Reactivity of the unsaturated triosmium cluster [(μ-H)Os3(CO)8{Ph2PCH2P(Ph)C 6H4}] with dithiols; X-ray structures of [Os3(CO)8(μ-SCH2CH2CH 2S)(Ph2PCH2PPh2)]·1/2CH 2Cl2

Article abstract of DOI:10.1016/S0022-328X(00)00901-3

Treatment of the unsaturated cluster [(μ-H)Os₃(CO)₈{Ph₂PCH₂P(Ph)C ₆H₄}] (1) with HS(CH₂)_nSH (n=1, 1,2-ethanedithiol; n=2, 1,3-propanedithiol) lead to the novel compounds [(μ-H)Os₃(CO)₈{μ-S(CH₂) _nS}{Ph₂PCH₂P(Ph)C₆H₄}] (9, n=2, 49%; 12, n=3, 56%) and [Os₃(CO)₈{μ-S(CH₂)_nS} (μ-Ph₂PCH₂PPh₂)] (10, n=2, 20%; 13, n=3, 22%). The 52-electron compounds 9 and 12 contain a bridging hydride, a bridging dithiolato and an orthometallated dppm ligand while the 50-electron compounds 10 and 13 contain a doubly bridging dithiolato and a bridging dppm ligand. Compounds 9 and 12 are converted into 10 and 13 in 55 and 56% yields, respectively, by thermolysis at 110°C. Photolysis of 9 and 12 also gives 10 and 13 but in somewhat lower yields. Compounds 10 and 13 undergo decarbonylation and aliphatic C-H bond activation of the dithiolato moiety at 128°C to give [(μ-H)Os₃(CO)₇(μ₃-η ³-SCH₂CHS)(Ph₂PCH₂PPh₂] (11) and [(μ-H)Os₃(CO)₇(μ₃-η ³-SCH₂CH₂CHS)(Ph₂PCH ₂PPh₂] (14) containing a bridging hydride, a triply bridging dithiolato and a bridging dppm ligand. Thermolysis of 9 and 12 at 128°C also gives 11 and 14 in 43 and 51% yields, respectively. Compounds 13 and 14 have been characterised by X-ray crystallography.

Full text of DOI:10.1016/S0022-328X(00)00901-3

Journal of Organometallic Chemistry 625 (2001) 112–120
www.elsevier.nl/locate/jorganchem
Reactivity of the unsaturated triosmium cluster
[(m-H)Os3(CO)8{Ph2PCH2P(Ph)C6H4}] with dithiols; X-ray
structures of
[Os3(CO)8(m-SCH2CH2CH2S)(Ph2PCH2PPh2)]·1/2CH2Cl2 and
[(m-H)Os3(CO)7(m3-h3-SCH2CH2CHS)(Ph2PCH2PPh2)]·1/2H2O
Shariff E. Kabir a, Caroline A. Johns b, K.M. Abdul Malik b,*, M. Abdul Mottalib a,
Edward Rosenberg c
a Department of Chemistry, Jahangirnagar Uni6ersity, Sa6ar, Dhaka 1342, Bangladesh
b Department of Chemistry, Cardiff Uni6ersity, PO Box 912, Park Place, Cardiff CF10 3TB, UK
c Department of Chemistry, The Uni6ersity of Montana, Missoula, MT 59812, USA
Received 2 October 2000; received in revised form 15 November 2000; accepted 15 November 2000
Abstract
Treatment of the unsaturated cluster [(m-H)Os3(CO)8{Ph2PCH2P(Ph)C6H4}] (1) with HS(CH2)nSH (n=1, 1,2-ethanedithiol;
n=2, 1,3-propanedithiol) lead to the novel compounds [(m-H)Os3(CO)8{m-S(CH2)nS}{Ph2PCH2P(Ph)C6H4}] (9, n=2, 49%; 12,
n=3, 56%) and [Os3(CO)8{m-S(CH2)nS} (m-Ph2PCH2PPh2)] (10, n=2, 20%; 13, n=3, 22%). The 52-electron compounds 9 and
12 contain a bridging hydride, a bridging dithiolato and an orthometallated dppm ligand while the 50-electron compounds 10 and
13 contain a doubly bridging dithiolato and a bridging dppm ligand. Compounds 9 and 12 are converted into 10 and 13 in 55
and 56% yields, respectively, by thermolysis at 110°C. Photolysis of 9 and 12 also gives 10 and 13 but in somewhat lower yields.
