Syntheses, structures, and reactions of Di-μ-hydroxo dinuclear complexes of tungsten(IV) and molybdenum(IV)

Article abstract of DOI:10.1021/om950609m

The title compounds have been prepared in good yields by reaction of Cp₂MH₂ (M = W or Mo) with Cp₂M(OTs)₂ (OTs = p-CH₃C₆H₄SO₃) in aqueous acetone. The products were investigated by IR, ¹H NMR, and ¹³C NMR spectroscopy as well as by X-ray crystallography. The molecules of the two compounds are isostructural. The structures comprise a planar four-membered ring consisting of alternating M and O atoms. In methanol solution, ¹H NMR chemical shifts for the cyclopentadienyl units of the complexes are significantly deshielded with respect to those for the parent dihydrides. The reactions between these complexes and tertiary phosphines in alcoholic solvents yield novel alkoxo complexes [Cp₂M(PR₃)(R′O)]⁺(OTs^-) (2) (R = Et, Buⁿ, and Ph; R′ = Me, Et, Prⁱ, CF₃CH₂, and Ph). The structure of the complex with (R = Buⁿ and R′ = CF₃CH₂, determined by a single-crystal X-ray diffraction study, exhibits a distorted tetrahedral geometry with Mo-P = 2.540 ? and internal angle CP1-Mo-CP2 (CP is the centroid of the cyclopentadienyl ligand) = 132.8°.

Full text of DOI:10.1021/om950609m

852
Organometallics 1996, 15, 852-859
Syn th eses, Str u ctu r es, a n d Rea ction s of Di-µ-h yd r oxo
Din u clea r Com p lexes of Tu n gsten (IV) a n d
Molybd en u m (IV)
J ian-Guo Ren, Hideshi Tomita, Makoto Minato, and Takashi Ito*
Department of Materials Chemistry, Faculty of Engineering, Yokohama National University,
156 Tokiwadai, Hodogaya-ku, Yokohama 240, J apan
Kohtaro Osakada
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226, J apan
Mikio Yamasaki
Rigaku Corporation, Matsubara-Cho, Akishima, Tokyo 196, J apan
Received August 7, 1995X
The title compounds have been prepared in good yields by reaction of Cp2MH2 (M ) W or
Mo) with Cp2M(OTs)2 (OTs ) p-CH3C6H4SO3) in aqueous acetone. The products were
investigated by IR, 1H NMR, and 13C NMR spectroscopy as well as by X-ray crystallography.
The molecules of the two compounds are isostructural. The structures comprise a planar
1
four-membered ring consisting of alternating M and O atoms. In methanol solution, H
NMR chemical shifts for the cyclopentadienyl units of the complexes are significantly
deshielded with respect to those for the parent dihydrides. The reactions between these
complexes and tertiary phosphines in alcoholic solvents yield novel alkoxo complexes
[Cp2M(PR3)(R′O)]+(OTs-) (2) (R ) Et, Bun, and Ph; R′ ) Me, Et, Pri, CF3CH2, and Ph). The
structure of the complex with (R ) Bun and R′ ) CF3CH2, determined by a single-crystal
X-ray diffraction study, exhibits a distorted tetrahedral geometry with Mo-P ) 2.540 Å
and internal angle CP1-Mo-CP2 (CP is the centroid of the cyclopentadienyl ligand) ) 132.8°.
In tr od u ction
molybdenum trihydride complex [Cp2MoH3]+OTs- (OTs
) p-CH3C6H4SO3) was readily converted to hydrido
tosylato complex Cp2MoH(OTs) with accompanying
evolution of 1 mol of H2 when warmed in ethanol.4 This
complex was found to react with a wide variety of
substrates, affording molybdenocene derivatives, and
hence, it is useful as a precursor of these types of
compounds.5 We also showed that the complex is
important as a stereoselective reducing agent in organic
synthesis.6 For example, an extremely high diastereo-
selectivity was achieved by using this complex in the
reduction of 4-tert-butylcyclohexanone to cis-4-tert-bu-
tylcyclohexanol. We have tried to extend this work to
tungsten complexes. In contrast to the molybdenum
complex, however, tungsten trihydride is found to be so
inert owing to the thermostability that the hydrido
tosylato complex should be prepared by an alternate
A variety of binuclear and polynuclear transition-
metal complexes have been known for many years, and
they continue to be the focus of investigations of their
synthesis and reactivity. Especially, these complexes
are currently of great interest because of their potential
to induce unique catalytic transformations as a result
of cooperative interaction between adjacent metals.
Various kinds of ligands, such as CO, halides, tertiary
phosphines, phosphides, hydride, methylene, or sulfides
have been known to bridge two metal centers. In
particular, the hydroxy group as a bridging ligand is
important, since µ-hydroxo complexes sometimes work
as precursors for the µ-oxo complexes.1 The latter
complexes are especially interesting in view of their
ability to activate molecular oxygen as well as being
used for the syntheses of oxide materials by sol-gel and
related hydrothermal syntheses. A number of µ-hy-
droxo-bridged complexes which included the f- and
d-block metals have been reviewed recently.2
(3) (a) Green, M. L. H.; McCleverty, J . A.; Pratt, L.; Wilkinson, G.
J . Chem. Soc. 1961, 4854. (b) Wilkinson, G., Stone, F. G. A., Abel, E.
W., Eds. Comprehensive Organometallic Chemistry; Pergamon: Oxford,
U.K., 1982; Vol. 3, p 1198. (c) Green, M. L. H.; Knowles, P. J . J . Chem.
Soc., Perkin Trans. 1973, 1155.
We have been investigating the chemistry of the
molybdenum and tungsten dihydrides Cp2MH2 (Cp )
η-C5H5; M ) Mo or W), which are capable of acting as
a Lewis base and are easily protonated to give cationic
trihydrides [Cp2MH3]+.3 Recently, we reported that
(4) Igarashi, T.; Ito, T. Chem. Lett. 1985, 1699.
(5) (a) Ito, T.; Tokunaga, T.; Minato, M.; Nakamura, T. Chem. Lett.
1991, 1893. (b) Ito, T.; Igarashi, T.; Suzuki, F. J . Organomet. Chem.
1987, 320, C16. (c) Ito, T.; Haji, K.; Suzuki, F.; Igarashi, T. Organo-
metallics 1993, 12, 2325. (d) Ito, T.; Yoden, T. Bull. Chem. Soc. J pn.
1993, 66, 2365. (e) Minato, M.; Tomita, H.; Igarashi, T.; Ren, J .-G.;
Tokunaga, T.; Ito, T. J . Organomet. Chem. 1994, 473, 149.
(6) (a) Ito, T.; Koga, M.; Kurishima, S.; Natori, M.; Sekizuka, N.;
Yoshioka, K. J . Chem. Soc., Chem. Commun. 1990, 988. (b) Minato,
M.; Fujiwara, Y.; Ito, T. Chem. Lett. 1995, 647.
X Abstract published in Advance ACS Abstracts, J anuary 1, 1996.
(1) For example see: Kitajima, N.; Osawa, M.; Tanaka, M.; Moro-
oka, Y. J . Am. Chem. Soc. 1991, 113, 8952.
(2) Gilje, J . W.; Roesky, H. W. Chem. Rev. 1994, 94, 895.
