Heterobimetallic Complexes with Phenylcyclopentadienyl Ligand: Syntheses and Structures of Tricarbonylchromium-η6,η 5-Phenylcyclopentadienyl-Transition Metal Complexes

Article abstract of DOI:10.1021/ic951630i

A new synthetic method of heterobimetallic complexes bridging with a π,π-phenylcyclopentadienyl ligand, tricarbonylchromium-η₆,η ₅-phenylcyclopentadienyl-transition metal complexes, was developed through the reactions of (η₆-C₆H₅C₅H ₅)Cr(CO)₃ or its sodium salt with transition metal complexes. The method is suitable for most transition metal elements with the advantages of easy manipulation, mild reaction conditions, and moderate to high yields. As indicated by ¹H NMR spectra, the interactions between the two π systems of phenyl and cyclopentadienyl rings were weak. X-ray crystal structures of seven complexes were studied. Compound 23, [η₆-C₆H₅Cr(CO)₃] ₂C₁₀H₁₀, crystallizes in orthorhombic space group Pbca with cell constants a = 29.616(8) A?, b = 12.861(5) A?, c = 12.397(7) A?, V = 4721(6) A?³, Z = 8, R = 0.045, and R_w = 0.045. Compound 3, (η₆-C₆H₅C₉H ₇)Cr(CO)₃, crystallizes in monoclinic space group P2₁/c with cell constants a = 7.901(3) A?, b = 14.799-(2) A?, c = 12.917(2) A?, β= 99.72(2)°, V = 1488.7(4) A?³, Z = 4, R = 0.044, and R_w = 0.051. Compound 7, Cr(CO)₃(η₆nη₅-C₆H ₅C₅H₄)Ti(CO)₂(η ₅-C₅H₅), crystallizes in monoclinic space group P2₁/c with cell constants a = 12.361(4) A?, b = 12.487(6) A?, c = 12.531(7) A?, β= 93.48(4)°, V = 1930 A?³, Z = 4, R = 0.047, and R_w = 0.048. Compound 13, Cr(CO)₃(η₆,η₅-C₆H ₅C₅H₄)Mo(CO)₃Br, crystallizes in monoclinic space group P2₁/c with cell constants a = 14.685(2) A?, b = 8.509(3) A?, c = 14.960(3) A?, β = 104.46(1)°, V= 1810.0(7) A?³, Z = 4, R = 0.037, and R_w = 0.037. Compound 19, Cr(CO)₃(η₆,η₅-C₆H ₅C₉H₆)Mn(CO)₃, crystallizes in triclinic space group P_-1 with cell constants a = 11.660(4) A?, b = 12.578(5) A?, c = 6.987(2) A?, α = 100.03(3)°, β= 104.19(2)°, γ = 71.99(3)°, V = 939.3(6) A?³, Z = 2, R = 0.048, and R_w = 0.065. Compound 21, Cr(CO)₃(η₆,η₅-C₆H ₅C₅H₄)Ru(PPh₃)₂Cl, crystallizes with one molecule of EtOH in triclinic space group P_-1 with cell constants a = 14.033(4) A?, b = 16.163(6) A?, c = 10.411(3) A?, α = 104.22(3)°, β = 103.50(2)°, γ = 90.81(3)°, V = 2219(1) A?³, Z = 2, R = 0.081, and R_w = 0.096. Compound 22, Cr(CO)₃(η₆,η₅-C₆H ₅C₅H₄)Co(CO)₂, crystallizes in orthorhombic space group P2₁2₁2₁ with cell constants a = 15.083(5) A?, b = 16.391(5) A?, c = 6.351(4) A?, V = 1570(1) A?³, Z = 4, R = 0.036, and R_w = 0.039. The trans configurations of the two metal atoms in these molecules were found as expected; the phenyl and cyclopentadienyl or indenyl rings in the molecules were found to be not coplanar.

Full text of DOI:10.1021/ic951630i

1286
Inorg. Chem. 1997, 36, 1286-1295
Heterobimetallic Complexes with Phenylcyclopentadienyl Ligand: Syntheses and
Structures of Tricarbonylchromium-η6,η5-Phenylcyclopentadienyl-Transition Metal
Complexes1
Changtao Qian,* Jianhua Guo, and Jie Sun
Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,
354 Fenglin Lu, Shanghai, 200032, China
Jian Chen and Peiju Zheng
Center of Analysis and Measurement, Fudan University, Shanghai, 200433, China
ReceiVed December 21, 1995X
A new synthetic method of heterobimetallic complexes bridging with a π,π-phenylcyclopentadienyl ligand,
tricarbonylchromium-η6,η5-phenylcyclopentadienyl-transition metal complexes, was developed through the
reactions of (η6-C6H5C5H5)Cr(CO)3 or its sodium salt with transition metal complexes. The method is suitable
for most transition metal elements with the advantages of easy manipulation, mild reaction conditions, and moderate
1
to high yields. As indicated by H NMR spectra, the interactions between the two π systems of phenyl and
cyclopentadienyl rings were weak. X-ray crystal structures of seven complexes were studied. Compound 23,
[η6-C6H5Cr(CO)3]2C10H10, crystallizes in orthorhombic space group Pbca with cell constants a ) 29.616(8) Å,
b ) 12.861(5) Å, c ) 12.397(7) Å, V ) 4721(6) Å3, Z ) 8, R ) 0.045, and Rw ) 0.045. Compound 3, (η6-
C6H5C9H7)Cr(CO)3, crystallizes in monoclinic space group P21/c with cell constants a ) 7.901(3) Å, b ) 14.799-
(2) Å, c ) 12.917(2) Å, â ) 99.72(2)°, V ) 1488.7(4) Å3, Z ) 4, R ) 0.044, and Rw ) 0.051. Compound 7,
Cr(CO)3(η6,η5-C6H5C5H4)Ti(CO)2(η5-C5H5), crystallizes in monoclinic space group P21/c with cell constants a
) 12.361(4) Å, b ) 12.487(6) Å, c ) 12.531(7) Å, â ) 93.48(4)°, V ) 1930 Å3, Z ) 4, R ) 0.047, and Rw )
0.048. Compound 13, Cr(CO)3(η6,η5-C6H5C5H4)Mo(CO)3Br, crystallizes in monoclinic space group P21/c with
cell constants a ) 14.685(2) Å, b ) 8.509(3) Å, c ) 14.960(3) Å, â ) 104.46(1)°, V ) 1810.0(7) Å3, Z ) 4, R
) 0.037, and Rw ) 0.037. Compound 19, Cr(CO)3(η6,η5-C6H5C9H6)Mn(CO)3, crystallizes in triclinic space group
P-1 with cell constants a ) 11.660(4) Å, b ) 12.578(5) Å, c ) 6.987(2) Å, R ) 100.03(3)°, â ) 104.19(2)°, γ
) 71.99(3)°, V ) 939.3(6) Å3, Z ) 2, R ) 0.048, and Rw ) 0.065. Compound 21, Cr(CO)3(η6,η5-
C6H5C5H4)Ru(PPh3)2Cl, crystallizes with one molecule of EtOH in triclinic space group P-1 with cell constants
a ) 14.033(4) Å, b ) 16.163(6) Å, c ) 10.411(3) Å, R ) 104.22(3)°, â ) 103.50(2)°, γ ) 90.81(3)°, V )
2219(1) Å3, Z ) 2, R ) 0.081, and Rw ) 0.096. Compound 22, Cr(CO)3(η6,η5-C6H5C5H4)Co(CO)2, crystallizes
in orthorhombic space group P212121 with cell constants a ) 15.083(5) Å, b ) 16.391(5) Å, c ) 6.351(4) Å, V
) 1570(1) Å3, Z ) 4, R ) 0.036, and Rw ) 0.039. The trans configurations of the two metal atoms in these
molecules were found as expected; the phenyl and cyclopentadienyl or indenyl rings in the molecules were found
to be not coplanar.
Introduction
Scheme 1
Heterobimetallic complexes incorporating hydrocarbons as
bridges between metal atoms have become increasingly interest-
ing.2,3 With two metal atoms in close proximity, the synergism
of two different metal centers in these compounds may generate
unique reaction patterns or enhanced reactivity. Considering
the diverse reactivity and wide range applications of (π-arene)4,5
and cyclopentadienyl transition metal complexes,6 heterobime-
tallic complexes containing both types of species which
were bridged by hydrocarbon ligands are especially interest-
ing. Heterobimetallic complexes with a bridging π,π-phenyl-
cyclopentadienyl ligand are very typical ones of this class
(Scheme 1).
In these complexes, two π systems were combined closely.
The possible electronic interactions through the bridging ligand
or synergism between the two proximate organometallic species
may produce novel properties. Because (π-arene)Cr(CO)3 are
representative π-arene complexes,7-9 we intend to synthesize
X Abstract published in AdVance ACS Abstracts, March 1, 1997.
(1) Part of this work has been communicated, see: Qian, C.; Guo, J.;
Sun, J. Chin. Chem. Lett. 1996, 7, 189.
(2) Stephen, D. W. Coord. Chem. ReV. 1989, 95, 41.
(3) Beck, W.; Niemer B.; Wieser, M. Angew. Chem., Int. Ed. Engl. 1993,
32, 923.
(4) Semmelback, M. F. ComprehensiVe Organometallic Chemistry II;
Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press:
Oxford, U.K., 1995; Vol. 12, pp 979, 1017.
