Investigations on novel tandem reaction of three components, [η5-RC5H4(CO)2Mo]2, Ph2Te2, and Cp2TiCl2, Cp2ZrCl2, or Cp2ZrBr2.

Article abstract of DOI:10.1021/om9904448

While reaction of triply bonded dimers [η⁵-RC₅H₄(CO)₂Mo]₂ (R = MeCO, MeO₂C) with Ph₂-Te₂ in xylene at 110°C and subsequent treatment with Cp₂TiCl₂ at reflux gives novel tetrakis-bridged complexes (η⁵-RC₅H₄Mo)₂(μ-PhTe) ₄ (1, R = MeCO; 3, R = MeO₂C) and (η₅-RC₅H₄Mo) ₂(μ-Cl)(μ-PhTe)₃ (2a,b, R = MeCO; 4a,b, R = MeO₂C), the dimers [μ⁵-RC₅H₄(CO)₂Mo]₂ (R = MeO₂C, EtO₂C) reacted with Ph₂Te₂ and Cp₂ZrCl₂ or Cp₂ZrBr₂ under similar conditions to afford novel tetrakis-bridged complexes (η⁵-RC₅H₄Mo)₂(μ-PhTe) ₄ (3, R = MeO₂C; 5, R = EtO₂C), (η⁵-RC₅H₄Mo) ₂(μ-Cl)(μ-PhTe)₃ (4a,b, R = MeO₂C; 6a,b, R = EtO₂C), and (η⁵-RC₅H₄-Mo) ₂(μ-Br)(μ-PhTe)₃ (7a,b, R = MeO₂C; 8a,b, R = EtO₂C). A possible pathway for production of such tetrakis-bridged complexes has been suggested primarily on the basis of the following facts: (i) Treatment of triply bonded dimers [η⁵-RC₅H₄(CO)₂Mo]₂ (R = MeO₂C, EtO₂C) with Ph₂Te₂ in xylene at 110°C produces bis-bridged complexes [η⁵-RC₅H₄(CO)₂Mo] ₂(μ-PhTe)₂ (9, R = MeO₂C; 10, R = EtO₂C) and (ii) reaction of 9 with Cp₂MCl₂ (M = Ti, Zr) yields tetrakis-bridged complexes 3 and 4a,b. All the new products 1-10 are fully characterized by elemental analysis and IR, ¹H, and ¹²⁵Te NMR spectroscopies, and 4b and 9 by single-crystal X-ray diffraction techniques.

Full text of DOI:10.1021/om9904448

156
Organometallics 2000, 19, 156-162
In vestiga tion s on Novel Ta n d em Rea ction of Th r ee
Com p on en ts, [η5-RC5H4(CO)2Mo]2, P h 2Te2, a n d Cp 2TiCl2,
Cp 2Zr Cl2, or Cp 2Zr Br 2. Syn th esis a n d Str u ctu r a l
Ch a r a cter iza tion of Tetr a k is- a n d Bis-Br id ged
Dim olybd en u m Com p lexes (η5-RC5H4Mo)2(µ-P h Te)4
(R ) MeCO, MeO2C, EtO2C), (η5-RC5H4Mo)2(µ-Cl)(µ-P h Te)3
(R ) MeCO, MeO2C, EtO2C), (η5-RC5H4Mo)2(µ-Br )(µ-P h Te)3
(R ) MeO2C, EtO2C), a n d [η5-RC5H4(CO)2Mo]2(µ-P h Te)2
(R ) MeO2C, EtO2C)
Li-Cheng Song,*,† Yao-Cheng Shi,† Wen-Feng Zhu,† Qing-Mei Hu,†
Xiao-Ying Huang,‡ Fei Du,# and Xi-An Mao#
Department of Chemistry, Nankai University, Tianjin 300071, China, State Key Laboratory of
Structural Chemistry, Fuzhou 350002, China, and Wuhan Institute of Physics,
Chinese Academy of Sciences, Wuhan 430071, China
Received J une 8, 1999
While reaction of triply bonded dimers [η5-RC5H4(CO)2Mo]2 (R ) MeCO, MeO2C) with Ph2-
Te2 in xylene at 110 °C and subsequent treatment with Cp2TiCl2 at reflux gives novel tetrakis-
bridged complexes (η5-RC5H4Mo)2(µ-PhTe)4 (1, R ) MeCO; 3, R ) MeO2C) and (η5-
RC5H4Mo)2(µ-Cl)(µ-PhTe)3 (2a,b, R ) MeCO; 4a,b, R ) MeO2C), the dimers [η5-RC5H4(CO)2Mo]2
(R ) MeO2C, EtO2C) reacted with Ph2Te2 and Cp2ZrCl2 or Cp2ZrBr2 under similar conditions
to afford novel tetrakis-bridged complexes (η5-RC5H4Mo)2(µ-PhTe)4 (3, R ) MeO2C; 5, R )
EtO2C), (η5-RC5H4Mo)2(µ-Cl)(µ-PhTe)3 (4a ,b, R ) MeO2C; 6a ,b, R ) EtO2C), and (η5-RC5H4-
Mo)2(µ-Br)(µ-PhTe)3 (7a ,b, R ) MeO2C; 8a ,b, R ) EtO2C). A possible pathway for production
of such tetrakis-bridged complexes has been suggested primarily on the basis of the following
facts: (i) Treatment of triply bonded dimers [η5-RC5H4(CO)2Mo]2 (R ) MeO2C, EtO2C) with
Ph2Te2 in xylene at 110 °C produces bis-bridged complexes [η5-RC5H4(CO)2Mo]2(µ-PhTe)2
(9, R ) MeO2C; 10, R ) EtO2C) and (ii) reaction of 9 with Cp2MCl2 (M ) Ti, Zr) yields
tetrakis-bridged complexes 3 and 4a ,b. All the new products 1-10 are fully characterized
1
by elemental analysis and IR, H, and 125Te NMR spectroscopies, and 4b and 9 by single-
crystal X-ray diffraction techniques.
In tr od u ction
[Et3NH][(µ-R′S)(µ-CO)Fe2(CO)6] and oxygen, which af-
fords a novel type of thiolato-bridged and oxo-capped
trimetallic clusters (η5-RC5H4)(CO)2MFe2(µ3-O)(µ-R′S)
(CO)6.2g As a continuation of this project, we recently
carried out another tandem reaction of triply bonded
dimers [η5-RC5H4(CO)2Mo]2 with Ph2Te2 and subse-
quently with Cp2TiCl2, Cp2ZrCl2, or Cp2ZrBr2. Herein
we report the results obtained from this study.