Compounds 10 and 13 undergo decarbonylation and aliphatic C–H bond activation of the dithiolato moiety at 128°C to give
[(m-H)Os3(CO)7(m3-h3-SCH2CHS)(Ph2PCH2PPh2] (11) and [(m-H)Os3(CO)7(m3-h3-SCH2CH2CHS)(Ph2PCH2PPh2] (14) containing
a bridging hydride, a triply bridging dithiolato and a bridging dppm ligand. Thermolysis of 9 and 12 at 128°C also gives 11 and
14 in 43 and 51% yields, respectively. Compounds 13 and 14 have been characterised by X-ray crystallography. © 2001 Elsevier
Science B.V. All rights reserved.
Keywords: Osmium; Dithiolate; Phosphine; Carbonyl; Crystal structures
ganic thiols to give [(m-H)Os3(CO)8(m-SR)(m-dppm)]
(R=Et or Ph) in which the hydride and thiolato ligand
bridge one of the unbridged osmium–osmium edges
[4,5]. We have previously reported the reactions of the
1. Introduction
Thiolato bridged triosmium clusters of the type [(m-
H)Os3(CO)10(m-SR)] (R=Et or Ph) with the hydride
and SR bridging the same Os–Os edge have been
formed by simple oxidative addition reaction of thiols
with [Os3(CO)12] or better with [Os3(CO)10(MeCN)2]
and [Os3(CO)10(C6H8)] [1–3]. The dppm substituted
compound [Os3(CO)10(m-dppm)] and its acetonitrile
derivative [Os3(CO)9(m-dppm)(MeCN)] react with or-
unsaturated
triosmium
compound
[(m-
H)Os3(CO)8{Ph2PCH2P(Ph)C6H4}] (1) with thiols such
as ethanethiol, propane-2-thiol and thiophenol, and
observed a remarkable influence of the steric bulk of
the thiols on the type of product obtained [6]. For
example, thiophenol having the bulkiest substituent
gives only the simple oxidative addition product [(m-
H)Os3(CO)8(m-dppm)(m-SPh)] while less bulky thiols
such as ethanethiol and propane-2-thiol give the novel
50-electron compounds [(m-H)Os3(CO)8(m-SC2H5)(h1-
* Corresponding author. Tel.: +44-29-20874950; fax: +44-29-
20874030.
E-mail address: malikka@cardiff.ac.uk (K.M. Abdul Malik).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00901-3

S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
113
Scheme 1.
SC2H5){Ph2PCH2P(Ph)C6H4}]
(2)
and
[(m-
mium compound [Os2(CO)6(m-SCH2CH2S)] was ob-
tained from the pyrolysis of [{(m-H)Os3(CO)11-
(SCH2CH2SCH2CH2)] as well as from the direct reac-
tion of [Os3(CO)12] with 1,4-dithiacyclohexane [21].
Lewis et al. [22] reported [{(m-H)Os3(CO)10}2(m-
SCH2CH2CH2S)] from the reaction of the lightly lig-
H)Os3(CO)8{m-SCH (CH3)CH3}{h1-SCH(CH3)CH3}-
{Ph2PCH2P(Ph)C6H4}] (3) as the major products and
the
48
electron
species
[Os3(CO)8(m-SC2H5)-
and [Os3(CO)8(m-
(Ph2PCH2P(Ph)C6H4}]
(4)
SCH(CH3)CH3}{Ph2PCH2P(Ph)C6H4} (5) as the minor
products along with small amount of [(m-
a
ated
cluster
[Os3(CO)10(MeCN)2]
with
H)Os3(CO)8(m-dppm)(m-SEt)] in case of ethanethiol [6]
(Scheme 1).
1,3-propanedithiol. In a recent study we found that
[Ru3(CO)12] reacts with 1,2-ethanedithiol at 68°C to
afford the known compound [Ru2(CO)6(m-SCH2CH2S)]
while the analogous reaction with 1,3-propanedithiol
yields [{(m-H)Ru3(CO)10}2(m-SCH2CH2CH2S)] and
[Ru2(CO)6(m-SCH2CH2CH2S)] [23]. The bidentate dithi-
Recently we reported [7] the reactions of 1 with
organic heterocyclic thiols such as pyridine-2-thiol and
pyrimidine-2-thiol; the latter gives only simple oxidative
addition product [(m-H)Os3(CO)8(m-N2SC4H3)(m-dppm)]
in high yield while the former affords the 52-electron
compounds [H(m-H)Os3(CO)8(h2-NSC5H4){Ph2PCH2P-
(Ph)C4H4}]
(6)
and
[Os3(CO)8(m-h2-NSC5H4)-
{Ph2PCH2P(Ph)C6H4}] (7) and the simple oxidative
addition product [Os3(CO)8 (m-NSC5H4)(m-dppm)] (8)
(Scheme 2).
