) 540(10) 311414) 3639(14) 4242(17) 4086(17) 3404(15) 1906(11) 1507(14) 2352(12) 2561(13) 1962(11) 1923(12) 3710(13) 1630(15) 3957(20) 1969(17) 3238(18) 611(16)
Y
914(1) 2293(2) 543(2) -1427(2) 1725(6) 1113(6) 728(6) 1082(7) 1705(6) 1744(8) 1719(8) 1115(12) 745(8) 1126(10) 3113(6) 2336(8) 741(6) 677(7) -62(6) -617(6) 1289(7) 366(9) -174(9) -1358(8) -1890(8) -1888(7)
2
9080(2) 7678(4) 13373(4) 7404(4) 8218(12) 775411) 8562(13) 9581(11) 9369(11) 8222(16) 9387(20) 9603(18) 8666(23) 7800(15) 832812) 6130(12) 10834(12) 11851(13) 8461(10) 8043(11) 1404U12) 14043(12) 13606(13) 5938(12) 8062(17) 7622(16)
U(eq) 56(1) 82(2) lOO(2) 85(2) 55(6) 63(6) 63(6) 59(6) 53(6) 73(7) 93( 10) 116(11) 115(12) 9U8) 120(8) 170(11) 74(6) 84(71 67(6) 67(6) 141(9) 223(14) 339(19) 218(14) 321(19) 251(16)
C214
b
\
4 c11
Figure 3. ORTEP drawing (drawn at 50% probability level) of 7 (with exclusion of the hydrogen atoms) with the atom-numbering scheme (Tables 1, 6, and 7). substituted zirconocene [(r15-CsH4Xr15-CsH3SiMe3)SiMe& Zr(C=CSiMe3)(Cl) (9). In much better yields 7 is accessible by the reaction of [(r15-CsH4)(95-CsH3SiMe3)SiMe2 JZrCl2 ( with 6 first ) 1 equiv of LiC=CSiMe3 (2) and secondly with 1 additional equiv of n-butyllithium. Analytically pure 7 can be obtained by filtration of the crude reaction material through a pad of Celite with n-pentane. Crystallization at -30 "C affords 7 as orange crystals in 45%yield. The
6
...*Me %e
7
diamagnetic complex 7 is soluble in polar solvents (THF, EtzO) and slightly soluble in toluene or n-pentane. While solid 7 is stable in air for days, solutions of 7 decompose on exposition to air and in chlorinated Figure 1). Similar observations were made for all other solvents. [(r15-CsH4SiMe3)2Ti(C~CSiMe3)2]ML,compounds.l-1° One hint on the diamagnetic structure of 7 is given Alkynyl ansa-Zirconocenes. Using the reaction by the proton NMR spectrum. It shows a 3:3:1:1 ratio conditions already described for the preparation of the of the protons of the methyl resonances of the q5-C5H3bis(alkyny1)ansa-titanocenes3a-c, the ansa-zirconocene SiMe3, C=CSiMe3, and SiMe2 units. The E1 mass dichloride [(r15-CsH4Xr15-CgH3SiMe3)SiMe2]Z~12 (6)leads spectrum of 7 confirms its dimeric nature, with the M+ with 2 equiv of Lic~CSiMe3(2) to a multitude of ion observed at m l e = 892 as its base peak. Another reaction products, of which the dimeric alkynyl-bridged spectroscopic proof of dimeric 7 is the appearance of an complex { [(r15-Cs~Xr15-CsH3Sie3)SiM~]Z~C~SiMe3)}~ IR-absorption band a t 1741 cm-l, a region typical for CGC triple bonds q2-coordinatedto group 4 metallocene (7)can be crystallized in 10%yield. Spectroscopicmeafragments, suggesting a significantlyreduced C=C bond surements of the reaction mixture show unreacted 6, which gives rise to the formation of the expected bis(alkynyl) ansa-zirconocene [(r15-CsH4)(rt5-CsH3SiMe3)- The result of the X-ray structure analysis of 7, depicted in Figure 3 (crystallographic parameters are SiMenJZr(CWSiMe3)2( 8 ) as well as the monoalkynyl-