The group 6 metal-metal triply bonded dimers [η5-
RC5H4(CO)2M]2 (M ) Cr, Mo, W; η5-RC5H4 ) parent and
substituted cyclopentadienyls) are of considerable inter-
est since they are important synthons to react with
organic, inorganic, and organometallic substrates, yield-
ing a great variety of novel group 6 metal-containing
complexes.1 Some years ago, we started a project
regarding such dimers, aimed to develop their new
reaction modes and to prepare new types of group 6
metal-containing complexes, particularly organometallic
clusters. Among our published papers related to this
project2 is an interesting tandem reaction of triply
bonded dimers [η5-RC5H4(CO)2M]2 (M ) Mo, W) with
Resu lts a n d Discu ssion
Tan dem Reaction of [η5-RC5H4(CO)2Mo]2, P h 2Te2,
a n d Cp 2MX2 (M ) Ti, Zr ; X ) Cl, Br ). Syn th esis a n d
Ch a r a cter iza tion of 1-8. We found that the Mo-Mo
(2) For example see: (a) Song, L.-C.; Wang J .-Q.; Hu, Q.-M.; Gao,
W.-Q.; Han, B.-S. Polyhedron 1997, 16, 481. (b) Song, L.-C.; Wang,
J .-Q.; Hu, Q.-M.; Huang, X.-Y. Polyhedron 1997, 16, 2249. (c) Song,
L.-C.; Wang, J .-Q.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W. Inorg. Chim.
Acta 1997, 256, 129. (d) Song, L.-C.; Wang, J .-Q.; Hu, Q.-M.; Sun, J .
J . Coord. Chem. 1997, 42, 63. (e) Song, L.-C.; Shi, Y.-C.; Hu, Q.-M.;
Du, F.; Mao, X.-A. Polyhedron 1998, 18, 19. (f) Song, L.-C.; Wang, J .-
Q.; Hu, Q.-M.; Huang, X.-Y. J . Coord. Chem. 1999, 46, 245. (g) Song,
L.-C.; Fan, H.-T.; Hu, Q.-M.; Qin, X.-D.; Zhu, W.-F.; Chen, Y.; Sun, J .
Organometallics 1998, 17, 3454.
† Nankai University.
‡ State Key Laboratory of Structural Chemistry.
#
Wuhan Institute of Physics.
(1) For a general review, see for example: (a) Davis, R.; Kane-
Maguire, L. A. P. In Comprehensive Organometallic Chemistry; Wilkin-
son, G., Stone, F. G. A., Abel, E. W., Eds.; Pergamon Press: New York,
l982; Vol. 3, Chapters 26-28, and references therein. (b) Curtis, M.
D. Polyhedron 1987, 6, 759, and references threrein. (c) Song, L.-C.;
Wang, J . Q. Youji Huaxue 1994, 14, 225, and references therein.
10.1021/om9904448 CCC: $19.00 © 2000 American Chemical Society
Publication on Web 12/29/1999

Tetrakis- and Bis-Bridged Dimolybdenum Complexes
Organometallics, Vol. 19, No. 2, 2000 157
Sch em e 1
triply bonded dimers [η5-RC5H4(CO)2Mo]2 (R ) MeCO,
MeO2C) reacted with Ph2Te2 in xylene at 110 °C
followed by treatment with Cp2TiCl2 at this temperature
and then at reflux to give tetrakis-bridged complexes
(η5-RC5H4Mo)2(µ-PhTe)4 (1, R ) MeCO; 3, R ) MeO2C)
and (η5-RC5H4Mo)2(µ-Cl)(µ-PhTe)3 (2a ,b, R ) MeCO;
4a ,b, R ) MeO2C), whereas reaction of [η5-RC5H4(CO)2-
Mo]2 (R ) MeO2C, EtO2C) with Ph2Te2 and subse-
quently with Cp2ZrCl2 or Cp2ZrBr2 under similar con-
ditions afforded tetrakis-bridged complexes (η5-
RC5H4Mo)2(µ-PhTe)4 (3, R ) MeO2C; 5, R ) EtO2C), (η5-
RC5H4Mo)2(µ-Cl)(µ-PhTe)3 (4a ,b, R ) MeO2C; 6a ,b, R
) EtO2C), and (η5-RC5H4Mo)2(µ-Br)(µ-PhTe)3 (7a ,b, R
) MeO2C; 8a ,b, R ) EtO2C), as shown in Scheme 1.
While products 1, 3, and 5 belong to homo-tetrakis-
bridged complexes which contain four identical PhTe
ligands, products 2, 4, 6, 7, and 8 are mixed-tetrakis-
bridged complexes, which have one halogenido (Cl or
Br) and three PhTe ligands. The mixed-bridged com-
plexes each have two isomers a and b, in which isomer
a has two phenyl groups attached to the planar four-
membered ring Mo2Te2 cis to the halogenido ligand,
whereas isomer b has these two phenyl groups cis and
trans to the halogenido ligand with respect to the planar
Mo2Te2 ring, respectively. Although isomers a and b
both contain two consecutive Mo2Te2 butterfly structural
units, isomer a has two equatorial Ph groups in one of
its butterfly units, whereas b has one axial Ph group
and one equatorial Ph group in its corresponding one
butterfly unit (for details, see crystal structure of 4b).
The homo-bridged complexes could be regarded as being
generated by replacement of the halogenido ligand in
isomer a or b by one PhTe ligand. Such homo-bridged
complexes consist of four sequential Mo2Te2 butterfly
structural units, each of which contains one axial Ph
group and one equatorial Ph group. It is worth noting
that in any two contiguous butterfly units if the Ph
group attached to the Te atom of the common wing is
equatorial in the first unit, then it will be axial in the
second unit, and vice versa. In fact, all the products
shown in Scheme 1 are new types of tetrakis-bridged
complexes, which have been characterized by elemental
analysis, by IR and NMR spectroscopies, and particu-
larly by an X-ray diffraction analysis of isomer 4b.
The IR spectra of 1 and 2a ,b showed one absorption
band at about 1657 cm-1 for their acetyl groups, and
those of 3, 4a ,b, 5, 6a ,b, 7a ,b, and 8a ,b exhibited one
absorption band at around 1703 cm-1 for their ester
1
groups. The H NMR spectra of 1 and 2a ,b showed a
singlet at ca. 2.1 ppm for their methyl groups of acetyls,
whereas those of 3, 4a ,b, and 7a ,b displayed a singlet
at ca. 3.5 ppm for their methyl groups of methoxycar-
bonyls and those of 5, 6a ,b, and 8a ,b exhibited a triplet
at ca. 1.2 ppm and a quartet at ca. 4.1 ppm for their
ethoxycarbonyls. In addition, all the complexes 1-8
showed one multiplet at between 6.80 and 7.76 ppm for
their phenyl groups and two multiplets for their mono-
substituted Cp rings, one between 5.56 and 6.20 ppm
assigned to H2 and H5 protons close to the substituents
and the other between 5.40 and 5.86 ppm attributed to
H3 and H4 protons remote from the substituents since
the substituents are electron-withdrawing.3-6 It is
noteworthy that the two isomers for the Mo2Te3X (X )
Cl, Br) complexes have similar but slightly different
physical and spectroscopic properties. For example, the
melting points and Rf values of isomer type a are greater
than those of type b. In addition, as can be seen from
the 1H NMR spactra of one representative pair of
(3) Macomber, D. W.; Rausch, M. D. J . Organomet. Chem. 1983, 258,
33l.