0276-7333/96/2315-0852$12.00/0 © 1996 American Chemical Society

Di-µ-hydroxo Complexes of W(IV) and Mo(IV)
Organometallics, Vol. 15, No. 2, 1996 853
Ta ble 1. P r ep a r a tion of [Cp 2M(µ-OH)2MCp 2]2+(OTs-)2 (M ) W (1a ) a n d Mo (1b))
solvent/mL
Cp2MH2/mmol
Cp2M(OTs)2/mmol
acetone/H2O
temp/°C
time/h
yield of 1/%
M ) W
M ) Mo
0.231
1.96
0.229
1.94
20/0.2
30/0.2
50
50
8
10
83
97
Ta ble 2. Sp ectr oscop ic P r op er ties of
[Cp 2M(µ-OH)2MCp 2]2+(OTs-)2 (M ) W (1a ) a n d
Mo (1b))
synthetic route. We have explored the reaction condi-
tions and found that it can be successfully obtained by
treating [Cp2WH3]+OTs- with a hydrogen acceptor such
as acetone or 2-butanone (eq 1). In these reactions, we
IR/cm-1 a
1H NMR/ppmb 13C NMR/ppmc
complex
ν[CH(Cp)] ν(OH)
δ(Cp)
δ(Cp)
1a (M ) W)
1b (M ) Mo)
3078
3075
3550
3540
6.00
5.99
98.5
103.6
a
b
KBr disk. 270 MHz in CD3OD. c 67.8 MHz in CD3OD.
The reaction of Cp2WH2 with Cp2W(OTs)2 in aqueous
acetone at 50 °C afforded complex 1a almost quantita-
tively (Table 1). In this system, we could not observe a
side reaction. Namely, the formation of the monohy-
drido tosylato complex or the trihydride complex was
not observed. This procedure was found to be also
applicable to the molybdenum analog [Cp2Mo(µ-OH)2-
MoCp2]2+(OTs-)2 (1b) (Table 1). Complexes 1a and 1b
are moderately air-stable grayish solids and are very
soluble in polar solvents such as methanol but not
soluble in a nonpolar solvent such as benzene or toluene.
Sp ect r oscop ic P r op er t ies of [Cp 2M(µ-OH )2M-
Cp 2]2+(OTs-)2 (M ) W (1a ) a n d Mo (1b)). In Table
2, selected spectroscopic data for the complexes 1a ,b are
collected. The IR spectra of 1a ,b show strong bands at
3550 and 3540 cm-1, respectively, due to the bridging
O-H stretching vibrations. The C-H stretching bands
of Cp ligands are observed at 3078 cm-1 for 1a and at
3075 cm-1 for 1b, both being at lower frequency than
that of the parent dihydrides Cp2MH2 (M ) W or Mo)
have isolated an unexpected novel di-µ-hydroxo di-
nuclear complex [Cp2W(µ-OH)2WCp2]2+(OTs-)2 (1a )
though in low yield.7 Afterwards this complex is most
conveniently prepared in high yield via the direct
reaction of Cp2WH2 with Cp2W(OTs)2 in aqueous ac-
etone (eq 2).
The analogous molybdenum complex [Cp2Mo(µ-OH)2-
MoCp2]2+(OTs-)2 (1b) was prepared in a similar fashion
to 1a . Although µ-hydroxo dinuclear molybdenum and
tungsten complexes containing H2O8 or CO9 as ligand
are well-known, the analogous complex with cyclopen-
tadienyl ligand is relatively rare.10 In this paper, we
report full details on the preparation and the structures
of these complexes. We also report the reactions of
complexes 1a and 1b with tertiary phosphines in
alcoholic solvents which result in the formation of novel
alkoxo complexes. Some of these results have appeared
in a preliminary communication.11
1
by about 20 cm-1. In the H NMR spectrum of 1a , the
resonance of the hydrogens of Cp ligands appears as a
singlet at δ ) 6.00 ppm, which is at lower field than
that of the parent complex Cp2WH2 by about 1.7 ppm.
This downfield shift in 1a presumably reflects a higher
degree of a drift of electron density from Cp ligands to
the cationic tungsten metal center as compared with the
neutral Cp2WH2. The Cp protons of complex 1b appear
at δ ) 5.99 ppm, which are almost identical to those of
1a . The 13C NMR spectra of complexes 1a ,b give a
signal for cyclopentadienyl carbons at 98.5 and 103.6
ppm, respectively.
Cr ysta l Str u ctu r e Deter m in a tion s of Com p lexes
[Cp 2M(µ-OH)2MCp 2]2+(OTs-)2 (M ) W (1a ) a n d Mo
(1b)). Figure 1 shows the molecular structure for the
tungsten complex 1a and the numbering scheme for the
atoms. This drawing will also serve to represent the
molybdenum compound 1b since the only differences are
slight changes in some internuclear distances and
angles and the atom numbering schemes are parallel.
The molecular structure is a neat and simple one, as
can be clearly seen in Figure 1. The analyses for 1a ,b
indicate that the molecules are dimeric in the solid state
with formulations {[Cp2M(OH)]+(OTs-)}2 in which one
molecule of water is included as a crystallization solvent.
O(24) corresponds to the oxygen atom of the water
molecule. Selected interatomic bond distances and
angles are presented in Tables 3 and 4. Complexes 1a ,b
Resu lts a n d Discu ssion
F or m a tion s of [Cp 2M(µ-OH)2MCp 2]2+(OTs-)2 (M
) W (1a ) a n d Mo (1b)). In the reaction of Cp2WH2
with TsOH in acetone (eq 1), the detailed observation
indicated that purplish complex Cp2W(OTs)2 was first
formed, and then it was converted to grayish complex
1a . Furthermore, it appears that water takes part in
the reaction significantly, since no formation of complex
1a was observed when the reaction was carried out
under rigorously anhydrous conditions. We therefore
tried an alternate system that involved the use of water
and Cp2W(OTs)2 (eq 3).
(7) Minato, M.; Tomita, H.; Ren, J .-G.; Ito, T. Chem. Lett. 1993, 1191.
(8) Cotton, F. A.; Wilkinson, G. Advanced Inorganic Chemistry, 5th
ed.; J ohn Wiley & Sons: New York, 1988; p 825.
(9) Albano, V. G.; Ciani, G.; Manassero, M. J . Organomet. Chem.
1970, 25, C55.
(10) Prout, K.; Couldwell, M. C. Acta Crystallogr. 1977, B33, 2146.
(11) Ren, J .-G.; Tomita, H.; Minato, M.; Osakada, K.; Ito, T. Chem.
Lett. 1994, 637.

854 Organometallics, Vol. 15, No. 2, 1996
Ren et al.
hydrogen bond to O(14), one of three oxygen atoms of
the counteranion, OTs-. The bond distances O(24)-
O(14) are 2.952 Å in 1a and 2.974 Å in 1b, and O(24)-
O(16) distances are 3.348 Å in 1a and 3.419 Å in 1b,
which suggest that hydrogen bondings occur also be-
tween the water molecule and oxygen atoms of OTs-
anions. The average C-C bond distances for the Cp
ring in 1a (1.399 Å) and in 1b (1.392 Å) are comparable
to the average C-C bond distance in Prout’s complex
(1.42 Å). The internal C-C-C ring angles in 1a range
from 102.45 to 110.33° and in 1b from 103.03 to 110.57°.
