Reactivity of the ansa-bridged metallocene dichlorides [X(η5-C5H4)2]MCl2 (X = SiMe2, CMe2; M = Mo, W) toward metallophosphide anions [PPh2M′(CO)x]- (M′ = Cr, Mo, W, x = 5; M′ = Fe, x = 4)

Article abstract of DOI:10.1021/om970630i

Two kinds of ansa derivatives, [SiMe₂(η⁵-C₅H₄) ₂]MCl₂ and [CMe₂(η⁵-C₅H₄) ₂]MCl₂ (M = Mo, W), are reacted with metallophosphide anions [PPh₂M′(CO)_x]^- (M′ = Cr, Mo, W, x = 5; M′ = Fe, x = 4). The silicon-bridged derivatives give the bimetallic systems [SiMe₂(η⁵-C₅H₄)(η ⁵-C₅H₃PPh₂M′CO) _x]M(H)(Cl), which result from a regioselective substitution at the 3-position on the cyclopentadienyl ligand. In contrast, with the CMe₂-bridged compounds, the substitution reaction occurs at the metallic center, giving μ-phosphido bimetallic complexes [CMe₂(η⁵-C₅H₄) ₂]M(Cl)(μ-PPh₂)M′(CO)_x. The solid-state structure of the bimetallic complex [CMe₂(η⁵-C₅H₄) ₂]W(Cl)(μ-PPh₂)Fe(CO)₄ (7d) is reported.

Full text of DOI:10.1021/om970630i

Organometallics 1997, 16, 5763-5769
5763
Rea ctivity of th e a n sa -Br id ged Meta llocen e Dich lor id es
[X(η5-C5H4)2]MCl2 (X ) SiMe2, CMe2; M ) Mo, W) tow a r d
Meta llop h osp h id e An ion s [P P h 2M′(CO)x]- (M′ ) Cr , Mo,
W, x ) 5; M′ ) F e, x ) 4). F or m a tion of Heter obim eta llic
Com p lexes by Nu cleop h ilic Su bstitu tion on a
Cyclop en ta d ien yl Liga n d or on th e Meta l M
Virginie Comte, Olivier Blacque, Marek M. Kubicki, and Claude Mo¨ıse*
Laboratoire de Synthe`se et d’Electrosynthe`se Organome´talliques UMR 5632 (LSEO),
Faculte´ des Sciences Gabriel, Universite´ de Bourgogne, 21000 Dijon, France
Received J uly 24, 1997X
Two kinds of ansa derivatives, [SiMe2(η5-C5H4)2]MCl2 and [CMe2(η5-C5H4)2]MCl2 (M ) Mo,
W), are reacted with metallophosphide anions [PPh2M′(CO)x]- (M′ ) Cr, Mo, W, x ) 5; M′
) Fe, x ) 4). The silicon-bridged derivatives give the bimetallic systems [SiMe2(η5-C5H4)(η5-
C5H3PPh2M′(CO)x)]M(H)(Cl), which result from a regioselective substitution at the 3-position
on the cyclopentadienyl ligand. In contrast, with the CMe2-bridged compounds, the
substitution reaction occurs at the metallic center, giving µ-phosphido bimetallic complexes
[CMe2(η5-C5H4)2]M(Cl)(µ-PPh2)M′(CO)x. The solid-state structure of the bimetallic complex
[CMe2(η5-C5H4)2]W(Cl)(µ-PPh2)Fe(CO)4 (7d ) is reported.
In tr od u ction
substitution reaction when opposed to Grignard
reagents;5c,d MgCl2 is postulated to promote the reaction
by Lewis acid complexation of a chloride in Cp2WCl2.
We have recently shown that the dichlorides Cp2MCl2
(M ) Mo, W) display similar reactivity with metallo-
phosphide anions [PPh2M′(CO)x]-. Bimetallic systems
are easily built through a nucleophilic substitution of
the cyclopentadienyl ligand by an anionic metallophos-
phide moiety.6 The presence of methyl or tert-butyl
groups on the rings does not affect the site of the
substitution reaction.7 Thus, one may anticipate that
geometrical factors could be predominant in the orienta-
tion of the reaction between the two electrophilic zones
of reactivity: the metal center or Cp ligands. On the
basis of this belief, we undertook a study with ansa
derivatives. Such structures are known to afford sig-
nificant variations in the tilt of Cp rings and conse-
quently in the π electron density distribution within the
rings.8 In this paper we wish to report the results
obtained for SiMe2 and CMe2 ansa-bridged systems.
Electrophilic substitution reactions leading to func-
tionalized cyclopentadienyl ligands are commonly en-
countered in electron-rich complexes such as ferrocene.1
The d6 electronic structure of the metal and the parallel
Cp rings account for a rather high electron density on
the rings. Metallocenes with early or middle transition
metals do not exhibit this property, and the usual
synthetic routes to Cp-functionalized derivatives involve
complexation on prefunctionalized ligands, which limit
the range of functional groups available on the com-
plexes. In fact, the bending of cyclopentadienyl planes
in early-metal metallocenes leads to a decrease of
electron density retained on these rings.2 However,
there are some rare examples of the introduction of
substituents on Cp ligands in group 6 metallocenes.
Tungstenocene derivatives with exocyclic boron3 or silyl4
substituents have been recently reported but their
formation results from a ligand transfer from metal to
the Cp ring. On the other hand, substituted tung-
stenocene complexes have been prepared by reaction of
heteroanionic nucleophiles with the cationic derivative
[Cp2W(SMe2)Br]+.5a,b In this last case the positive
metallic charge draining some electron density from the
aromatic ligands may be responsible for the activation
of the Cp rings. However, as also mentioned by Cooper,
the neutral dichloride Cp2WCl2 is able to undergo a ring
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions were carried out under
an atmosphere of purified argon. The solvents and eluents
were dried by the appropriate procedure and distilled under
argon from sodium and benzophenone immediately before use.
Standard Schlenk techniques and conventional glass vessels
were employed. Column chromatography was performed
under argon with silica gel (70-230 mesh). Elemental analy-
ses were carried out with a EA 1108 CHNS-O FISONS
Instruments apparatus. Electron ionization mass spectra were
run on a Kratos Concept 32S.
X Abstract published in Advance ACS Abstracts, November 15, 1997.
(1) Deeming, A. J. Comprehensive Organometallic Chemistry; Wilkin-
son, G., Stone, F. G. A., Abel, E. W., Eds., Pergamon: Oxford, U.K.,
1982; Vol. 4.
(2) Kubicki, M. M.; Kergoat, R.; Guerchais, J . E.; Bkouche-Waks-
man, I.; Bois, C.; L’Haridon, P. J . Organomet. Chem. 1981, 219, 329.
(3) (a) Braunschweig, H.; Wagner, T. Chem. Ber. 1994, 127, 1613.
(b) Hartwig, J . F.; He, X. Organometallics 1996, 15, 5350.