U(eq) is defined as one-third of the trace of the orthogonalized U, tensor. a
a,$-Alkynyl-Bridged Bimetallic Complexes
Organometallics, Vol. 14, No. 7, 1995 3221
Table 6. Selected Bond Lengths (di) and Angles (deg) for 7 (Molecule 1Ia Distances Bond Lengths
NonBonding Distances
Table 7. Atomic Coordinates ( x 104) and Equivalent Isotro ic Displacement Parameters x 10s) for 7
(k
atom
X
V
z
U(ea)
2791(1) 2709(1) 1171(1) 3225(1) 36511) 1954(1) Zr(l)-C(16) 2.177(6) Zr( 1)-Zr(2) 3.489 1974(1) 4022(1) 190(1) 2.3084 Zrtl)-C(217) 2.394(6) Zr( 1)-MP26 1838(1) 4443(1) 3092(1) Zr(l)-C(216) 2.394(5) Zr(2)-MPlb 2.3124 - 1159(1) 243U 1) 680(1) Zr(2)-C(216) 2.187(6) Zr(l)-DIC 2.238 - 1140(1) 3945(1) 2956(1) Zr(2)-C(16) 2.394(5) Zr(l)-D1'C 2.256 927(1) -217(2) 2999( 1) Zr(2)-C(17) 2.397(6) Zr(2)-D2? 2.234 4340(1) 4042( 1) 1713(1) C(16)-C(17) 1.254(8) Zr(2)-D2" 2.250 2921(3) -36(3) 3349(4) C(216)-C(217) 1.270(8) 111(3) 3524(3) 3786(5) Angles 4041(31 114(3) 2957(5) C(16)-Zr(l)-C(216) 80.9(2) C(217)-C(216)-Zr(2) 167.5(5) 3780(3) -10(3) 1988(5) C(216)-Zr(2)-C(16) 80.7(2) Zr(2)-C(216)-Zr(l) 99.1(2) 3091(3) -98(3) 2223(5) C(l7)-C(l6)-Zr(l) 168.7(5) C(216)-C(217)-Si(22) 145.2(5) 1686(3) 1161(3) 3857(4) Zrtl)-C(l6)-Zr(2) 99.4(2) C(216)-C(217)-Zr(l) 74.6(3) 1398(3) 2906(5) 1527(3) C(16)-C(17)-Zr(2) 74.7(3) Dl-Zr(l)-Dl'c 125.1 1480(3) 2901(4) 2183(3) C(16)-(17)-Si(l2) 143.7(5) D2-Z1f2)-D2'~ 124.7 1819(3) 2247(3) 3854(4) 1969(3) 4430(4) 1608(3) Molecule 1and molecule 2 are essentially identical; the set of 2025(4) 5473(5) -55(3) data on molecule 2 is available as supporting information. MP1, 1378(3) 3256(5) -161(3) MP2 = midpoints of the C=C triple bonds. D1, Dl', D2, D2' = 847(4) 3707(3) 4603(6) centroids of the cyclopentadienyl ligands. 2360(4) 3615(5) 3548(3) 2235(4) 2895(3) 5796(5) given in Table 1;bond lengths and angles are given in 2568(3) 996(4) 1208(3) Table 61, explains these features. Compound 7 crystal1178(3) 2577(3) -18(5) lizes in the triclinic space group Pi with two crystallo2789(8) -2479(9) 922(7) -336(7) 3166(8) -936(13) graphically independent molecules, both being essen1575(22) 421(18) -751(26) tially identical. Only the numbering of molecule 1 is 1960(12) 1406(8) -2284( 13) shown in Figure 3. Final atomic coordinates and - 1657(17) 3126(10) 28(10) equivalent isotropic thermal parameters for non-hydro1545(19) -1169(23) 645(17) 4339(3) 2000(3) -765(5) gen atoms are presented in Table 7. The most repre4130(3) 1469(3) -1240(5) sentative bond distances and angles are given in Table 4288(3) -54x5) 888(3) 6. In 7 two identical [(r5-C5H4)(r5-C5H3SiMe3)SiMe21378(5) 4569(3) 1056(3) Zr(CWSiMe3) building blocks have dimerized to form 4600(3) 1730(3) 249(5) 3007(3) -440(4) 3133(3) a central organometallic framework consisting of two 2833(3) 3251(3) 673(4) early transition metal centers (Zr(l), Zr(2)) and four 2161(3) 930(5) 3137(3) acetylide carbon atoms (C(16), C(17), (22161, C(217)). 