These angles are compared favorably with the expected
internal angle, 108°, for a planar pentagon. The Cp
ligands attached to the metal atoms are positioned
above and below the M2O2 planes. These complexes
have geometry typical of bent metallocene with M-CP
(CP is the centroid of the cyclopentadienyl ligand)
distances close to 2.0 Å and with CP1-M-CP2 angles
equal to 130.95° in 1a and 128.3° in 1b, and these
results are in accord with expectation based on the
orbital configuration of tungsten or molybdenum atom
and the steric interaction around it.12 The average
metal-ring carbon distances are 2.316 Å in 1a and
2.326 Å in 1b; therefore, Mo-ring distances are slightly
longer than W-ring distances. The ring angles M-O-M
are 114.65° in 1a and 113.79° in 1b, and M-M distances
are 3.51 Å in 1a and 3.52 Å in 1b. The M-M interac-
tions are considered to be nonbonding since the observed
separations are substantially longer than the M-M
distances of 2.60 Å (M ) W) and of 2.72 Å (M ) Mo),
estimated from the sum of covalent radii.13
F igu r e 1. ORTEP drawing of the molecular structure of
1a with the atom-numbering scheme.
Ta ble 3. In ter a tom ic Dista n ces (Å) a n d An gles
(d eg) for 1a
Distances
W(1)-O(2)
W(1)-C(3)
W(1)-C(5)
W(1)-C(7)
W(1)-C(9)
W(1)-C(11)
O(2)-H(2)
W(1)-CP1
O(2)-O(2′)
O(14)-O(24)
2.076(7)
2.294(12)
2.278(12)
2.369(13)
2.371(13)
2.261(14)
1.106(7)
1.982(0)
2.254(14)
2.952(8)
W(1)-O(2′)
W(1)-C(4)
W(1)-C(6)
W(1)-C(8)
W(1)-C(10)
W(1)-C(12)
O(14)-H(2)
W(1)-CP2
O(2)-O(14)
O(16)-O(24)
2.099(7)
2.254(12)
2.370(11)
2.357(13)
2.281(14)
2.327(12)
1.711(8)
1.994(0)
2.625(11)
3.348(10)
Angles
65.35(32) W(1)-O(2)-W(1′) 114.65(32)
Rea ction s of 1a or 1b w ith Ter tia r y P h osp h in es.
The hydroxy groups in complex 1a or 1b were suf-
ficiently labile to undergo displacement by tertiary
phosphines in alcoholic solvents to afford novel mono-
nuclear cationic alkoxo complexes 2 (eq 4). These
O(2)-W(1)-O(2′)
W(1)-O(2)-H(2) 127.21(48) O(2)-H(2)-O(14) 136.36(45)
CP1-W(1)-CP2
130.95(2)
W(1)-O(2′)-H(2′) 111.69(45)
Ta ble 4. In ter a tom ic Dista n ces (Å) a n d An gles
(d eg) for 1b
Distances
Mo(1)-O(2)
Mo(1)-C(3)
Mo(1)-C(5)
Mo(1)-C(7)
Mo(1)-C(9)
Mo(1)-C(11)
O(2)-H(2)
Mo(1)-CP1
O(2)-O(2′)
O(14)-O(24)
2.092(2)
2.314(4)
2.286(5)
2.388(5)
2.365(4)
2.296(5)
0.986(2)
1.996(5)
2.298(5)
2.974
Mo(1)-O(2′)
Mo(1)-C(4)
Mo(1)-C(6)
Mo(1)-C(8)
Mo(1)-C(10)
Mo(1)-C(12)
O(14)-H(2)
Mo(1)-CP2
O(2)-O(14)
O(16)-O(24)
2.100(2)
2.282(4)
2.365(4)
2.356(4)
2.286(5)
2.323(5)
1.703(3)
2.001(5)
2.679
3.419
Angles
O(2)-Mo(1)-O(2′) 66.21(10) Mo(1)-O(2)-Mo(1′) 113.79(10)
Mo(1)-O(2)-H(2) 122.11(18) O(2)-H(2)-O(14) 171.48(17)
CP1-Mo(1)-CP2 128.3 Mo(1)-O(2′)-H(2′) 124.01(17)
have an orthorhombic system. The molecular structures
of 1a ,b contain a four-membered ring consisting of
alternating M and O atoms, and there is an inversion
center in the molecule with half the molecule consisting
of {[Cp2M(OH)]+(OTs-)} being the symmetric unit. The
positions of the H(2) and H(2′) atoms were located from
difference Fourier maps and included as fixed contribu-
tions. The M-O bridge bond distances (the average of
M(1)-O(2) and M(1)-O(2′) distances) are 2.088 and
2.096 Å for 1a ,b, respectively. This distance (1b) is very
close to that found by Prout in [Mo2(η5-C5H5)2(µ-η5-C5H4-
η5-C5H4)(µ-H)(µ-OH)]2+(PF6-)2 as 2.08 Å.10 The O(2)-
O(14) distance in 1a is 2.625 Å and in 1b is 2.679 Å,
and it seems reasonable to assume that H(2) forms a
complexes were stable to air to some extent in the solid
state and were found to be soluble in polar solvents such
as methanol, ethanol, and acetone but insoluble in
hexane or pentane, although tributylphosphine com-
plexes were found to be soluble in benzene.
(12) Nakamura, A.; Otsuka, S. J . Am. Chem. Soc. 1973, 95, 7262.
(13) Dean, J . A. Lange’s Handbook of Chemistry; McGraw-Hill Book
Co.: New York, 1985; pp 3-126.

Di-µ-hydroxo Complexes of W(IV) and Mo(IV)
Ta ble 5. P r ep a r a tion s of Com p lexes [Cp 2MP R3(OR′)]+OTs- (2)
conditions
Organometallics, Vol. 15, No. 2, 1996 855
compd (M)
R
R′
complex 1/mmol
PR3/mmol
R′OH/mL
temp/°C
time/h
yield/%
2a (Mo)
2a ′ (W)
2c (Mo)
2c′ (W)
2e (Mo)
2e′ (W)
2h (Mo)
2h ′ (W)
2i (Mo)
2i′ (W)
2j (Mo)
2j′ (W)
Et
Et
Et
Et
Et
Et
Me
Me
Et
0.433
0.204
0.180
0.247
0.192
0.100
0.195
0.152
0.101
0.040
0.246
0.167
1.02
20
20
20
20
5
10
3
3
r.t.b
r.t.
r.t.
r.t.
50
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
8
8
85
87
82
75
92
83
97
97
95
95
88
87
0.510
0.365
0.533
0.398
0.332
0.442
0.362
0.218
0.115
0.660
0.528
40
40
2.5
100
2
Et
Pri
Pri
Bun
Bun
Ph
Ph
Et
CF3CH2
CF3CH2
CF3CH2
CF3CH2
Ph
2
1
100
100
2
1
3a
5a
Et
Ph
3
a
b
PhOH/Et2O ) 1/1 (mL/mL). r.t. ) room temperature.
Ta ble 6. P r op er ties a n d An a lytica l Da ta for
2k , and 2k ′ are stored in the Supporting Information
as Tables S13-S15. The syntheses of complexes 2 as
described in Tables 5 and S13 show the following trends.
In methanol, ethanol, or 2-propanol, only basic phos-
phines such as triethylphosphine or tributylphosphine
react with 1a ,b. On the other hand, no substitution of
the hydroxy bridging groups by triphenylphosphine has
been observed in these solvents. Interestingly, in
moderately acidic alcohol, such as trifluoroethanol, or
in the presence of phenol, the reactions proceeded more
smoothly affording 2 in good yields. Moreover, tri-
phenyphosphine reacted also in trifluoroethanol with 1a
or 1b to give monomeric complexes. Therefore these
substitution reactions seem to be effected with both the
basicity of tertiary phosphine ligands and the acidity
of solvents.