(4) Hart, W. P.; Rausch, M. D. J . Organomet. Chem. 1988, 355, 455.
(5) Song, L.-C.; Shen, J .-Y.; Hu, Q.-M.; Wang, R.-J .; Wang, H.-G.
Organometallics 1993, 12, 408.
(6) Song, L.-C.; Shen, J .-Y.; Hu, Q.-M.; Huang, X.-Y. Organometallics
1995, 14, 98.

158 Organometallics, Vol. 19, No. 2, 2000
Song et al.
three PhTe and one Cl are bridged to the Mo(1)-Mo(2)
bond. The dihedral angle between the two cyclopenta-
dienyl planes C(11) through C(15) and C(21) through
C(25) is calculated as 9.69°. In addition, Mo(1), Mo(2),
Te(1), and Te(2) atoms, as well as Mo(1), Mo(2), Te(3),
and Cl(1) atoms, are calculated to be coplanar, and the
two planes are actually perpendicular, with a dihedral
angle of 89.14°. It is noteworthy that the two phenyl
groups attached to Te(1) and Te(2) are trans to each
other with respect to the plane Mo(1)Mo(2)Te(1)Te(2),
whereas the phenyl group bonded to Te(3) is cis to the
phenyl group attached to Te(2). Interestingly, Te(1),
Te(2), Te(3), and Cl(1) atoms are also coplanar. This
plane is perpendicular to both Mo(1)Mo(2)Te(1)Te(2)
and Mo(1)Mo(2)Te(3)Cl(1) planes, which is passed
through the midpoint of the Mo(1)-Mo(2) bond. The
bond angles Mo(1)-Te(1)-Mo(2), Mo(1)-Te(2)-Mo(2),
and Mo(1)-Te(3)-Mo(2) are virtually the same (59.2-
(2)°, 59.1(2)°, and 59.4(1)°, respectively), which are
smaller than that of Mo(1)-Cl(1)-Mo(2) (66.2(1)°).
While the bond lengths of Mo-Cl equal 2.486(2) and
2.487(2) Å, those of Mo-Te are between 2.735(1) and
2.756(3)Å, which are very close to those in Cp2Mo2 (CO)4-
(µ-TePh)2 (2.785(4)-2.865(4)Å).11 The bond length of
Mo(1)-Mo(2) is 2.714(6) Å, which is slightly longer than
that of Cp2Mo2(µ-SMe)4 (2.603(2) Å)12 and very close to
that in Cp2Mo2(CO)2(µ-SMe)3Br (2.785(2) Å).13 Since the
oxidation state of Mo(1) and Mo(2) is +III, 4b belongs
to a d3-d3 type of complex, and the electronic configu-
ration of the Mo(1)-Mo(2) single bond would be best
described as σ2δ2δ*2.14 In view of the determined
structure of isomer 4b, we might suggest that isomer
4a would have the phenyl group attached to Te(2) in
the cis position to both the Cl ligand and the phenyl
group attached to Te(1). This is because it is impossible
for all three phenyl groups to be in cis positions with
respect to Mo(1)Mo(2)Te(1)Te(2) plane, due to very
strong steric repulsion between the two phenyl groups
axially bonded to Te(1) and Te(3) in the butterfly-shaped
skeleton Mo(1)Mo(2)Te(1)Te(3).15
Rea ction of [η5-RC5H4(CO)2Mo]2 w ith P h 2Te2.
Syn th esis a n d Ch a r a cter iza tion of 9 a n d 10. To
know the pathway for production of the tetrakis-bridged
dimolybdenum complexes 1-8 from the novel tandem
reaction, we carried out the reaction of an equimolar
amount of [η5-RC5H4(CO)2Mo]2 (R ) MeO2C, EtO2C)
with Ph2Te2 in xylene at 110 °C. As a result, two homo-
bis-bridged dimolybdenum complexes 9 and 10 were
obtained in high yields without tetrakis-bridged dimo-
lybdenum complexes 3 and 5 produced, as shown in
Scheme 2.
It is worth noting that when the triply bonded dimer
[η5-MeO2CC5H4(CO)2Mo]2 reacted with Ph2Te2 in 1:2
molar ratio at higher temperature (in refluxing xylene,
about 145 °C), only 14% of 9 was obtained (primarily
due to serious thermal decomposition of the triply
bonded dimer) and no tetrakis-bridged dimolybdenum
F igu r e 1. 1H NMR spectra of one pair of isomers 7a and
7b.
isomers 7a and 7b (Figure 1), the 1H NMR spectral
patterns, particularly the shapes of the substituted Cp
rings for isomers of type a , are somewhat different from
those for isomers of type b.
During recent years, 125Te NMR spectroscopy has
been developed as an important tool for characterizing
Te-containing organometallic compounds.7-10 To further
characterize our homo- and mixed-tetrakis-bridged com-
plexes, the 125Te NMR spectra of representatives 3 and
4b (Figure 2) were determined with reference to exter-
nal Ph2Te2. As seen from Figure 2, while 3 showed one
singlet at -l39 ppm, 4b displayed three singlets at 113,
-9, and -249 ppm. Apparently, this is consistent with
the homo-bridged complexes having four environmen-
tally identical Te atoms and the mixed-bridged com-
plexes containing three environmentally different bridg-
ing Te atoms, respectively.
Cr ysta l Str u ctu r e of 4b. To unequivocally confirm
the structures of isomer type a and type b for the mixed-
tetrakis-bridged complexes and to provide more struc-
tural evidence for the homo-tetrakis-bridged complexes,
we carried out the single-crystal diffraction analysis for
isomer 4b. The ORTEP drawing and unit cell plot of
4b are shown in Figures 3 and 4. Table 1 lists its
selected bond lengths and angles. As seen from Figure
4, in the unit cell each molecule of 4b carries two solvent
molecules of CH2Cl2. Figure 3 shows that 4b consists
of two substituted cyclopentadienyl ligands η5-MeO2-
CC5H4, three PhTe ligands, one Cl ligand, and two Mo
atoms. The two η5-MeO2 CC5H4 ligands are trans to each
other with respect to the Mo(1)-Mo(2) bond, and the
(7) Herrmann, W. A.; Rohrmann, J .; Hecht, C. J . Organomet. Chem.