(4) Schubert, U.; Schenkel, A. Chem. Ber. 1988, 121, 939.
(5) (a) McNally, J . P.; Glueck, D.; Cooper, N. J . J . Am. Chem. Soc.
1988, 110, 4838. (b) McNally, J . P.; Cooper, N. J . J . Am. Chem. Soc.
1989, 111, 4500. (c) Forschner, T. C.; Cooper, N. J . J . Am. Chem. Soc.
1989, 111, 7420. (d) Forschner, T. C.; Corella, J . A., II Cooper, N. J .
Organometallics 1990, 9, 2478.
(6) Rigny, S.; Leblanc, J . C.; Mo¨ıse, C. New J . Chem. 1995, 19, 145.
(7) (a) Rigny, S.; Bakhmutov, V. I.; Nuber, B.; Leblanc, J . C.; Mo¨ıse,
C. Inorg. Chem. 1996, 35, 3202. (b) Comte, V.; Rigny, S.; Mo¨ıse, C.
Bull. Soc. Chim. Fr. 1997, 134, 609.
(8) Stern, D.; Sabat, M.; Marks, T. J . J . Am. Chem. Soc. 1990, 112,
9558.
S0276-7333(97)00630-4 CCC: $14.00 © 1997 American Chemical Society

5764 Organometallics, Vol. 16, No. 26, 1997
Comte et al.
1H and 31P spectra were recorded on a Bruker AC 200
spectrometer. Chemical shifts are relative to internal TMS
(1H) or external H3PO4 (31P). IR spectra were recorded on a
Nicolet 205 IR-FT. PPh2Cl (Strem) and NaAlH2(OCH2CH2-
OMe)2 (Aldrich) were used as received. M′(CO)5(THF) was
prepared by the method indicated in the literature.9 The
lithium reagent, Li[PPh2M′(CO)x] (x ) 5, M′ ) Cr, Mo, W; x )
4, M′ ) Fe), was prepared according to the literature method10
using low-chloride methyllithium (J anssen).
[CMe2(η5-C5H4)2]Mo(Cl)(µ-P P h 2)Cr (CO)5 (6a ). IR (νCO
,
THF): 2064 (m), 1930 (S), 1915 (S), 1893 (S) cm-1 1H NMR
.
(CDCl3): δ 0.37 (s, 3H, Me), 1.07 (s, 3H, Me), 7.20-7.80 (m,
10H, C6H5). 1H NMR (DMSO-d6): δ 0.37 (s, 3H, Me), 1.07 (s,
3H, Me), 3.34 (m, 2H, C5H4), 5.70 (m, 2H, C5H4), 5.86 (m, 2H,
C5H4), 6.02 (m, 2H, C5H4), 7.21-7.53 (m, 6H, C6H5), 7.75-7.82
(m, 4H, C6H5). 31P{1H} NMR (DMSO-d6): δ 3,61 (s). Anal.
Calcd for C30H24O5ClPMoCr: C, 52.94; H, 3.56. Found: C,
52.39; H, 4.1.
The ansa dichlorides (4, 5) and dihydrides (8, 9) were all
prepared by adapting the procedure described by Green et al.11
[CMe2(η5-C5H4)2]Mo(Cl)(µ-P P h 2)Mo(CO)5 (6b). IR (νCO
THF): 2060 (m), 1935 (S), 1920 (S), 1894 (S) cm-1 1H NMR
,
.
[SiMe2(η5-C5H4)2]MCl2 (M ) Mo (1), M ) W (2)). The
procedure employed to prepare Li2[SiMe2(η5-C5H4)2] has been
described by Petersen et al. in the literature.12 [SiMe2(η5-
C5H4)2]MCl2 was synthesized by the same procedure used for
ansa CMe2 complexes.11 [SiMe2(η5-C5H4)2]MoCl2 (1) was ob-
tained as a brown powder in 30% yield and [SiMe2(η5-C5H4)2]-
WCl2 (2) as a gray powder in 40% yield after recrystallization
from chloroform.
[SiMe2(η5-C5H4)2]MoCl2 (1). 1H NMR (CDCl3): δ 0.06 (s,
6H, Me), 5.33 (m, 4H, C5H4), 6.54 (m, 4H, C5H4). Anal. Calcd
for C12H14Cl2MoSi: C, 40.81; H, 4.00. Found: C, 41.11; H,
3.86.
(CDCl3): δ 0.27 (s, 3H, Me), 1.01 (s, 3H, Me), 7.21-7.80 (m,
10H, C6H5). Unsatisfactory analysis was obtained for this
compound, but the mass spectrum displays the M+ fragment.
[CMe2(η5-C5H 4)2]Mo(Cl)(µ-P P h 2)W(CO)5 (6c). IR (νCO
THF): 2062 (m), 1927 (S), 1916 (S), 1893 (S) cm-1 1H NMR
,
.
(CDCl3): δ 0.07 (s, 3H, Me), 0.41 (s, 3H, Me), 7.20-7.83 (m,
10H, C6H5). 1H NMR (DMSO-d6): δ 0.30 (s, 3H, Me), 1.08 (s,
3H, Me), 3.22 (m, 2H, C5H4), 5.71 (m, 2H, C5H4), 5.83 (m, 2H,
C5H4), 6.0 (m, 2H, C5H4), 7.18-7.79 (m, 10H, C6H5). 31P{1H}
1
NMR (DMSO-d6): δ -23.7 (s + d, J WP ) 191 Hz). Anal.
Calcd for C30H24O5ClPMoW: C, 44.95; H, 2.98. Found: C,
45.39; H, 2.73.
[CMe2(η5-C5H4)2]W(Cl)(µ-P P h 2)M′(CO)x (7). A procedure
similar to that for the molybdocene derivatives was followed
using [CMe2(η5-C5H4)2]WCl2 (5; 430 mg, 1 mmol) and Li-
[PPh2M′(CO)x] (1 mmol; x ) 5, M′ ) Cr, Mo, W; x ) 4, M′ )
Fe). All complexes were obtained as red crystals after recrys-
tallization from acetone in 40% yield for 7a (300 mg), in 20%
yield for 7b (160 mg), in 30% yield for 7c (270 mg), and in
20% yield for 7d (150 mg).
[SiMe2(η5-C5H4)2]WCl2 (2). 1H NMR (CDCl3): δ 0.13 (s,
6H, Me), 5.78 (m, 4H, C5H4), 6.16 (m, 4H, C5H4). Anal. Calcd
for C12H14Cl2WSi: C, 32.68; H, 3.2. Found: C, 32.44; H, 3.3.