The use of alkanedithiolates to stabilize transition
metal cluster compounds by serving as chelating or
bridging ligands preventing cluster fragmentation dur-
ing the course of catalytic reactions has received in-
creasing attention [8–18]. Adams et al. [19] reported the
synthesis of dithiolato bridged di- and tri-metallic com-
pounds
anti-[Ru3(CO)7(m-SCH2CH2S)2],
syn-
[Ru3(CO)7(m-SCH2CH2S)2] and [Ru2(CO)6(m-SCH2-
CH2S)] from the ring opening reaction of 1,2,5,6-te-
trathiacyclooctane with [Ru3(CO)12] at 40°C. The dithi-
olato
bridged
di-iron
compound
[Fe2(CO)6-
(m-SCH2CH2S)] has been reported from the reaction of
[Fe3(CO)12] with 1,2-ethanedithiol [20] while the os-
Scheme 2.

114
S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
2. Results and discussion
Treatment of 1 with two equivalents of HS(CH2)nSH
(n=2, 1, 2-ethanedithiol; n=3, 1,3-propanedithiol) at
room temperature gave the novel compounds [(m-
H)Os3(CO)8{m-S(CH2)nS)}{Ph2PCH2P(Ph)C6H4}]
(9,
n=2, 49%; 12, n=3, 56%) and [Os3(CO)8-
{(mS(CH2)nS)(Ph2PCH2 PPh2)] (10, n=2, 20%; 13, n=
3, 22%) (Scheme 3), which were characterized by spec-
troscopic methods, together with a single crystal X-ray
analysis for 13·1/2CH2Cl2.
Scheme 3.
The infrared spectra of 9 and 12 are very similar and
indicate that all the carbonyl ligands are terminal. The
13C{1H}-NMR spectra indicate the presence of eight
carbonyl groups. The aromatic regions show well sepa-
rated multiplets characteristic of orthometallated dppm
ligand, in addition to the usual resonances arising from
the methylene protons of the ligands. The high field
doublets of a doublet is assigned to the bridging hy-
dride which is coupled to two nonequivalent 31P nuclei.
Futhermore, the appearance of the hydride resonances
as a doublet of doublets is indicative of the hydride
bridging the same Os–Os edge as the phosphorus
atoms of the orthometallated dppm ligand. The
31P{1H}-NMR spectra show two doublets indicating
that the two phosphorus nuclei are nonequivalent. The
mass spectra contain molecular ion peaks and fragment
ions formed by the loss of up to eight CO ligands.
Assuming that the dithiolato ligand serves as a six-elec-
tron donor and the orthometallated diphosphine ligand
donates five electron, the molecule contains a total of
52 valence electrons and in the presence of one metal-
metal bond each metal atom formally obeys the 18-elec-
tron rule. The dithiolato ligand bridges one of the open
osmium-osmium edges with each sulfur atom bonded to
both metal atoms. The coordination of the dithiolato
ligands in these compounds is very similar to that
observed in the compounds [Os2(CO)6(m-SCH2CH2S)]
and [Os3(CO)10(m-SCH2CH2S)] [21].
Fig. 1. X-ray structure of [Os3(CO)8{m-S(CH2)3S} (m-Ph2PCH2PPh2)]
(13) showing the atom numbering scheme. Thermal ellipsoids are
drawn at 40% probability level. The hydrogen atoms are omitted for
clarity.
olato ligands in these complexes are generally robust
and lend stability of these complexes. We also investi-
gated the reaction of diphosphine substituted triruthe-
The X-ray structure of 13 is depicted in Fig. 1, and
selected bond distances and angles are listed in Table 1.
It is based on an Os3 unit with two metal-metal bonds,
nium
compounds
[Ru3(CO)10(m-dppm)]
and
Os(1)–Os(3)=2.8790(12)
and
Os(2)–Os(3)=
[Ru3(CO)10(m-dppe)] with dithiols and observed that the
product formation depends on the length of the methyl-
ene chain of the diphosphine ligand [24]. For example,
the reaction of [Ru3(CO)10(m-dppm)] with 1,3-
,
2.9031(10) A, and
a non-bonded separation of
,
3.4252(11) A between Os(1) and Os(2). The metal–
metal bonded distances in this complex are close to the
,
average value 2.877 A in [Os3(CO)12] [25] and the
propanedithiol
[Ru2(CO)4{m-S(CH2)3S}(m-dppm)] while [Ru3(CO)10(m-
dppe)] gives the trinuclear complexes [(m-
gives
the
dinuclear
product
non-bonded distance is somewhat longer than those in
,
the related doubly bridged complexes, 3.365(1) A in
,
[Os3(CO)10(m-SCH2CH2S)] [21] and 3.233(2)
A in
H)Ru3(CO)8{m-S(CH2)3SH}(m-dppe)] and [Ru3(CO)5-
{m-S(CH2)3S}2 (h2-dppe)]. In the present paper we de-
scribe the results of our studies on the reactions of 1
with dithiols, including an unprecedented C-H bond
activation of the methylene group of the coordinated
dithiolato ligand.