1909(3) 2946(3) -8(5) These atoms form a plane (maximum deviation: 0.156 2451(3) 29233) -864(4) 8).The Zr(l)-C(216)-C(217) plane is folded by 21.51' 4429(4) -528(6) 3487(3) 3097(3) 3863(3) -2616(5) relative to the Zr(2)-C(16)-C(17) plane. As compared 388(9) 3835(8) 850(18) toz7 [(r5-C5H5)2Zr(C~CSiMe3)1228 (5.4') the folding in 7 3342(12) 633(9) -1452(15) (molecule 1)is much larger, which can be best explained 3834(8) 288(8) -97(12) by the bulkiness of the ansa-zirconocene building blocks 2702(7) 960(8) -1784(10) 2335(3) 600(3) 401(5) [(r5-C5H4)(1;15-CgH3SiMe3)SiMe2]Zr. The Zr-D1 and Zr1911(3) 3457(3) 2083(4) D2 distances (Dl, D2 = centroids of the cyclopentadienyl 3655(3) 1742(3) 3043(5) the angles ligands) are in the range of 2.234-2.250 4197(4) 1276(3) 5331(5) Dl-Zr-D2 are 124.7' and 125.1' (Table 6) and are 4296(4) 2620(4) 4316(5) thereby similar to other compounds of this type.25,28 5288(4) 1189(4) 3460(6) The structure of 7 is similar to that of [(r5-C5H4a Molecule 1 and molecule 2 are essentially identical; the set of data on molecule 2 is available as supporting information. U(q, [(r5-C5H5)zZr(C~CSiMes)l~,28 and Me)zZr(C~CPh)l2,~~ is defined as one-third of the trace of the orthogonalized U"tensor. [(q5-C5H5)2Ti(C=CSiMe3)12,26,27,29 respectively. The ZrTwo of the trimethylsilyl groups [C(18)-C(20); C(213), C(214)l (1)-Zr(2) distance of 3.489 8 is in the nonbonding are disordered.
8,
region. The carbon-carbon triple-bond length in 7 is with 1.270(8)8 [C(216)-C(217)] due to the y2-coordination to a zirconium atom somewhat longer than that found in (r5-C5H5)2Zr(C~CMe)225 [1.206(4)81. The ZrC, bonds are with 2.177(6) 8 and 2.187(6) 8 CZr(1)C(16), Zr(2)-C(216)1 significantly shorter than the zirconium-carbon distances found in (r5-C5H4SiMe3)2Zr(C1)[CH(SiMe3)2130(2.327(3) 8) or (r5-C5H5)2Zr(CHPh2)z31(2.396(6) and, 2.379(6) 81, but almost as (26)Rosenthal, U.;Gorls, H. J. Organomet. Chem. 1992,439, C36. (27) Wood, G. L.; Knobler, C. B.; Hawthorne, M. F. Inorg. Chem. 1989, 28, 382. (28)Metzler, N.; Noth, H. J. Organomet. Chem. 1993, 454, C5. (29) Cuenca, T.; Gomez, R.; G6mez-Sal, P.; Rodriguez, G. M.; Royo,
P. Organometallics 1992, 11, 1229.
short as the Zr-C,, bond in (r5-CsHs)zZr(C0)~.32 This suggests that compound 7 can be described by the resonance formulae A,B,and C as shown in Scheme 1, attributing a n-interaction between the zirconium centers and the adjacent alkynyl n-system via the connecting Zr-C o-bond. Due to the q2-coordinationof the Z r C i C - S i units in 7 t o an adjacent zirconium atom the CZC-Si (30)Lappert,M. F.; Riley, P. I.; Yarrow,P. I. W.; Atwood, J. L.; Hunter, W. E.; Zaworotko, M. J. J. Chem. Soc., Dalton Trans. 1981, 814.