[SiMe2(η5-C5H4)(η5-C5H3P P h 2M′(CO)x)]W(H)(Cl) (3). A
5 mL amount of a THF solution of Li[PPh2M′(CO)x] (1 mmol)
was rapidly added to 20 mL of a THF suspension of [SiMe2-
(η5-C5H4)2]WCl2 (2; 440 mg, 1 mmol). The mixture was stirred
at room temperature for 5 h. THF was removed in vacuo, and
the residue was washed with pentane (2 × 20 mL) and
chromatographed on silica gel (eluent toluene/THF (9/1)) to
give an orange powder in 40% yield for 3a , in 30% yield for
3b, and in 30% yield for 3c.
1H and 31P NMR spectra were recorded at 50 °C in CDCl3
and at 80 °C in DMSO-d6 to obtain better resolution.
[CMe2(η5-C5H 4)2]W(Cl)(µ-P P h 2)Cr (CO)5 (7a ). IR (νCO
,
THF): 2051 (m), 1930 (S), 1916 (S), 1894 (S) cm-1 1H NMR
.
[SiMe2(η5-C5H4)(η5-C5H3P P h 2Cr (CO)5)]W(H)(Cl) (3a). IR
(CDCl3): δ 0.86 (s, 3H, Me), 0.30 (s, 3H, Me), 7.20-7.78 (m,
10H, C6H5). 1H NMR (DMSO-d6): δ 0.27 (s, 3H, Me), 1.03 (s,
3H, Me), 3.50 (m, 2H, C5H4), 5.76 (m, 2H, C5H4), 5.85 (m, 2H,
C5H4), 5.96 (m, 2H, C5H4), 7.22-7.44 (m, 6H, C6H5), 7.70-7.82
(m, 4H, C6H5). 31P{1H} NMR (DMSO-d6): δ -32.75 (s + d,
1J WP ) 185 Hz). Anal. Calcd for C30H24O5ClPWCr: C, 46.99;
H, 3.15. Found: C, 46.41; H, 3.37.
(νCO, THF): 2063 (m), 1940 (S + sh) cm-1
.
1H NMR (CD3-
COCD3): δ -0.04 (s, 3H, Me), 0.47 (s, 3H, Me), 7.40-7.68 (m,
10H, C6H5). Anal. Calcd for C29H24O5ClWCrSi: C, 44.49; H,
3.09. Found: C, 44.41; H, 3.2.
[SiMe2(η5-C5H4)(η5-C5H3P P h 2W(CO)5)]W(H)(Cl) (3b). IR
(νCO, THF): 2071 (m), 1938 (S + sh) cm-1
.
1H NMR (CD3-
[CMe2(η5-C5H 4)2]W(Cl)(µ-P P h 2)Mo(CO)5 (7b ). IR (νCO
THF): 2060 (m), 1927 (S), 1915 (S), 1894 (S) cm-1 1H NMR
,
COCD3): δ -0.05 (s, 3H, Me), 0.48 (s, 3H, Me), 7.18-7.68 (m,
10H, C6H5). Anal. Calcd for C29H24O5ClW2Si: C, 38.08; H,
2.64. Found: C, 38.62; H, 2.94.
.
(CDCl3): δ 0.31 (s, 3H, Me), 0.96 (s, 3H, Me), 7.18-7.74 (m,
10H, C6H5). 1H NMR (DMSO-d6): δ 0.29 (s, 3H, Me), 1.04 (s,
3H, Me), 3.54 (m, 2H, C5H4), 5.67 (m, 2H, C5H4), 5.82 (m, 2H,
C5H4), 5.96 (m, 2H, C5H4), 7.18-7.45 (m, 6H, C6H5), 7.68-7.76
(m, 4H, C6H5). 31P{1H} NMR (DMSO-d6): δ -57.7 (s + d, 1J WP
) 190 Hz). Anal. Calcd for C30H24O5ClPWMo: C, 44.45; H,
2.98. Found: C, 44.69; H, 3.04.
[SiMe2(η5-C5H4)(η5-C5H3P P h 2Fe(CO)4)]W(H)(Cl) (3c). IR
(νCO, THF): 2048 (m), 1970 (S), 1940 (S) cm-1
.
1H NMR
(CD3COCD3): δ -0.01 (s, 3H, Me), 0.47 (s, 3H, Me), 7.41-
7.60 (m, 6H, C6H5), 7.70-7.83 (m, 4H, C6H5). Anal. Calcd for
28H24O4ClWFeSi: C, 44.33; H, 3.19. Found: C, 43.86; H,
3.02.
[CMe2(η5-C5H4)2]Mo(Cl)(µ-P P h 2)M′(CO)5 (6). To 15 mL
C
[CMe2(η5-C5H 4)2]W(Cl)(µ-P P h 2)W(CO)4 (7c). IR (νCO
THF): 2060 (m), 1927 (S), 1915 (S), 1893 (S) cm-1 1H NMR
,
.
of a THF suspension of [CMe2(η5-C5H4)2]MoCl2 (4; 340 mg, 1
mmol) was rapidly added 5 mL of a THF solution of Li[PPh2M′-
(CO)x] (1 mmol; x ) 5, M′ ) Cr, Mo, W). The mixture was
stirred at room temperature for 5 h. THF was removed in
vacuo; the residue was washed with pentane (2 × 20 mL) and
chromatographed (eluent toluene/THF (9/1)) to give a red
powder. All complexes were recrystallized from acetone as red
crystals in 25% yield for 6a (170 mg), in 15% yield for 6b (60
mg), and in 35% yield for 6c (240 mg). 1H and 31P NMR
spectra were recorded at 50 °C in CDCl3 and at 80 °C in
DMSO-d6 to obtain better resolution.
(CDCl3): δ 0.30 (s, 3H, Me), 0.96 (s, 3H, Me), 7.20-7.74 (m,
10H, C6H5). 1H NMR (DMSO-d6): δ 0.29 (s, 3H, Me), 1.04 (s,
3H, Me), 3.55 (m, 2H, C5H4), 5.73 (m, 2H, C5H4), 5.84 (m, 2H,
C5H4), 5.97 (m, 2H, C5H4), 7.17-7.45 (m, 6H, C6H5), 7.68-7.76
(m, 4H, C6H5). 31P{1H} NMR (DMSO-d6): δ -55.35 (s + d,
1J WP ) 193 Hz). Anal. Calcd for C30H24O5ClPW2: C, 40.10;
H, 2.69. Found: C, 40.08; H, 3.07.
[CMe2(η5-C5H 4)2]W(Cl)(µ-P P h 2)F e(CO)4 (7d ). IR (νCO
THF): 2028 (m), 1950 (S), 1926 (S), 1901 (S) cm-1 1H NMR
,
.
(CDCl3): δ 0.65 (s, 3H, Me), 1.10 (s, 3H, Me), 7.20-7.83 (m,
10H, C6H5). 1H NMR (DMSO-d6): δ 0.61 (s, 3H, Me), 0.98 (s,
3H, Me), 4.10 (m, 2H, C5H4), 5.46 (m, 2H, C5H4), 5.54 (m, 2H,
C5H4), 5.78 (m, 2H, C5H4), 7.14-7.40 (m, 6H, C6H5), 7.68-7.77
(m, 4H, C6H5). 31P{1H} NMR (DMSO-d6): δ -16.33 (s + d,
1J WP ) 190 Hz). Anal. Calcd for C29H24O4ClPWFe: C, 46.9;
H, 3.26. Found: C, 46.9; H, 3.13.