1985, 290, 53.
(8) Bogan, L. E.; Clark, G. R.; Rauchfuss, T. B. Inorg. Chem. 1986,
25, 4050.
(9) Mathur, P.; Dash, A. K.; Hossain, Md, M.; Umbarkar, S. B.;
Satyanarayana, C. V. V.; Chen, Y.-S.; Holt, E. M.; Rao, S. N.; Soriano,
M. Organometallics 1996, 15, 1356.
(11) J aitner, P.; Wohlgenannt, W.; Gieren, A.; Betz, H.; Hu¨bner, T.
J . Organomet. Chem. 1985, 297, 281.
(12) Connelly, N. G.; Dahl, L. F. J . Am. Chem. Soc. 1970, 92, 7470.
(13) de Lima, M. B. G.; Guerchais, J . E.; Mercier, R.; Pe´tillon, F. Y.
Organometallics 1986, 5, 1952.
(14) Tremel, W.; Hoffmann, R.; J emmis, E. D. Inorg. Chem. 1989,
28, 1213.
(10) Bachman, R. E.; Whitmire, K. H. Organometallics 1993, 12,
1988.
(15) Shaver, A.; Fitzpatrick, P. J .; Steliou, K.; Butler, I. S. J . Am.
Chem. Soc. 1979, 101, 1313.

Tetrakis- and Bis-Bridged Dimolybdenum Complexes
Organometallics, Vol. 19, No. 2, 2000 159
F igu r e 2. 125Te NMR spectra of (η5-MeO2CC5H4Mo)2(µ-PhTe)4 (3) and (η5-MeO2CC5H4Mo)2(µ-Cl)(µ-PhTe)3 (4b).
F igu r e 4. Unit cell plot of 4b.
Ta ble 1. Selected Bon d Len gth s (Å) a n d Bon d s
An gles (d eg) for 4b
F igu r e 3. ORTEP drawing of 4b with atom-labeling
scheme.
Mo(1)-Mo(2)
Te(1)-Mo(1)
Te(2)-Mo(2)
Te(3)-Mo(1)
Mo(2)-Cl(1)
Mo(1)-C(12)
2.714(6)
2.752(2)
2.756(3)
2.741(1)
2.486(2)
2.242(6)
Te(1)-Mo(2)
Te(2)-Mo(1)
Te(3)-Mo(2)
Mo(1)-Cl(1)
Te(1)-C(31)
Mo(2)-C(22)
2.747(4)
2.748(4)
2.735(1)
2.487(2)
2.140(6)
2.237(5)
complex 3 was isolated. These experiments imply that
the homo-tetrakis-bridged complexes 1, 3, and 5 could
not be produced directly from reaction of triply bonded
dimers [η5-RC5H4(CO)2Mo]2 with Ph2Te2 in the absence
of Cp2MX2 (M ) Ti, Zr; X ) Cl, Br). In addition, TLC
showed that the reaction of 9 with Ph2Te2 in 1:1 molar
ratio in xylene at lower temperatures than that of
refluxing xylene such as 105, 115, 125, or 135 °C for 2
h also gave no homo-tetrakis-bridged complex 3, both
starting materials 9 and Ph2Te2 being basically un-
changed with trace amounts of immobile residue (CH2-
Cl2 as eluent) left on the original spot.
Mo(2)-Te(1)-Mo(1)
Mo(2)-Te(3)-Mo(1)
Mo(2)-Mo(1)-Te(2)
Te(3)-Mo(1)-Te(2)
Mo(1)-Mo(2)-Te(1)
Te(3)-Mo(2)-Te(1)
59.2(2)
59.4(1)
Mo(1)-Te(2)-Mo(2) 59.1(2)
Mo(2)-Mo(1)-Te(3) 60.18(6)
60.60(4) Mo(2)-Mo(1)-Te(1) 60.3(2)
76.93(8) Mo(1)-Mo(2)-Te(3) 60.40(8)
60.53(4) Mo(1)-Mo(2)-Te(2) 60.3(2)
76.2(1)
Te(3)-Mo(2)-Te(2) 76.90(5)
Mo(2)-Cl(1)-Mo(1) 66.2(1)
Te(1)-Mo(2)-Te(2) 120.8(2)
Sch em e 2
9 and 10 are new and have been fully characterized
by combustion analysis and IR and NMR spectroscopy,
as well as by an X-ray diffraction analysis for 9 . The
IR spectra of 9 and 10 each showed one absorption band
at 1720 or 1716 cm-1 for their ester functionalities and
four to five absorption bands in the range 1954-1846
cm-1 for their terminal carbonyls. The 1H NMR spectra
showed the signals assignable to all the hydrogen-
containing groups, whereas the 125Te NMR spectra each
displayed one broad peak at -1160 or -1164 ppm with
reference to external Ph2Te2 (Figure 5). It is interesting
to note that such high-field 125Te NMR values, compared
to those of 3 and 4b, imply that the Te atoms in bis-
bridged complexes 9 and 10 are much more shielded
than those in the tetrakis-bridged complexes by corre-
sponding structural units around Te atoms. In addition,
such high-field 125Te NMR values were also observed
in other tellurium-containing organometallic com-

160 Organometallics, Vol. 19, No. 2, 2000
Song et al.
Ta ble 2. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) for 9
Mo(1)-Mo(2)
Te(1)-Mo(2)
Te(2)-Mo(1)
Te(2)-C(21)
4.259(3)
2.829(2)
2.824(2)
2.15(2)
Te(1)-Mo(1)
2.825(2)
2.811(2)
2.13(1)
1.95(2)
Te(2)-Mo(2)
Te(1)-C(11)
Mo(1)-C(1)
Te(2)-Mo(1)-Te(1)
70.81(6) Te(2)-Mo(2)-Te(1)
70.94(6)
Mo(1)-Te(1)-Mo(2) 97.76(6) Mo(2)-Te(2)-Mo(1) 98.19(6)
C(11)-Te(1)-Mo(1) 106.3(4) C(11)-Te(1)-Mo(2) 105.8(4)
C(21)-Te(2)-Mo(2) 106.9(4) C(21)-Te(2)-Mo(1) 108.3(4)
C(1)-Mo(1)-C(3)
78.8(8) C(2)-Mo(2)-C(4)
76.5(7)
Sch em e 3
F igu r e 5. 125Te NMR spectra of [η5-MeO2CC5H4Mo]2(µ-
PhTe)2 (9) and [η5-EtO2CC5H4(CO)2Mo]2(µ-PhTe)2 (10).
terminal carbonyls trans to each other, whereas the Te-
(1) and Te(2) atoms are attached to two phenyl groups
by an axial and an equatorial bond, respectively. So, 9
belongs to the trans/ae isomer.20 While the dihedral
angle between the two cyclopentadienyl planes C(31)
through C(35) and C(41) through C(45) is 44.27°, that
between the two benzene ring planes C(11) through
C(16) and C(21) through C(26) equals 72.41°. It is worth
noting that the distance between Mo(1) and Mo(2) is
4.259(3) Å, which is even longer than those in its
analogues [CpMo(CO)2]2(µ-EPh)2 (E ) S,21 3.940 Å; E
) Se,11 4.054 Å, E ) Te,22 4.23 Å). This implies that
there is no bonding interactions between the two Mo
atoms in 9.