(31)Atwood, J. L.; Barker, G. IC;Holton, J.; Hunter, W. E.; Lappert, M. F.; Pearce, R. J.Am. Chem. Soc. 1977, 99, 6645. (32)Atwood, J. L.; Rogers, R. D; Hunter, W. E.; Floriani, C.; Fachinetti, G.; Chiesi-Villa, A. Inorg. Chem. 1980, 19, 3812.
3222 Organometallics, Vol. 14, No. 7, 1995
L a n g et al.
Scheme 1. Possible Resonance Formulae of { [(t15-CsH4)(t15-CaH3SiMeg)SiMeZ1ZI(C'CSie3)}~ (7)
MeJSi
B
C
A
Scheme 2. Possible Mechanism for the Formation of 7 by the Reaction of 6 with 2 and "C.&Li; [Zrl =
[(t15-C5H4)(t15-C5H~SiMeS)SiMeZIZF
SiMe,
I
C
Fragments with a higher electrophilicity, e.g., (7f-C~Me&Ln (Ln = Sm, Eu, Yb), tend to coordinate preferentially to the Ca atom of the {[Til(Ca~C,jSiMe3)2} moiety, giving rise t o a bonding situation better described as asymmetric bridging of Me3SiC=C groups between two metal centers (in analogy to intermediate F). Compounds of this type could be crystallographically characterized, involving main group elements,37 f-orbital centers,38or platinum atoms.39 Symmetrical cleavage of F by breaking of two zirconium-Caacetylide bonds, which afterwards can recombine to form dimeric { [(v5-C5H4)(v5-C5H3SiMe3)SiMe21Zr(C~CSiMe3))z (type A molecule).
Ill
Experimental Section
C I SiMe,
F
/
A
moieties are deformed from linearity (CsC-SiMe3: 143.7(5)"and 145.2(5)").This deformation is consistent with the previously reported structure of [(v5-C5H4Me)zZr(C~CPh)32~~ (146.8(2)")and [(v5-C5H5)2Zr(CsC SiMe3)1228(142.5(4)").The Zr-CW angles are almost linear at 167.5(5)" and 168.7(5)". Usually both the Zr-CEC and CGC-Si angles are decreased on v2coordination of the C2 unit to a transition metal atom. In the case of 7, the Zr-CW angle is not that much affected, which can be explained by using a geometrical argument: Additional deformation of the Z r C M entity would weaken the alkyne-to-metal (Zr') n-interaction. A possible way for the formation of dimeric 7 by the reaction of [(v5-CsH4)(v5-CgH3SiMe3)SiMe21ZrC12 (6) with Lic~CSiMes(2) and *CdHgLi is given in Scheme 2. Presumably in the first step, the bis(alkiny1)zirconocene D acts as an organometallic chelating ligand (organometallic n-tweezers compound) and affords with "[Zrla ([Zrl = [(v5-C5H4)(v5-CgH3SiMe3)SiMe21Zr, generated from [(175-C5H4X175-C5H3SiMe3)SiM~]Z~12 (6)and nCqH9Li) the dinuclear intermediate E (Scheme 2). E contains two bridging o,n-alkynyl ligands between two zirconium atoms. Structural type E molecules are well defined for compounds of general type [LxM(C=CR)21ML, [ Z M = (v5-CsH4SiMe3)2Ti,(v5-C5H4SiMe3)2Hf,Re(C0)3(PPh3), (q5-C5H5)Ru, Ir(PPh&(C=CR)2, Rh(PPh&(C=CR)2, (C5F&Pt, (dppe)Pt, Pt(PPhd2; ML, = Ni(CO), Co(C0); CuX, AgX, X = singly bonded inorganic or organic ligand; R = singly bonded organic ligand11-7,33-36 and could be isolated if the chelated organometallic building block provides a center with low Lewis-acidity, e.g., Ni(CO),1,2F e c l ~or , ~Cu, Ag.6,7