(9) Werner, H.; Leonhard, K.; Burschka, C. J . Organomet. Chem.
1978, 160, 291.
(10) Breen, M. J .; Shulman, P. M.; Geoffroy, G. L.; Rheingold, A.
L.; Fultz, W. C. Organometallics 1984, 3, 782.
(11) Labella, L.; Chernega, A.; Green, M. L. H. J . Chem. Soc., Dalton
Trans. 1995, 395.
[CMe2(η5-C5H4)2M(H)(P P h 2H)]Cl (M ) Mo (10), M ) W
(12) Bajgur, C. S.; Tikkanen, W. R.; Petersen, J . L. Inorg. Chem.
1985, 24, 2539.
(11)) a n d [CMe2(η5-C5H4)2]M(H)(P P h 2) (M ) Mo (12), M

ansa-Bridged Metallocene Dichlorides
Organometallics, Vol. 16, No. 26, 1997 5765
) W (13)). Syntheses of the salts 10 and 1113 and the
complexes 12 and 1314 were adapted from the procedures
described in the literature. Treatment of 8 or 9 with PPh2Cl
in toluene leads to the phosphine salt [CMe2(η5-C5H4)2M(H)-
(PPh2H)]Cl, which is deprotonated in aqueous KOH. 12 is
obtained as a gray powder in 50% yield and 13 as a brown
powder in 80% yield.
[CMe2(η5-C5H4)2]Mo(H)(µ-P P h 2)Cr (CO)5 (14a ). IR (νCO
,
THF): 2046 (m), 1966 (S), 1929 (S), 1895 (S) cm-1 1H NMR
.
(CD3COCD3): δ 0.93 (s, 3H, Me), 0.98 (s, 3H, Me), 7.18-7.35
(m, 6H, C6H5), 7.50-7.65 (m, 4H, C6H5).
[CMe2(η5-C5H4)2]Mo(H)(µ-P P h 2)Mo(CO)5 (14b). not iso-
lated.
[CMe2(η5-C5H4)2]Mo(H)(µ-P P h 2)W(CO)5 (14c). IR (νCO
THF): 2075 (m), 1948 (S), 1928 (S), 1881 (S) cm-1 1H NMR
,
[CMe2(η5-C5H4)2Mo(H)(P P h 2H)]Cl (10). 1H NMR (CD3-
.
2
(CD3COCD3): δ 1.03 (s, 3H, Me), 1.2 (s, 3H, Me), 7.22-7.68
(m, 10H, C6H5).
COCD3): δ -6.19 (d, J PH ) 42 Hz, 1H, Mo-H), 1.15 (s, 3H,
Me), 1.38 (s, 3H, Me), 5.18 (m, 2H, C5H4), 5.23 (m, 2H, C5H4),
5.32 (m, 2H, C5H4), 5.85 (m, 2H, C5H4), 7.18-7.81 (m, 10H,
[CMe2(η5-C5H4)2]Mo(µ-P P h 2,H)Cr (CO)4 (14′a ). IR (νCO
,
THF): 1987 (m), 1892 (S), 1872 (S), 1855 (S) cm-1 1H NMR
.
2
C6H5), 7.76 (d, J PH ) 395 Hz, 1H, P-H). 31P{1H} NMR
(CD3COCD3): δ 1.35 (s, 3H, Me), 1.41 (s, 3H, Me), 7.28-7.40
(m, 6H, C6H5), 8.1-8.12 (m, 4H, C6H5). Anal. Calcd for
(CD3COCD3): δ 33.22 (s). Anal. Calcd for C25H26ClPMo: C,
61.43; H, 5.36. Found: C, 60.44; H, 6.02.
[CMe2(η5-C5H 4)2W(H )(P P h 2H )]Cl (11). 1H NMR (CD3-
C
29H25O4PMoCr: C, 56.51; H, 4.09. Found: C, 56.82; H, 4.13.
[CMe2(η5-C5H4)2]Mo(µ-P P h 2,H)Mo(CO)4 (14′b). IR (νCO
THF): 2001 (m), 1896 (S), 1882 (S), 1857 (S) cm-1 1H NMR
2
1
,
COCD3): δ -8.6 (d + dd, J PH ) 37.5 Hz, J WH ) 118 Hz, 1H,
W-H), 1.09 (s, 3H, Me), 1.24 (s, 3H, Me), 5.13 (m, 2H, C5H4),
5.16 (m, 2H, C5H4), 5.27 (m, 2H, C5H4), 5.67 (m, 2H, C5H4),
.
(CD3COCD3): δ 1.34 (s, 3H, Me), 1.37 (s, 3H, Me), 7.24-7.35
(m, 6H, C6H5), 8.04-8.12 (m, 4H, C6H5). Unsatisfactory
analysis was obtained for this compound, but the mass
spectrum displays the M+ fragment.
2
7.36-7.62 (m, 10H, C6H5), 7.91 (d, J PH ) 398 Hz, 1H, P-H).
1
31P{1H} NMR (CD3COCD3): δ -13.85 (s + d, J WP ) 229 Hz).
Anal. Calcd for C25H26ClPW: C, 52.06; H, 4.54. Found: C,
53.0; H, 4.93.
[CMe2(η5-C5H 4)2]Mo(µ-P P h 2,H )W(CO)4 (14′c). IR (νCO
THF): 1995 (m), 1890 (S), 1874 (S), 1852 (S) cm-1 1H NMR
,
.
[CMe2(η5-C5H 4)2]Mo(H )(P P h 2) (12). 1H NMR (CD3-
(CD3COCD3): δ 1.34 (s, 3H, Me), 1.39 (s, 3H, Me), 7.25-7.51
(m, 6H, C6H5), 8.04-8.12 (m, 6H, C6H5). Anal. Calcd for
2
COCD3): δ -5.23 (d, J PH ) 36 Hz, 1H, Mo-H), 1.11 (s, 3H,
Me), 1.14 (s, 3H, Me), 3.82 (m, 2H, C5H4), 4.71 (m, 2H, C5H4),
4.8 (m, 2H, C5H4), 5.24 (m, 2H, C5H4), 7.18-8.10 (m, 10H,
C6H5). 31P{1H} NMR (CD3COCD3): δ -22.79 (s). Anal. Calcd
for C25H25PMo: C, 66.38; H, 5.57. Found: C, 67.14; H, 6.33.
C
29H25O4PMoW: C, 46.55; H, 3.37. Found: C, 46.25; H, 3.65.
