Binuclear CpV, Cp*V, and Cp*Ta complexes containing organochalcogenolato bridges, μ-ER (E = sulfur, selenium, tellurium; R = methyl, phenyl, and ferrocenyl)

Article abstract of DOI:10.1002/(SICI)1521-3749(200006)626:6<1289::AID-ZAAC1289>3.0.CO;2-O

Photolysis of the halfsandwich tetracarbonylmetal complexes CpV(CO)₄, Cp*V(CO)₄ and Cp*Ta(CO)₄ in solution in the presence of di(organyl)dichalcogenides E₂R₂ (E = S, Se, Te; R = Me, Ph, Fc) leads to diamagnetic doubly organochalcogenolato-bridged compounds, [Cp⁰M(CO)₂(μ-ER)]₂. According to the X-ray structure determinations carried out for [CpV(CO)₂(μ-TeMe)]₂, [Cp*V(CO)₂(μ-TePh)]₂ and [Cp*Ta(CO)₂(μ-SPh)]₂, the molecular framework consists of a folded M₂(μ-ER)₂ ring with the cyclopentadienyl ligands in cis-configuration and the organyl substituents R in a syn-equatorial arrangement, thus forming a bowl-shaped molecule with the four terminal CO ligands protruding into the inner sphere. The M ... M distances (in the range between 305 and 330pm) are not considered to indicate direct bonding interactions. The vanadium complexes [Cp⁰V(CO)₂(μ-ER)]₂ are completely decarbonylated in the presence of an excess of E₂R₂ in boiling toluene, and in many cases the paramagnetic quadruply-bridged products, [CpV(μ-ER)₂]₂, can be isolated.

Full text of DOI:10.1002/(SICI)1521-3749(200006)626:6<1289::AID-ZAAC1289>3.0.CO;2-O

ARTIKEL
Binuclear CpV, Cp*V, and Cp*Ta Complexes containing
Organochalcogenolato Bridges, l-ER (E = Sulfur, Selenium, Tellurium;
R = Methyl, Phenyl, and Ferrocenyl)
Max Herberhold*, JuÈrgen Peukert, Michaela KruÈger, Daniela Daschner, and Wolfgang Milius
Bayreuth, Laboratorium fuÈr Anorganische Chemie der UniversitaÈt
Received August 31st, 1999.
Dedicated to Professor Heinrich Vahrenkamp on the Occasion of his 60th Birthday
Abstract.1) Photolysis of the halfsandwich tetracarbonylme-
tal complexes CpV(CO)4, Cp*V(CO)4 and Cp*Ta(CO)4 in
solution in the presence of di(organyl)dichalcogenides E2R2
(E = S, Se, Te; R = Me, Ph, Fc) leads to diamagnetic doubly
organochalcogenolato-bridged compounds, [Cp()M(CO)2(l-
ER)]2. According to the X-ray structure determinations car-
ried out for [CpV(CO)2(l-TeMe)]2, [Cp*V(CO)2(l-TePh)]2
and [Cp*Ta(CO)2(l-SPh)]2, the molecular framework con-
sists of a folded M2(l-ER)2 ring with the cyclopentadienyl li-
gands in cis-configuration and the organyl substituents R in
a syn-equatorial arrangement, thus forming a bowl-shaped
molecule with the four terminal CO ligands protruding into
the inner sphere. The M ´ ´ ´ M distances (in the range
between 305 and 330 pm) are not considered to indicate
direct bonding interactions. The vanadium complexes
[Cp()V(CO)2(l-ER)]2 are completely decarbonylated in the
presence of an excess of E2R2 in boiling toluene, and in
many cases the paramagnetic quadruply-bridged products,
[CpV(l-ER)2]2, can be isolated.
Keywords: Vanadium; Tantalum; Halfsandwich complexes;
Organochalcogenolato bridges; Crystal structure
Zweikernige CpV-, Cp*V- und Cp*Ta-Komplexe mit Organochalkogenolato-
BruÈcken, l-ER (E = Schwefel, Selen, Tellur; R = Methyl, Phenyl und Ferrocenyl)
InhaltsuÈbersicht.1) Die Photolyse der Halbsandwich-tetra-
carbonylmetall-Komplexe CpV(CO)4, Cp*V(CO)4 und
Cp*Ta(CO)4 in LoÈsung in Gegenwart von Di(organyl)di-
chalkogeniden E2R2 (E = S, Se, Te; R = Me, Ph, Fc) fuÈhrt
zu den diamagnetischen, zweifach organochalkogenolat-
verbruÈckten Verbindungen, [Cp()M(CO)2(l-ER)]2. Nach den
RoÈntgenstrukturanalysen, die fuÈr [CpV(CO)2(l-TeMe)]2,
[Cp*V(CO)2(l-TePh)]2 und [Cp*Ta(CO)2(l-SPh)]2 durch-
gefuÈhrt wurden, besteht das MolekuÈlgeruÈst aus einem nicht-
ebenen Vierring mit den Cyclopentadienyl-Liganden in
cis-Konfiguration und den Organyl-Substituenten R in syn-
equatorialer Anordnung. So entsteht ein wannenfoÈrmiges
MolekuÈl, in dessen inneren Bereich die vier endstaÈndigen
CO-Liganden hineinragen. Die Metall ´ ´ ´ Metall-AbstaÈnde
(im Bereich von 305±330 pm) werden nicht als Hinweis auf
direkte bindende Wechselwirkungen angesehen. Die Vanadi-
umkomplexe [Cp()V(CO)2(l-ER)]2 werden in Gegenwart
von uÈberschuÈssigem E2R2 in siedendem Toluol vollstaÈndig
decarbonyliert, und in vielen FaÈllen lassen sich paramagneti-
sche, vierfach verbruÈckte Produkte [CpV(l-ER)2]2 isolieren.