General Comments. All reactions were carried out under a n atmosphere of nitrogen using standard Schlenk techniques. Tetrahydrofuran (THF) and diethylether (Et201 were purified by distillation from sodiumhenzophenone ketyl; toluene and n-pentane were purified by distillation from calcium hydride. Infrared spectra were obtained with a Perkin-Elmer 983G spectrometer. lH NMR spectra were recorded on a Bruker AC 200 spectrometer operating a t 200.132 MHz in the Fourier transform mode, and 13CNMR spectra were recorded a t 50.323 MHz. Chemical shifts are reported in B units (parts per million) downfield from tetramethylsilane with the solvent as the reference signal. E1 mass spectra were recorded on a Finnigan 8230 mass spectrometer operating in the positiveion mode. Melting points were determined with use of analytically pure samples, which were sealed in nitrogenpurged capillaries on a Gallenkamp MFB 595 010 M melting point apparatus. Microanalyses were performed by the Organisch-Chemisches Institut der Universitat Heidelberg. (A) Synthesis of 3a-c. The ansa-titanocene dichlorides la-c (la, 1.6 g; lb, 2.0 g; IC,2.7 g; 5.3 mmol)14 were added at 25 "C in one portion to a solution of L i c ~ C S i M e 3 (1.1 g, 10.6 mmol) in 100 mL of Et20 (to dissolve compound l a a n additional 100 mL portion of THF had to be added). After stirring for 2 h a t 25 "C all volatile materials were removed in vacuo, and the residues were each extracted with 100 mL ~
~~
~~~~~~~
(33)(a) Abu Salah, 0. M.; Bruce, M. I. Aust. J . Chem. 1976, 29, 531. (b)Abu Salah, 0. M.; Bruce, M. I. Aust. J . Chem. 1977,30, 2639. ( c )Abu Salah, 0. M.; Bruce, M. I. J . Chem. SOC.,Chem. Commun. 1974, 688. (d)Abu Salah, 0. M.; Bruce, M. I.; Redhouse, A. D. J . Chem. SOC., Chem. Commun. 1974, 855. Abu Salah, 0. M.; Bruce, M. I. J . Chem.
SOC.,Dalton Trans. 1975, 2311. (34)(a)Fornies, J.; Lalinde, E.; Martinez, F.; Moreno, M. T.; Welch, A. J. J.Organomet. Chem. 1993,455,271.(b)Berenguer, J. R.; Fornies, J.; Lalinde, E.; Martin, A. Angew. Chem. 1994, 106, 2196. (35)Ciriano, M.; Howard, J. A. K.; Spencer, J. L.; Stone, F. G. A.; Wadepohl, H. J . Chem. SOC.,Dalton Trans. 1979, 1749. (36)Troyanov, S. I.; Varga, V.; Mach, K. Organometallics 1993,12,
2820. (37)Erker, G.; Albrecht, M.; Kruger, C.; Nolte, M.; Werner, S. Organometallics 1993, 12, 4979. (38)(a) Evans, W. J.; Drummond, D. K.; Hanusa, T. P.; Olofson, J. M. J . Organomet. Chem. 1989, 376, 311. (b) Evans, W. J.; Keyer, R. A,; Ziller, J. W. Organometallics 1993, 12, 2618 and literature cited therein. ...-. -. ...