[CMe2(η5-C5H 4)2]W(H )(µ-P P h 2)Cr (CO)5 (15a ). IR (νCO
THF): 2048 (m), 1930 (S), 1915 (S), 1898 (S) cm-1 1H NMR
,
.
(CD3COCD3): δ 0.85 (s, 3H, Me), 0.88 (s, 3H, Me), 7.17-7.4
(m, 6H, C6H5), 7.59-7.67 (m, 4H, C6H5). Anal. Calcd for
[CMe2(η5-C5H4)2]W(H)(P P h 2) (13). 1H NMR (CD3CO-
2
1
CD3): δ -7.14 (d + dd, J PH ) 32 Hz, J WH, 1H, W-H), 0.87
(s, 3H, Me), 0.98 (s, 3H, Me), 4.62 (m, 4H, C5H4), 4.82 (m, 1H,
C5H4), 4.89 (m, 1H, C5H4), 5.09 (m, 2H, C5H4), 6.93-7.84 (m,
10H, C6H5). 31P{1H} NMR (CD3COCD3): δ -50.36 (s + d,
1J WP). Anal. Calcd for C25H25PW: C, 55.58; H, 4.66. Found:
C, 54.27; H, 4.90.
C
30H25O5PWCr: C, 49.20; H, 3.44. Found: C, 49.91; H, 3.81.
[CMe2(η5-C5H4)2]W(H)(µ-P P h 2)Mo(CO)5 (15b). IR (νCO
THF): 2060 (m), 1934 (S), 1921 (S), 1898 (S) cm-1 1H NMR
,
.
(CD3COCD3): δ 0.85 (s, 3H, Me), 0.93 (s, 3H, Me), 7.15-7.34
(m, 6H, C6H5), 7.64-7.7 (m, 4H, C6H5). Anal. Calcd for
C
30H25O5PWMo: C, 46.42; H, 3.25. Found: C, 45.91; H, 3.42.
[CMe2(η5-C5H 4)2]W(H )(µ-P P h 2)W(CO)5 (15c). IR (νCO
THF): 2059 (m), 1927 (S), 1916 (S), 1894 (S) cm-1 1H NMR
[CMe2(η5-C5H4)2]M(H)(µ-P P h 2)M′(CO)5 (M ) Mo (14), M
) W (15)) a n d [CMe2(η5-C5H4)2]M(µ-P P h 2,H)M′(CO)4 (M
) Mo (14′), M ) W (15′)). The complexes 14 + 14′ and 15 +
15′ were prepared by adapting a procedure described for the
parent Cp complexes in the literature.15 To a THF solution
(20 mL) of [CMe2(η5-C5H4)2]M(H)(PPh2) (1 mmol) was added
an excess (30%) of M′(CO)5(THF). The mixture was stirred
for 1 h at room temperature. During this time, the solution
turned from yellow to orange. The solvent was removed under
vacuum, and the crude product was washed with pentane and
purified by chromatography.
,
.
(CD3COCD3): δ 0.86 (s, 3H, Me), 0.94 (s, 3H, Me), 7.14-7.32
(m, 6H, C6H5), 7.50-7.66 (m, 4H, C6H5). Anal. Calcd for
C
30H25O5PW2: C, 41.7; H, 2.92. Found: C, 39.7; H, 2.6.
[CMe2(η5-C5H 4)2]W(µ-P P h 2,H )Cr (CO)4 (15′a ). IR (νCO
,
THF): 1987 (m), 1890 (S), 1870 (S), 1852 (S) cm-1 1H NMR
.
(CD3COCD3): δ 1.27 (s, 3H, Me), 1.32 (s, 3H, Me), 7.12-7.36
(m, 6H, C6H5), 8.07-8.15 (m, 4H, C6H5). Anal. Calcd for
C
29H25O4PWCr: C, 49.45; H, 3.58. Found: C, 49.07; H, 3.47.
[CMe2(η5-C5H4)2]W(µ-P P h 2,H)Mo(CO)4 (15′b ). IR (νCO
THF): 2002 (m), 1880 (S), 1861 (S), 1804 (S) cm-1 1H NMR
,
Tu n gsten Com p lexes. The complexes 15 and 15′ were
separated by chromatography with toluene as eluent. The
monobridged compound was obtained in 35% yield for 15a ,
20% yield for 15b, and 40% yield for 15c (based on the complex
[CMe2(η5-C5H4)2]M(H)(PPh2)) from the first yellow band, and
the dibridged complex was recovered (20% yield for 15′a , 15%
yield for 15′b, and 30% yield for 15′c) from the second orange
band.
.
(CD3COCD3): δ 1.26 (s, 3H, Me), 1.29 (s, 3H, Me), 7.24-7.36
(m, 6H, C6H5), 8.05-8.14 (m, 4H, C6H5). Anal. Calcd for
C
29H25O4PWMo: C, 46.55; H, 3.37. Found: C, 47.12; H, 3. 82.
[CMe2(η5-C5H 4)2]W(µ-P P h 2,H )W(CO)4 (15′c). IR (νCO
THF): 1996 (m), 1888 (S), 1874 (S), 1851 (S) cm-1 1H NMR
,
.
(CD3COCD3): δ 1.25 (s, 3H, Me), 1.30 (s, 3H, Me), 7.30-7.36
(m, 6H, C6H5), 8.10-8.14 (m, 4H, C6H5). Anal. Calcd for
Molybd en u m Com p lexes. An analogous reaction leads
to tetracarbonyl product together with a small amount of
pentacarbonyl product, and for M′ ) Mo, only the dibridged
complex 14′b is obtained. Monobridged complexes are light-
and temperature-sensitive and spontaneously give in solution
the dibridged compounds. All recrystallizations of mono-
bridged complexes were unsuccessful. Red or orange crystals
were obtained by recrystallization from acetone for the dibridged
complexes (20% yield for 14′a , 10% yield for 14′b, and 25%
yield for 14′c).
C
29H25O4PW2: C, 41.66; H, 3.01. Found: C, 42.01; H, 3.42.
Red u ction of 7c. 7c was reduced by NaAlH2(OCH2CH2-
OMe)2 (2 M in toluene) in toluene. After 4 h of stirring, the
solution was hydrolyzed slowly by degassed water. The orange
organic layer was decanted and extracted. Evaporation of the
solvent afforded 15c.
Ch lor in a tion of 15c. To a solution of 15c (2 mmol) in 10
mL of chloroform was added 5 mL of CCl4. Then, the mixture
was stirred at room temperature overnight. 7c was then
isolated as a red powder.
Ir r a d ia tion of [CMe2(η5-C5H4)2]M(Cl)(µ-P P h 2)W(CO)5.
A solution of 6c (M ) Mo) or 7c (M ) W) (1.5 mmol) in THF
was irradiated with a HANAU TQ 150 lamp for 2 h at room
temperature. The solvent was evaporated off to give a red
powder. The crude product was chromatographed (eluent
toluene) and was recrystallized from toluene as red crystals.