Com p lexes [Cp 2MP R3(OR′)]+OTs- (2)
elemental anal.a
compd (M)
R
R′
mp °C
C/%
H/%
2a (Mo)
2a ′ (W)
2c (Mo)
2c′ (W)
2e (Mo)
2e′ (W)
2h (Mo)
2h ′ (W)
2i (Mo)
2i′ (W)
2j (Mo)
2j′ (W)
Et
Me
Me
Et
91.0-93.0
52.19 (52.75) 6.62 (6.45)
105.0-107.0 44.81 (45.44) 5.70 (5.56)
Et
Et
Et
Et
Et
93.5-95.0
87.5-89.5
69.0-71.0
73.5-74.5
b
b
b
b
b
b
b
b
Et
Pri
Pri
Bun CF3CH2 128.5-129.5 52.76 (53.29) 6.69 (6.63)
Bun CF3CH2 132.0-133.5 48.04 (47.34) 5.90 (5.89)
Ph
Ph
Et
Et
CF3CH2 102.0-104.0
CF3CH2 105.0-107.0 52.08 (52.49) 4.19 (4.06)
Ph
Ph
b
b
119.0-121.0 56.86 (57.23) 5.88 (6.13)
121.0-124.0
b
b
a
b
Calculated values in parentheses. Analytically pure sample
was not obtainable (see text).
As shown in Table 7, 1H NMR resonances for the
cyclopentadienyl ring protons of 2 appear in the range
δ 5.4-5.6 ppm as a doublet coupled to phosphorus; this
represents significant deshielding of these protons
compared with chemical shifts in parent neutral Cp2-
MH2 (M ) W and Mo) complexes (δ 4.2-4.3 ppm) but
is compatible with the observed chemical shifts of
cationic complex 1a or 1b.
The cationic complexes analogous to 2 with hydride
ligand in the place of alkoxide and a halide counteranion
have been prepared by Dias et al. starting from Cp2-
MoHX (X ) Cl, Br, and I)14 for PPh3, PMe2Ph, PEt2-
Ph,15 and the X-ray structure of [Cp2MoH(PPh3)]+I- was
determined to be a distorted tetrahedron.16
Preparations, analytical data, and spectroscopic prop-
erties for complexes 2a , 2a ′, 2c, 2c′, 2e, 2e′, 2h , 2h ′, 2i,
2i′, 2j, and 2j′ are compiled in Tables 5-7, respectively.
The data for complexes 2b, 2b′, 2d , 2d ′, 2f, 2f′, 2g, 2g′,
The 1H NMR studies showed that ethoxo, isopropoxo,
and trifluoroethoxo complexes were converted slowly to
methoxo species in methanol (eq 5). These alkoxo
Ta ble 7. 1H NMR Sp ectr a l Da ta for [Cp 2M(OR′)(P R3)]+(OTs-) (2)
compd (M)a
R
R′
δ (ppm)
2a (Mo)
2a ′ (W)
2c (Mo)
Et
Et
Et
Me
Me
Et
5.58 (d, Cp, J P-H ) 1.22 Hz, 10H), 3.34 (s, OMe, 3H), 1.94-2.06 (m, PCH2, 6H), 1.04-1.16 (m, CH3, 9H)
5.55 (d, Cp, J P-H ) 1.22 Hz, 10H), 3.21 (s, OMe, 3H), 1.87-1.96 (m, PCH2, 6H), 0.96-1.07 (m, CH3, 9H)
5.55 (d, Cp, J P-H ) 1.83 Hz, 10H), 2.90 (q, CH2 of OEt, J H-H ) 6.33 Hz, 2H), 1.97-2.09 (m, PCH2, 6H),
1.06-1.18(m, CH3, 9H), 0.78 (t, CH3 of OEt, J H-H ) 6.71 Hz, 3H)
2c′ (W)
2e (Mo)
2e′ (W)
2h (Mo)
2h ′ (W)
Et
Et
Et
Et
5.52 (d, Cp, J P-H ) 7.93 Hz, 10H), 3.09 (q, CH2 of OEt, J H-H ) 6.91 Hz, 2H), 1.97-2.09 (m, PCH2, 6H),
1.06-1.17(m, CH3, 9H), 0.72 (t, CH3 of OEt, J H-H ) 6.71 Hz, 3H)
Pri
Pri
5.56 (d, Cp, J P-H ) 1.83 Hz, 10H), 2.92 (dspt, CH of Pri, J H-H ) 6.11 Hz, J P-H ) 1.22 Hz, 1H), 1.96-2.08
(m, PCH2, 6H),1.05-1.18 (m, CH3, 9H), 0.75 (d, CH3 of Pri, J H-H ) 5.49 Hz, 6H)
5.54 (d, Cp, J P-H ) 1.22 Hz, 10H), 3.23 (dspt, CH of Pri, J H-H ) 6.11 Hz, J P-H ) 1.83 Hz, 1H), 1.94-2.05
(m, PCH2, 6H),1.05-1.19 (m, CH3, 9H), 0.73 (d, CH3 of Pri, J H-H ) 6.11 Hz, 6H)
Bun CH2CF3 5.62 (d, Cp, J P-H ) 1.84 Hz, 10H), 3.16 (q, CH2 of CH2CF3, J F-H ) 9.77 Hz, 2H), 1.90-2.03 (m, PCH2, 6H),
1.38-1.50(m, CH2CH2, 12H), 0.88-1.00 (m, CH3, 9H)
Bun CH2CF3 5.60 (d, Cp, J P-H ) 1.22 Hz, 10H), 3.36 (q, CH2 of CH2CF3, J F-H ) 9.77 Hz, 2H), 1.90-2.05 (m, PCH2, 6H),
1.40-1.55(m, CH2CH2, 12H), 0.85-1.02 (m, CH3, 9H)
2i (Mo)
2i′ (W)
2j (Mo)
Ph
Ph
Et
CH2CF3 7.40-7.63 (m, Ph, 15H), 5.45 (d, Cp, J P-H ) 1.22 Hz, 10H), 3.84 (q, CH2 of CH2CF3, J F-H ) 9.16 Hz, 2H)
CH2CF3 7.40-7.63 (m, Ph, 15H), 5.45 (d, Cp, J P-H ) 1.22 Hz, 10H), 3.55 (q, CH2 of CH2CF3, J F-H ) 9.77 Hz, 2H)
Ph
7.01 (t, Ph (meta), J H-H ) 7.33 Hz, 2H), 6.54 (t, Ph (para), J H-H ) 7.33 Hz, 1H), 6.19 (d, Ph (ortho),
J H-H ) 7.33 Hz, 2H),5.65 (d, Cp, J P-H ) 1.22 Hz, 10H), 2.05-2.20 (m, PCH2, 6H), 1.14-1.26
(m, CH3, 9H)
2j′ (W)
Et
Ph
7.07 (t, Ph (meta), J H-H ) 7.33 Hz, 2H), 6.57 (t, Ph (para), J H-H ) 7.33 Hz, 1H), 6.30 (dd, Ph (ortho),
J H-H ) 8.54 Hz, J P-H ) 1.22 Hz, 2H), 5.63 (d, Cp, J P-H ) 1.83 Hz, 10H), 2.05-2.25 (m, PCH2, 6H),
1.15-1.28 (m, CH3, 9H)
a
For complexes 2b, 2b′, 2d , 2d ′, 2f, 2f′, 2g, 2g′, 2k , and 2k ′, see the Supporting Information.