Mech a n ist ic Con sid er a t ion s for t h e Ta n d em
Rea ction . To further reveal the pathway for the
tandem reaction, we carried out the reaction of an
equimolar amount of 9 with Cp2TiCl2 or Cp2ZrCl2 in
xylene at reflux. As a result, 34% of 4a and a much less
amount of 4b and 3 (for Cp2TiCl2) and 9% of 4a and
trace of amounts of 4b and 3 (for Cp2ZrCl2) were
produced, respectively. So, based on these results and
the above facts indicated by reaction of [η5-RC5H4(CO)2-
Mo]2 with equimolar or excess Ph2Te2, a plausible
pathway for the tandem reaction might be proposed as
shown in Scheme 3.
F igu r e 6. ORTEP drawing of 9 with atom-labeling
scheme.
pounds, such as (µ-Te2)[Cp*Re(CO)2]2,16 (µ-Te2)Fe2-
(CO)6,17 [η5-MeC5H4MoFeTe2(CO)5]SbF6,18 and [(CO)3-
Fe(µ-CH2)Te]2.19
Theoretically, the bridged complexes of type [η5-
RC5H4(CO)2Mo](µ-ER)2 (η5-RC5H4 ) parent and substi-
tuted Cp; M ) Cr, Mo, W; E ) S, Se, Te) may have six
isomers (namely, trans/ae, trans/ee, trans/aa, cis/ae, cis/
ee, and cis/aa; a ) axial, e ) equatorial), in terms of
the trans or cis arrangement of either η5-RC5H4 or
carbonyl ligands with respect to the M‚‚‚M vector and
the ae, ee, or aa orientations of two R groups bonded to
the bridged E atoms in the butterfly skeleton M2E2.20
So, to further establish the structures of 9 and 10, we
carried out the crystallographic study of 9 by X-ray
diffraction techniques.
The ORTEP plot of 9 is presented in Figure 6, and
its selected bond lengths and angles are listed in Table
2. As seen in Figure 6, this molecule contains a butterfly
Mo(1)Mo(2)Te(1)Te(2) skeleton; the Mo(1) and Mo(2)
atoms each carry one substituted Cp ring and two
In the first step of the tandem reaction, the Mo-Mo
triply bonded dimers react with Ph2Te2 to give inter-
mediate bis-bridged complexes [η5-RC5H4(CO)2Mo]2(µ-
PhTe)2, and in the second step the bis-bridged complexes
will further react with Cp2MX2 to give homo- and mixed-
tetrakis-bridged complexes (η5-RC5H4Mo)2(µ-PhTe)4 and
(η5-RC5H4 Mo)2(µ-X)(µ-PhTe)3. Apparently, in the second
step Cp2MX2 played an important role both as a Cl or
(16) Herrmann, W. A.; Kneuper, H.-J . J . Organomet. Chem. 1998,
348, 193.
(17) Lesch, D. A.; Rauchfuss, T. B. Inorg. Chem. 1981, 20, 3583.
(18) Bogan, L. E.; Rauchfuss, T. B. Inorg. Chem. 1985, 24, 3720.
(19) Mathur, P.; Manimaran, B.; Hossain, Md. M.; Satyanarayana,
C. V. V.; Puranik, V. G.; Tavale, S. S. J . Organomet. Chem. l995, 493,
251.
(21) Benson, I. B.; Killops, S. D.; Knox, S. A. R.; Welch, A. J . J . Chem.
Soc., Chem. Commun. 1980, 1137.
(20) Shaver, A.; Lum, B. S.; Bird, P.; Livingstone, E.; Schweitzer,
M. Inorg. Chem. l990, 29, 1832.
(22) Rakoczy, H.; Schollenberger, M.; Nuber, B.; Ziegler, M. L. J .
Organomet. Chem. l994, 467, 217.

Tetrakis- and Bis-Bridged Dimolybdenum Complexes
Organometallics, Vol. 19, No. 2, 2000 161
Found: C, 37.47; H, 2.85. IR (KBr disk): νCdO 1654(vs) cm-1
.
Br source and causing the transformation of the bis-
bridged complexes [η5-RC5H4(CO)2Mo]2(µ-PhTe)2 into
homo- and mixed-tetrakis-bridged products. It should
be further pointed out that (i) the homo- and mixed-
tetrakis-bridged complexes are most likely produced
independently from the intermediate bis-bridged com-
plexes under the action of Cp2MX2, since reaction of 3
with Cp2TiCl2 or 4b with Ph2Te2 under those conditions
gave no corresponding RTe/Cl ligand exchange products
and about 90% of starting material 3 or 4b was
recovered. (ii) While n-Bu4NBr can replace Cp2ZrBr2 as
a bromide source in reaction of [η5-MeO2CC5H4(CO)2-
Mo]2 with Ph2Te2 to give 7a and 7b, Me4NCl cannot
replace Cp2MCl2 (M ) Ti, Zr) as a chloride source to
give the expected 4a and 4b, possibly due to its very
low solubility in xylene. (iii) We have never found any
TLC isolated products that contain a Cp2M unit, which
should remain in the insoluble residues. It is believed
that Cp2MX2 are not simply halide sources but are
responsible for production of homo-tetrakis-bridged
complexes 1, 3, and 5. The metallocenes in this tandem
reaction should be involved in the redox process, through
which each Mo atom with an oxidation state of +I in
triply bonded dimers is oxidized to the Mo atom with
an oxidation state of +III in products 1-8. However,
at present the detailed pathway regarding this tandem
reaction is still unclear, and more work remains to be
studied in the future.
1H NMR (CDCl3): 2.14(s, 6H, 2CH3), 5.48-5.78(m, 4H, 2H3,
2H4), 5.84-6.12(m, 4H, 2H2, 2H5), 6.80-7.60(m, 20H, 4C6H5)
ppm. The second main band afforded 0.196 g (19%) of 2a as a
brown solid, mp 222 °C dec. Anal. Calcd for C32H29ClMo2O2-
Te3: C, 36.41; H, 2.77. Found: C, 36.50; H, 2.71. IR (KBr
disk): νCdO 1654(vs) cm-1. 1H NMR (CDCl3): 2.12(s, 6H, 2CH3),
5.48-5.62(m, 4H, 2H3, 2H4), 5.63-5.86(m, 4H, 2H2, 2H5),
6.88-7.39(m, 15H, 3C6H5) ppm. The third main band afforded
0.379 g (37%) of 2b as a black-brown solid, mp 210 °C dec.