(5) Davies, S. G., Mccarthy, T. D. ComprehensiVe Organometallic
Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.;
Pergamon Press: Oxford, U.K., 1995; Vol. 12, p 1039.
(6) Connor, J. M.; Casey, C. P. Chem. ReV. 1987, 87, 307 and references
therein.
(7) Hunter, A. D.; Mozol V.; Tsai, S. D. Organometallics 1992, 11, 2251
and references therein.
(8) Sodeoka M.; Shibasaki, M. Synthesis 1993, 643 and references therein.
S0020-1669(95)01630-2 CCC: $14.00 © 1997 American Chemical Society

Heterobimetallic Complexes with Cp Ligands
Inorganic Chemistry, Vol. 36, No. 7, 1997 1287
Scheme 2
bromination, and nitrosolation of these sodium salts were carried
out by reacting them with CH3I, Br2, and Diazald. For Mo and
W, expected products can be obtained in moderate yields. For
Cr only nitrosolation was successfully processed.
2 reacted with [Mn(CO)4Br]2 to produce compound 18, Cr-
(CO)3(η6,η5-C6H5C5H4)Mn(CO)3. The synthesis of 18 has been
completed through route I shown in Scheme 2 by two
groups.11,13 Compared with their methods, our synthetic method
is superior in the following aspects: mild reaction conditions,
easy manipulation, and high yield. In addition, when [Mn-
(CO)4Br]2 was treated with 4, a heterobimetallic compound with
the bridging phenylindenyl ligand ((tricarbonylchromio)-η6,η5-
phenylindenyl))tricarbonylmanganese (19) was obtained (Scheme
4).
It is difficult to prepare 19 by following the literature
procedure for 18, for complicated mixtures may form. Indenyl
complexes are known to be different from cyclopentadienyl
transition metal complexes in many aspects.16-18 The synthesis
of other tricarbonylchromium-η6,η5-phenylindenyl-transition
metal complexes with a similar method is in progress.
Considering the unique applications of CpRu(PPh3)2Cl in
organic synthesis,19 we are interested in the synthesis of
compound 21, Cr(CO)3(η6,η5-C6H5C5H4)Ru(PPh3)2Cl. Follow-
ing the literature procedure for the preparation of CpRu(PPh3)2-
Cl20 (1), RuCl3‚3H2O, excess PPh3, and EtOH were mixed and
heated to reflux for several hours. A reaction did occur with
the color of the mixture changing from dark green to bright
yellow. But compound 20 instead of 21 was obtained after
workup. The replacement of the arene coordinated to Cr(CO)3
by PPh3 in the reaction process can explain this result. It seemed
a milder reaction condition was necessary for 21. When 1 and
RuCl2(PPh3)3 were mixed in benzene and stirred at room
temperature, 21 indeed formed. We also found that addition
of zinc powder to the reaction system can speed up this
reaction.21
A Cr/Co complex (22), Cr(CO)3(η6,η5-C6H5C5H4)Co(CO)2,
can also be prepared by reaction between 1 and Co2(CO)8 using
t-BuCHdCH2 as a hydrogen abstractor.22,23 The reaction
needed gentle reflux in CH2Cl2. Though dimerization of some
1 took place in the process, the yield of 22 was still satisfactory.
The synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Pd(η3-C3H5), from
the reaction of 2 with (η3-C3H5)Pd2Cl2, was unsuccessful. The
product was too unstable to be isolated.
In summary, starting from 1, tricarbonylchromium-η6,η5-
phenylcyclopentadienyl-transition metal complexes of some
group IVB, VIB, VIIB, and VIII elements were successfully
synthesized.
tricarbonylchromium-η6,η5-phenylcyclopentadienyl-transi-
tion metal complexes.
There are three possible synthetic routes (as shown in Scheme
2). Compared with route III, routes I and II are more
complicated and forcing reaction conditions are needed.10-13
We will introduce later in this paper that route III is a general
method for the syntheses of these compounds, with advantages
of easy manipulation, mild reaction conditions, and moderate
to high yields.
Results and Discussion
Synthesis. The synthetic methods of some tricarbonylchro-
mium-η6,η5-phenylcyclopentadienyl-transition metal com-
plexes were summarized in Scheme 3.
(η6-C6H5C5H5)Cr(CO)3 (1) can be prepared in excellent yield
by nucleophilic substitution between (η6-C6H5F)Cr(CO)3 and
CpK, as reported by F. Gottardi et al.14 Though 1 is unstable
in solution at room temperature, it can be stored in solid state
at low temperature for several days. 1 reacted with NaH in
THF at 0 °C to produce the corresponding sodium salt (2).
3-[(Tricarbonylchromio) phenyl]indene (3)14 and its sodium salt
(4) could be obtained similarly. When 2 was treated with
equimolecular CpTiCl3 or CpZrCl3‚DME, complexes Cr(CO)3-
(η6,η5-C6H5C5H4)Ti(η5-C5H5)Cl2 (5) and Cr(CO)3(η6,η5-C6H5-
C5H4)Zr(η5-C5H5)Cl2 (6) were formed. It is interesting to find
that 5 was a green powder. As most Ti(IV) organometallic com-
plexes are red, the special color of 5 may arise from unclear
interactions between Ti and Cr atoms.15 The color of 6 was
yellow as expected. When 5 was treated with Mg/HgCl2 under
carbon monoxide atmosphere, a Ti(II) carbonyl complex (7),
Cr(CO)3(η6,η5-C6H5C5H4)Ti(CO)2(η5-C5H5), was obtained which
was a very air-sensitive red solid.
Spectra. The infrared spectra of these complexes display
the anticipated νCO stretching bands of virtual A and E symmetry
of the Cr(CO)3 moiety.24 To our surprise, though the metal
atoms connected to the Cp′ ring (Cp′ ) C5H4) are quite different,
the νCO values were almost the same. In 1, the νCO(THF) were
1960 cm-1 (A) and 1886 cm-1 (E) for the local C3V symmetry
of Cr(CO)3. Except for compound 5, very small frequency shifts
(about 3 cm-1 ) were observed for A and E peaks of all other
2 reacted with M(CO)3(RCN)3 (M ) Cr, Mo, W; R ) Me,
Et) to produce compounds 8, 9, and 10, respectively, which
were used as solutions without purification. Methylation,
(16) Szajek, L. P.; Shapley, J. R. Organometallics 1994, 13, 1395 and
references therein.
(9) Solladie-Callallo, A. Polyhedron 1985, 4, 901 and references therein.
(10) Gubin, S. P.; Khandkarova, V. S. J. Organomet. Chem. 1970, 22, 449.
(11) Gogan, N. J.; Chu, C. K. J. Organomet. Chem. 1977, 132, 103.
(12) Bitterwolf, T. E. Polym. Mater. Sci. Eng. 1983, 49, 368.
(13) Yur’eva, L. P.; Zaitseva N. N.; Kravtsov, D. N. Metalloorg. Khim.
1989, 2, 1328.
(17) Rerek M. E.; Basolo, F. J. Am. Chem. Soc. 1984, 106, 5908.
(18) Rerek M. E.; Basolo, F. Organometallics 1984, 13, 740.
(19) Trost, B. M.; Dyker G.; Kulawie, R. J. J. Am. Chem. Soc. 1990, 112,
7809.
(20) Bruce, M. I.; Windsor, N. J. Aust. J. Chem. 1977, 30, 1601.
(21) Gilbert, J. D.; Wilkinson, G. J. Chem. Soc. (A) 1969, 1749.
(22) Crabtree, R. H.; Mihelcic J. M.; Quirk, J. M. J. Am. Chem. Soc. 1979,
101, 7738.
(14) Ceccon, A.; Gambaro, A.; Gottordi, F.; Manoli F.; Venzo, A. J.
Organomet. Chem. 1989, 363, 91.
(15) Rooyen, P. H.; Schindehutte, M.; Lotz, S. Organometallics 1992, 11,
1104.
(23) Lee, W.; Brintzinger, H. H. J. Organomet. Chem. 1977, 127, 87.
(24) Cotton, F. A.; Kraihanzel, C. S. J. Am. Chem. Soc. 1962, 84, 4432.

1288 Inorganic Chemistry, Vol. 36, No. 7, 1997
Qian et al.
Scheme 3. Summary of the Synthesis of Tricarbonylchromium-η6,η5-Phenylcyclopentadienyl-Transition Metal Complexesa
a (i) CpK, DME, 0 °C; (ii) NaH, THF, 0 °C; (iii) CpTiCl3 or CpZrCl3‚DME, THF, rt; (iv) Mg, HgCl2, CO; (v) M(CO)3(RCN)3, rt; (vi) MeI, 0
°C; (vii) Br2/THF, -78 °C f rt; (viii) Diazald, 0 °C f rt; (ix) [1/2Mn(CO)4Br]2, rt; (x) RuCl3‚3H2O, PPh3 (excess), EtOH, reflux; (xi) RuCl2(PPh3)3,
Zn, benzene, rt; (xii) t-BuCHdCH2, Co2(CO)8, CH2Cl2, reflux.