(13) Kubicki, M. M.; Kergoat, R.; Cariou, M.; Guerchais, J . E.;
L’Haridon, P. J . Organomet. Chem. 1987, 322, 357.
(14) Barre´, C.; Kubicki, M. M.; Leblanc, J . C.; Mo¨ıse, C. Inorg. Chem.
1990, 29, 5244.
(15) Barre´, C.; Boudot, P.; Kubicki, M. M.; Mo¨ıse, C. Inorg. Chem.
1995, 34, 284.

5766 Organometallics, Vol. 16, No. 26, 1997
Comte et al.
Ta ble 1. Cr ysta llogr a p h ic Da ta for
Sch em e 1
[CMe2(η5-C5H4)2]W(Cl)(µ-P P h 2)F e(CO)4 (7d )
mol formula
fw
WFeClPO5C32H30
800.72
color, dimens, mm
cryst syst
space group
cell dimens
a, Å
red; 0.35 × 0.20 × 0.10
triclinic
P1h (No. 2)
10.095(2)
10.846(3)
14.526(2)
87.47(2)
81.09(1)
83.14(2)
1559.4(6)
2
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
d
calcd, g cm-3
1.705
F(000)
788
radiation, Å
scan type
λ(Mo KR), 0.710 73
ω
scan speed, deg min-1
scan width, deg
θ range, deg
2.30-9.23
∆ω ) 0.88 + 0.347 tan θ
2-25
44.045
6683
Sch em e 2
linear abs, µ, cm-1
no. of rflns measd
temp, K
296(1)
decay, %
-26.5, corrected
I g 3.3σ(I)
4396
440
0.035
cutoff for obsd data
no. of unique obsd data (NO)
no. of variables (NV)
R(F)
Rw(F)
0.046
0.04
wght, w-1 ) [σ2(I) + (pFo2)2]1/2, p
GOF
3.090
Fmax/Fmin (DF)
1.76a/-0.18
a
Close to the tungsten atom.
[CMe2(η5-C5H 4)2]Mo(µ-P P h 2,Cl)W(CO)4 (16). IR (νCO
THF): 2036 (m), 1910 (S), 1884 (S) cm-1 1H NMR (CDCl3):
,
.
δ 1.08 (s, 3H, Me), 1.14 (s, 3H, Me), 7.26-8.15 (m, 10H, C6H5).
Unsatisfactory analysis was obtained for this compound, but
the mass spectrum displays the M+ fragment.
[CMe2(η5-C5H 4)2]W(µ-P P h 2,Cl)W(CO)4 (17). IR (νCO
THF): 2037 (m), 1910 (S), 1890 (S) cm-1 1H NMR (CDCl3):
δ 1.08 (s, 3H, Me), 1.32 (s, 3H, Me), 7.26-7.39 (m, 6H, C6H5),
8.12-8.22 (m, 4H, C6H5). Anal. Calcd for C28H25O4ClPW2: C,
40.01; H, 2.78. Found: C, 40.00; H, 2.99.
,
W, L ) dme) and the corresponding dilithium salt Li2-
[SiMe2(η5-C5H4)2] according to the recent work of Green
et al.11 These complexes are isolated as maroon powders
sparingly soluble in dichloromethane and chloroform.
Surprisingly, no characterizable material can be isolated
from molybdenum dichloride 1 and the metallophos-
phide anions. In contrast, reactions performed with the
tungstenocene derivative 2 proceed cleanly, affording
the Cp substituted products 3 (Scheme 1).
Substitution on the Cp ring occurs with total regi-
oselectivity at the 3 position as evidenced by COSY and
selective decoupling experiments. Furthermore, it must
be pointed out that the reaction leads to a unique
diastereoisomer (racemic), although two stereogenic
unitssplane and centersare formed simultaneously.
The same stereochemical trend was previously observed
with the methyl and tert-butyl tungstenocene deriva-
tives.7
.
X-r a y Str u ctu r e An a lysis of 7d . A red crystal having the
approximate dimensions 0.35 × 0.2 × 0.1 mm was used for
unit cell measurements and intensity data collection, carried
out at 296 K on an Enraf-Nonius CAD4 diffractometer with
Mo KR radiation (λ ) 0.710 73 Å). The pertinent crystal-
lographic data are given in Table 1. All calculations have been
carried out by use of the MOLEN package with neutral-atom
scattering factors taken from the usual source.
Intensities were corrected for Lorentz and polarization
effects as well as for rather large linear decay. The structure
was solved and refined by conventional three-dimensional
Patterson, difference Fourier, and full-matrix least-squares
methods. There is one solvent (acetone) molecule per orga-
nometallic molecule. All non-hydrogen atoms of the organo-
metallic molecule were refined with anisotropic thermal
parameters, and the hydrogen atoms were placed in calculated
positions. The solvent molecule was refined in an isotropic
model. The hydrogen atoms for both the organometallic and
the acetone molecules were ridden on the atoms bearing them
and included in the final calculations with Biso fixed at values
equal to 1.3Beq for the corresponding carbon atoms.
CMe2-Br id ged Com p lexes. We have also synthe-
sized the ansa precursors [CMe2(η5-C5H4)2]MCl2 (M )
Mo (4), W (5)) according to the Green’s procedure.11
Treatment of dichlorides 4 and 5 with anions
[PPh2M′(CO)x]- in THF for 5 h at room temperature
results in the formation of bimetallic complexes 6 and
7 (Scheme 2). These compounds are isolated in moder-
ate yields (20-40%) after chromatographic purification
as red solids insoluble in hydrocarbon or aromatic
solvents and sparingly soluble in chloroform or acetone.