Introduction
[CpM(CO)2(l-ER)]2 (M = Cr, Mo; E = S, Se, Te;
R = Ph), may occur in 6 different geometrical forms
[3] (A±F in Scheme 1) with Cp either in trans or cis,
and the phenyl substituents either in syn or anti ar-
rangements; in the case of syn, the two phenyl groups
may be attached either in equatorial (ªendoº) or axial
(ªexoº) positions. Each metal also carries two termi-
nal carbonyl ligands. In the solid state, only the trans-
Cp/anti-Ph arrangement (D) has been observed, e. g.
Binuclear halfsandwich-type complexes with organo-
chalcogenolato bridges can have various structural ar-
rangements of the folded inner M(l-ER)2M core
[1, 2, 3]. In principle, compounds of the group 6 metals
with non-planar M(l-ER)2M center, such as
* Prof. Dr. M. Herberhold,
Laboratorium fuÈr Anorganische Chemie,
UniversitaÈtsstraûe 30,
D-95440 Bayreuth,
Fax: +49(0)9 21 55 21 57
Abbreviations: Cp = g5-cyclopentadienyl, g5-C5H5; Cp* =
1)
g5-pentamethylcyclopentadienyl, g5-C5Me5; Cp() = Cp or
Cp*. Fc = g1-ferrocenyl, CpFe(C5H4-)
e-mail: max.herberhold@uni-bayreuth.de
Z. Anorg. Allg. Chem. 2000, 626, 1289±1295 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000 0044±2313/00/6261289±1295 $ 17.50+.50/0 1289

M. Herberhold, J. Peukert, M. KruÈger, D. Daschner, W. Milius
Scheme 1 Possible geometrical isomers of [CpM(CO)2(l-ER)]2 complexes (M = transition metal; E = S, Se, Te; the carbonylli-
gands are omitted for clarity)
in [CpCr(CO)2(l-EPh)]2 (E = S [4], Te [5]) and in
[CpMo(CO)2(l-EPh)]2 (E = S [6, 7]), Se [8], Te [9]).
However, several isomers appear to be present in so-
lution [3] (s. Scheme 1).
On the other hand, the crystal structure determina-
tions of the analogous complexes known so far with
group 5 metals consistently indicate the cis-Cp/syn-R
(eq.) arrangement (B), e. g. in [Cp*V(CO)2(l-SR)]2
(R = Me, Ph) [10] and in [CpNb(CO)2(l-SR)]2
(R = Me) [11].
dium educts CpV(CO)4 (1) and Cp*V(CO)4 (2) in te-
trahydrofuran solution at 0 °C in the presence of the
stoichiometric amount of di(organyl)dichalcogenide,
REER. The corresponding Cp*Ta compounds were
prepared similarly from Cp*Ta(CO)4 (3) under irra-
diation in hexane solution. A survey of the products is
given in Scheme 2 together with the numbering sys-
tem. The complexes [CpV(CO)2(l-ER)]2 (4 a±12 a)
(containing the unsubstituted cyclopentadienyl ring)
and the Cp*V analogues (4 b±12 b) (containing the
pentamethylcyclopentadienyl ring) are compared with
the Cp*Ta complexes (4 c±14 c) (s. Scheme 2).
In other binuclear bis(organochalcogenolato)-
bridged compounds, various other geometrical forms
were confirmed by X-ray crystallography. Thus, the
carbonyl-free rhodium complex [CpRh(l-SPh)]2 is
present in the crystal lattice in the cis-Cp/anti-Ph form
(A) [12, 13], whereas [CpRh(SePh)(l-SePh)]2 adopts
the trans-Cp/anti-Ph (D) arrangement [14]. The
iron complexes [CpFe(CO)(l-SPh)]2 [15] and
In boiling toluene (110 °C), the vanadium(II) com-
plexes [Cp()V(CO)2(l-ER)]2 lose all remaining CO li-
gands to give, in the presence of excess REER, para-
magnetic vanadium(III) derivatives, [Cp()V(l-ER)2]2.
However, the tantalum(II) compounds could not be
decarbonylated under comparable conditions, includ-
ing boiling xylene (isomer mixture, b. p. ca. 140 °C).
+
[CpFe(CO)(l-SMe)]2 [16] are both present in the cis-
Cp/syn-R (eq.) geometry (B). (In contrast, the for-
mally analogous monocarbonyl molybdenum complex
[CpMo(CO)(l-SPh)]2 has a planar M2S2 core; both
trans-Cp/anti-Ph and trans-Cp/syn-Ph geometries have
been observed [17]).