Scheme 4
complexes. For 5, a 19 cm-1 to high-frequency shift for A and
a 28 cm-1 to low-frequency shift for E were found. It might
arise from unclear interaction between Cr and Ti atoms. There
were some overlaps of the νCO stretching bands for carbonyls
attached to other metal atoms in some cases. For instance, νCO
of the Mo(CO)3Me moiety in 11 was expected to appear as
three peaks because of its local Cs symmetry.25 But only two
bands at 2018 and 1927 cm-1 were found. The νNO in 15-17
were also obviously found at 1699, 1670, and 1664 cm-1 for
Cr, Mo, and W, respectively.
protons on the phenyl and Cp′ rings. For example, in THF-d8,
the ortho, para, and meta resonances of the phenyl ring of 5
appear at 5.51 (t), 5.59 (t), and 6.09 (d) ppm, while the protons
on the Cp′ ring resonances appeared at 6.64 (s) and 6.78 (s)
ppm. The resonance of the protons on the Cp ring are at 6.60
(s) ppm. The difference between the chemical shifts of protons
on Cp′ and Cp was small. The chemical shifts of the R and â
position protons on Cp′ in 20 and 21 showed remarkable
difference, which were 3.34 (s, âH) and 4.59 (s, RH) for 21
and 3.52 (s, âH) and 4.63 (s, RH) for 22, respectively. These
results are similar to those of some literature reports,26 such as
(CH3C5H4)RuCl(PPh3)2 (3.30, 4.0 ppm) and (CH3COC5H4)-
RuCl(PPh3)2 (3.6, 5.1 ppm). The unusual differences may be
ascribed to a special property of ruthenium metal.27 From 20
to 21, a downfield shift of 0.18 ppm for the â protons and 0.04
ppm for the R protons was observed. It implied that complex-
ation of Cr(CO)3 to the phenyl ring only results in a small
change for the chemical shifts of Cp′ protons. Similar results
were also found for other compounds. The small differences
indicate that interactions between the two organometallic
moieties are quite weak.
Under EI mass spectra conditions, the carbonyls in these
compounds were found to dissociate successively from the
molecular ion and then two metal atoms were lost one by one
from the ligand. The ligand ion can still easily lose C2H2 to
produce corresponding fragments.
1
The H NMR spectra of these complexes were expected to
display a AA′BB′X pattern for the protons on the substituted
η6-phenyl ring and an AA′BB′ pattern for the protons on the
η5-Cp′ ring. In CDCl3 or THF-d8, the protons on the phenyl
rings in most of these complexes were consistent with the
adoption of a substituted η6-arene bonding mode, displaying a
characteristic AA′BB′X pattern at room temperature. But the
protons on the Cp′ ring usually resonated as two singlets. In
some cases there was some overlap for the chemical shifts of
(26) Reventons, L. B.; Alonso, A. G. J. Organomet. Chem. 1986, 309,
179.
(27) Slocum, D. W.; Ernast, C. R.; Jones, W. E. J. Org. Chem. 1972, 37,
(25) King, R. B.; Houk, L. W. Can. J. Chem. 1969, 47, 2959.
4278.

Heterobimetallic Complexes with Cp Ligands
Inorganic Chemistry, Vol. 36, No. 7, 1997 1289
Table 1. Crystal Data and Summary of Intensity Data Collection and Structure Refinement
formula
formula
C28H20O6Cr2 (23) C18H12CrO3 (3) C21H14O5CrTi (7) C17H9O6BrCrMo (13) C21H11O6CrMn (19) C50H39O3ClCrP2Ru (21) C16H9O5CrCo (22)
556.45
328.29
446.23
537.09
466.25
984.39
392.17
weight
space group Pbca (No. 61)
P21/c (No. 14) P21/c (No. 14)
P21/c (No. 14)
14.685(2)
8.509(3)
P-1 (No. 2)
11.660(4)
12.578(5)
6.987(2)
100.03(3)
104.19(2)
71.99(3)
939.3(6)
2
P-1 (No. 2)
14.033(4)
16.163(6)
10.411(3)
104.22(3)
103.50(2)
90.81(3)
2219(1)
2
P212121 (No. 19)
15.083(5)
16.391(5)
a, Å
b, Å
c, Å
29.616(8)
12.861(5)
12.397(7)
7.901(3)
14.799(2)
12.917(2)
12.361(4)
12.487(6)
12.531(7)
14.960(3)
6.351(4)
R, deg
â, deg
γ, deg
V, Å3
Z
99.72(2)
93.48(4)
104.46(1)
4721(6)
8
1488.7(4)
4
1930(1)
4
1810.0(7)
4
1.971
35.36
1570(1)
4
1.659
17.69
d
calc, g cm-3 1.565
1.465
7.569
1.535
10.06
1.648
12.87
1.473
7.64
µ(Mo KR), 9.64
cm-1
T, °C
λ, Å
R a
20
20
20
20
20
20
20
0.710 69
0.045
0.045
0.710 69
0.044
0.051
0.710 69
0.047
0.048
0.710 69
0.037
0.037
0.710 69
0.048
0.065
0.710 69
0.081
0.096
0.710 69
0.036
0.039
b
Rw
a R ) ∑ni)1(|Fo|i - |Fc|i)/∑n |Fo|i. b Rw ) [∑in)1wi(|Fo|i - |Fc|i)2/∑ni)1wi|Fo| ]
.
2 1/2
i)1
Scheme 5
Table 2. Selected Bond Lengths (Å) and (deg) of 23
Cr(1)-C(17)
Cr(1)-C(26)
Cr(2)-C(4)
O(1)-C(23)
C(4)-C(7)
C(9)-C(10)
C(14)-C(15)
C(15)-C(17)
2.235(8)
1.85(1)
2.248(7)
1.159(10)
1.50(1)
1.50(1)
1.51(1)
1.48(1)
Cr(1)-C(20)
Cr(2)-C(1)
Cr(2)-C(23)
O(6)-C(26)
C(8)-C(9)
C(10)-C(11)
C(15)-C(16)
2.193(9)
2.228(9)
1.83(1)
1.138(10)
1.53(1)
1.32(1)
1.33(1)
C(17)-Cr(1)-C(26)
C(26)-Cr(1)-C(27)
C(4)-Cr(2)-C(25)
C(3)-C(4)-C(5)
C(7)-C(8)-C(9)
95.3(3) C(18)-Cr(1)-C(26)
87.5(4) C(3)-Cr(2)-C(25)
94.6(3) C(23)-Cr(2)-C(24)
116.9(7) C(11)-C(7)-C(12)
94.2(6) C(9)-C(13)-C(14)
87.8(3)
94.5(4)
89.5(4)
106.0(6)
117.0(8)
C(14)-C(15)-C(16) 111.6(7) C(18)-C(17)-C(22) 116.4(8)
C(9)-C(13)-H(15) 102.9
Crystal Structures. X-ray crystal structures of seven
complexes were determined. Crystallographic data are listed
in Table 1.
Figure 1. Molecular structure of compound [η6-C6H5Cr(CO)3]2C10H10
(23).
For the use of structural comparison, we tried to determine
the crystal structures of 1 and 3. But 1 was unstable in solution
and easily dimerized to 1,4-bis[(tricarbonylchromio)phenyl]-
tricyclo[5.2.1.02,6]deca-3,8-diene (23) after recrystallization in
THF/hexane at 0 °C (Scheme 5).
Shown in Figure 1 is an ORTEP diagram of the molecular
structure of 23. Selected bond distances and bond angles are
listed in Table 2.
As can be seen from Figure 1, 23 is the endo Diels-Alder
addition product of 1. The angle of C(9)-C(13)-C(14) is
117.0(8)°. Taking two phenyl rings as reference, we found that
the two Cr(CO)3 fragments are both in peripheral positions,
avoiding strong steric interaction. The structural parameters of
the two Cr(CO)3 moieties are very similar. The two phenyl
rings were outward distorted by the substituent as indicated by
the δd value proposed by Hunter.28,29 One apparent difference
between the two (arene)Cr(CO)3 moieties is the relative (arene)-
Cr(CO)3 conformations. Diverse conformations of (arene)Cr-
(CO)3 attracted much attention due to its significant influence
on the regioselectivity of nucleophilic/electrophilic attack on
arene.9 For monosubstituted arene, the conformation of (arene)-
Cr(CO)3 is either syn-eclipsed for an electron-withdrawing
substituent or anti-eclipsed for an electron-donating substituent.
As can be seen from Figure 2, Cr(1)(CO)3 has approximately
an anti-eclipsed conformation, while Cr(2)(CO)3 is obviously
a staggered conformation. The reason for the difference is
unclear, but may arise from the different steric environments.
(28) Hunter, A. D.; Shilliday, L.; Furey, W. S.; Zaworotko, M. J.
Organometallics 1992, 11, 1550.
(29) Li, J.; Hunter, A. D.; McDonald, R.; Santarsiero, B. D.; Bott, S. G.;
Atwood, J. L. Organometallics 1992, 11, 3050.

1290 Inorganic Chemistry, Vol. 36, No. 7, 1997
Qian et al.
Figure 2. Top view of (arene)Cr(CO)3 of 23.
Figure 4. Molecular structure of Cr(CO)3(η6,η5-C6H5C5H4)Ti(CO)2-
Cp (7).
Table 4. Selected Bond Lengths (Å) and Bond Angles (deg) of 7
Cr-C(11)
Cr-C(21)
Ti-C(6)
O(1)-C(17)
C(1)-C(2)
C(6)-C(10)
C(9)-C(11)
2.258(6)
1.826(7)
2.384(6)
1.151(7)
1.39(1)
1.423(8)
1.481(8)
Cr-C(14)
Ti-C(1)
2.228(6)
2.330(8)
2.336(6)
2.025(7)
1.150(7)
1.414(8)
Ti-C(9)
Ti-C(17)
O(5)-C(21)
C(11)-C(12)
C(11)-Cr-C(19)
C(9)-Ti-C(17)
Ti-C(9)-C(11)
89.5(3) C(19)-Cr-C(20)
78.9(2) C(17)-Ti-C(18)
89.6(3)
88.9(3)
Figure 3. Molecular structure of compound Cr(CO)3-η6-C6H5C9H7 (3).