856 Organometallics, Vol. 15, No. 2, 1996
Ren et al.
exchange reactions were found to follow the pseudo-first-
order kinetics with the rate constants shown in Table
8. At 20 °C, trifluoroethoxo complex was found to be
quite stable, whereas relatively slow transformation was
observed at 60 °C.
F igu r e 2. ORTEP drawing of the molecular structure of
2h with the atom-numbering scheme.
Ta ble 8. P seu d o-F ir st-Or d er Ra te Con sta n ts for
th e Rea ction s of [Cp 2W(P Bu n 3)(OR′)]+(OTs-) w ith
Meth a n ola
Molecu la r St r u ct u r e of [Cp 2Mo(P Bu n 3)(CF 3-
CH2O)]+(OTs-) (2h ). While the spectroscopic analyses
of complexes 2 established their overall structures, we
were interested in further details of the structure.
Consequently, the structure of complex 2h (R ) Bun;
R′ ) CF3CH2) was confirmed by single-crystal X-ray
analysis. A dark-red crystal suitable for X-ray analysis
was obtained by recrystallization from benzene. An
ORTEP view, together with the atom-numbering scheme,
is shown in Figure 2. Bond lengths and bond angles
appear in Table 9. The crystals belong to the triclinic
system. The structure of the complex shows that
molybdenum is surrounded by a distorted tetrahedral
array of the center of two cyclopentadienyl ligands, the
phosphine atom of PBun3, and the oxygen atom of CF3-
CH2O. This structure can be compared and contrasted
with that of the neutral phosphine complex Cp2Mo-
(PBun3) (3), which was synthesized and characterized
by our group.5a
complex
R′
rate const k/s-1
2d ′
2f′
2h ′
Et
4.86 × 10-5 b
3.70 × 10-4 b
4.98 × 10-5 c
Pri
CF3CH2
a
The progress of the reaction was monitored by observing the
liberation of the corresponding alcohol from the complex with an
b
1H NMR spectrometer. The measurement was carried out at 20
°C. c The measurment was carried out at 60 °C.
Ta ble 9. In ter a tom ic Dista n ces (Å) a n d An gles
(d eg) for 2h
Distances
Mo(1)-P(3)
Mo(1)-C(18)
Mo(1)-C(20)
Mo(1)-C(22)
Mo(1)-C(24)
Mo(1)-C(26)
O(2)-C(4)
2.540(4)
2.31(2)
2.25(2)
2.30(2)
2.26(1)
2.31(1)
1.39(2)
1.83(2)
1.82(1)
1.58(3)
1.24(3)
1.52(3)
1.96
Mo(1)-O(2)
Mo(1)-C(19)
Mo(1)-C(21)
Mo(1)-C(23)
Mo(1)-C(25)
Mo(1)-C(27)
C(4)-C(5)
2.019(8)
2.30(2)
2.28(2)
2.30(1)
2.24(1)
2.36(1)
1.50(2)
1.84(2)
1.46(2)
1.39(3)
1.51(2)
1.27(3)
The cyclopentadienyl rings are bound to molybdenum
in an η5 fashion, and each of the ring carbon atoms are
coplanar. The internal ligand C-C-C bond angles
average 107.6°, which is approximately equal to that of
complex 3 (107.9°). The C-C bond distances for Cp
rings average 1.38 Å, which is a little shorter than that
of complex 3 by ca. 0.03 Å. The Mo-CP1 (CP1 is the
centroid of the cyclopentadienyl ligand) bond distance
is 1.96 Å, and it closely resembles that found in 3 (Mo-
CP1 ) 1.95 Å). The CP1-Mo-CP2 angle is 132.8° and
differs notably from the angle CP1-Mo-CP2 in 3
(143.8°). This clearly reflects the steric repulsion be-
tween the large cyclopentadienyl ligand and the tri-
fluoroethoxo ligand. The PBun3 molecule is coordinated
to molybdenum atom with a Mo-P bond distance of
2.540 Å. It appears to be long in contrast to the known
Mo-P bond length of 2.494 Å in complex 3, again
reflecting the bulkiness of the trifluoroethoxo ligand.
Rea ction of [Cp 2M(P Bu n 3)(OR′)]+OTs- (R′ ) Me,
P(3)-C(6)
P(3)-C(10)
C(6)-C(7)
P(3)-C(14)
C(7)-C(8)
C(10)-C(11)
C(15)-C(16)
Cp-Mo(1)
C(8)-C(9)
C(14)-C(15)
C(16)-C(17)
Angles
P(3)-Mo(1)-O(2)
Mo(1)-P(3)-C(10)
Mo(1)-O(2)-C(4)
C(19)-C(18)-C(22) 114(2)
C(19)-C(20)-C(21) 101(2)
C(18)-C(22)-C(21) 103(2)
C(23)-C(24)-C(25) 108(1)
C(25)-C(26)-C(27) 108(1)
Cp(1)-Mo(1)-Cp(2) 132.8
74.4(3) Mo(1)-P(3)-C(6)
118.0(5) Mo(1)-P(3)-C(14)
121.4(8) O(2)-C(4)-C(5)
117.9(6)
111.1(5)
110(1)
C(18)-C(19)-C(20) 107(2)
C(20)-C(21)-C(22) 113(2)
C(24)-C(23)-C(27) 106(1)
C(24)-C(25)-C(26) 107(1)
C(23)-C(27)-C(26) 109(1)
the liberation of the phosphine ligand (eq 6). On the
other hand, triethylphosphine complexes were not soluble
in benzene at all and they were unreactive to water.
E t , P r i) w it h H2O. The complexes [Cp2MPBun
-
3
(OR′)]+OTs- (2) (M ) Mo, W; R′ ) Me, Et, Pri) have
been readily and quantitatively reverted to the original
complex 1a or 1b on dissolving the former in benzene
containing a small quantity of water, accompanied by
(14) Dias, A. R.; Roma˜o, C. C. J . Organomet. Chem. 1982, 233, 223.
(15) Azevedo, C. G.; Dias, A. R.; Martins, A. M.; Roma˜o, C. C. J .
Organomet. Chem. 1989, 368, 57.
(16) Azevedo, C. G.; Calhorda, M. J .; Carrondo, M. A. F. d. C. T.;
Dias, A. R.; Felix, V.; Roma˜o, C. C. J . Organomet. Chem. 1990, 391,
345.
(17) Carmona, E.; Mar`ın, J . M.; Paneque, M.; Poveda, M. L.
Organometallics 1987, 6, 1757.