Resu lts a n d Discu ssion
SiMe2-Br id ged Com p lexes. The ansa dimethylsilyl
dichlorides [SiMe2(η5-C5H4)2]MCl2 (M ) Mo (1), W (2))
were prepared from MCl4L (M ) Mo, L ) (OEt2)2; M )
1
Their H NMR data are consistent with a substitution

ansa-Bridged Metallocene Dichlorides
Organometallics, Vol. 16, No. 26, 1997 5767
Ta ble 2. NMR Da ta for th e Com p lexes 3,b 6,a 7,a 14,b 14′,b 15,b 15′,b 16,a a n d 17a
1H NMR (ppm)
compd
C5H4
M-H
31P NMR (ppm) PPh2
1
3a
3b
3c
6a
6b
6c
7a
7b
4.21, 4.47, 4.84, 5.06, 5.70, 5.80, 6.06
4.28, 4.51, 4.90, 5.07, 5.74, 5.91, 6.02
4.38, 4.48, 4.92, 5.07, 5.71, 5.88 (2H)
2.97, 3.10, 5.2 (2H), 5.68, 5.82, 6.19 (2H)
3.09, 5.00, 5.21, 5.26, 5.47, 5.67, 5.89, 6.29
3.11 (2H), 5.22 (2H), 5.97 (4H)
3.30, 5.28, 5.47 (2H), 5.60 (2H), 5.96, 6.18
4.88 (2H), 5.50 (2H), 5.68 (2H), 5.96 (2H)
3.31 (2H), 5.45 (2H), 5.66 (2H), 5.87 (2H)
4.19 (2H), 5.54 (2H), 5.80 (2H), 5.85 (2H)
4.58 (2H), 4.78 (2H), 4.87 (2H), 5.33 (2H)
4.71 (2H), 4.91 (2H), 5.01 (2H), 5.41 (2H)
3.35 (2H), 5.19 (2H), 5.51 (2H), 5.61 (2H)
3.44 (2H), 5.34 (4H), 5.60 (2H)
3.35 (2H), 5.19 (2H), 5.51 (2H), 5.61 (2H)
4.5 (2H), 4.93 (4H), 5.25 (2H)
4.69 (2H), 4.84 (2H), 4.93 (2H), 5.10 (2H)
4.70 (2H), 4.85 (2H), 4.95 (2H), 5.12 (2H)
3.35 (2H), 4.48 (2H), 5.25 (2H), 5.66 (2H)
3.40 (2H), 5.37 (4H), 5.65 (2H)
-9.6 (d + dd, J WH ) 60 Hz, J PH ) 9 Hz)
49.67 (s)
1
-9.5 (d + dd, J WH ) 60 Hz, J PH ) 10 Hz)
15.46 (s + d, 1J WP ) 253 Hz)
1
-9.8 (d + dd, J WH ) 57 Hz, J PH ) 7 Hz)
62.03 (s)
1.02 (s)
-11.5 (s)
1
-29.43 (s + d, J WP ) 193 Hz)
1
-35.29 (s + d, J WP ) 185 Hz)
1
-62.98 (s + d, J WP ) 189 Hz)
1
7c
7d
-62.97 (s + d, J WP ) 189 Hz)
1
-13.6 (s + d, J WP ) 202 Hz)
2
14a
14c
14′a
14′b
14′c
15a
15b
15c
15′a
15′b
15′c
-4.85 (d, J PH ) 44 Hz)
3.02 (s)
2
-5.55 (d, J PH ) 43 Hz)
-1.02 (s + d,1J WP ) 190 Hz)
132.33 (s)
2
-13.65 (d, J PH ) 22 Hz)
2
-12.32 (d, J PH ) 18 Hz)
103.01 (s)
1
2
1
-12.08 (d + dd, J WH ) 31 Hz, J PH ) 14 Hz)
91.6 (s + d, J WP ) 190 Hz)
1
2
1
-7.25 (d + dd, J WH ) 96 Hz, J PH ) 37 Hz)
-37.15 (s + d, J WP ) 180 Hz)
1
2
1
-7.25 (d + dd, J WH ) 89 Hz, J PH ) 37 Hz)
-48.61 (s + d, J WP ) 173 Hz)
1
2
1
-7.15 (d + dd, J WH ) 82 Hz, J PH ) 37 Hz)
-65.6 (s + d, J WP ) 185 Hz)
1
2
1
-15.35 (d + dd, J WH ) 70 Hz, J PH ) 15 Hz)
91.9 (s + d, J WP ) 205 Hz)
1
2
1
-14.4 (d + dd, J WH ) 77 Hz, J PH ) 10 Hz)
62.7 (s + d, J WP ) 193 Hz)
1
1
3.44 (2H), 5.41 (2H), 5.47 (2H), 5.73 (2H)
-15.2 (d + ddd, J WH ) 76 Hz,
47.72 (s + dd, J WP ) 193 Hz,
1J WH ) 32 Hz, J PH ) 6 Hz)
1J WP ) 229 Hz)
2
1
16
17
3.69 (2H), 5.01 (2H), 5.16, 5.44, 6.3 (2H)
3.63 (2H), 5.12 (2H), 5.35 (2H), 5.46 (2H)
87.14 (s + d, J WP ) 256 Hz)
1
47.2 (s + d, J WP ) 248 Hz)
a
b
NMR spectra recorded in CDCl3. NMR spectra recorded in CD3COCD3.
Sch em e 3
occurring on the metal center by displacement of a
chloride ion. The eight Cp protons resonate in two well-
separated ranges: a set of three or four signals located
between 6 and 5 ppm and a set of one (2H) or two (1H)
signals shifted to high field near 3.5 ppm (Table 2). All
these signals appear as broad multiplets at room
temperature. They become sharp at higher tempera-
ture, indicating severe molecular steric strains. 31P
NMR data agree with the coordination of the phosphido
group to the metal center. The shielding of 31P reso-
nances displayed by complexes 6 and 7 is typical of
µ-phosphido structures.15-18 The chemical shifts are,
as expected, dependent on the nature of M and M′, and
the resonances in 7 are accompanied by a pair of 183W
satellites. Only one pair of satellites is observed for
ditungsten complex 7c, suggesting the same value (190
1
Hz) of J PW coupling constant for both metals.
The complexes 6 and 7 may also be formed by starting
from ansa hydrides. This approach is based on our
general strategy of terminal phosphido complex forma-
tion followed by metal carbonyl unit complexation15
(Scheme 3).
Dihydrides 8 and 911 react instantaneously with PPh2-
14 or 15. Such a downfield shift is indicative of a large
decrease of the M-P-M′ angle in the cyclic dibridged
structures.
Treatment of complex 15c by CCl4 results in the
formation of 7c. In reverse, chloro compound 7c can
be transformed to the hydride 15c by reaction with
NaAlH2(OCH2CH2OMe)2 (Scheme 4).
Upon photochemical irradiation, the chloro complexes
6c and 7c give, as shown in Scheme 5, the µ-phosphido
µ-chloro compounds 16 and 17, respectively. The 1H
NMR spectra exhibit for the Cp proton resonances a set
of three multiplets between 5 and 5.5 ppm and a more
shielded one at 3.8 ppm. The 31P NMR resonances of
16 and 17 are shifted downfield (∆δ +100 ppm) relative
to 6c and 7c. As for the hydrido-bridged analogs, such
a deshielding is due to the ring closure upon the
formation of the chloro bridge.
Cl, affording after treatment with base the metallo-
phosphines 12 and 13. These terminal phosphido
complexes react at room temperature with [M′(CO)5]
fragments (M′ ) Cr, Mo, W), leading to a mixture of
mono- and dibridged complexes 14 + 14′ and 15 + 15′,
respectively. Separation of the complexes is achieved
by chromatography. Hydrido bridging in 14′ or 15′ is
clearly evidenced by the high-field resonances of M-H
protons and the deshielding (by some 100 ppm) of 31P
resonances with respect to the monobridged complexes
(16) (a) Boni, G.; Sauvageot, P.; Mo¨ıse, C. J . Organomet. Chem. 1995,
489, C32. (b) Boni, G.; Sauvageot, P.; Marpeaux, E.; Mo¨ıse, C.