Table 3. Selected Bond Lengths (Å) and Bond Angles (deg) of 3
124.3(4) C(8)-C(9)-C(10) 107.4(5)
C(12)-C(11)-C(16) 117.6(5) Cr-C(11)-C(9)
Ti-C(17)-O(1) 179.1(6) Cr-C(19)-O(3)
130.3(4)
179.5(7)
Cr-C(3)
2.213(4)
1.831(5)
1.472(7)
Cr-C(6)
2.242(4)
1.157(6)
1.343(6)
bulky substitutent of (Cp′)CpTi(CO)2. The (Cp′)CpTi(CO)2
moiety adopts an eclipsed configuration as found in Cp2Ti-
(CO)2.30 The OC-Ti-CO angle in the (CO)2Ti(Cp′)Cp moiety
is nearly 90° (88.9(3)°). The dihedral angle between Cp′ and
Cp is 38.34°. In contrast to the outward distortion of the phenyl
ring, an inward distortion of the Cp′ ring was found. Due to
the Cp′ being linked on (arene)Cr(CO)3, the C-C bond lengths
and the distances between Ti and the carbon atoms of the Cp′
ring were longer than those of the Cp ring. The following data
show this trend: [(C-C)Cp]av, 1.38 Å; [(C-C)Cp′]av, 1.415 Å;
[(Ti-C)Cp]av, 2.233 Å; [(Ti-C)Cp′]av, 2.362 Å; Ti-Cp(plane),
2.017 Å; Ti-Cp′(plane), 2.031 Å. It is unexpected that the
phenyl and Cp′ rings are not coplanar. The dihedral angle
between the two planes is 17.22°.
Cr-C(16)
C(6)-C(7)
C(16)-O(16)
C(7)-C(8)
C(1)-Cr-C(18)
92.1(2)
C(6)-Cr-C(18)
C(1)-C(6)-C(5)
C(8)-C(9)-C(10)
Cr-C(16)-O(16)
89.1(2)
118.4(4)
102.5(4)
179.4(5)
C(16)-Cr-C(17)
C(8)-C(7)-C(11)
H(91)-C(9)-H(92)
88.2(2)
109.2(4)
107.0(4)
The dihedral angle between the plane of C(12)-C(16)-
C(15)-C(14) and C(17)-C(18)-C(19)-C(20)-C(21)-C22
was found to be 14.99°. Thus the conjugation between C(15)-
C(16) and the C(17)-C(18)-C(19)-C(20)-C(21)-C(22) ring
was small.
Crystals of 3-[(tricarbonylchromio)phenyl]indene (3) suitable
for X-ray analysis were obtained from a THF/hexane solution.
The ORTEP diagram of 3 is shown in Figure 3, while selected
bond parameters are listed in Table 3.
The relative (arene)Cr(CO)3 conformation of 3 is staggered.
The special conformation may arise from the bulky substituent
on the phenyl ring. An outward distortion of the phenyl ring
was also found. The dihedral angle between the C6H5 and
indenyl rings is 47.30°. The structure features do not result in
steric interactions between the metal atom and the substituent;
the distances between chromium and the subsituent atoms are
longer than 3.2 Å.
Crystals of Cr(CO)3(η6,η5-C6H5C5H4)Ti(CO)2C5H5 (7) suit-
able for X-ray analysis were obtained from a THF/hexane
solution. The ORTEP diagram of 7 is shown in Figure 4, and
selected bond distances and bond angles are listed in Table 4.
As expected, in 7 the two metal atoms lie opposite the bridge
due to the steric effects. A staggered conformation of Cr(CO)3
relative to the phenyl ring was found. It may arise from the
Crystals of Cr(CO)3(η6,η5-C6H5C5H4)Mo(CO)3Br (13) suit-
able for X-ray analysis were obtained from a THF/hexane
solution. The ORTEP diagram of 13 is shown in Figure 5, and
selected bond distances and bond angles are listed in Table 5.
Similar to the result of 7, Cr and Mo atoms are also in a
trans position of the phenylcyclopentadienyl ligand in 13.
Outward distortion of the phenyl ring was found. The confor-
mation of Cr(CO)3 is in pseudoeclipsed form. Mo(CO)3Br
adopts the usual irregular “four-legged piano stool” arrangement
of typical CpM(CO)3X (M ) Cr, Mo, W) derivatives. Boyle
et al.31 found that the distance between Mo and C of the carbonyl
trans to Br, [Mo-C(CO)trans], is shorter than that of the
corresponding [Mo-C(CO)cis], due to the greater extent of back-
(30) Atwood, J. L.; Stone, K. E.; Alt, H. G.; Hrncir, D. C.; Rausch, M. D.
J. Organomet. Chem. 1976, 96, C4.
(31) Boyle, T. J.; Takusagawa, F.; Heppert, J. A. Acta Crystallogr. 1990,
C46, 892.

Heterobimetallic Complexes with Cp Ligands
Inorganic Chemistry, Vol. 36, No. 7, 1997 1291
Figure 6. Molecular structure of Cr(CO)3(η6,η5-C6H5C9H6)Mn(CO)3
(19).
Table 6. Selected Bond Lengths (Å) and Bond Angles (deg) of 19
Mn-C(5)
2.201(4)
1.788(5)
2.213(5)
1.144(6)
1.452(6)
1.417(7)
Mn-C(9)
2.222(4)
2.240(4)
1.850(6)
1.146(8)
1.479(6)
1.421(6)
Mn-C(16)
Cr-C(13)
O(1)-C(18)
C(5)-C(6)
C(7)-C(8)
Cr-C(10)
Cr-C(19)
Figure 5. Molecular structure of Cr(CO)3(η6,η5-C6H5C5H4)Mo(CO)3-
Br (13).
O(4)-C(19)
C(6)-C(10)
C(10)-C(11)
Table 5. Selected Bond Lengths (Å) and Bond Angles (deg) of 13
C(16)-Mn-C(17)
C(10)-Cr-C(21)
Mn-C(6)-C(10)
C(11)-C(10)-C(15)
Mn-C(16)-O(2)
90.9(2)
C(19)-Cr-C(20)
C(5)-C(6)-C(7)
Cr-C(10)-C(6)
Cr-C(19)-O(14)
89.0(3)
106.8(4)
128.3(3)
178.8(6)
Mo-Br
2.640(1)
2.276(7)
2.002(7)
2.224(5)
1.848(7)
1.140(8)
1.471(8)
Mo-C(1)
2.346(5)
2.019(7)
1.990(8)
2.212(7)
1.151(7)
1.422(8)
1.400(8)
88.8(2)
126.5(3)
118.5(4)
178.7(5)
Mo-C(3)
Mo-C(16)
Cr-C(6)
Mo-C(15)
Mo-C(17)
Cr-C(9)
Cr-C(12)
O(1)-C(15)
C(1)-C(6)
O(7)-C(12)
C(1)-C(2)
C(6)-C(11)
Table 7. Selected Bond Lengths (Å) and Bond Angles (deg) of 21
Ru-Cl
2.454(3)
2.339(4)
2.17(1)
2.16(2)
1.16(2)
1.49(2)
Ru-P(1)
Ru-C(10)
Cr-C(4)
P(1)-C(20)
C(4)-C(5)
C(10)-C(11)
2.316(4)
2.27(1)
2.20(1)
1.83(2)
1.38(2)
1.42(2)
Br-Mo-C(1)
97.9(1)
136.1(2)
80.1(3)
Br-Mo-C(15)
Br-Mo-C(17)
C(15)-Mo-C(17)
C(12)-Cr-C(13)
Mo-C(1)-C(6)
C(7)-C(6)-C(11)
Cr-C(12)-O(7)
77.3(2)
77.2(2)
110.9(3)
90.9(3)
122.2(4)
118.9(6)
178.6(6)
Ru-P(2)
Ru-C(12)
Cr-C(7)
Br-Mo-C(16)
C(15)-Mo-C(16)
C(16)-Mo-C(17)
C(2)-C(1)-C(5)
Cr-C(6)-C(1)
Mo-C(15)-O(1)
76.5(3)
O(2)-C(2)
C(4)-C(10)
106.0(6)
129.4(4)
177.7(7)
Cl-Ru-P(1)
90.1(1)
91.5(4)
89.7(8)
108.3(5)
178(2)
Cl-Ru-P(2)
P(1)-Ru-P(2)
C(39)-P(2)-C(45)
Cr-C(4)-C(10)
C(5)-C(4)-C(9)
C(11)-C(10)-C(14)
94.2(1)
101.5(1)
95.7(6)
127.5(9)
118(1)
Cl-Ru-C(10)
C(1)-Cr-C(2)
Ru-P(1)-C(20)
Cr-C(2)-O(2)
Ru-C(10)-C(4)
bonding to the trans carbonyl. On the contrary, we found that
[Mo-C(CO)cis], Mo-C(17) 1.990(8) Å in 13, was shorter than
[Mo-C(CO)trans], Mo-C(16) 2.002(7) Å, although the differ-
ence is only 0.01 Å. Unlike that in 7, the Cp′ ring has no
obvious distortion. In 13 the dihedral angle between the phenyl
and Cp′ rings was 25.03°.