(39) Berenguer, J. R.; Falvello, L. R.; Fornies, J.;Lalinde, E.; Tomas, M. Organometallics 1993, 12, 6. (40) Lang, H.; Keller, H.; Imhof, W.; Martin, S. Chem. Ber. 1990, 123, 417.
a,$Alkynyl-Bridged
Organometallics, Vol. 14,No. 7, 1995 3223
Bimetallic Complexes
of n-pentane and filtered through a pad of Celite. Crystallization a t -30 "C yielded 3a and 3c (3a, 0.8 g, 1.75 mmol, 35%; 3c, 2.9 g, 4.54 mmol, 86%) as orange-colored solids; 3b (2.4 g, 4.77 mmol, go%), an intense orange-colored oil, could not be crystallized. Data for 3a: mp 176 "C; IR (KBr) v(C=C) 2015 cm-'; 'H NMR (CDC13) d 0.10 (s, 18 H, SiMea), 0.58 (s, 6 = 2.1 Hz, 4 H, C5H41, 7.40 (pt, JHH = H, SiMez), 5.65 (pt, JHH 2.1 Hz, 4 H, C5H4);13C{lH}NMR (CDC13) 6 -5.5 (s, SiMed, 0.5 (s, SiMes), 97.3 (s, C5H4), 98.2 (s, CIC), 115.7 (s, C5H4), 126.1 (s, C5H4), 170.0 (s, CEC); E1 mass spectrum, m l e (relative intensity) M+, 428 (23); M+ - CzSiMe3, 330 (40); M+ - 2CzSiMe3, 234 (100). Anal. Calcd for C22H32Si3Ti (428.63): C, 61.65; H, 7.52. Found: C, 61.08; H, 7.27. For 3b: IR (neat, NaCl plates) v(C=C) 2017 cm-'; 'H NMR (CDC13) 6 0.09 (s, 18 H, C=CSiMe3), 0.37 (s, 9 H, CsH$Wfea), 0.49 (s, 3 H, SiMez), 0.60 (s, 3 H, SiMez), 5.65 (m, 1 H, C5H41, 5.84 (pt, JHH = 2.3 Hz, 1 H, C&SiMe3), 5.91 (m, 2 H, C5H4, C&.SiMe3), 7.09 (m, 1 H, C5H4),7.45 (m, 2 H, C5H4, C~lhSiMe3);I3C{lH} NMR (CDC13) 6 -6.7, -3.9 (s, SiMe2); -0.3 (s, C5H&Wfe3); 0.1, 0.3 (s, CWSiMe3); 99.5,101.0, 111.8,116.2,120.7,123.1,125.0, 127.6, 132.7, 134.9 (s, C5H4,C5H3SiMe3,C s C ) , 169.0 (s, C=C); E1 mass spectrum, m l e (relative intensity) M+, 501 (22); M+ - Me, 486 (8);M+ - CzSiMe3,402 (100); M+ - 2CzSiMe3,306 (60); SiMe3,+ 73 (18). Anal. Calcd for C25H40Si4Ti (500.82): C, 59.96; H, 8.05. Found: C, 59.15; H, 7.91. For 3c: mp 140 "C; IR (KBr)v(C=C) 2014 cm-'; 'H NMR (CDC13) d 0.06 (s, 9 H, C=CSiMe3), 0.11 (s, 9 H, C=CSiMe3), 0.39 (s, 9 H, C5H3SiMes), 0.40 (s, 9 H, C5H3SiMe3), 0.68 (s, 3 H, SiMe), 5.62 (pt, JHH = 1.8 Hz, 2 H, C&SiMe3), 5.78 (pt, JHH = 2.3 Hz, 2 H, = 2.3 Hz, 2 H, Ca3SiMe31, 5.97 (pt, C&3SiMe3), 5.84 (pt, JHH JHH = 1.8 Hz, 2 H, C,&SiMe3), 6.17 (pt, JHH = 2.3 Hz, 2 H, = 1.8Hz, 2 H, CasSiMed, 7.3-7.9 Ca3SiMe3), 6.60 (pt, JHH (m, 5 H, Ph); E1 mass spectrum, m l e (relative intensity) M+, 634 (28); M+ - CzSiMe3, 537 (100);M+ - 2CzSiMe3, 440 (20); SiMe3+, 73 (19). Anal. Calcd for C33H50Si5Ti (635.07): C, 62.41; H, 7.94. Found: C, 61.90; H, 8.20. (B) Synthesis of 5a-c. The bis(alkyny1)ansa-titanocenes 