We had earlier investigated binuclear vanadium com-
plexes, [CpV(CO)2(l-ER)]2 and [Cp*V(CO)2(l-ER)]2
(E = S, Se; R = Me, Ph) [10]. We now report on an ex-
tension of this work, including ferrocenyl-substituted
chalcogenolato-bridges (EFc), tellurolato ligands (TeR;
R = Me, Ph, Fc) and pentamethylcyclopentadienyl tan-
talum complexes.
The
paramagnetic
vanadium(III)
complexes
[CpV(l-SR)2]2 (4 d, 7 d, 10 d) are the stable end
products of the thermal reaction of CpV(CO)4 (1) with
organosulfur compounds. Following the initial report
by Stone and coworkers [18] in 1963, some examples
such as [CpV(l-SMe)2]2 (4 d) [18, 19, 10] and [CpV(l-
SPh)2]2 (7 d) [20, 21, 22, 10] had been described, and
analogous ethane or ethene dithiolate complexes such
as [CpV(l2-SCH2CH(R)S)]2 (R = H, CH3) [23] and
[CpV(l2-SC(CF3)=C(CF3)S)]2 [24] have been studied
with respect to the nature of their metal-metal interac-
tion [20, 21, 23]. One organoselenido-bridged complex,
[CpV(l-SePh)2]2 (8 d), had also been characterized
[20, 21]. The diamagnetic vanadium(II) dicarbonyl
complexes, e. g. [CpV(CO)2(l-SPh)]2 (7 a) [19, 10], are
apparently intermediates on the route from 1 to the
fully decarbonylated end product, e. g. [CpV(l-SPh)2]2
(7 d), and can be isolated if the CO displacement is
conducted photochemically [19, 10].
Results and Discussion
Syntheses
The binuclear, organochalcogenolato-bridged vana-
dium complexes [Cp()V(CO)2(l-ER)]2 were obtained
by photolysis of the mononuclear tetracarbonylvana-
1290
Z. Anorg. Allg. Chem. 2000, 626, 1289±1295

Binuclear CpV, Cp*V, and Cp*Ta Complexes containing Organochalcogenolato Bridges
Scheme 2 Synthesis of the complexes and numbering system
Table 1 Characteristic spectroscopic data of the binuclear complexes [CpV(CO)2(l-ER)]2 (4 a±12 a), [Cp*V(CO)2(l-ER)]2
(4 b±12 b) and [Cp*Ta(CO)2(l-ER)]2 (4 c±14 c)
Complex
ER
Yield
Infrared m(CO), cm±1 a)
NMR (C6D6)
d(1H) (Cp())
d(13C) (Cp())
d(51V) (I1/2[Hz])
4 a
5 a
6 a
7 a
8 a
9 a
SMe b)
SeMe b)
TeMe b)
SPh
64%
30%
66%
50%
20%
55%
1997 m,
1992 s,
1990 vs,
1988 s,
1933 s
4.60
4.64
4.60
4.62
4.567
4.570
4.75
4.79
4.76
4.80
4.71
4.77
4.95
4.91
4.96
4.86
4.89
93.7
94.0
92.4
92.5
89.7
±772 (610)
1935 s
±803 (650)
±968 (500)
±670 (750)
±695 (960)
±908 (1500)
1986 vs,
1934 s
1995 vs,
1993 vs,
1987 vs,
1955 s,
1948 s,
1933 s,
1916 m
1917 sh
1896 sh
95.3
SePh
93.3
93.6
90.1
90.3
94.8
93.0
93.1
90.1
TePh
10 a
11 a
SFc
SeFc
26%
12%
1991 vs,
1989 s,
1949 s
1942 m
±642 (1000)
±693 (1000)
12 a
TeFc
71%
1985 s,
1930 s
±906 (1550)
4 b
5 b
6 b
7 b
8 b
SMe c)
SeMe c)
TeMe c)
SPh
SePh
TePh
SFc
47%
35%
77%
51%
23%
76%
22%
21%
42%
1971 vs,
1969 vs,
1965 vs,
1971 vs,
1972 vs,
1969 vs,
1978 s,
1910 s
1912 s
1913 s
1933 m,
1933 s,
1930 s,
1935 m
1934 m
1930 m
1.65
1.69
1.80
1.54
1.62
1.76
1.88
1.90
1.97
11.2/103.7
11.9/103.1
13.3/102.0
11.1/104.9
11.8/104.1
13.2/102.9
12.5/105.1
12.7/104.0
13.6/102.6
±751 (870)
±757 (800)
±860 (1150)
±686 (1270)
±703 (1340)
±804 (1600)
±495 (1400)
±573 (1600)
±750 (2000)
1886 m
1887 m
1891 m
9 b
10 b
11 b
12 b
SeFc
TeFc
1976 s,
1973 s,
4 c
5 c
6 c
7 c
8 c
SMe d)
SeMe d), e)
TeMe d), f)
SPh
±
1934 s,
1880 s
2.00
1.91
1.80
1.74
1.83
1.73
2.03
2.07
2.09
1.91
1.84
11.6/102.8
11.9/101.3
12.6/102.3
11.1/102.3
11.8/101.5
12.7/103.1
12.2/102.1
12.5/101.2
13.5/100.3
11.6/101.8
12.6/102.2
38%
29%
45%
28%
33%
21%
18%
16%
38%
35%
1969 s,
1901 vs
1874 vs
1862 m
1863 m
1899 vs
1871 m
1870 w
1897 m
1880 s
1934 vs,
1915 s,
1917 s,
1962 vs,
1964 vs,
1958 s,
1965 s,
1965 s,
1968 s,
1956 vs,
1960 s,
SePh e)
TePh f)
SFc
9 c
10 c
11 c
12 c
13 c
14 c
1915 s,
1906 vs,
1917 w,
SeFc e)
TeFc f)
SnBu
StBu
1888 s
a)
IR solution spectra in hexane (4 a±6 a and 4 b±12 b); if the solubility in particular cases was insufficent, the series were measured either in toluene
(7 a±12 a) or tetrahydrofuran (4 c±14 c).