Anal. Calcd for C32H29ClMo2O2Te3: C, 36.41; H, 2.77. Found:
C, 36.25; H, 2.63. IR (KBr disk): νCdO 1660(vs) cm-1. 1H NMR
(CDCl3): 2.00(s, 6H, 2CH3), 5.40-5.72(m, 4H, 2H3, 2H4), 5.80-
6.12(m, 4H, 2H2, 2H5), 6.92-7.56(m, 15H, 3C6H5) ppm.
P r ep a r a tion of (η5-MeO2CC5H4Mo)2(µ-P h Te)4 (3) a n d
(η5-MeO2CC5H4Mo)2(µ-Cl)(µ-P h Te)3 (4a ,b). The same pro-
cedure as that for 1 and 2a ,b was followed, but 0.550 g (1.00
mmol) of [η5-MeO2CC5H4(CO)2Mo]2 was used instead of [η5-
MeCOC5H4(CO)2Mo]2. Using 4:1 (v/v) CH2Cl2/petroleum ether
as eluent, the first main band afforded 0.159 g (13%) of 3 as a
brown solid, mp 208-210 °C. Anal. Calcd for C38H34Mo2O4-
Te4: C, 36.31; H, 2.73. Found: C, 36.25; H, 2.56. IR (KBr
1
disk): νCdO 1707(vs) cm-1. H NMR (acetone-d6): 3.62(s, 6H,
2CH3), 5.60-5.76(m, 4H, 2H3, 2H4), 5.92-6.02(m, 4H, 2H2,
2H5), 6.88-7.56(m, 20H, 4C6H5) ppm. 125Te NMR (CDCl3, Ph2-
Te2): -139(s) ppm. The second main band afforded 0.114 g
(10%) of 4a as a dark green solid, mp 216-218 °C. Anal. Calcd
for C32H29ClMo2O4Te3: C, 35.32; H, 2.71. Found: C, 35.60; H,
3.13. IR (KBr disk): νCdO 1706(vs) cm-1 1H NMR (CDCl3):
.
3.63(s, 6H, 2CH3), 5.56-5.76(m, 4H, 2H3, 2H4), 5.92-6.04(m,
4H, 2H2, 2H5), 6.88-7.56(m, 15H, 3C6H5) ppm. The third main
band afforded 0.421 g (39%) of 4b as a dark green solid, mp
198-202 °C. Anal. Calcd for C32H29ClMo2O4Te3: C, 35.32; H,
2.71. Found: C, 35.46; H, 2.50. IR (KBr disk): νCdO 1707(vs)
Exp er im en ta l Section
1
cm-1. H NMR (CDCl3): 3.56(s, 6H, 2CH3), 5.52-5.68(m, 4H,
Gen er a l P r oced u r es. All reactions were carried out under
an atmosphere of purified nitrogen using standard Schlenk
and vacuum-line techniques. Xylene was distilled from sodium-
benzophenone ketyl under nitrogen. Me4NCl and n-Bu4NBr
were commercially available. Ph2Te2,23 [η5-RC5H4(CO)2Mo]2,24
2H3, 2H4), 5.84-6.04(m, 4H, 2H2, 2H5), 6.88-7.76(m, 15H,
3C6H5) ppm. 125Te NMR (CDCl3, Ph2Te2): 113, -9, -249(s, s,
s) ppm. In addition, while 0.096 g (8%) of 3, 0.078 g (7%) of
4a , and 0.189 g (17%) of 4b could be also prepared from 0.550
g (1.00 mmol) of [η5-MeO2CC5H4(CO)2 Mo]2, 0.615 g (1.50
mmol) of Ph2Te2, and 0.292 g (1.00 mmol) of Cp2ZrCl2, the
reaction of 0.712 g (1.3 mmol) of [η5-MeO2CC5H4(CO)2Mo]2,
0.532 g (1.3 mmol) of Ph2Te2, and 0.142 g (1.3 mmol) of Me4-
NCl under similar conditions did not give any amount of 3
and 4a ,b.
Cp2TiCl2,25 Cp2ZrCl2,25 and Cp2Zr Br2 were prepared accord-
26
ing to the literature. The products were separated by TLC (20
× 25 × 0.25 cm, silica gel G) and further purified by
recrystallization from CH2Cl2/hexane. The yields of the prod-
ucts were calculated based on Mo-Mo triply bonded dimers
[η5-RC5H4(CO)2Mo]2. IR spectra were recorded on a Nicolet FT-
IR 170 SX spectrophotometer; 1H and 125Te NMR spectra were
recorded on Brucker AC-P 200 and Bruker ARX-500 NMR
spectrometers. 125Te NMR spectra were referenced to Ph2Te2
(δ 0). Combustion analyses were performed on a Yanaco CHN
corder MT-3 analyzer, and melting points were determined
on Yanaco Mp-500 apparatus.
P r ep a r a tion of (η5-MeCOC5H4Mo)2(µ-P h Te)4 (1) a n d
(η5-MeCOC5H4Mo)2(µ-Cl)(µ-P h Te)3 (2a ,b). A 100 mL three-
necked flask fitted with a magnetic stir-bar, a rubber septum,
and a reflux condenser topped with a nitrogen inlet tube was
charged with 0.518 g (1.00 mmol) of [η5-MeCOC5H4(CO)2Mo]2,
0.470 g (1.15 mmol) of Ph2Te2, and 40 mL of xylene. The
mixture was stirred at 110 °C for 1 h, and then 0.249 g (1.00
mmol) of Cp2TiCl2 was added. The mixture was stirred at 110
°C for 2 h and then at reflux (ca. 140 °C) for an additional 4 h.
Solvent was removed under reduced pressure. The residue was
subjected to TLC separation using CH2Cl2 as eluent. The first
main band afforded 0.138 g (11%) of 1 as a brown solid, mp
212-213 °C. Anal. Calcd for C38H34Mo2Te4: C, 37.26; H, 2.80.
P r ep a r a tion of (η5-EtO2CC5H4Mo)2(µ-P h Te)4 (5) a n d
(η5-EtO2CC5H4Mo)2(µ-Cl) (µ-P h Te)3 (6a ,b). Similarly, 0.578
g (1.00 mmol) of [η5-EtO2CC5H4(CO)2Mo]2 reacted with 0.615
g (1.50 mmol) of Ph2Te2 and 0.292 g (1.00 mmol) of Cp2ZrCl2
to give three main bands. The first main band afforded 0.153
g (12%) of 5 as a green solid, mp 202-204 °C. Anal. Calcd for
C
40H38Mo2O4Te4: C, 37.38; H, 2.98. Found: C, 37.29; H, 3.11.