Organometallics 1995, 14, 5652.
(17) Oudet, P.; Perrey, D.; Bonnet, G.; Mo¨ıse, C.; Kubicki, M. M.
Inorg. Chim. Acta 1995, 237, 79.
(18) Sauvageot, P.; Blacque, O.; Kubicki, M. M.; J uge´, S.; Mo¨ıse, C.
Organometallics 1996, 15, 2399.

5768 Organometallics, Vol. 16, No. 26, 1997
Comte et al.
Sch em e 4
F igu r e 1. Molecular structure of [CMe2(η5-C5H4)2]W(Cl)-
(µ-PPh2)Fe(CO)4 (7d ) (30% probability level).
Sch em e 5
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for [CMe2(η5-C5H4)2]W(Cl)(µ-P P h 2)F e(CO)4 (7d )
W-Fe
W-CP1
W-CP2
W-Cl
W-P
W-C1
W-C2
W-C3
W-C4
W-C5
4.412(1)
1.94
1.96
2.430(2)
2.626(2)
2.239(9)
2.244(9)
2.35(1)
1.36(1)
2.244(8)
W-C6
2.23(1)
2.280(9)
2.371(9)
2.36(1)
2.23(1)
2.371(3)
1.786(9)
1.79(1)
1.78(1)
1.75(1)
W-C7
W-C8
W-C9
W-C10
Fe-P
Fe-C26
Fe-C27
Fe-C28
Fe-C29
CP1-W-CP2
Cl-W-P
P-Fe-C26
P-Fe-C27
P-Fe-C28
125.5
82.17(7)
90.9(3)
85.7(3)
95.4(3)
P-Fe-C29
W-P-Fe
C14-P-C20
C1-C11-C6
C5(1)-C5(2)b
175.5(4)
123.95(9)
102.6(4)
94.0(7)
115.9
a
CP1 and CP2 are the geometrical centers of C1-C5 and C6-
The molecular geometry of 7d has been etablished by
X-ray analysis. The crystal structure is built from
organometallic and solvent acetone molecules. The
dinuclear organometallic molecule (Figure 1) consists
of ansa-tungstenocene monochloride and tetracarbonyl
iron fragments singly bridged by a diphenylphosphide
group.
Selected bond lengths and angles are gathered in
Table 3. 7d exhibits a largely opened W-P-Fe angle
and rather long W-P and Fe-P bonds resulting from
steric requirements of the metallic units (Table 3).
The W‚‚‚Fe separation of 4.412(1) Å is nonbonding.
These overall features agree with the parameters
generally observed in monobridged µ-PR2 complexes
containing a metallocene and metal carbonyl frag-
ments.15,17,18
b
C10 rings, respectively. Dihedral angle between C5 (C1-C5) and
C5 (C6-C10) planes.
cyclopentadienyl rings indicates that the presence of the
methylene bridge between these rings leads to some
geometrical modifications with respect to the usual non-
ansa bis(cyclopentadienides). The CP1-W-CP2 angle
(125.5°) as well as the bending (dihedral) angle between
the best planes of the cyclopentadienyl rings (115.9°)
correspond very well to the parameters reported for
other ansa-metallocenes.11,12 The pairs of C3/C4 and
C8/C9 atoms deviate by 0.1 and 0.08 Å from the planes
defined by C1/C2/C5 and C6/C7/C10 atoms, respectively,
away from the tungsten atom. The W-C distances
involving the atoms of these pairs (mean 2.36 Å) are
longer than for the other six carbons (mean 2.24 Å). This
shows that the substitution of a bulky PPh2Fe(CO)4
ligand by one chloride in the coordination polyhedron
of the tungsten atom has little or no steric effect,
confirming a considerable opening of the metal coordi-
nation sphere in the vicinity of the metallocene frontier
orbitals22 in ansa complexes.
The Fe-P bond length of 2.371(3) Å is longer than
the usual range observed for PR3Fe(CO)4 molecules19
(2.25-2.30 Å). It is even longer than that reported for
the tetracarbonyliron complex with PtBu320 (2.364(1)Å).
Thus, our chloro ansa-tungstenocene phosphine seems
to be slightly bulkier than the tert-butyl one.
The Cl-W-P angle of 82.17(7)° is essentially the
same as the Cl-M-Cl angles found for ansa or non-
ansa group 6 metallocenes.11,21 However, an examina-
tion of the structural parameters associated with the
The striking difference in reactivity observed between
the two ansa structures can be rationalized by consider-
ing the Cp ring tilting effect introduced by the single
atom bridging. Comparison of Cp-M-Cp angles be-
tween ansa CMe2 bridged and non-ansa derivatives for
M ) Mo, W11 and for M ) Ti, Zr23 shows that the tie
(19) (a) Howell, J . A. S.; Palin, M. G.; McArdle, P.; Cunningham,
D.; Goldschmidt, Z.; Gottlieb, H. E.; Hezroni-Langerman, D. Inorg.
Chem. 1993, 32, 3493 and references cited therein. (b) Kilbourn, B.
T.; Raeburn, U. A.; Thompson, D. T. J . Chem. Soc. A 1969, 1906.
(20) Pickard, J .; Ro¨sch, L.; Schumann, H. J . Organomet. Chem.
1976, 107, 241.
(21) Labella, L.; Chernega, A.; Green, M. L. H. J . Organomet. Chem.
1995, 485, C18.
(22) Lauher, J . W.; Hoffmann, R. J . Am. Chem. Soc. 1976, 1729.

ansa-Bridged Metallocene Dichlorides
Organometallics, Vol. 16, No. 26, 1997 5769
causes a decrease in the bending angle of 15-20°.
Consequently, such decreases open the metal environ-
ment and render possible the approach of the sterically
demanding metallophosphide anion to the metallic
center. In contrast, the crystallographic data available
for the ansa complexes [SiMe2(η5-C5H4)2]MCl2 (M ) Ti,
Zr,Hf23 or M ) Nb24) indicate no significant modification
in the Cp tilting (small decrease of about 2°) with
respect to the unsubstituted parent compounds. This
is not surprising, since the covalent radius of silicon is
about 1.5 times that of carbon. Therefore, it becomes
understandable why the same substitution site is
observed both in the ansa SiMe2 and in Cp2MCl2
complexes.
Su p p or tin g In for m a tion Ava ila ble: For 7d , tables of
X-ray crystallographic data, including atomic coordinates,
anisotropic thermal parameters, interatomic distances and
angles, and least-squares planes (5 pages). Ordering informa-
tion is given on any current masthead page.
(23) Shaltout, R. M.; Corey, J . Y. Tetrahedron 1995, 51, 4309.
(24) Antinolo, A.; Martinez-Ripoll, M.; Mugnier, Y.; Otero, A.;
Prashar, S.; Rodriguez, A. M. Organometallics 1996, 15, 3241.
OM970630I