b)
c)
d)
e)
f)
Methyl group NMR data (C6D6): d(1H): 1.99/2.03 (4 a), 1.91/1.98 (5 a); d(13C): 23.5/23.7 (4 a), 6.5 (5 a), ±9.3/±12.3 (6 a).
Methyl group NMR data (C6D6): d(1H): 2.06 (4 b), 2.01 (5 b), 2.01 (6 b); d(13C): 22.4 (4 b), 4.7 (5 b), ±30.6 (6 b).
Methyl group NMR data (C6D6): d(1H): 1.65 (4 c), 1.77 (5 c), 1.84 (6 c); d(13C): 10.8 (4 c), 12.0 (5 c).
Selenium NMR data (C6D6): d(77Se): ±220 (5 c), +60 (8 c), ±55 (11 c).
Tellurium NMR data (C6D6): d(125Te): ±593 (6 c), ±946 (9 c), ±213 (12 c).
Z. Anorg. Allg. Chem. 2000, 626, 1289±1295
1291

M. Herberhold, J. Peukert, M. KruÈger, D. Daschner, W. Milius
Spectroscopy
cogen is varied in the order S < Se < Te; a particularly
large difference is always observed between the sele-
nolato and the tellurolato compounds. Furthermore,
the 51V NMR signal is moving to lower field, if the or-
ganyl group in ER changes from R = methyl via phe-
nyl to ferrocenyl, and also if Cp is replaced by Cp*.
According to the m(CO) frequencies which are de-
creasing in the same direction, the electron-donating
character of the bridging ligands increases in the order
EMe < EPh < EFc, and the Cp* ring ligand increases
the charge density at the metal as compared to the un-
substituted Cp ligand.
Some diagnostic IR and NMR spectra of the carbo-
nyl-containing complexes are collected in Table 1. Ac-
cording to the m(CO) absorptions in the IR spectra, all
CO ligands are terminal.
1
In the H and 13C NMR spectra of the complexes
[CpV(CO)2(l-ER)]2 (4 a±12 a), generally two signals
are observed for the (unsubstituted) cyclopentadienyl
ring ligand, indicating the presence of isomers (cf.
[10, 19]). In a similar manner, two methyl signals are
present in the methylchalcogenolato-bridged com-
pounds 4 a±6 a. However, the 51V NMR signals are
apparently too broad to allow the identification of iso-
meric forms.
X-Ray Crystallographic Structure Determinations
The NMR spectra of the Cp*-containing complexes
[Cp*V(CO)2(l-ER)]2 (M = V, Ta) did not give any indi-
cations of the existence of isomers in solution; only one
The molecular structures of [CpV(CO)2(l-TeMe)]2
(6 a), [Cp*V(CO)2(l-TePh)]2 (9 b), and [Cp*Ta(CO)2-
(l-SPh)]2 (7 c) are presented in Figs. 1±3, together
with selected distances and angles.
The basic structure of these 3 dinuclear complexes
corresponds consistently to the cis-Cp/syn-R (eq.) ar-
rangement (B in Scheme 1) and is therefore analogous
to that of the Cp*V and CpNb compounds of this type
which had been investigated earlier [10, 11]. A com-
1
single signal was found for the Cp* ligands in the H-
and two signals in the 13C NMR spectra, and only one
broad absorption appeared in the 51V NMR spectra.