[Os3(CO)10(m-Cl)2] [26]. The structure contains eight
terminal carbonyl groups, a bridging demetallated
dppm ligand and a bridging dithiolato moiety. Os(1)
and Os(3) are each associated with three and Os(2) is
linked to two terminal carbonyl ligands. The 1,3-
propanedithiolato ligand forms two bridges between

S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
115
contains a total of 50 valence electrons and in the
presence of two metal–metal bonds, each metal atom
formally achieves an 18-electron configuration.
the pair of non-bonded osmium atoms through the S
atoms and serves as a six-electron donor. The dppm
ligand bridges one of the metal–metal bonded edges
and acts as a four-electron donor. It is observed that
the dppm bridged Os–Os bond is considerably longer
than the unbridged bond. The two Os–P bonds are
The spectroscopic data of 13 are consistent with its
crystal structure. The infrared spectrum indicates the
presence of eight terminal carbonyl ligands, and the
1H-NMR spectrum contains four multiplets for the
methylene protons, in addition to the usual resonances
arising from the phenyl protons of the dppm ligand. No
signals have been observed in the bridging hydride
region. The 31P{1H}-NMR spectrum shows two dou-
blets indicating that the two phosphorus atoms are
nonequivalent. The 13C{1H}-NMR spectrum indicates
,
different, with the Os(2)–P(1) distance of 2.346(4) A
being slightly longer than the Os(3)–P(2) distance of
,
2.322(4) A. This is presumably a consequences of the
extra electron density on Os(2) due to the thiolato
bridge. The Os–S–Os bridges are nearly symmetrical
with Os–S distances lying in the narrow range
,
2.435(4)–2.467(4) A and these values are similar to
1
the presence of eight carbonyl ligands. The IR, H-,
those reported for the related osmium and ruthenium
complexes [19,21]. The Os(1)–S(1)/S(2)–Os(2) angles
[88.14(14)/89.25(14)°] are nearly identical. The molecule
31P{1H}- and 13C{1H}-NMR spectra of 10 are very
similar to those of 13, suggesting that the compounds
are structurally similar.
It is known that trimetallic clusters with only one or
two metal–metal bonds undergo decarbonylation by
both thermal and photochemical methods. We there-
fore explored the thermal and photochemical reactivity
of 9 and 12 to see if one or both of their Os–Os bonds
could be reformed by removal of one or two carbonyl
ligands respectively. Thermolysis of 9 and 12 in reflux-
ing toluene followed by the usual chromatographic
work up gave the demetallated compounds
[Os3(CO)8(m-SCH2CH2S)(Ph2PCH2PPh2)] (10) and
[Os3(CO)8(m-SCH2CH2CH2S)(Ph2PCH2PPh2)] (13) re-
sulting from the transfer of the bridging hydride to the
orthometallated phenyl ring of the dppm ligand fol-
lowed by reformation of one of the metal–metal bonds.
Compounds 10 and 13 were also formed in the initial
reactions of 1 with HS(CH2)nSH at 25°C. It was also
noted that the compounds 9 and 12 could be converted
into 10 and 13 at 110°C but not at an appreciable rate
under the conditions of the original preparation at
25°C. It thus appears that the products in the original
reaction were formed by different routes.
Table 1
,
Selected bond lengths (A) and bond angles (°) for 13
Bond lengths
Os(1)–Os(3)
Os(1)–S(2)
Os(2)–P(1)
Os(2)–S(1)
S(1)–C(9)
P(1)–C(12)
P(1)–C(19)
P(2)–C(25)
2.8790(12)Os(2)–Os(3)
2.441(4) Os(1)–S(1)
2.346(4) Os(2)–S(2)
2.467(4) Os(3)–P(2)
2.9031(10)
2.457(4)
2.435(4)
2.322(4)
1.79(2)
1.845(8)
1.848(14)
1.832(10)
1.85(2)
S(2)–C(11)
1.793(14) P(1)–C(13)
1.796(9) P(2)–C(12)
1.856(9) P(2)–C(31)
Bond angles
Os(1)–Os(3)–Os(2)
S(2)–Os(2)–S(1)
P(1)–Os(2)–S(1)
C(9)–S(1)–Os(2)
C(11)–S(2)–Os(2)
Os(2)–S(2)–Os(1)
72.65(3)
76.92(14 P(1)–Os(2)–S(2)
102.09(14) C(9)–S(1)–Os(1)
104.8(5)
106.8(6)
89.25(14)
S(2)–Os(1)–S(1)
77.01(14)
168.14(14)
107.3(6)
Os(1)–S(1)–Os(2)
88.14(14)
C(11)–S(2)–Os(1) 107.6(7)
The decarbonylation reactions of 10 and 13 were
investigated to see if the open Os–Os edge in these
compounds could be reformed by the removal of CO. It
was found that the decarbonylation of 10 and 13 in
refluxing octane at 128°C gave the methylene activated
products 11 and 14, which were characterized by spec-
troscopic methods together with a single crystal struc-
ture analysis for 14·1/2H2O (Scheme 4).