Interestingly, it was found that the trifluoroethoxo
and phenoxo complexes, which were appreciably soluble

Di-µ-hydroxo Complexes of W(IV) and Mo(IV)
Organometallics, Vol. 15, No. 2, 1996 857
Ta ble 10. Cr ysta llogr a p h ic Da ta for Com p lexes 1a ,b
complex
formula
fw
1a
1b
C
34H38O9S2W2
C34H38O9S2Mo2
846.37
1022.5
cryst system
space group
a/Å
orthorhombic
Pbna (No. 50)
15.262(3)
orthorhombic
Pbna (No. 50)
15.436(10)
b/Å
16.101(4)
16.308(9)
c/Å
13.049(3)
3207
12.963(7)
3263
V/Å3
Z
4
4
9.27
1720
µ/cm-1
75.04
1976
F(000)
Fcalcd g cm-3
temp/°C
cryst size/mm
2θ range/deg
Scan rate/deg min-1
h, k, l
2.118
25(1)
1.723
25(1)
0.20 × 0.35 × 0.53
0.28 × 0.33 × 0.80
3.0-50.0
3.0-50.0
4
6
0 e h e 18, 0 e k e 19, 0 e l e 15
0 e h e 18, 0 e k e 20, 0 e l e 15
unique reflcns
reflcns used
(Fo g 3σ(Fo))
Ra
2771
2057
3188
2456
0.044
0.050
0.042
0.047
b
Rw
weighting scheme
[{σ(Fo)}2 + {0.020(Fo)}2]-1
[{σ(Fo)}2 + {0.020(Fo)}2]-1
R ) ∑|Fo| - |Fc|/∑|Fo|. Rw ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2
.
a
b
2
Sch em e 1
dinuclear complex 1, accompanied by the migration of
OTs- group from the inner sphere to the outer (eq 7).
Apparently the greater tendency of the OH- group, as
compared with halide anions such as Cl- and I-, to act
as a bridging ligand would be responsible for the
formation of these dimeric species.17 Complex 1 and
monomeric 4 may possibly coexist at equilibrium in
solution, though there is no direct evidence to support
it. Only one signal for Cp protons was observed in the
1H NMR of complex 1. p-Toluenesulfonic acid formed
in eq 7 is immediately trapped by basic Cp2MH2
affording monohydrido tosylato complex Cp2MH(OTs)
(5) through the cationic trihydride intermediate [Cp2-
MH3]+OTs- (eq 8). We believe this neutralization
reaction provides the driving force for the whole system,
especially for the protonolysis of Cp2M(OTs)2 with such
a weak acid as H2O. The resulting complex 5 reacts
with an additional acid to give ditosylato complex Cp2M-
(OTs)2 (eq 9). This process is thought to occur via the
dihydrido M(VI) intermediate with a subsequent dehy-
drogenation reaction affording the ditosylato complex,
which is subjected to the further reaction as the starting
material. Consequently, Cp2MH2 plays an important
role not only as a stimulator of the reaction but also as
a source for the starting material Cp2M(OTs)2.
in benzene, were unreactive to water. The results may
be ascribed to the fact that both trifluoroethanol and
phenol are more acidic than water. It is particularly
interesting in light of the fact that the nucleophilicity
of trifluoroethoxo or phenoxo group is weaker than that
of ethoxo or methoxo group, and thereby the former
seems to bind to the metals more weakly.
Further investigations of the reactions of complexes
1a ,b with various kinds of nucleophiles and the mech-
anism of the formation are now in progress.
Mech a n istic Con sid er a tion s for th e F or m a tion
of Com p lex 1a or 1b. Although several mechanisms
for the formation of complexes 1a ,b can be considered,
the mechanism suggested in Scheme 1 can account for
the reaction most adequately, since Cp2MH2 and Cp2M-
(OTs)2 are essential for the formation of complexes 1a ,b
and the source of the bridging OH seems to be water.
The initial stage of this reaction is replacement of one
OTs- group in ditosylato complex Cp2M(OTs)2 by OH-.
Although the equilibrium might lie well over to the left
in this hydrolysis process, trapping of p-toluenesulfonic
acid formed by Cp2MH2 as described later may cause
the displacement of the position of the equilibrium. The
resulting hydroxy complex 4 is dimerized into the
Exp er im en ta l Section
Gen er a l Com m en t s. Unless indicated otherwise, all
manipulations were conducted under purified argon or nitro-
gen. Air-sensitive reagents and products were handled by
standard Schlenk techniques. Commercially available chemi-
cals were used as such without any further purification.
Infrared spectra were determined on
a J ASCO A-202
spectrometer or a Perkin-Elmer 1600 series spectrometer.
NMR spectra were recorded on a J EOL J NMEX-270 spec-
trometer. 1H and 13C NMR chemical shifts were referenced
to tetramethylsilane (TMS). All solvents were dried by
(18) Fan, F. SAPI 85, Chinese Academy of Science, Beijing, China,
1985.

858 Organometallics, Vol. 15, No. 2, 1996
Ren et al.
Ta ble 11. F r a ction a l Atom ic Coor d in a tes a n d
Ta ble 12. F r a ction a l Atom ic Coor d in a tes a n d
Biso/Beq Va lu es (Å2) for Com p lex 1b
Biso/Beq Va lu es (Å2) for Com p lex 1a
atom
x/ a
y/ b
z/ c
B
atom
x/ a
y/ b
z/ c
B
W(1) 0.897 33(2)
0.479 98(2)
0.555 04(44)
0.353 18(77)
0.417 06(81)
0.464 93(78)
0.427 73(89)
0.361 24(81)
0.055 75(2) f
-0.041 00(47)
0.038 12(81)
0.030 12(89)
-0.055 55(86)
-0.107 21(80)
-0.050 25(96)
0.229 05(98)
2.54(1)
Mo(1) 0.898 21(2)
0.479 22(2)
0.054 37(2)
2.58(0)
3.22(5)
O(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
0.970 78(44)
0.830 51(80)
0.767 21(75)
0.783 45(87)
0.856 48(81)
0.883 66(72)
2.79(16)
3.93(32)
4.02(32)
4.02(33)
4.06(33)
3.91(32)
5.42(45)
O(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
0.972 01(25) 0.557 14(14) -0.038 75(16)
0.828 24(31) 0.355 58(25)
0.767 48(25) 0.417 28(29)
0.029 36(32)
0.026 74(32)
4.84(11)
4.80(11)
5.17(13)
4.80(11)
4.78(11)
5.34(13)
5.23(13)
5.81(13)
5.46(13)
5.57(13)
4.23(2)
5.44(8)
5.04(8)
5.68(8)
3.51(8)
4.19(10)
4.55(11)
0.785 31(29) 0.469 13(29) -0.058 75(34)
0.856 23(29) 0.433 35(29) -0.110 92(31)
0.881 14(28) 0.364 09(28) -0.056 98(34)
0.589 29(35) 0.465 13(29)
0.937 49(32) 0.497 80(32)
0.854 85(111) 0.470 54(96)