The 51V NMR signals of the binuclear complexes
4 a±12 a and 4 b±12 b are observed between ±500 and
±1000 ppm (Table 1). Some trends are apparent: The
51V NMR signal is shifted to higher fields as the chal-
Fig. 1 Molecular geometry of [CpV(CO)2(l-TeMe)]2 (6 a)
(the hydrogen atoms are omitted; Cp(1) and Cp(2) are the
centers of the Cp rings attached to V(1) and V(2), respec-
tively)
Fig. 2 Molecular geometry of [Cp*V(CO)2(l-TePh)]2 (9 b)
(the hydrogen atoms are omitted; Cp*(1) and Cp*(2) are the
centers of the Cp* rings attached to V(1) and V(2), respec-
tively)
Selected distances/pm and angles/°:
Selected distances/pm and angles/°:
V(1) ´ ´ ´ V(2) 328.9(1) V(1)±Te(1) 274.1(1) V(1)±C(11) 194.2(5)
V(1) ´ ´ ´ V(2) 329.5(1) V(1)±Te(1) 272.4(1) V(1)±C(11) 193.9(6)
Te(1) ´ ´ ´ Te(2) 330.2
V(1) ´ ´ ´ Cp(1) 193.8
V(2) ´ ´ ´ Cp(2) 193.4
V(1)±Te(2) 272.0(1) V(1)±C(12) 194.8(5)
V(2)±Te(1) 272.3(1) V(2)±C(13) 193.6(4)
V(2)±Te(2) 272.4(1) V(2)±C(14) 192.8(5)
Te(1) ´ ´ ´ Te(2) 319.3
V(1) ´ ´ ´ Cp*(1) 195.9
V(2) ´ ´ ´ Cp*(2) 196.4
V(1)±Te(2) 276.5(1) V(1)±C(12) 194.5(7)
V(2)±Te(1) 271.9(1) V(2)±C(25) 193.5(6)
V(2)±Te(2) 274.1(1) V(2)±C(26) 192.8(7)
V(1)±Te(1)±V(2)
Te(1)±V(1)±Te(2)
C(11)±V(1)±C(12)
V(1)±C(11)±O(1)
V(2)±C(13)±O(3)
Cp(1)±V(1)±Te(1)
Cp(1)±V(1)±C(11)
Cp(2)±V(2)±Te(1)
Cp(2)±V(2)±C(13)
74.0(1)
74.4(1)
84.2(2)
173.6(5)
173.3(4)
114.3
107.2
117.1
109.1
V(1)±Te(2)±V(2)
Te(1)±V(2)±Te(2)
C(13)±V(2)±C(14)
V(1)±C(12)±O(2)
V(2)±C(14)±O(4)
Cp(1)±V(1)±Te(2)
Cp(1)±V(1)±C(12)
Cp(2)±V(2)±Te(2)
Cp(2)±V(2)±C(14)
74.3(1)
74.6(1)
82.7(2)
172.3(5)
173.5(5)
116.5
108.7
114.4
108.2
V(1)±Te(1)±V(2)
Te(1)±V(1)±Te(2)
C(11)±V(1)±C(12)
V(1)±C(11)±O(1)
V(2)±C(25)±O(3)
Cp*(1)±V(1)±Te(1)
Cp*(1)±V(1)±C(11)
Cp*(2)±V(2)±Te(1)
Cp*(2)±V(2)±C(25)
74.5(1)
71.2(1)
81.0(3)
170.2(6)
171.1(6)
112.9
106.7
116.3
106.6
V(1)±Te(2)±V(2)
Te(1)±V(2)±Te(2)
C(25)±V(2)±C(26)
V(1)±C(12)±O(2)
V(2)±C(26)±O(4)
Cp*(1)±V(1)±Te(2)
Cp*(1)±V(1)±C(12)
Cp*(2)±V(2)±Te(2)
Cp*(2)±V(2)±C(26)
73.5(1)
71.6(1)
79.3(3)
173.0(7)
170.6(6)
120.6
108.5
116.9
109.3
1292
Z. Anorg. Allg. Chem. 2000, 626, 1289±1295

Binuclear CpV, Cp*V, and Cp*Ta Complexes containing Organochalcogenolato Bridges
parison of important structural data for all 6 com-
plexes is given in Table 2. The methyl or phenyl sub-
stituents (R) occupy an equatorial (ªendoº) position
with respect to the folded M2E2 ring.
Although the complexes are diamagnetic, as indi-
cated by the NMR spectra, the presence of direct me-
tal ´ ´ ´ metal interactions is a matter of debate [10].
The M ´ ´ ´ M separations are found in the range be-
tween 305 and 330 pm and apparently depend mainly
on the size of the chalcogen, ± the long distances
(329 ± 1 pm) being observed in the organotellurolato-
bridged molecules 6 a and 9 b. It is reasonable to as-
sume that interaction and communication between the
two metals is essentially transferred through the two
ER bridges. The transannular distances between the
two chalcogens (280 ± 2 pm in the sulfur, 319.3 and
330.2 pm in the tellurium compounds) can be con-
sidered as non-bonding. The angles at the metal
(E±M±E, 67±75°) are generally more acute than those
at the chalcogen (M±E±M, 73±79°), although they are
comparable (74±75°) in the methyltellurolato com-
plex, [CpV(CO)2(l-TeMe)]2 (6 a). The four carbonyl
ligands are all protruding into the inner sphere of the
bowl-shaped molecular framework which is formed by
the Cp()2M2(l-ER)2 skeleton.
In contrast to the carbonyl-containing vanadium(II)
complexes, [Cp()V(CO)2(l-ER)]2, the fully decarbony-
lated vanadium(III) compounds [Cp( )V(l-ER)2]2 very
probably contain direct metal-metal interactions.
Although the (temperature-dependent) magnetic data,
reported in the literature for the quadruply bridged
dimers [CpV(l-SMe)2]2 (4 d) [18], [CpV(l-SPh)2]2
(7 d) [21, 22], [CpV(l2-SCH2CH(R)S)]2 (R = H, Me)
[23] and [CpV(l2-SC(CF3)=C(CF3)S)]2 [24], are some-
what confusing [cf. 23], they are definitely below the
spin-only value of 2.83 lB per vanadium which would
indicate two uncoupled vanadium(III) centers. There-
fore either a direct V±V bond and/or partial antiferro-
magnetic coupling through the organochalcogenolato
bridges has to be assumed [23]. An X-ray structure
analysis of [CpV(l2-SCH2CH2S)]2 [23] revealed a
short V±V' contact of 254.2(1) pm and an acute
V±S±V angle of 63.4(1)°, which are both consistent
with a metal-metal bond. An attempt to obtain mole-
cular parameters for [CpV(l-SeMe)2]2 (4 b) was se-
verely hampered by insufficient quality of the crystal
and disorder of the selenium atoms; however, a short
V±V contact of 263.6(4) pm and an acute V±Se±V an-
gle of 61.4(1)° could be firmly established [25].