The solid state structure of 14 is shown in Fig. 2, and
selected bond distances and angles are collected in
Table 2. Only one of the two independent complex
molecules is shown in this figure; the other independent
molecule has the same structure with very similar ge-
ometry parameters. For the sake of brevity, the follow-
ing discussion is based on the parameters of molecule 1
only. The structure of 14 consists of an Os3 triangle
with two metal–metal bonds [Os(1)–Os(3)=2.863(2),
Scheme 4.
,
Os(2)–Os(3)=2.9724(13) A] and a non bonded separa-

116
S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
,
tion of 3.822(2) A along Os(1)···Os(2). The molecule
contains seven terminal carbonyl ligands, a bridging
hydride ligand, a bridging dppm ligand, and a triply
bridging m3-h3-SCH2CH2CHS grouping formed by the
activation of methylene C–H bond of the coordinated
m-SCH2CH2CH2S ligand. Due to poor crystal quality,
we were unable to locate the bridging hydride from
difference map, but its presence along the Os(2)–Os(3)
edge was indicated by spectroscopic data [27,28]. This
conclusion is further supported by carbonyl ligand dis-
tribution. Thus the much wider Os(3)–Os(2)–C(4) and
Os(2)–Os(3)–C(6) angles, 121.3(8) and 117.2(9)°, re-
spectively, compared with Os(3)–Os(1)–C(1)/C(2) and
Os(1)–Os(3)–C(6)/C(7) angles 90.3(8)/88.2(8) and
97.1(9)/93.0(7)°, respectively, are consistent with the
presence of a bridging hydride along the Os(2)–Os(3)
edge on the opposite side of the S(1) bridge. In 14, the
,
bridged Os(2)–Os(3) bond 2.9724(13) A is significantly
longer than the corresponding bond 2.9031(10) in 13,
Fig. 2. X-ray structure of a single molecule of [(m-H)Os3(CO)7(m3-h3-
SCH2CH2CHS)(Ph2PCH2PPh2)] (14) showing the atom numbering
scheme. Thermal ellipsoids are drawn at 40% probability level. The
hydrogen atoms are omitted for clarity.
,
and the unbridged Os(1)–Os(3) bond 2.863(2) A is
slightly shorter than the corresponding bond 2.8790(12)
,
A in 13. The binding of the SCH2CH2CHS ligand in
the cluster is particularly interesting. The S(2) atom of
the –CH2S group forms a bridge between the pair of
non–bonded Os atoms along Os(1)···Os(2) whilst the
S(1) of the –CHS group links the dppm and hydride
bridged Os(2)–Os(3) bond which is thus triply bridged.
The C(8) atom of the –CHS moiety is also bonded to
Os(1). This type of bonding of the dithiolato ligand
(m3-h3-mode) is quite remarkable, and constitutes a
very interesting aspect of the structure of 14. The two
Os–P bond distances in 14 [Os(2)–P(1)=2.358(6),
Table 2
,
Selected bond lengths (A) and bond angles (°) for 14
Molecule 1
Molecule 2
Bond lengths
Os(1)–Os(3)
Os(2)–Os(3)
Os(1)–C(8)
Os(1)–S(2)
Os(2)–P(1)
Os(2)–S(2)
Os(2)–S(1)
Os(3)–P(2)
Os(3)–S(1)
S(1)–C(8)
2.863(2)
2.9724(13)
2.21(2)
2.441(6)
2.358(6)
2.420(6)
2.424(5)
2.337(6)
2.406(6)
1.81(2)
2.8692(14)
2.986(2)
2.07(2)
2.425(6)
2.360(6)
2.424(6)
2.435(5)
2.360(6)
2.388(6)
1.85(2)
,
Os(3)–P(2)=2.337(6) A] show only minor differences
and are comparable with the values found in 13
,
[2.346(4), 2.322(4) A] and [Os3(CO)10(m-dppm)]
,
[2.331(3), 2.308(3) A} [29]
The m3-h3-SCH2CH2CHS ligand serves as a seven
electron donor and bridging dppm acts as a four elec-