The crystal structure of Cr(CO)3(η6,η5-C6H5C9H6)Mn(CO)3
(19), a heterobimetallic compound with a bridging phenylindenyl
ligand, was also determined. Suitable crystals were obtained
from a THF/hexane solution. The ORTEP diagram of 19 is
shown in Figure 6, and selected bond distances and bond angles
are listed in Table 6.
In 19, Cr and Mn atoms are in a trans position too. For the
(arene)Cr(CO)3 moiety, outward distortion of the phenyl ring
and a staggered conformation of Cr(CO)3 were found. Though
the Mn was bonded with the C(5)-C(9) five-membered ring
in a η5 fashion, differences among the C-C bond lengths are
obvious. C(5)-C(6) is obviously longer than the other C-C
bonds. It indicates that the bonds between Mn and Cp′ are
not symmetrical in our structure. Butler et al.32 have also found
there are different C-C bond lengths in the Cp ring of CpMn-
(CO)3. The reason for the difference was attributed to electronic
130.4(9)
108(1)
effects other than the arrangement style in the solid state. The
phenyl and indenyl rings are also not coplanar. The dihedral
angle is 38.30°, which is smaller than the one in compound 3
(47.30°), which has no coordination of Mn(CO)3 with the
indenyl ring.
We obtained single crystals of the EtOH adduct of Cr(CO)3-
(η6,η5-C6H5C5H4)Ru(PPh3)2Cl (21) in the process of recrystal-
lization of 21 from CH2Cl2/hexane. The ORTEP diagram of
21 is shown in Figure 7, and selected bond distances and bond
angles are listed in Table 7.
Though Ru was bonded to PPh3 instead of carbonyls, Cr and
Ru are still in the trans position of the ligand like in 7, 13, and
19. Outward distortion of the phenyl ring and a staggered
conformation of Cr(CO)3 were found. In contrast to the inward
distortion of the Cp′ ring in 7, an outward distortion of the Cp′
plane was found, i.e., Ru-C(10) is longer than other Ru-
C(Cp′). The Ru-Cl distance of 2.454(3) Å is similar to that
found in CpRu(PPh3)2Cl (2.453(2) Å).33 The two Ru-P bonds
(32) Fitzpatrick, P. J.; Page, Y. L.; Sedman, J.; Butler, I. S. Inorg. Chem.
1981, 20, 2852.
(33) Bruce, M. I.; Wong, F. S.; Skelton, B. W.; White, A. H. J. Chem.
Soc., Dalton Trans. 1981, 1398.

1292 Inorganic Chemistry, Vol. 36, No. 7, 1997
Qian et al.
Table 8. Selected Bond Lengths (Å) and Bond Angles (deg) of 22
Co-C(7)
2.129(8)
1.75(1)
2.258(8)
1.16(1)
1.42(1)
1.43(1)
Co-C(10)
Cr-C(1)
Cr-C(14)
O(4)-C(13)
C(4)-C(7)
2.095(9)
2.21(1)
1.827(9)
1.16(1)
1.45(1)
Co-C(12)
Cr-C(4)
O(1)-C(16)
C(3)-C(4)
C(7)-C(8)
C(7)-Co-C(13)
C(4)-Cr-C(14)
Cr-C(4)-C(7)
Co-C(7)-C(4)
Co-C(13)-O(4)
119.1(4)
90.2(3)
131.2(6)
126.2(6)
179.4(9)
C(12)-Co-C(13)
C(14)-Cr-C(15)
C(3)-C(4)-C(5)
C(8)-C(7)-C(11)
Cr-C(14)-O(3)
94.8(5)
89.5(4)
116.6(9)
104.9(8)
178.1(9)
Scheme 6
Figure 7. Molecular structure of Cr(CO)3(η6,η5-C6H5C5H4)Ru(PPh3)2-
Cl (21).
Like CpCo(CO)2,34 the plane formed by Co and two coordinated
carbonyls is perpendicular to the Cp′ ring with a dihedral angle
of 91.34°. The phenyl ring and the Cp′ ring are not coplanar
either; the dihedral angle is 25.00° (Scheme 6).
Table 9 summarizes some important structural data of the
above-mentioned compounds.
Though the poor crystal quality of 21 generated some
incoherent results, it can be seen from these data that the bond
parameters of (arene)Cr(CO)3 moieties in these complexes are
very similar, although the metal atoms attached to the Cp′ ring
are quite different. On the other hand, except for the similar
C-C bond distances of the Cp′ ring, the bond parameters of
Cp′MLnX moieties are obviously different. For the first-row
transition metals, along the sequence of Ti, Mn, and Co, the
distances of [M-C(Cp′)]av, [M-C(carbonyl)]av, and [M-PL-
(Cp′)] have an obvious tendency to decrease. The dihedral
angles of the phenyl and Cp′ planes vary for different metal
atoms and ligands.
General Comments. A good synthetic method for hetero-
bimetallic complexes with bridging phenylcyclopentadienyl
ligands of the type tricarbonylchromium-η6,η5-phenylcyclo-
pentadienyl-transition metal complexes was developed. The
method has advantages such as suitability for most transition
metal complexes, mild reaction conditions, easy manipulation,
and moderate to high yields. Spectroscopic properties of the
complexes were studied. An X-ray crystallographic study of
five heterobimetallic compounds was completed, and some
interesting structural features were also found.
Figure 8. Molecular structure of Cr(CO)3(η6,η5-C6H5C5H4)Co(CO)2
(22).
were unequal with a difference of 0.023 Å. It is interesting to
note that the dihedral angle between the phenyl and Cp′ rings
is 9.31°.
Experimental Section
We also obtained suitable crystals of Cr(CO)3(η6,η5-C6H5C5H4)-
Co(CO)2 (22) from a THF/hexane solution and determined its
structure.1 The ORTEP diagram of 22 is shown in Figure 8,
and selected bond distances and bond angles are listed in
Table 8.
All procedures were performed using standard Schlenk techniques
under an atmosphere of dry oxygen-free argon. Tetrahydrofuran,
diethyl ether, 1,2-dimethoxyethane, benzene, toluene, and hexane were
distilled from sodium benzophenone ketyl under argon. Chloroform,
dichloromethane, and acetonitrile were distilled from calcium hydride
or P2O5 under argon. THF-d8 was treated with a sodium-potassium
alloy and was deoxygenated by several freeze-pump-thaw cycles.
Like before, Cr and Co atoms lie in the trans position of the
ligand too. Outward distortion of the phenyl ring and a
staggered conformation of Cr(CO)3 were found. Similar to that
of 21, an outward distortion of the Cp′ ring was found, i.e.,
Co-C(7) of 2.219(8) Å is longer than other Co-C(Cp′) bonds.
(34) Yu, M.; Struchkov, Y. T.; Chernega, A. N.; Meidine, M. F.; Nixon,
J. F. J. Organomet. Chem. 1992, 436, 79.

Heterobimetallic Complexes with Cp Ligands
Inorganic Chemistry, Vol. 36, No. 7, 1997 1293
Table 9. Comparison of Some Selected Bond Parameters
length (Å) and angle (deg)
23a
3
7
13
19
21
22
[(C-C)arene]av
[Cr-C(arene)]av
[Cr-C(carbonyl)]av
Cr-PL(arene)b
[C(a)-C(b)]
1.40
2.218
1.84
1.721
1.48
1.410
2.224
1.833
1.720
1.472
1.403
2.225
1.832
1.727
1.481
1.415
2.362
2.033
2.031
38.34
1.400
2.213
1.840
1.713
1.471
1.415
2.235
2.004
1.986
25.03
1.404
2.214
1.846
1.712
1.479
1.427
2.170
1.793
1.799 g
38.30 g
1.39
2.19
1.85
1.687
1.49
1.41
2.21
1.40
2.213
1.82
1.718
1.45
1.42
2.087
1.74
[(C-C)Cp′]av
[M-C(Cp′)]av
[M-C(carbonyl)]av
M-PL(Cp′)c
1.857
9.31
1.700
25.00
PL(arene)∧PL(Cp′)d
14.99e
47.30 f
a Cr(1) fragment of the compound. b PL(arene) represents the plane of C6H5. c PL(Cp′) represents the plane of C5H4. d The dihedral angle between
the two planes. e For 23 the PL(Cp′) is replaced by the plane formed by the four bold carbon atoms in Figure 1. f For 3 the PL(Cp′) is replaced by
the plane of C9H7. g Here PL(Cp′) is replaced by PL(C9H6).
CDCl3 was dried by being allowed to stand for several hours with
molecular sieves (4A) and was purified by vacuum transfer from CaH2.
1H NMR spectra were recorded with a Bruker AM-300 spectrometer;
chemical shifts are reported in ppm relative to internal TMS. IR spectra
of solution in THF were recorded on a Perkin-Elmer Model 983
spectrometer. Mass spectra were recorded on an HP5989A instrument.
Elementary analyses were performed on an Italian Carlo-Eyba Model
1106 analyzer. Melting points were determined in sealed argon-filled
capillaries and were uncorrected. ZrCl4 was sublimed before use. Other
reagent grade chemicals were used without further purification. The
following compounds were prepared by following literature proce-
dures: (η6-C6H5C5H5)Cr(CO)3,14 (η6-C6H5C9H7)Cr(CO)3,14 Cp2TiCl2,35
C5H5SiMe3,36 CpTiCl3,37,38 CpZrCl3(DME),39 Cr(CO)3(CH3CN)3,40 Mo-
(CO)3(CH3CN)3,40 W(CO)3(EtCN)3,41 Mn(CO)5Br,42 [Mn(CO)4Br]2,43
RuCl2(PPh3)3,44 and (η3-C3H5)2Pd2Cl2.45 All column chromatography
was completed using deactivated neutral alumina (Al2O3).