Fig. 3 Molecular geometry of [Cp*Ta(CO)2(l-SPh)]2 (7 c)
(the hydrogen atoms are omitted; Cp*(1) and Cp*(2) are the
centers of the Cp* rings attached to Ta(1) and Ta(2), respec-
tively)
Selected distances/pm and angles/°:
Ta(1) ´ ´ ´ Ta(2)
S(1) ´ ´ ´ S(2)
Ta(1) ´ ´ ´ Cp*(1) 207.6
Ta(2) ´ ´ ´ Cp*(2) 208.0
312.0(1) Ta(1)±S(1) 253.4(2) Ta(1)±C(11) 205.1(7)
281.4
Ta(1)±S(2) 255.2(2) Ta(1)±C(12) 204.0(7)
Ta(2)±S(1) 252.0(2) Ta(2)±C(25) 201.7(9)
Ta(2)±S(2) 256.1(2) Ta(2)±C(26) 203.8(8)
Ta(1)±S(1)±Ta(2)
S(1)±Ta(1)±S(2)
C(11)±Ta(1)±C(12)
Ta(1)±C(11)±O(1)
Ta(2)±C(25)±O(3)
Cp*(1)±Ta(1)±S(1)
Cp*(1)±Ta(1)±C(11) 105.0
Cp*(2)±Ta(2)±S(1) 111.8
Cp*(2)±Ta(2)±C(25) 106.4
76.3(1)
67.2(1)
77.6(3)
173.5(6)
171.5(6)
113.9
Ta(1)±S(2)±Ta(2)
S(1)±Ta(2)±S(2)
75.2(1)
67.3(1)
79.1(3)
172.8(6)
174.9(6)
114.7
107.6
117.6
108.1
C(25)±Ta(2)±C(26)
Ta(1)±C(12)±O(2)
Ta(2)±C(26)±O(4)
Cp*(1)±Ta(1)±S(2)
Cp*(1)±Ta(1)±C(12)
Cp*(2)±Ta(2)±S(2)
Cp*(2)±Ta(2)±C(26)
Table 2 Characteristic structural data of the binuclear complexes [Cp()M(CO)2(l-ER)]2 (M = V, Nb, Ta)
Complex
Distance, pm Distance, pm Angle, °
Angle, °
M±E±M
Angle, °
E±E±C
Dihedral Angles, °
Angle, °
M ´ ´ ´ M
E ´ ´ ´ E
E±M±E
at E ´ ´ ´ E
at M ´ ´ ´ M
Cp()M/MCp()
6 a [CpV(CO)2(l-TeMe)]2
4 b [Cp*V(CO)2(l-SMe)]2 [10]
7 b [Cp*V(CO)2(l-SPh)]2 [10]
9 b [Cp*V(CO)2(l-TePh)]2
[CpNb(CO)2(l-SMe)]2 [11]
7 c [Cp*Ta(CO)2(l-SPh)]2
328.9(1)
330.2
74.4(1)
74.6(1)
71.2(1)
74.0(1)
74.3(1)
78.9(1)
153.4
153.4
161.7
161.7
169.5
170.2
162.2
162.8
81.5
81.3
97.8
93.6
86.1
94.6
91.0
142.2°
140.6°
144.0°
150.8°
308.3(1)
307.0(1)
329.5(1)
316.4(9)
312.0(1)
281
77.2
80.7
84.3
278
69.1(1)
69.1(1)
71.2(1)
71.6(1)
70.9(5)
77.7(1)
77.7(1)
74.5(1)
73.5(1)
76.1(5)
76.5(3)
76.3(1)
75.2(1)
319.3
281.4
67.2(1)
67.3(1)
172.4
170.4
85.0
169.7°
Z. Anorg. Allg. Chem. 2000, 626, 1289±1295
1293

M. Herberhold, J. Peukert, M. KruÈger, D. Daschner, W. Milius
71.073 pm, graphite monochromator). Crystal and refine-
ment data for 6 a, 9 b, and 7 c are listed in Table 3. All non-
hydrogen atoms were refined with anisotropic temperature
factors. The H-atoms were refined on calculated positions
Apparently, the molecular geometry of the para-
magnetic vanadium complex [CpV(l-SeMe)2]2 (4 b)
corresponds closely to that of the diamagnetic
molybdenum analogue, [CpMo(l-SMe)2]2 (Mo±Mo
260.3(2) pm, angle Mo±S±Mo 64.0(2)°) and its para-
magnetic cation in [CpMo(l-SMe)2]2 (PF6 ) (Mo±Mo
261.7(4) pm, angle Mo±S±Mo 65.0(2)°), for both of
which strong metal-metal interaction has been as-
sumed [26].
applying the riding model with fixed temperature factors
2
Ê
(0.08 A ).