tron donor; the molecule contains a total of 50 valence
electrons and in the presence of two metal–metal
bonds, each metal atom formally achieves an 18-elec-
tron configuration. The osmium–methyne carbon bond
S(2)–C(10)
1.74(2)
1.77(2)
Bond angles
C(2)–Os(1)–Os(3)
C(1)–Os(1)–Os(3)
S(2)–Os(1)–Os(3)
P(1)–Os(2)–S(2)
P(1)–Os(2)–S(1)
S(2)–Os(2)–S(1)
C(4)–Os(2)–Os(3)
P(2)–Os(3)–S(1)
C(6)–Os(3)–Os(1)
P(2)–Os(3)–Os(1)
S(1)–Os(3)–Os(1)
C(6)–Os(3)–Os(2)
Os(1)–Os(3)–Os(2)
C(8)–S(1)–Os(3)
C(8)–S(1)–Os(2)
Os(3)–S(1)–Os(2)
C(10)–S(2)–Os(2)
C(10)–S(2)–Os(1)
Os(2)–S(2)–Os(1)
88.2(8)
90.3(8)
86.13(14)
173.4(2)
94.3(2)
86.0(2)
121.3(8)
98.6(2)
89.2(7)
88.6(8)
87.58(14)
174.3(2)
94.1(2)
85.3(2)
118.6(8)
98.0(2)
,
distance, Os(1)–C(8)=2.21(2) A, is comparable to
,
those in the related compounds, e.g. 2.23(2) A in
,
[Os3(CO)11{m–SC(H)PhCH2CHPh}] [30], 2.19(2) A in
[(m-H)2Os3(CO)9(m3-h2-CHCꢀNCH2CH2CH3)]
[31],
97.1(9)
94.4(8)
171.19(14)
73.50(14)
117.2(9)
81.81(4)
100.9(7)
106.1(8)
76.0(2)
105.4(8)
94.8(8)
103.7(2)
171.3(2)
74.08(13)
116.9(8)
81.15(4)
95.8(8)
104.8(7)
76.5(2)
106.5(8)
96.7(7)
,
2.229(11)
A
in [(m-H)2Os3(CO)7(CNPr){Ph2PCHP-
,
(Ph)C6H4}] [32] and 2.229(7) A in [(m-H)Ru3(CO)7{m3-
h4-PhPCHP(Ph)C6H4}(dppm)] [33]. Another notable
feature of the structure is the severe compression of the
metal chain from a linear arrangement; thus the Os(1)–
Os(3)–Os(2) angle narrows down to only 81.81(4)°, and
this is undoubtedly due to the bridging ligands between
non-bonded pair of osmium atoms. Similar distortions
in the Os–Os–Os angles from linearity have been re-
103.5(2)

S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
117
ported for other triosmium clusters containing two
metal–metal bonds, one of which is bridged by an
organic ligand. Examples of such compounds include
[Os3(CO)11{m-SC(H)PhCH2CHPh}] [84.06(5)°] [30] and
[H(m-H)Os3(CO)7(m-dppm)(m-PPh2)2] [82.99(2)°] [34].
The Os-S bond distances [Os(2)-S(1)=2.424(5), Os(3)-
S(1)=2.406(5), Os(1)-S(2)=2.441(5) and Os(2)–
that 10 and 13 can be converted into 11 and 14 in
moderate yields. This indicates that the formation 11
and 14 from the thermolysis of 9 and 12 takes place via
the intermediate formation of 10 and 13. It thus ap-
pears that in the original reactions, the compounds 10
and 13 are formed by two competing reactions involv-
ing two different processes.
,
S(2)=2.420(6) A] in 14 are similar to those reported
for [30],
[Os3(CO)11{m-SC(H)PhCH2CHPh}]
[Os3(CO)10(m-SCH2CH2S)] [21] and [Ru3(CO)7{m-
S(CH2)3S}2] [19].
3. Experimental
The spectroscopic data of 14 are in accord with its
X-ray structure. The H-NMR spectrum shows seven
All reactions were carried out under nitrogen using
standard Schlenk techniques. Solvents were dried over
appropriate drying agents, distilled under nitrogen and
degassed prior to use. Infrared spectra were recorded
on a Shimadzu FTIR-8101 spectrophotometer. NMR
spectra were recorded on a Varian Unity Plus 400 MHz
and ARX 250 MHz spectrometers. Elemental analyses
were performed by the Schwarzkopf Microanalytical
Laboratories, New York. 1,2-Ethanedithol and 1,3-
propanedithiol were purchased from Aldrich and used
as received. The cluster [(m-H)Os3(CO)8{Ph2PCH2P-
(Ph)C6H4}] was prepared according to the published
procedure [35].