IR (KBr disk): νCdO 1702(vs) cm-1. 1H NMR (acetone-d6): 1.19-
(t, J ) 7.2 Hz, 6H, 2CH3), 4.11(q, J ) 7.2 Hz, 4H, 2CH2), 5.56-
5.68(m, 4H, 2H3, 2H4), 5.94-6.00(m, 4H, 2H2, 2H5), 6.80-
7.52(m, 20H, 4C6H5) ppm. The second main band afforded
0.196 g (18%) of 6a as a yellow-green solid, mp 209-211 °C.
Anal. Calcd for C34H33ClMo2O4Te3: C, 36.59; H, 3.01. Found:
C, 36.51; H, 3.07. IR (KBr disk): νCdO 1702(vs) cm-1. 1H NMR
(CDCl3): 1.21(t, J ) 7.2 Hz, 6H, 2CH3), 4.15(q, J ) 7.2 Hz,
4H, 2CH2), 5.54(br.s, 4H, 2H3, 2H4), 5.56-5.92(m, 4H, 2H2,
2H5), 6.88-7.24(m, 15H, 3C6H5) ppm. The third main band
afforded 0.374 g (34%) of 6b as a dark green solid, mp 176-
178 °C. Anal. Calcd for C34H33ClMo2 O4Te3: C, 36.59; H, 3.01.
Found: C, 36.60; H, 3.37. IR (KBr disk): νCdO 1703(vs) cm-1
.
1H NMR (acetone-d6): 1.10(t, J ) 7.2 Hz, 6H, 2CH3), 4.14(q, J
) 7.2 Hz, 4H, 2CH2), 5.60-5.80(m, 4H, 2H3, 2H4), 5.98-6.20-
(m, 4H, 2H2, 2H5), 7.00-7.76(m, 15H, 3C6H5) ppm.
(23) Haller, W. S.; Irgolic, K. J . J . Organomet. Chem. 1972, 38, 97.
(24) Song, L.-C.; Shen, J .-Y.; Wang, J .-Q.; Hu, Q.-M.; Wang, R.-J .;
Wang, H.-G. Polyhedron 1994, 13, 3235.
(25) King, R. B. Organometallic Syntheses: Transition-Metal Com-
pounds; Academic Press: New York, 1965; Vol. 1, p 75.
(26) Wilkinson, G.; Birmingham, J . M. J . Am. Chem. Soc. 1954, 76,
4281.
P r ep a r a tion of (η5-MeO2CC5H4Mo)2(µ-P h Te)4 (3) a n d
(η5-MeO2CC5H4Mo)2(µ-Br )(µ-P h Te)3 (7a ,b). Similarly, 0.550
g (1.00 mmol) of [η5-MeO2CC5H4(CO)2Mo]2 reacted with 0.615

162 Organometallics, Vol. 19, No. 2, 2000
Song et al.
Ta ble 3. Cr ysta lllogr a p h ic Da ta for 4b a n d 9
4b
g (1.50 mmol) of Ph2Te2 and 0.379 g (1.00 mmol) of Cp2ZrBr2
to give three main bands. The first main band afforded 0.049
g (4%) of 3. The second main band afforded 0.096 g (9%) of 7a
9
mol formula
mol wt
cryst dimens,
mm
C32H29ClMo2O4Te3‚2CH2Cl2 C30H24Mo2O8Te2
as black-green solid, mp 214-216 °C. Anal. Calcd for C32H29
-
1257.58
959.59
BrMo2O4Te3: C, 33.95; H, 2.58. Found: C, 33.85; H, 2.51. IR
(KBr disk): νCdO 1705(vs) cm-1. 1H NMR (acetone-d6): 3.63(s,
6H, 2CH3), 5.56-5.68(m, 4H, 2H3, 2H4), 5.88-6.00(m, 4H, 2H2,
2H5), 6.84-7.52(m, 15H, 3C6H5) ppm. The second main band
afforded 0.218 g (19%) of 7b as a yellow-green solid, mp 192-
194 °C. Anal. Cacld for C32H29BrMo2O4Te3: C, 33.95; H, 2.58.
0.90 × 0.40 × 0.30
0.60 × 0.20 × 0.10
cryst syst
space group
a, Å
monoclinic
P21/c (No. 14)
9.856(3)
19.4599(6)
20.418(3)
triclinic
P1h (No. 2)
11.949(4)
12.809(7)
11.503(4)
82.48(4)
78.62(2)
73.92(4)
1653(3)
2
b, Å
c, Å
Found: C, 34.12; H, 2.60. IR (KBr disk): νCdO 1707(vs) cm-1
.
1H NMR (acetone-d6): 3.58(s, 6H, 2CH3), 5.48-5.68(m, 4H,
2H3, 2H4), 5.76-6.00(m, 4H, 2H2, 2H5), 6.97-7.56(m, 15H,
3C6H5) ppm. However, when 0.550 g (1 mmol) of [η5-MeO2-
CC5H4(CO)2Mo]2 and 0.409 g (1 mmol) of Ph2Te2 reacted with
0.322 g (1 mmol) of n-Bu4NBr under conditions similar to those
in the case of Cp2ZrBr2, 0.042 g (4%) of 7a and 0.285 g (26%)
of 7b were obtained without any amount of 3 isolated.
P r ep a r a tion of (η5-EtO2CC5H4Mo)2(µ-P h Te)4 (5) a n d
(η5-EtO2CC5H4Mo)2(µ-Br )(µ-P h Te)3 (8a ,b). Similarly, 0.578
g (1.00 mmol) of [η5-EtO2CC5H4(CO)2Mo]2 reacted with 0.615
g (1.50 mmol) of Ph2Te2 and 0.379 g (1.00 mmol) of Cp2ZrBr2
to give three main bands. The first main band afforded 0.046
g (4%) of 5. The second main band afforded 0.112 g (10%) of
8a as a black-green solid, mp 206-208 °C. Anal. Calcd for
R, deg
â, deg
95.91(3)
γ, deg
V, Å3
3895(2)
4
Z
density(calcd), 2.083
1.960
g/cm-3
F(000)
2304
928
25.24
Rigaku-AFC 5R
µ(Mo KR), cm-1 32.18
diffractometer Enraf-Nonius CAD 4
temp, °C
23
23
scan type
ω/2θ
0.034
0.047
1.38
0.706
ω/2θ
0.073
0.094
2.30
2.76
R
Rw
S
largest peak
(e/Å-3
)
C
34H33BrMo2O4Te3: C, 35.20; H, 2.87. Found: C, 35.49; H,
2.92. IR (KBr disk): νCdO 1700(vs) cm-1 1H NMR (acetone-
.