0.936 67(105) 0.503 20(102)
0.229 01(32)
0.228 82(32)
0.177 93(35)
0.147 31(34)
0.182 90(35)
-0.240 40(7)
0.229 14(93)f 5.33(44)
0.175 38(109) 5.10(38)
0.139 48(98)
C(10) 0.934 72(96)
C(11) 0.844 17(101) 0.591 94(87)
0.576 96(87)
C(10) 0.933 38(32) 0.573 09(32)
C(11) 0.844 04(35) 0.587 22(28)
C(12) 0.801 74(29) 0.517 63(35)
4.93(39)
C(12) 0.799 07(87)
S(13) 0.859 82(19)
O(14) 0.892 32(53)
O(15) 0.876 08(54)
O(16) 0.771 29(57)
C(17) 0.925 57(74)
C(18) 0.890 41(74)
C(19) 0.945 01(92)
C(20) 1.034 96(74)
C(21) 1.070 96(81)
C(22) 1.016 22(77)
C(23) 1.093 65(105) 0.901 97(108) -0.483 96(136) 6.60(51)
O(24) 0.750 0(0)
H(2) 0.96146(0)
Cp(1) 0.824 3(10)
Cp(2) 0.873 9(10)
0.524 53(101)
0.673 73(19)
0.681 81(56)
0.591 01(53)
0.700 91(53)
0.743 03(69)
0.797 25(74)
0.847 02(81)
0.845 83(77)
0.791 82(80)
0.739 45(68)
0.190 57(111) 5.20(41)
-0.234 52(22)
-0.128 04(60)
-0.275 90(77)
-0.248 06(74)
-0.306 53(74)
3.74(7)
S(13)
0.858 87(6)
0.673 16(6)
4.56(24)
4.70(24)
5.26(25)
3.22(28)
O(14) 0.887 82(20) 0.679 45(19) -0.133 55(22)
O(15) 0.875 85(19) 0.592 70(16) -0.283 17(25)
O(16) 0.770 98(19) 0.700 74(19) -0.255 16(25)
C(17) 0.925 77(23) 0.742 03(22) -0.308 24(28)
C(18) 0.890 19(25) 0.797 52(25) -0.377 53(32)
C(19) 0.945 61(29) 0.849 75(25) -0.432 89(32)
-0.376 79(105) 4.04(32)
-0.431 47(92)
-0.421 22(90)
4.56(35)
3.93(31)
C(20) 1.033 79(29) 0.846 77(26) -0.419 4 6(34) 4.84(12)
-0.350 56(102) 4.39(34)
C(21) 1.068 37(26) 0.792 30(28) -0.348 93(37)
C(22) 1.013 70(28) 0.739 58(25) -0.293 97(34)
C(23) 1.091 46(38) 0.903 09(35) -0.477 70(53)
4.87(11)
4.63(11)
7.23(18)
8.25(0)
-0.294 30(96)
4.02(32)
0.750 0(0)
0.622 13(0)
0.404 8(10)
0.533 4(10)
0.000 0(0)
-0.05577(0)
-0.028 9(10)
0.190 8(10)
9.76(0)
2.79(0)
2.00(0)
2.00(0)
O(24) 0.750 0(0)
H(2) 0.946 42(0)
Cp(1) 0.823 8(4)
Cp(2) 0.875 1(4)
0.750 0(0)
0.604 56(0)
0.407 9(4)
0.528 2(4)
0.000 0(0)
-0.074 57(0)
-0.034 1(4)
0.193 2(4)
3.22(0)
Ta ble 13. Cr ysta llogr a p h ic Da ta for 2h
standard methods and distilled before use. Literature methods
were used to prepare Cp2WH2, Cp2W(OTs)2, Cp2MoH2, and Cp2-
Mo(OTs)2, and they were judged pure by IR and NMR
spectroscopy.3,11 p-Toluenesulfonic acid was dehydrated by the
use of the benzene azeotrope.
formula
fw
C31H46F3O4MoSP
698.67
cryst system
space group
a/Å
b/Å
c/Å
triclinic
P1h (No. 2)
10.351(2)
17.025(7)
10.128(3)
105.64(3)
101.69(3)
86.98(3)
2
X-r a y Cr ysta llogr a p h ic Stu d ies of 1a ,b. Crystals of
complexes 1a ,b suitable for diffraction analyses were grown
in methanol at -40 °C. The dark green crystals thus obtained
were mounted in glass capillary tubes under argon. The unit-
cell parameters were obtained by least-squares refinement of
2θ values of reflections with 3° e 2θ e 50°. Four crystallo-
graphically independent molecules were found to be present
in a unit cell. Intensities were collected on a Rigaku AFC-5
four-circle diffractometer. Mo KR radiations were used (λ )
0.710 69 Å) with µ ) 75.04 cm-1 (1a ) and 9.27 cm-1 (1b), and
F(000) ) 1976 Å (1a ) and 1720 Å (1b). The parameters used
during the collection of diffraction data are given in Table 10.
Calculations were carried out with the program systems
SAPI 8518 on a FACOM A-70 computer. The structures were
solved by common Fourier methods. A full-matrix least-
squares refinement procedure was used with anisotropic
thermal parameters or with isotropic thermal parameters for
the non-hydrogen atoms. Positions of hydrogen atoms of
hydroxo groups were located from the Fourier difference map.
All other hydrogen atoms were located at a distance of 1.00 Å
from the carbon atoms by assuming idealized geometry. The
listings of atomic coordinates are provided in Tables 11 and
12.
R/deg
â/deg
γ/deg
Z
temp/°C
µ/cm-1
F(000)
25(1)
46.25
728.00
1.379
F
calcd/g cm-1
cryst size/mm
2θ range/deg
scan rate/deg min-1
unique reflcns
reflcns used
Ra
0.28 × 0.22 × 0.06
48.2-49.8
16.0
3618
3464
0.059
0.078
b
RW
weighting scheme
function minimized
[σ2(Fo)]-1
∑w(|Fo| - |Fc|)2
R ) ∑||Fo| - |Fc||/∑|Fo|. Rw ) [∑w(|Fo| - |Fc|)2/∑wFo
]
.
a
b
2 1/2
cm-1; 1H NMR (CD3OD) δ 7.68 (d, 7.9 Hz, 4H, meta-tolyl), 7.27
(d, 7.9 Hz, 4H, ortho-tolyl), 6.00 (s, 20H, Cp), 2.38 (s, 6H, Me-
tolyl); 13C NMR (CD3OD) δ 143.48, 141.92, 129.95, 126.63
P r ep a r a tion of [Cp 2W(µ-OH)2WCp 2]2+(OTs-)2 (1a ) a n d
[Cp 2Mo(µ-OH)2MoCp 2]2+(OTs-)2 (1b). A mixture of 0.0727
g of Cp2WH2 (0.231 mmol) and 0.151 g of Cp2W(OTs)2 (0.229
mmol) in acetone/H2O (20 mL/0.2 mL) was heated at 50 °C
for 8 h under argon. The grayish precipitate thus obtained
was separated by filtration, and extracted with methanol, and
solvent was removed under vacuum. Purification of the
residue by recrystallization from methanol afforded a good
columnar solid suitable for the X-ray analysis. Exhaustive
washing with ether removed the water included as crystal-
lization solvent and produced the material that analyzed as
[Cp2W(µ-OH)2WCp2]2+(OTs-)2 (1a ) (0.193 g) in yield of 84%.
This procedure is also applicable to the synthesis of the
molybdenum analog 1b, [Cp2Mo(µ-OH)2MoCp2]2+(OTs-)2 (yield
) 97%). 1a : mp 115 °C dec; IR ν(OH) 3550 cm-1, ν(CH) 3078
(tolyl), 98.47 (Cp), 21.35 (Me-tolyl). Anal. Calcd for C34
-
H
36O8S2W2: C, 40.66; H, 3.61; S, 6.38. Found: C, 40.44; H,
4.14; S, 6.32. 1b: mp 115 °C dec; IR ν(OH) 3540 cm-1, ν(CH)
3075 cm-1; 1H NMR (CD3OD) δ 7.70 (d, 7.9 Hz, 4H, meta-tolyl),
7.27 (d, 7.9 Hz, 4H, ortho-tolyl), 6.00 (s, 20H, Cp), 2.38 (s, 6H,
Me-tolyl); 13C NMR (CD3OD) δ 143.45, 141.92, 129.95, 126.93
(tolyl), 103.59 (Cp), 21.35 (Me-tolyl). Anal. Calcd for C34H36
O8S2Mo2: C, 49.27; H, 4.38; S, 7.74. Found: C, 49.02; H, 4.47;
S, 7.72.