1
equal intensity multiplets for seven different protons of
thiolato and dppm ligands and one multiplet due to the
phenyl protons of the dppm ligand. The hydride region
contains a triplet implying that intra-molecular activa-
tion of a C–H bond had occurred in the cluster. The
hydride resonance appears as a triplet because it is
coupled equally to the two phosphorus atoms. The
spectroscopic data of 11 are very similar to that 14
indicating that they are structurally similar. The
31P{1H}-NMR spectrum of 14 shows two doublets
corresponding to two nonequivalent phosphorus atoms.
The mass spectrum of 14 shows the molecular ion peak
and the fragmentation pattern consistent with the loss
of seven CO groups. Compounds 11 and 14 have also
been synthesized by direct decarbonylation of 10 and 12
at 128°C. It is thus observed that formation of 11 and
14 takes place via the intermediate formation of 10 and
13.
3.1. Reaction of [(v-H)Os3(CO)8{Ph2PCH2P-
(Ph)C6H4}] (1) with 1,3-propanedithiol
To a CH2Cl2 solution (50 cm3) of 1 (0.140 g, 0.119
mmol) was added 1,3-propanedithiol (0.026 g, 0.238
mmol) and the reaction mixture was stirred at room
temperature for 18 h during which time the color
changed from green to yellow. The solvent was re-
moved under reduced pressure and the residue chro-
matographed by TLC on silica gel. Elution with
hexane/CH2Cl2 (1:1, v/v) developed two bands. The
In summary, the reactivity of 1 with dithiols is
smooth and remarkable, and provides access to two
types of novel open triosmium compounds; (a) the 52
electrons compounds [(m-H)Os3(CO)8(m-SCH2CH2S)-
{Ph2PCH2P(Ph)C6H4}] (9) and [(m-H)Os3(CO)8(m-
SCH2CH2CH2S){Ph2PCH2P(Ph)C6H4}] (12), contain-
ing a bridging dithiolato, a bridging hydride and an
orthometallated dppm ligand, and (b) the 50-electron
compounds [Os3(CO)8(m-SCH2CH2S)(Ph2PCH2PPh2)]
(10) and [Os3(CO)8(m-SCH2CH2CH2S)(Ph2PCH2PPh2)]
(13) containing a bridging dppm and a bridging dithio-
lato ligand. Compounds 9 and 12 can be converted into
10 and 13 at 110°C or by photolysis but not under the
conditions of the original preparation, at 25°C. How-
ever, the reaction conditions for the transformation of 9
and 11 to 10 and 13 are considerably more forcing than
those used in the original reactions. When heated to
128°C, 9 and 10 undergo decarbonylation to yield the
faster
moving
band
yielded
[Os3(CO)8(m-
SCH2CH2CH2S)(Ph2PCH2PPh2)] (13) 1/2CH2Cl2 (0.033
g, 22%) as yellow crystals after recrystallization from
hexane/CH2Cl2 at
−20°C (Anal. Calc. for
C36H28O8Os3P2S2, 1/2CH2Cl2: C, 33.02; H, 2.20.
Found: C, 33.15; H, 2.32%). IR (wCO, CH2Cl2): 2064
vs, 2012 m, 1987 vs, 1958 w, 1944 m, 1919 w cm−1
;
1H-NMR (400 MHz, CDCl3): l 7.40 (m, 20H), 4.87 (m,
1H), 4.17 (m, 1H), 3.09 (m, 4H), 2.42 (m, 2H); 31P{1H}-
NMR (CDCl3): l 13.0 (d), −2.6 (d), J=78.2 Hz;
13C{1H}-NMR (CDCl3): l 188.7 (dd, J=7.4, 3.8 Hz
1C), 186.8 (dd, J=7.5, 4.0 Hz, 1C), 185.8 (d, J=5.3
Hz, 1C), 183.6 (s, 1C), 181.4 (s, 1C), 180.9 (s, 1C), 174.7
(d, J=5.4 Hz, 1C), 169.8 (dd, J=7.2, 3.4 Hz, 1C);
mass spectrum (m/z): 1284 [M]+. The second band
gave [(m-H)Os3(CO)8(m-SCH2CH2CH2S) {Ph2PCH2P-
(Ph)C6H4}] (12) (0.086 g, 56%) as yellow crystals after
recrystallization from hexane/CH2Cl2 at −20°C (Anal.