0.185 g (34%) of 4b and a much less amount (not weighed) of
4a and 3. When 0.146 g (0.50 mmol) of Cp2ZrCl2 was used in
place of Cp2TiCl2, 0.054 g (10%) of 4b and a much less amount
of 4a and 3 were produced.
Rea ction of 3 w ith Cp 2TiCl2. A mixture of 0.063 g (0.05
mmol) of 3 and 0.013 g (0.05 mmol) of Cp2TiCl2 in 40 mL of
xylene was stirred and refluxed for 6 h. After removal of
solvent under vacuum the residue was subjected to TLC
separation using CH2Cl2 as eluent to recover 0.055 g (87%) of
starting material 3.
d6): 1.18(t, J ) 7.2 Hz, 6H, 2CH3), 4.11(q, J ) 7.2 Hz, 4H,
2CH2), 5.56-5.68(m, 4H, 2H3, 2H4), 5.88-6.00(m, 4H, 2H2,
2H5), 6.84-7.56(m, 15H, 3C6H5) ppm. The second main band
afforded 0.236 g (20%) of 8b as a yellow-green solid, mp 188-
192 °C. Anal. Calcd for C34H33BrMo2O4Te3: C, 35.20; H, 2.87.
Found: C, 34.83; H, 3.02. IR (KBr disk): νCdO 1707(vs) cm-1
.
1H NMR (acetone-d6): 1.10(t, J ) 7.2 Hz, 6H, 2CH3), 4.08(q, J
) 7.2 Hz, 4H, 2CH2), 5.48-5.68(m, 4H, 2H3, 2H4), 5.76-6.04-
(m, 4H, 2H2, 2H5), 6.88-7.60(m, 15H, 3C6H5) ppm.
P r ep a r a tion of [η5-MeO2CC5H4(CO)2Mo]2(µ-P h Te)2 (9).
To the same equipped flask described above were added 0.550
g (1.00 mmol) of [η5-MeO2CC5H4(CO)2Mo]2 0.409 g (1.00 mmol)
of Ph2Te2, and 40 mL of xylene. The mixture was stirred at
110 °C for 6 h. Solvent was removed under reduced pressure.
The residue was subjected to column chromatography using
CH2Cl2 as eluent. From the main brown band was obtained
0.850 g (89%) of 9 as a brown solid, mp 149-150 °C. Anal.
Calcd for C30H24Mo2O8Te2: C, 37.55; H, 2.52. Found: C, 37.51;
H, 2.40. IR (KBr disk): νCtO 1954(s), 1936(vs), 1898(m), 1875-
(vs), 1863(s); νCdO1720(vs) cm-1. 1H NMR (CDCl3): 3.72(s, 6H,
2CH3), 5.28-5.58(m, 4H, 2H3, 2H4), 5.58-5.86(m, 4H, 2H2,
2H5), 7.00-7.64(m, 10H, 2C6H5) ppm. 125Te NMR (CDCl3, Ph2-
Te2): -1160(s) ppm. However, when 0.275 g (0.50 mmol) of
[η5-MeO2C C5H4(CO)2Mo]2 reacted with 0.409 g (1 mmol) of
Ph2Te2 in 40 mL of xylene at reflux for 4 h, a much less amount
of 9 (0.067 g, 14%) was obtained.
Rea ction of 4b w ith P h 2Te2. A mixture of 0.109 g (0.10
mmol) of 4b and 0.082 g (0.20 mmol) of Ph2Te2 in 40 mL of
xylene was stirred at reflux for 6 h. After the same workup as
above, 0.099 g (91%) of starting material 4b was recovered.
Sin gle-Cr ysta l Str u ctu r e Deter m in a tion s of 4b a n d 9.
Single crystals of 4b and 9 suitable for X-ray diffraction
analyses were grown from CH2Cl2/hexane solutions at about
5 °C. A crystal was mounted on a glass fiber and placed on
the diffractometer with a graphite monochromator with Mo-
KR radiation. A total of 7502 (4b) or 6128 (9) independent
reflections were collected at 23 °C by the ω/2θ scan mode, of
which 7189 (4b) or 5820 (9) independent reflections with I g
3σ(I) were considered to be observed and used in subsequent
refinement. The data were corrected for Lorentz polarization
factors. Crystallographic data are listed in Table 3.
The structures were solved by direct methods and expanded
using Fourier techniques. The non-hydrogen atoms were
refined anisotropically, and H atoms were included but not
refined. The final refinement by a full-matrix least-squares
method with non-H atoms converged to give the unweighted
and weighted agreement factors. All calculations were per-
formed using the TEXSAN program system crystallographic
software of the Molecular Structure Corporation.
P r ep a r a tion of [η5-EtO2CC5H4(CO)2Mo]2(µ-P h Te)2 (10).
The same procedure as that for 9 was followed, but 0.578 g
(1.00 mmol) of [η5-EtO2CC5H4(CO)2Mo]2 was used instead of
[η5-MeO2CC5H4(CO)2Mo]2. The main brown band afforded
0.857 g (87%) of 10 as a brown solid, mp 124-125 °C. Anal.
Calcd for C32H28Mo2O8Te2: C, 38.92; H, 2.86. Found: C, 39.00;
H, 3.01. IR (KBr disk): νCtO 1954(s), 1938(vs), 1882(vs), 1846-
1
(vs); νCdO1716(s) cm-1. H NMR (CDCl3): 1.27(t, J ) 7.2 Hz,
Ack n ow led gm en t. We are grateful to the National
Natural Science Foundation of China, the State Key
Laboratory of Elemento-Organic Chemistry, and the
State Key Laboratory of Structural Chemistry for
financial support of this work.
6H, 2CH3), 4.26(q, J ) 7.2 Hz, 4H, 2CH2), 5.40-5.62(m, 4H,
2H3, 2H4), 5.62-5.94(m, 4H, 2H2, 2H5), 7.08-7.68(m, 10H,
2C6H5) ppm. 125Te NMR (CDCl3, Ph2Te2): -1164(s) ppm.
Rea ction of 9 w ith Cp 2TiCl2 or Cp 2Zr Cl2. To the same
equipped flask described above were added 0.480 g (0.50 mmol)
of [η5-MeO2CC5H4(CO)2Mo]2(µ-PhTe)2 (9), 0.125 g (0.50 mmol)
of Cp2TiCl2, and 40 mL of xylene. The mixture was stirred at
reflux for 4 h. Solvent was removed under reduced pressure.
The residue was subjected to TLC separation using CH2Cl2/
petroleum ether as eluent. The dark green main band afforded
Su p p or tin g In for m a tion Ava ila ble: Full tables of crystal
data, atomic coordinates and thermal parameters, and bond
lengths and angles for 4b and 9. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM9904448