CrO3Ti: C, 49.49; H, 3.06. Found: C, 49.24; H, 2.72. IR (THF, cm-1):
CO 1979 vs, 1858 vs. 1H NMR (CDCl3): δ (ppm) 6.78 (s, 2H), 6.64
(s, 2H), 6.60 (s, 5H), 6.09 (d, 2H), 5.59 (t, 2H), 5.51 (t, 1H). Mass
spectrum (EI): m/z (relative intensity) 376 (M+ - 3CO, 23%), 341
(M+ - 3CO - Cl, 6%), 311 (M+ - 3CO - Cp, 7%), 254 (M+ - 3CO
- Cr - 2Cl, 100%), 193 ([C11H9 + Cr]+, 57%), 141 (C11H9+, 64%),
115 (C9H7+, 39%), 65 (Cp+, 15%), 52 (Cr+, 35%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)ZrCl2(Cp) (6). Following
the procedure for 5, CpZrCl3(DME) (0.48 g, 1.4 mmol) and the sodium
salt of 1 (0.38 g, 1.4 mmol) were used, and 6 was obtained as a yellow
powder (0.40 g, 49%), mp 203-205 °C dec. Anal. Calcd for C19H14-
Cl2CrO3Zr: C, 45.24; H, 2.80. Found: C, 44.72; H, 2.92. IR (THF,
cm-1): νCO 1960 vs, 1888 vs. 1H NMR (CDCl3): δ (ppm) 6.61 (m,
2H), 6.50 (m, 7H), 5.85 (m, 2H), 5.58 (m, 3H). Mass spectrum (EI):
m/z (relative intensity) 446 (M+ - 2CO, 5%), 418 (M+ - 3CO, 60%),
366 (M+ - 3CO - Cr, 23%), 331 (M+ - 3CO - Cr -Cl, 100%), 301
(M+ - 3CO - Cp - Cr, 76%), 296 (M+ - 3CO - Cr - 2Cl, 39%),
193 ([C11H9 + Cr]+, 44%), 141 (C11H9+, 26%), 65 (C9H7+, 12%), 52
(Cr+, 51%).
ν
Synthesis of (η6-C6H5C5H5)Cr(CO)3 (1). At 0 °C, 33 mL of a 0.86
M CpK (28.2 mmol) solution in DME was added dropwise to the stirred
solution of (C6H5F)Cr(CO)3 (1.09 g, 4.7 mmol) in 15 mL of DME.
After being stirred at 0 °C for an additional 2.5 h, the reaction was
quenched by deoxygenated NH4Cl-saturated aqueous solution and the
organic layer was separated. The aqueous layer was extracted by Et2O
(40 mL × 3), and the Et2O extractant was combined with the organic
layer. After distillation of the solvent and cyclopentadiene in vacuo,
40 mL of Et2O was added to the residue and the solution was dried
over MgSO4. Chromatographic separation on Al2O3 (Et2O/hexane )
1:5) afforded 1.2 g of a yellow mixture of compounds 1 and 1′ (92%
yield, mp 92-94 °C). IR (THF, cm-1): νCO 1960 vs, 1886 vs. 1H
NMR (CDCl3): δ (ppm) 6.83-6.53 (m, 3H), 5.55-5.53 (m, 5H), 3.30
(m, 2H). Mass spectrum (EI): m/z (relative intensity) 278 (M+,
33.09%), 250 (M+ - CO, 5.61%), 222 (M+ - 2CO, 33.65%), 194
(M+ - 3CO, 100%), 142 (M+ - Cr(CO)3, 7.49%), 80 (Cr(CO), 5.95%),
52 (Cr, 73.12%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Ti(CO)2(Cp) (7). 5 (0.75
g, 1.6 mmol), magnesium powder (0.16 g, 6.4 mmol), and 30 mL of
THF were placed into a Schlenk tube and stirred magnetically. The
tube was flushed with carbon monoxide for 5 min, and HgCl2 (0.4 g,
1.5 mmol) was then added while carbon monoxide was allowed to flow
slowly over the solution through the side-arm stopcock and out to a
mercury overpressure valve. The reaction mixture was stirred in the
carbon monoxide atmosphere for 1 h at room temperature, during which
time the color changed from green to dark red. The clear solution
was decanted, and the solvent was removed under vacuum. The residue
was chromatographed on deactivated alumina. Eluting with Et2O/
hexane (1:10) produced a yellow band which was unreacted 1. Further
elution with Et2O/hexane (2:10) produced a yellow band which was
the dimer of 1. Further elution with Et2O/hexane (4:10) produced a
red band that was collected and the solvent removed under vacuum. A
red powder was obtained (0.30 g, 41%). 7: mp 132-135 °C dec. Anal.
Calcd for C21H14CrO5Ti: C, 56.52; H, 3.16. Found: C, 57.18; H, 3.42.
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)TiCl2(Cp) (5). To a solu-
tion of 1 (0.38 g, 1.4 mmol) in 20 mL of THF was added NaH (60 mg,
excess) in portions at 0 °C. The mixture was stirred for 1 h at 0 °C.
After centrifugation, a yellow solution of 2 was obtained. CpTiCl3
(0.30 g, 1.4 mmol) in THF (10 mL) was added to the solution dropwise.
After being stirred at room temperature overnight, the solvent was
removed under vacuum. The solid residue was placed in a Soxhlet
extractor and was extracted using CH2Cl2. After removal of the solvent
under reduced pressure, 0.4 g (63%) of 5 was obtained as a dark green
crystalline solid, mp 196-199 °C dec. Anal. Calcd for C19H14Cl2-
1
IR (THF, cm-1): νCO 1959 vs, 1887 vs. H NMR (CDCl3): δ (ppm)
5.79-5.36 (m, 9H), 5.03 (s, 5H). Mass spectrum (EI): m/z (relative
intensity) 390 (M+ - 2CO, 14%), 334 (M+ - 4CO, 8%), 254 (M+
-
5CO - Cr, 43%), 194 ([C11H10 + Cr]+, 100%), 141 (C11H9+, 41%),
115 (C9H7+, 29%), 65 (Cp+, 33%), 52 (Cr+, 98%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Mo(CO)3CH3 (11). To a
THF solution of 2 (1.4 mmol) was added Mo(CO)3(CH3CN)3 (0.42 g,
1.4 mmol) at 0 °C. The reaction mixture was stirred at room
temperature for 3 h. An orange yellow solution of 9 was obtained.
The solution was cooled to 0 °C, and CH3I (1 mL, excess) was added.
After the solution was stirred at room temperature for 2 h, the solvent
was removed under vacuum. The solid residue was then chromato-
graphed. Eluting with CH2Cl2/hexane (1:10 f 2:10) produced two
yellow bands which were 1 and a dimer of 1. Further elution with
CH2Cl2/hexane (3:10 f 7:10) produced a yellow band that was
collected and the solvent removed under vacuum. A yellow powder
was obtained (0.39 g, 61%). 11: mp 164-167 °C. Anal. Calcd for
C18H12CrMoO6: C, 45.78; H, 2.56. Found: C, 45.92; H, 2.37. IR
(THF, cm-1): νCO 2018 s, 1964 vs, 1927 vs, 1892 vs. 1H NMR
(CDCl3): δ (ppm) 5.57 (d, 2H), 5.46 (t, 2H), 5.37 (m, 4H), 5.30 (t,
(35) King, R. B. Organometallic Synthesis; Academic Press: New York,
1965; Vol. 1, p 75.
(36) Abel, E. W.; Dunster, M. O. J. Organomet. Chem. 1971, 33, 161.
(37) Gorsich, R. D. J. Am. Chem. Soc. 1960, 82, 4211.
(38) Cardoso, A. M.; Clark, R. J. H.; Moorhouse, S. J. Chem. Soc., Dalton
Trans. 1980, 1156.
(39) Lund, E. C.; Livinghouse, T. Organometallics 1990, 9, 2426.
(40) Tate, D. D.; Knipple, W. R.; Augl, J. M. Inorg. Chem. 1962, 1, 433.
(41) Kubas, G. J. Inorg. Chem. 1983, 22, 692.
(42) Quick, M. H.; Angelich, R. J. Inorg. Synth. 1990, 28, 156.
(43) Calderazzo, F.; Poli, R.; Vitali, D. Inorg. Synth. 1985, 23, 32.
(44) Hallman, P. S.; Stephenson, T. A.; Wilkinson, G. Inorg. Chem. 1970,
12, 1237.
(45) Tatsuno, Y.; Yoshida, T.; Otsuki, S. Inorg. Chem. 1990, 28, 342.

1294 Inorganic Chemistry, Vol. 36, No. 7, 1997
Qian et al.