3a-c (3a, 215 mg; 3b, 250 mg; 3c, 320 mg; 0.5 mmol) were dissolved in toluene (50 mL), and Ni(C0)4 (100 mg, 0.58 mmol) was added at 25 "C in one portion. After stirring for 1h a t 25 "C all volatile materials were removed in vacuo, and the residues were each extracted with 50 mL of n-pentane. Crystallization at -30 "C yielded compound 5c (315 mg, 0.44 mmol, 87%) as brown-golden solid; compounds 5a (230 mg, 0.45 mmol, 90%) and 5b (280 mg, 0.48 mmol, 95%) could not be crystallized. Data for 5a: IR (neat, NaCl plates) v(C0) 1995 cm-I (s),v(C=C) 1834 cm-l (m); 'H NMR (CDC13) 6 0.32 (s, 9 H, SiMes), 0.33 (s, 9 H, SiMes), 0.59 (s, 3 H, SiMez), 0.60 (s,3 H, SiMez), 5.33 (pt, JHH = 2 Hz, 4 H, C5H4), 5.68 (pt, JHH =2 Hz, 4 H, C5H4); E1 mass spectrum, m l e (relative intensity) M- - CO, 486 (64); M+ - NiCO - 2CzSiMe3, 234 (100); MenSiC5H5+,123 (84); SiMe3+, 73 (76). Anal. Calcd for C23H32NiOSi3Ti (515.33): C, 53.61; H, 6.26. Found: C, 53.41; H, 6.42. Data for 5b: IR (neat, NaCl plates) v(C0) 1995 cm-' (vs), v(C=C) 1834 cm-I (9); 'H NMR (CDC13) 6 0.01 (s, 9 H, C5H3SiMes), 0.31 (s, 18 H, C=CSiMe3), 0.57 (s, 3 H, SiMez), 0.60 (s, 3 H, SiMez), 5.11 (m, 1 H, C5H4), 5.33 (pt, JHH = 2.0 Hz, 1 H, Ca3SiMe3), 5.39 (m, 1 H, C5H4), 5.60 (m, 1H, C5H4), 5.64 (pt, JHH = 2.0 Hz, 1 H, CasSiMe3), 5.67 (m, 1H, C5H4), 5.88 (pt, JHH = 2.0 Hz, 1 H, CasSiMe3); I3C{lH} NMR (CDC13) d -5.2 (s, SiMe2); -0.3, 0.6, 0.8 (s, SiMe3); 81.3, 82.1, 105.2, 106.4, 109.3, 110.1, 110.4, 115.4, 117.1, 120.4, 125.3 (s,C5H4, C5H3SiMes, C=C); 189.8 (s, C=C), 200.8 (s, CO); E1 mass spectrum, m l e (relative intensity) M+, 586 (4); M+ - CO, 557 (100);M+
- CbH5SiMe3, 447 (16); M+ - C5H5SiMe3 - SiMe3, 373 (14); Si(C5&)2Ti+, 202 (24);SiMe3+,73 (20). Anal. Calcd for C26H40NiOSi4Ti(587.52): C, 53.15; H, 6.86. Found: C, 53.17; H, 6.42. Data for 5c: mp 62 "C; IR (KBr) v ( C 0 )2003 cm-' (s), v(CIC) 1831 cm-I (m); 'H NMR (CDCL) d 0.07 (s, 18 H, C5H3SiMe3), 0.28 (s, 9 H, CWSiMes), 0.33 (s, 9 H, CWSiMes), 0.84 (s, 3 H, SiMe), 5.05 (pt, JHH = 1.9 Hz, 2 H, C5H3SiMe3), 5.65 (pt, JHH = 1.9 Hz, 2 H, Ca3SiMe31, 5.95 (pt, JHH = 1.9 Hz,2 H, C&SiMe3), 7.51 (m, 3 H, CeH5), 7.93 (m, 2 H, C6H5); l3C(lH} NMR (CDC13) 6 -4.8 (s, SiMe); 0.0, 0.6, 0.8 (s, SiMe3); 109.9, 111.9, 112.9, 119.5, 127.1, 128.3, 130.3, 134.7 (s,C6H5, C5H3SiMe3, C=C); 190.1 (s, C=C), 203.5 (s, CO); E1 mass spectrum, m l e (relative intensity) M+, 721 (2); M+ - CH3, 707 (2);M+ CO, 693 (100); SiMes+,73 (10). Anal. Calcd for