+
±
Syntheses
The starting halfsandwich complexes (CpV(CO)4 (1) [27],
Cp*V(CO)4 (2) [28], Cp*Ta(CO)4 (3) [29]) and the di(ferro-
cenyl)dichalcogenides E2Fc2 (E = S, Se, Te) [30] were ob-
tained according to literature procedures. The silica used for
column chromatography (Merck Kieselgel 60, 0.06±0.2 mm)
was heated under vacuum to 400 °C and saturated with ar-
gon.
Experimental
All synthetic work was carried out under an atmosphere of
dry argon, using oven-dried glassware and Ar-saturated dry
solvents. A high-pressure mercury arc (Heraeus, Original
Hanau, TQ 718 (700 W)) was applied for the photo-induced
reactions; the solutions were irradiated under stirring in
water-cooled (10±16 °C) Schlenk tubes.
The NMR spectra were measured by using Jeol FX 90 Q,
Bruker ARX 250 or AC 300 spectrometers. Chemical shifts
are given with respect to Me4Si [d1H (CHCl3/CDCl3) = 7.24,
(C6D5H) = 7.15; d13C (CDCl3) = 77.0, (C6D6) = 128.0];
Me2Se [d77Se = 0 for N(77Se) = 19.071523 MHz]; Me2Te
[d125Te = 0 for N(125Te) = 31.549802 MHz]; VOCl3 [d51V = 0].
For the IR-spectra, Perkin Elmer spectrometers 983G and
FT-IR 2000 were available; the solution IR spectra were
measured in the carbonyl region (2200±1600 cm±1) in CaF2
cuvettes (0.1 cm). Electron impact (EI) mass spectra (70 eV)
were recorded using a Finnigan MAT 8500 spectrometer,
and field desorption (FD) mass spectra using a Varian
MAT 311 A spectrometer. Single crystal X-ray data were
collected on a Siemens P4 diffractometer (MoKa, k =
Bis[(l-organylchalcogenolato)-cyclopentadienyl-dicarbo-
nyl-vanadium] (4 a±12 a): A THF solution (50 ml) containing
230 mg (1 mmol) CpV(CO)4 (1) and either 1 mmol R2E2 (in
the cases of 4 a, 5 a, 7 a, 8 a) or 0.5 mmol R2E2 (in the cases
of 6 a, 9 a±12 a) was irradiated for 20±150 min at 0 °C. The
progress of the reaction was followed by IR spectroscopy in
the m(CO) region (2200±1600 cm±1). The solutions were
brought to dryness and the products purified by column
chromatography over silica (elution of 1 together with R2E2
using hexane, elution of [CpV(CO)2(l-ER)]2 (4 a±12 a) using
hexane containing additional portions of CH2Cl2. The di-
meric products were characterized by their m(CO) frequen-
1
cies, their H/13C NMR data of the Cp ring ligands, and by
the broad 51V NMR absorption (see Table 1).
Bis[(l-organylchalcogenolato)-pentamethylcyclopentadie-
nyl-dicarbonyl-vanadium] (4 b±12 b): In analogy to the pro-
Table 3 Crystal and Refinement Dataa)
Compound
[CpV(CO)2(l-TeMe)]2 (6 a)
16H16O4Te2V2
[Cp*V(CO)2(l-TePh)]2 (9 b)
[Cp*Ta(CO)2(l-SPh)]2 (7 c)
Formula
M
C
C36H40O4Te2V2
893.8
C36H40O4S2Ta2
962.7
629.4
Space group
Crystal system
a/pm
b/pm
c/pm
P21/n
P21/n
monoclinic
958.1(2)
2054.8(4)
1840.6(4)
99.97(3)
3568.9(13)
4
Pbca
monoclinic
851.8(2)
1689.2(3)
1376.3(3)
107.70(3)
1886.6(7)
4
orthorhombic
1578.8(2)
2059.0(2)
2121.1(2)
±
6895.0(13)
8
1.855
b/°
V (106 pm3)
Z
Dcalc (g ´ cm±3
)
2.216
1.663
F(000)
1176
1752
3728
Crystal size (mm)
Crystal colour
Crystal shape
0.22 ´ 0.25 ´ 0.20
dark red
isometric
173
0.45 ´ 0.20 ´ 0.18
0.35 ´ 0.18 ´ 0.15
dark red
red
prism
296
irregular
296
Temperature/K
Absorption correction
empirical (w-scans)
2.162
0.3097/0.3660
3.0±50.0
8124
6254
5147 (F > 2r(F))
SHELXTL-PLUS V. 4.2
0.043/0.035
0.62/±0.47
l(MoKa)/mm±1
4.038
6.501
0.3078/0.6166
3.0±60.0
12625
9947
Min./max. transmission factors
2h Range/°
0.1235/0.1674
2.0±50.0
4491
3321
3321
Collected reflections
Independent reflections
Observed reflections
Solution/Refinement
R/wR (w±1 = r2(F))
Max./min. residual electron
7442 (F > 2r(F))
0.032/0.023
1.13/±0.67
0.051/0.029
1.02/±1.77
density (e ´ 10±6 pm±3
)
a)
Full details of the crystal structure determinations (except structure factors) have been deposited under the numbers CCDC 135372 (6 a), -135373 (9 b),
and -135374 (7 c) at the Cambridge Crystallographic Data Centre. Copies may be obtained free of charge from: The Director, CCDC, 12 Union Road,
GB-Cambridge CB2 1EZ (Telefax: Int. + 12 23/3 36-0 33; E-mail: deposit@ccdc.cam.ac.uk)
1294
Z. Anorg. Allg. Chem. 2000, 626, 1289±1295

Binuclear CpV, Cp*V, and Cp*Ta Complexes containing Organochalcogenolato Bridges
cedure described for the syntheses of 4 a±12 a, a THF solu-
tion (50 ml) of 300 mg Cp*V(CO)4 (2) was used for the
photo-induced preparation of the Cp*V complexes 4 b±12 b.