1H), 0.32 (s, 3H). Mass spectrum (EI): m/z (relative intensity) 474
(M+, 17%), 390 (M+ - 3CO, 42%), 375 (M+ - 3CO - Me, 30%),
334 (M+ - 5CO, 31%), 306 (M+ - 6CO, 58%), 291 ([C11H9 + Cr +
Mo]+, 19%), 239 ([C11H9 + Mo]+, 28%), 193 ([C11H9 + Cr]+, 10%),
141 (C11H9+, 59%), 115 (C9H7+, 54%), 52 (Cr+, 100%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)W(CO)3CH3 (12). Fol-
lowing the procedure for 11, 1 (0.18 g, 0.6 mmol), W(CO)3(EtCN)3
(0.28 g, 0.6 mmol), and CH3I (1 mL) were used and a yellow powder
(0.26 g, 23%) was obtained. 12: mp 164-167 °C. Anal. Calcd for
C18H12CrO6W: C, 38.59; H, 2.16. Found: C, 38.85; H, 2.11. IR (THF,
cm-1): νCO 2014 s, 1964 vs, 1917 vs, 1892 vs. 1H NMR (CDCl3): δ
(ppm) 5.62 (s, 2H), 5.43 (m, 7H), 0.39 (s, 3H). Mass spectrum (EI):
m/z (relative intensity) 476 (M+ - 3CO, 37%), 461 (M+ - 3CO -
Me, 81%), 433 (M+ - 4CO - Me, 50%), 405 (M+ - 5CO - Me,
31%), 392 (M+ - 6CO, 28%), 377 ([C11H9 + Cr + W]+, 27%), 325
([C11H9 + W]+, 26%), 193 ([C11H9 + Cr]+, 9%), 141 (C11H9+, 17%),
115 (C9H7+, 23%), 52 (Cr+, 100%).
40%), 375 (M+ - 2CO - NO, 35%), 321 (M+ - 5CO, 89%), 319
(M+ - 4CO - NO, 100%), 291 (M+ - 5CO - NO, 18%), 267 (M+
- 4CO - NO - Cr, 23%), 213 (M+ - 4CO - NO - Cr - C2H2,
16%), 141 (C11H9+, 6%), 115 (C9H7+, 4%), 52 (Cr+, 31%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)W(CO)2NO (17). Follow-
ing the procedure for 15, W(CO)3(EtCN)3 (0.42 g, 1.0 mmol), 1 (0.27
g, 1.0 mmol), and Diazald (0.21 g, 1.0 mmol) were used to produce a
yellow powder (0.30 g, 56%). 17: mp 161-164 °C dec. Anal. Calcd
for C16H9CrNO6W: C, 35.12; H, 1.66. Found: C, 35.80; H, 1.81. IR
(THF, cm-1): νCO 2007 s, 1963 vs, 1923 s, 1890 vs; νNO 1664 s. 1H
NMR (CDCl3): δ (ppm) 5.57-5.22 (m, 9H). Mass spectrum (EI):
m/z (relative intensity) 491 (M+ - 2CO, 6%), 463 (M+ - 3CO, 30%),
461 (M+ - 2CO - NO, 24%), 407 (M+ - 5CO, 81%), 405 (M+
-
4CO - NO, 76%), 377 (M+ - 5CO - NO, 13%), 353 (M+ - 4CO -
NO - Cr, 14%), 299 (M+ - 4CO - NO - Cr - C2H2, 10%), 193
([C11H9 + Cr]+, 3%), 141 (C11H9+, 7%), 115 (C9H7+, 5%), 52 (Cr+,
100%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Mo(CO)3Br (13). To a
THF solution of 9 (1.2 mmol) was added Br2 (60 µL, 1.2 mmol) in
THF (10 mL) dropwise at -78 °C. The mixture was stirred at -78
°C for 0.5 h and then slowly warmed to room temperature and stirred
for an additional 0.5 h. The solvent was removed under vacuum, and
the solid residue was purified by chromatography on alumina. Eluting
with CH2Cl2/hexane (1:10 f 2:10) produced two yellow bands which
were 1 and a dimer of 1. Further elution with CH2Cl2/hexane (3:10 f
10:10) produced a red band that was collected and the solvent removed
under vacuum. A red powder was obtained (0.28 g, 45%). 13: mp
160-163 °C. Anal. Calcd for C17H9BrCrMoO6: C, 38.01; H, 1.69.
Found: C, 38.62; H, 2.04. IR (THF, cm-1): νCO 2047 s, 1963 vs,
1890 vs. 1H NMR (CDCl3): δ (ppm) 5.50-5.42 (m, 9H). Mass
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Mn(CO)3 (18). To a solu-
tion of 2 (0.9 mmol) was added [Mn(CO)4Br]2 (0.23 g, 0.5 mmol) in
THF (10 mL) slowly. The mixture was stirred overnight, and some
precipitants formed. After filtration, the solvent was evacuated to
dryness. Chromatography of the residue was performed over an
alumina column. After two small yellow fractions (eluted with CH2-
Cl2/hexane ) 2:10), a main yellow fraction (eluted with CH2Cl2/hexane
) 4:10 f 1:1) was obtained. A yellow powder was obtained after
removal of the solvent (0.31 g, 79%). 18: mp 179-182 °C dec. Anal.
Calcd for C17H9CrMnO6: C, 49.06; H, 2.18. Found: C, 49.17; H, 2.38.
IR (THF, cm-1): νCO 2022 s, 1964 vs, 1934 s, 1891 vs. 1H NMR
(CDCl3): δ (ppm) 5.43 (m, 4H), 5.29 (m, 1H), 5.12 (s, 2H), 4.82 (s,
2H). Mass spectrum (EI): m/z (relative intensity) 416 (M+, 13%), 322
(M+ - 3CO, 44%), 276 (M+ - 5CO, 41%), 249 (M+ - 4CO - Mn,
23%), 248 (M+ - 6CO, 100%), 196 ([C11H9 + Mn]+, 29%), 193
([C11H9 + Cr]+, 79%), 141 (C11H9+, 16%), 115 (C9H7+, 10%), 55 (Mn+,
13%), 52 (Cr+, 27%).
Synthesis of Cr(CO)3(η6,η5-C6H5C9H6)Mn(CO)3 (19). To a solu-
tion of 3 (0.29 g, 0.9 mmol) in THF (20 mL) at 0 °C was added NaH
(60 mg, excess) in portions. The reaction mixture was stirred for 1 h
at 0 °C. After centrifugation, a yellow solution of 4 was obtained. To
a solution of 4 (0.9 mmol) was added [Mn(CO)4Br]2 (0.23 g, 0.5 mmol)
in THF (10 mL) slowly. The mixture was stirred overnight at room
temperature. After filtration, the solvent was evacuated to dryness.
Chromatography of the residue was performed over an alumina column.
After two small yellow fractions (eluted with CH2Cl2/hexane ) 2:10),
a main yellow fraction (eluted with CH2Cl2/hexane ) 3:10) was
obtained. A yellow powder was obtained after removal of the solvent
(0.31 g, 75%). 19: mp 150-152 °C dec. Anal. Calcd for C21H11-
CrMnO6: C, 54.09; H, 2.38. Found: C, 54.41; H, 2.25. IR (THF,
cm-1): νCO 2021 s, 1963 vs, 1933 s, 1890 vs. 1H NMR (CDCl3): δ
(ppm) 7.77-7.20 (m, 4H), 5.87 (s, 1H), 5.70 (s, 1H), 5.46-5.28 (m,
5H). Mass spectrum (EI): m/z (relative intensity) 466 (M+, 8%), 382
(M+ - 3CO, 27%), 326 (M+ - 5CO, 32%), 299 (M+ - 4CO - Mn,
21%), 298 (M+ - 6CO, 78%), 246 ([C15H11 + Mn]+, 6%), 243 ([C15H11
+ Cr]+, 100%), 191 (C15H11+, 35%), 165 (C13H9+, 8%), 55 (Mn+, 8%),
52 (Cr+, 36%).
spectrum (EI): m/z (relative intensity) 318 (M+ - 6CO - Cr, 4%),
+
239 ([C11H9 + Mo]+, 14%), 193 ([C11H9 + Cr]+, 11%), 141 (C11H9
,
98%), 115 (C9H7+, 100%), 52 (Cr+, 14%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)W(CO)3Br (14). Following
the procedure for 13, W(CO)3(EtCN)3 (0.43 g, 1.0 mmol), (1) (0.28 g,
1.0 mmol), and Br2 (51 µL, 1.0 mmol) were used to produced a yellow
powder (0.26 g, 42%). 14: mp 172-174 °C dec. Anal. Calcd for
C17H9BrCrO6W: C, 32.67; H, 1.45. Found: C, 33.00; H, 1.69%. IR
(THF, cm-1): νCO 2020 s, 1964 vs, 1924 vs, 1892 vs. 1H NMR
(CDCl3): δ (ppm) 5.56-5.28 (m, 9H). Mass spectrum (EI): m/z
(relative intensity) 545 (M+ - Br, 6%), 512 (M+ - 4CO, 6%), 488
(M+ - 3CO - Cr, 15%), 461 (M+ - 3CO - Br, 25%), 433 (M+
-
4CO - Br, 41%), 432 (M+ - 5CO - Cr, 51%), 405 (M+ - 5CO -
Br, 51%), 404 (M+ - 6CO - Cr, 100%), 377 ([C11H9 + Cr + W]+,
29%), 325 ([C11H9 + W]+, 33%), 193 ([C11H9 + Cr]+, 15%), 141
(C11H9+, 91%), 115 (C9H7+, 66%), 52 (Cr+, 39%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Cr(CO)2NO (15). A solu-
tion of 8 was obtained in following the procedure for 9, with 1 (0.23
g, 0.8 mmol) and Cr(CO)3(CH3CN)3 (0.21 g, 0.8 mmol). The solution
was cooled to 0 °C, and Diazald (0.18 g, 0.8 mmol) in THF (10 mL)
was added slowly. The mixture was warmed to room temperature and
was stirred for 3 h. After filtration, the solvent was removed under
vacuum. The solid residue was purified by column chromatography.