C34H50NiOSi5Ti (721.77): C, 56.58; H, 6.98. Found: C, 56.38; H, 7.23. (C) Synthesis of 7. To [(r5-C5H3SiMe3)(~5-CgH4)SiMe21ZrCl2 (@I4 (2.0 g, 4.8 mmol) in THF (50 mL) were added at 25 (0.5 g, 4.8 mmol, 20 mL "C in one portion LiClCSiMes EtzO), and after 5 min, nC4HSLi(1.9 mL, 4.8 mmol; 2.5 M in hexane) in 100 mL of EtaO. After stirring for 2 h at 25 "C the solvents were evaporated under high vacuum; the residue was extracted with 50 mL of n-pentane and filtered through a pad of Celite. Crystallization from Et20 at -30 "C yielded 7 (0.96 g, 1.1mmol; 45%) as a n orange-colored solid: mp 131 "C; IR (KBr) v(C=C) 1741 cm-'; 'H NMR (CDC13) 6 0.14 (s, 9 H, SiMes), 0.45 (s, 9 H, SiMes), 0.52 (s, 3 H, SiMez), 0.70 (s, 3 H, SiMez), 4.16 (m, 2 H, C5H41, 4.99 (pt, JHH = 2 Hz, 2 H, C5H3= 2 Hz, 2 H, C5H3SiMea), 5.79 (m, 2 H, C5H4), 5.99 (pt, JHH SiMes), 6.03 (m, 6 H, C5H4, Ca3SiMe3); E1 mass spectrum, m l e (relative intensity) M+, 892 (100); W 2 + - CzSiMea, 348 (28). Anal. Calcd for C ~ O H ~ Z S ~(893.89): ~ Z I ' Z c, 53.75; H, 6.99. Found: C, 53.73; H, 7.07. X-ray Structure Determinations of lb, 3a, and 7. The structures of compounds lb, 3a, and 7 were determined from single-crystal X-ray diffraction data, which were collected using a Siemens R3mN (Nicolet Syntex) diffractometer. Crystallographic data for lb, 3a, and 7 are given in Table 1. All structures were solved by direct methods (SHELXTL PLUS; Sheldrick, G. M. University of Gottingen: Gottingen, Germany, 1988). An empirical absorption correction was applied. The structures of l b and 3a were refined by the leastsquares method based on F with all reflections (SHELXTL PLUS) the structure of 7 was refined by the least-squares method based on F2 with all reflections (SHEWLL 93; Sheldrick, G. M. University of Gottingen: Gottingen, Germany, 1993). All non-hydrogen atoms were refined anisotropically; the hydrogens were placed in calculated positions. Two of the trimethylsilyl groups (C(18)-C(20); C(213), C(214)) in 7 are disordered.
Acknowledgment. We are grateful to the Deutsche Forschungsgemeinschaft, the Volkswagenstiftung and the Fonds der Chemischen Industrie for financial support. We thank Th. Jannack for carrying out the MS measurements. Supporting Information Available: Tables of crystal data and structure refinement, bond lengths and bond angles, and anisotropic displacement factors for lb, 3a, and 7 (21 pages). Ordering information is given on any current masthead page. OM9500984