Rea ction of 1a ,b w ith Ter tia r y P h osp h in es. A typical
procedure is as follows. A solution containing 1a or 1b and
the tertiary phosphine in either methanol, ethanol, 2-propanol,
or trifluoroethanol was stirred under the conditions given in
Tables 5 and S13. During the stirring, the solution changed
from green to red. From the resulting solution, the solvent
-

Di-µ-hydroxo Complexes of W(IV) and Mo(IV)
Organometallics, Vol. 15, No. 2, 1996 859
Ta ble 14. F r a ction a l Atom ic Coor d in a tes a n d
complexes 2e, 2e′, 2f, and 2f′) or trifluoroethanol (for com-
plexes 2g, 2g′, 2h , 2h ′, 2i, and 2i′). Ether was added to the
extract to precipitate [Cp2MPR3(OR′)]+OTs- (2) as a reddish
powder. For complexes 2j, 2j′, 2k , and 2k ′, this extraction
procedure was not carried out.
Examples listed in Tables 5 and S13 were carried out under
essentially the same conditions. Analytical data and spectro-
scopic properties of complexes 2 are given in Tables 6 and S14
and Tables 7 and S15, respectively. Elemental analyses of
complexes 2c, 2c′, 2d , 2e, 2e′, 2f, 2f′, 2i, and 2j′ failed to
provide useful information because of impurities which were
difficult to remove.
X-r a y Cr ysta llogr a p h ic Stu d y of 2h . Crystals of complex
[Cp2Mo(PBun3)(CF3CH2O)]+OTs- (2h ) suitable for X-ray crys-
tallography were grown in benzene at 10 °C, and a dark-red
plate-shaped crystal thus obtained was mounted on a glass
fiber. All measurements were made on a Rigaku AFC7R
diffractometer by using Cu KR radiation (λ ) 1.541 78 Å) with
µ ) 46.25 cm-1 and F(000) ) 728.00 Å.
The unit-cell parameters were obtained from a least-squares
refinement using the setting angles of 25 carefully centered
reflections in the range 48.16° e 2θ e 49.81°. The parameters
used during the collection of diffraction data are given in Table
13. The structure was solved and expanded by using Fourier
techniques.19 The non-hydrogen atoms were refined anisotro-
pically. Hydrogen atoms were included but not refined. Final
results are summarized in Table 14.
Biso/Beq Va lu es (Å2) for 2h
atom
x/ a
y/ b
z/ c
B
Mo(1)
S(35)
P(3)
F(1)
F(2)
F(3)
O(2)
O(3)
O(4)
O(5)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
0.1579(1)
0.8797(4)
0.2808(4)
0.100(1)
0.176(1)
0.286(1)
0.1727(8)
0.981(1)
0.790(1)
0.933(1)
0.102(2)
0.166(2)
0.289(2)
0.348(2)
0.352(2)
0.372(3)
0.454(2)
0.474(2)
0.614(3)
0.690(3)
0.202(1)
0.267(2)
0.192(3)
0.192(5)
0.290(3)
0.368(2)
0.317(4)
0.224(3)
0.200(2)
0.024(1)
-0.023(2)
-0.060(1)
-0.044(2)
0.004(1)
0.782(1)
0.676(2)
0.606(1)
0.642(2)
0.749(2)
0.821(1)
0.546(2)
-0.18045(7)
-0.1409(3)
-0.2109(2)
-0.4845(7)
-0.4724(6)
-0.4303(6)
-0.3032(5)
-0.1886(7)
-0.1028(7)
-0.0852(6)
-0.353(1)
-0.435(1)
-0.131(1)
-0.053(1)
0.022(1)
0.1864(1)
0.6942(5)
0.4108(4)
-0.132(1)
0.082(1)
-0.035(1)
0.1420(9)
0.633(1)
0.600(1)
0.829(1)
0.019(2)
-0.016(2)
0.574(2)
0.582(2)
0.707(3)
0.837(2)
0.420(2)
0.323(2)
0.322(4)
0.310(3)
0.448(2)
0.575(2)
0.595(3)
0.503(3)
0.021(3)
0.148(3)
0.202(3)
0.094(4)
-0.016(3)
0.296(2)
0.150(2)
0.102(2)
0.220(2)
0.336(2)
0.734(1)
0.796(1)
0.836(2)
0.821(2)
0.760(2)
0.719(1)
0.859(2)
6.06(3)
8.2(1)
7.3(1)
14.0(4)
13.5(4)
13.3(4)
6.6(2)
11.2(4)
11.7(4)
9.5(3)
8.2(5)
10.3(7)
10.4(6)
11.4(7)
13.2(7)
14.8(9)
11.4(6)
13.2(7)
20(1)
0.007(2)
-0.244(1)
-0.324(1)
-0.372(2)
-0.323(2)
-0.2936(9)
-0.322(1)
-0.391(2)
-0.458(2)
-0.205(1)
-0.172(2)
-0.091(2)
-0.085(1)
-0.159(3)
-0.0834(9)
-0.102(1)
-0.183(1)
-0.214(1)
-0.153(1)
-0.2133(8)
-0.1846(9)
-0.238(1)
-0.317(1)
-0.3431(9)
-0.2912(10)
-0.373(1)
18(1)
8.1(4)
11.8(6)
15.0(9)
23(1)
10.3(8)
10.1(7)
13(1)
11.0(8)
13.0(9)
8.0(5)
9.3(6)
8.7(5)
8.1(5)
7.4(5)
6.2(4)
7.7(4)
7.9(5)
8.4(5)
8.7(5)
7.6(4)
12.5(7)
Ack n ow led gm en t. We thank Dr. M. Tanaka of
Tokyo Institute of Technology for the elemental analy-
ses. This work was supported by a Grant-in-Aid for
Scientific Research on Priority Area (No. 05236104) and
in part by a Grant-in-Aid for Scientific Research (B) (No.
07455354) from the Ministry of Education, Science, and
Culture of J apan.
Su p p or tin g In for m a tion Ava ila ble: Tables S1-S15,
listing fractional atomic coordinates and thermal parameters,
anisotropic thermal factors, and all bond distances and angles
for 1a ,b and 2h and experimental details and characterization
data for complexes 2b, 2b′, 2d , 2d ′, 2f, 2f′, 2g, 2g′, 2k , and
2k ′ (37 pages). Ordering information is given on any current
masthead page.
a
Beq
)
8/3π2(U11(aa*)2 + U22(bb*)2 + U33(cc*)2 + 2U12aa*bb*
cos γ + 2U13aa*cc* cos â + 2U23bb*cc* cos R.
OM950609M
was evaporated to dryness under reduced pressure. The
residue was washed with hexane and ether and then extracted
with either methanol (for complexes 2a , 2a ′, 2b, and 2b′),
ethanol (for complexes 2c, 2c′, 2d , and 2d ′), 2-propanol (for
(19) Beurskens, P. T.; Admiraal, G.; Bosman, W. P.; Garcia-Granda,
S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The DIRDIF program
system, Technical Report of the Crystallography Laboratory, Univer-
sity of Nijmegen, The Netherlands, 1992.