The products were eluted from the silica column in an or-
ange to red zone. For spectroscopic data and yields see Ta-
ble 1.
[4] L. Y. Goh, M. S. Tay, T. C. W. Mak, R.-J. Wang, Organo-
metallics 1992, 11, 1711.
[5] L. Y. Goh, M. S. Tay, C. Wei, Organometallics 1994, 13,
1813.
[6] R. D. Adams, D. F. Chodosh, E. Faraci, Cryst. Struct.
Commun. 1978, 7, 145.
Bis[(l-organylchalcogenolato)-pentamethylcyclopentadie-
nyl-dicarbonyl-tantalum] (4 c±14 c): The complexes 7 c±14 c
were prepared in the usual way by irradiation of a solution
containing 430 mg (1 mmol) Cp*Ta(CO)4 (3) and the appro-
priate amount of E2R2 (1±2 mmol) in 100 ml hexane. The
evolution of gas (CO) was followed until 1 mmol (25 ml)
had been collected, then the solvent was removed under
vacuum and the residue purified by column chromatography
on silica. In general, the complexes were isolated as red
solids.
The methylchalcogenolato complexes (4 c±6 c) could not
be chromatographed due to their easy decomposition with
concomitant reformation of E2M2. 4 c was only studied in
the NMR tube, whereas 5 c and 6 c were synthesized as de-
scribed above, but the precipitates were only washed repeat-
edly using hexane.
Bis[di(l-organylchalcogenolato)-cyclopentadienylvanadium]
(5 d, 6 d, 8 d±11 d) and bis[di(l-organylchalcogenolato)-pen-
tamethylcyclopentadienylvanadium] (4 e±9 e, 12 e). The car-
bonyl-containing dimers described above were decarbony-
lated in the presence of an excess of E2R2 in boiling toluene
solution. In general, 50±100 mg [Cp()V(CO)2(l-ER)]2 and an
excess of E2R2 in 15±20 ml toluene were held under reflux
for 15±60 min. The gas evolution (CO) was accompanied by
a colour change from red or violet to brown. The solvent
was removed under vacuum and the excess of E2R2 removed
by repeated washing with pentane. The black, paramagnetic
products were identified by their EI mass spectra. The mole-
cular ion (M+) was observed in all cases, but its intensity
decreased with increasing size of R, e. g. [CpV(l-SeR)2]2
(R = Me (5 d), m/e = 610 (M+), Irel = 90%; R = Ph (8 d),
m/e = 858 (M+), 10%; R = Fc (11 d), m/e = 1288 (M+), 5%.
The nature of the heaviest compound, [Cp*V(l-TeFc)2]2
(12 e) was confirmed by FD-MS, m/e = 1622 (M+, 100%), to
have the correct isotope pattern.
[7] I. B. Benson, S. D. Killops, S. A. R. Knox, A. J. Welch,
J. Chem. Soc. Chem. Commun. 1980, 1137.
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[10] M. Herberhold, M. Kuhnlein, W. Kremnitz, A. L. Rhein-
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[11] W. A. Herrmann, H. Biersack, M. L. Ziegler, B. Bal-
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[14] M. Herberhold, M. Keller, W. Kremnitz, T. Daniel,
W. Milius, B. Wrackmeyer, H. NoÈth, Z. Anorg. Allg.
Chem. 1998, 624, 1324.
[15] G. Ferguson, C. Hannaway, K. M. S. Islam, J. Chem.
Soc., Chem. Commun. 1968, 1165.
[16] N. G. Connelly, L. F. Dahl, J. Am. Chem. Soc. 1970, 92,
7472.
[17] L.-C. Song, J.-Q. Wang, Q.-M. Hu, R.-J. Wang, T. C. W.
Mak, Inorg. Chim. Acta 1997, 256, 129.
[18] R. H. Holm, R. B. King, F. G. A. Stone, Inorg. Chem.
1963, 2, 219.
[19] F. Y. PeÂtillon, J. L. Le Quere, J. E. Guerchais, Inorg.
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We thank Prof. A. L. Rheingold (Univ. of Delaware, USA)
for structural studies, Dr. Silke Gerstmann (Hamburg) for
numerous NMR measurements and helpful discussions,
Dr. Karl Úfele and Dr. Peter HaÈrter (MuÈnchen) for the
synthesis of Cp*Ta(CO)4 under high pressure. We are partic-
ularly grateful to the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie for continuous support
of our research.
[23] O. A. Rajan, M. McKenna, J. Noordik, R. C. Haltiwan-
ger, M. Rakowski DuBois, Organometallics 1984, 3, 831.
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Z. Anorg. Allg. Chem. 2000, 626, 1289±1295
1295