Eluting with CH2Cl2/hexane (1:10 f 2:10) produced two yellow bands
which were 1 and a dimer of 1. Further elution with CH2Cl2/hexane
(3:10 f 10:10) produced an orange band that was collected and the
solvent removed under vacuum. An orange powder was obtained (0.19
g, 55%). 15: mp 171-174 °C dec. Anal. Calcd for C16H9Cr2NO6:
C, 46.28; H, 2.18. Found: C, 46.93; H, 2.26. IR (THF, cm-1): νCO
2021 s, 1963 vs, 1890 vs; νNO 1699 s. 1H NMR (CDCl3): δ (ppm)
5.32-5.01 (m, 9H). Mass spectrum (EI): m/z (relative intensity) 415
(M+, 9%), 331 (M+ - 3CO, 23%), 275 (M+ - 5CO, 100%), 273 (M+
- 4CO - NO, 47%), 245 (M+ - 5CO - NO, 18%), 193 ([C11H9 +
Cr]+, 46%), 141 (C11H9+, 6%), 115 (C9H7+, 3%), 52 (Cr+, 17%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Mo(CO)2NO (16). Fol-
lowing the procedure for 15, Mo(CO)3 (MeCN)3 (0.37 g, 1.3 mmol), 1
(0.36 g, 1.3 mmol), and Diazald (0.28 g, 1.3 mmol) were used to
produce a yellow powder (0.36 g, 60%). 16: mp 161-164 °C dec.
Anal. Calcd for C16H9CrMoNO6: C, 41.85; H, 1.98. Found: C, 42.06;
H, 2.21. IR (THF, cm-1): νCO 2017 s, 1963 vs, 1938 vs, 1890 vs; νNO
1670 s. 1H NMR (CDCl3): δ (ppm) 5.60-5.30 (m, 9H). Mass
spectrum (EI): m/z (relative intensity) 461 (M+, 6%), 377 (M+ - 3CO,
Synthesis of (η5-C6H5C5H4)Ru(PPh3)2Cl (20). 1 (0.49 g, 1.8
mmol), RuCl3‚3H2O (0.38 g, 1.4 mmol), PPh3 (3 g, 11.4 mmol), and
EtOH (100 mL) were mixed and refluxed for 8 h. The color of the
mixture changed from dark green to orange. After being cooled to
room temperature, the reaction mixture was filtered and the filtrate was
evacuated to dryness and chromatographed on an alumina column. After
two small yellow fractions (CH2Cl2/hexane ) 2:10), a main red orange
fraction (CH2Cl2/hexane ) 3:10 f 1:1) was obtained. An orange
powder was obtained after removal of the solvent (0.47 g, 41%). 20:
mp 178-181 °C dec. Anal. Calcd for C47H39ClP2Ru: C, 70.36; H,
4.90. Found: C, 69.46; H, 4.69. 1H NMR (CDCl3): δ (ppm) 7.85
(m, 5H), 7.37-6.94 (m, 30H), 4.59 (s, 2H), 3.34 (s, 2H). Mass
spectrum (EI): m/z (relative intensity) 540 ([C11H9 + Ru(PPh3)Cl]+,
2%), 505 ([C11H9 + Ru(PPh3)]+, 3%), 262 ([PPh3]+, 100%), 183 ([PPh3
- C6H7]+, 79%), 108 ([PPh]+, 31%), 115 (C9H7+, 4%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Ru(PPh3)2Cl (21). To a
mixture of 1 (0.57 g, 2.0 mmol) and RuCl2(PPh3) (1.96 g, 2.0 mmol)
in benzene (40 mL) was added zinc powder (0.2 g, excess). The

Heterobimetallic Complexes with Cp Ligands
Inorganic Chemistry, Vol. 36, No. 7, 1997 1295
mixture was stirred for 48 h at room temperature. After centrifugation,
the clear solution was evaporated to dryness and chromatographed on
an alumina column. After two small yellow fractions (CH2Cl2/hexane
) 2:10), a main red orange fraction (CH2Cl2/hexane ) 3:10 f 1:1)
was obtained. An orange solid was obtained after removal of the
solvent (0.86 g, 45%). 21: mp 164-166 °C dec. Anal. Calcd for
C50H39ClCrO3P2Ru: C, 64.00; H, 4.19. Found: C, 64.35; H, 3.96. IR
(THF, cm-1): νCO 1957 vs, 1883 vs. 1H NMR (CDCl3): δ (ppm) 7.47-
7.07 (m, 30H), 5.50-5.27 (m, 5H), 4.63 (s, 2H), 3.52 (s, 2H). Mass
spectrum (EI): m/z (relative intensity) 505 ([C11H9 + Ru(PPh3)]+, 7%),
428 ([C11H9 + Ru(PPh2)]+, 2%), 262 ([PPh3]+, 100%), 183 ([PPh3 -
C6H7]+, 69%), 108 ([PPh]+, 23%), 115 (C9H7+, 3%), 52 (Cr+, 3%).
Synthesis of Cr(CO)3(η6,η5-C6H5C5H4)Co(CO)2 (22). A mixture
of 1 (0.43 g, 1.5 mmol), Co2(CO)8 (0.3 g, 0.9 mmol), t-BuCHdCH2
(0.4 mL), and CH2Cl2 (30 mL) was heated to gentle reflux for 10 h.
After the solution was cooled to room temperature, the solvent was
removed under vacuum. The solid residue was chromatographed on
an alumina column. Eluting with CH2Cl2/hexane ) 1:10 produced one
small yellow band of 1 at first, followed by a main red fraction. A red
powder was obtained after removal of the solvent (0.37 g, 61%). 22:
mp 107-109 °C dec. Anal. Calcd for C16H9CoCrO5: C, 49.00; H,
2.31. Found: C, 49.26; H, 2.33. IR (THF, cm-1): νCO 2025 s, 1962
vs, 1890 vs. 1H NMR (CDCl3): δ (ppm) 5.52 (d, 2H), 5.43 (t, 2H),
5.35 (s, 2H), 5.29 (t, 1H), 5.16 (s, 2H). Mass spectrum (EI): m/z
(relative intensity) 364 (M+ - CO, 20%), 336 (M+ - 2CO, 32%), 308
1.69 (m, 3H). Mass spectrum (EI): m/z (relative intensity) 472 (M+
- 3CO, 3%), 420 (M+ - 3CO - Cr, 4%), 388 (M+ - 6CO, 6%), 364
(M+ - 5CO - Cr, 3%), 336 (M+ - 6CO - Cr, 39%), 334 (M+
6CO - Cr - 2H, 100%), 52 (Cr+, 99%).
-
X-ray Structural Determinations. Single crystals were sealed in
thin-walled glass capillaries under argon. Intensity data were collected
on an Enraf-Nonius CAD4 diffractometer for 3 and on a Rigaku AFC7R
diffractometer for other compounds, using graphite-monochromated Mo
KR radiations in the ω-2θ scan mode at 20 °C. Final lattice parameters
were obtained by a least-squares refinement of the 2θ values of 25
reflections. The intensities were corrected for Lorentz and polarization
effects. The metal atom was located by the Patterson method, and the
other non-hydrogen atoms were located by difference Fourier method.
All positional parameters and anisotropic thermal parameters for non-
hydrogen atoms were refined by the full-matrix least-squares technique.
Finally, all hydrogen atoms were introduced in calculated positions.
Scattering factors were taken from ref 46. All calculations for 3 were
made on a Micro VAX-II computer with SDP plus ORTEP prorams.
All calculations for other compounds were performed using the teXsan47
crystallography software package of the Molecular Structure Corpora-
tion. The crystallography data are listed in Table 1.
Acknowledgment. We thank the National Science Founda-
tion of China and Chinese Academy of Sciences for financial
support.
(M+ - 3CO, 36%), 280 (M+ - 4CO, 64%), 252 (M+ - 5CO, 100%),
Supporting Information Available: X-ray crystallographic files
in CIF format for compounds 23, 3, 7, 13, 19, 21, and 22 are available.
Access information is given on any current masthead page.
+
196 ([C11H9 + Co]+, 21%), 193 ([C11H9 + Cr]+, 69%), 141 (C11H9
,
29%), 115 (C9H7+, 25%), 52 (Cr+, 19%).
Formation of 1,4-Bis[tricarbonylchromio)phenyl]tricyclo[5.2.1.02,6]-
deca-3,8-diene (23). Yellow crystals of compound 23 were obtained
from the THF/hexane solution of 1 after being allowed to stand at about
0 °C for several days. 23: mp 163-165 °C. Anal. Calcd for C28H20-
Cr2O6: C, 60.43; H, 3.62. Found: C, 59.95; H, 3.79. IR (THF, cm-1):
νCO 1959 vs, 1886 vs. 1H NMR (CDCl3): δ (ppm) 6.21-5.98 (m,
3H), 5.57-5.30 (m, 10H), 3.75-3.09 (m, 3H), 2.53 (m, 1H), 2.01-
IC951630I
(46) Cromer, D. T.; Waber, J. T. International Table for X-ray Crystal-
lography; Kynoch Press: Birmingham, 1974; Vol. 4.
(47) teXsan, Crystal Structure Analysis Package, Molecular Structure
Corporation, 1985 and 1992.