Calc. for C36H28O8Os3P2S2: C, 33.64; H, 2.20. Found:
unprecedented
complexes
[(m-H)Os3(CO)7{m3-h3-
SCH2CHS}{Ph2PCH2P(Ph)C6H4}] (11) and [(m-
H)Os3(CO)7{m3 - h3 - SCH2CH2CHS}{Ph2PCH2P(Ph)-
C6H4}] (14). Compounds 11 and 14 are formed by
converting the doubly bridging dithiolato ligand into a
hydride and a triply bridging S(CH2)nCHS ligand by
the cleavage of methylene C–H bond. Our studies show

118
S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
C, 33.58; H, 2.15%). IR(wCO, CH2Cl2): 2107 s, 2029 v,
2008 m, 1994 w,1990 w,1967 m, 1940 w cm−1 1H-
NMR(400 MHz, CDCl3): l 6.69, (m, 2H), 6.89 (m,
2H), 7.08 (m, 1H), 7.41 (m, 11H), 7.65 (m, 2H), 8.13
(m, 1H), 2.94 (m, 2H), 2.77 (m, 4H), 2.45 (m, 1H), 2.30
(m, 1H), −14.72 (dd, 1H, J=9.2 and 4.4 Hz);
31P{1H}-NMR (CDCl3): l −2.7 (d), −16.0 (d), J=
61.5 Hz; 13C{1H}-NMR (CDCl3): l 186.2 (s, 1C), 183.0
(m, 2C), 178.6 (m, 2C), 172.0 (m, 2C), 165.8 (d, J=1.8
Hz, 1C); mass spectrum (m/z): 1284 [M]+.
CH2Cl2 (50 cm3) for 19 h followed by similar chromato-
graphic separation gave [Os3(CO)8(m-
SCH2CH2S)(Ph2PCH2PPh2)] (10) (0.032 g, 20%) as
yellow crystals after recrystallization from hexane/
CH2Cl2 at −20°C (Anal. Calc. for C35H26O8Os3P2S2:
C, 33.06; H, 2.07. Found: C, 33.19; H, 2.17%); IR
(wCO, CH2Cl2): 2066 vs, 2011 m, 1988 vs, 1963 w, 1940
1
m, 1921 w cm−1; H-NMR (400 MHz, CDCl3): l 7.37
(m, 20H), 4.93 (m, 1H), 4.0 (m, 1H), 3.43 (m, 4H);
31P{1H}-NMR (CDCl3): l 12.9 (d), −2.2 (d), J=78.0
Hz; mass spectrum (m/z): 1270 [M]+ and [(m-
H)Os3(CO)8(m-SCH2CH2S){Ph2PCH2P(Ph)C6H4}] (9)
(0.080 g, 49%) as yellow crystals from hexane/CH2Cl2
at −20°C (Anal. Calc. for C35H26O8Os3P2S2: C, 33.06;
H, 2.07. Found: C, 33.25; H, 2.22%). IR (wCO,CH2Cl2):
2106 s, 2032 vs, 2009 m, 1995 w, 1970 m, 1942 m, 1915
3.2. Thermolysis of [(v-H)Os3(CO)8-
(v-SCH2CH2CH2S){Ph2PCH2P(Ph)C6H4}] (12)
3.2.1. At 110°C
A toluene solution (20 cm3) of 13 (0.070 g, 0.054
mmol) was refluxed at 110°C for 3 h. The solvent was
removed under reduced pressure and the residue was
chromatographed by TLC on silica gel. Elution with
hexane/CH2Cl2 (3:2, v/v) gave a single band which
afforded [Os3(CO)8(m-SCH2CH2CH2S)(Ph2PCH2PPh2)]
(13) 1/2CH2Cl2 (0.039 g, 56%) as yellow crystals after
recrystallization from hexane/CH2Cl2 at −20°C.
1
w cm−1; H-NMR (400 MHz, CDCl3): l 6.54 (m, 2H),
6.80 (m, 2H), 7.02 (m, 1H), 7.29 (m, 10H), 7.49 (m,
1H), 7.78 (m, 2H), 8.16 (m, 1H), 3.04 (m, 2H), 2.92 (m,
2H), 2.43 (m, 1H), 2.37 (m, 1H), −14.75 (dd, 1H,
J=9.2, 4.4 Hz); 31P{1H}-NMR (CDCl3): l 1.9 (d),
−13.5 (d), J=66.7, Hz; 13C{1H}-NMR (CDCl3): l
186.0 (s, 1C), 182.6 (m, 2C), 178.8 (m, 2C), 172.0 (m,
2C), 165.7 (d, J=1.5 Hz, 1C); mass spectrum (m/z):
1270 [M]+.
3.2.2. At 128°C
A similar thermolysis of 12 (0.075 g, 0.058 mmol) in
octane (20 cm3) at 128°C for 4 h followed by similar
chromatographic separation gave two bands. The faster
moving band gave too small an amount for complete
characterization. The second band gave [(m-
H)Os3(CO)7(m3-h3-SCH2CH2CHS)(Ph2PCH2PPh2)] (14)
1/2H2O (0.037, 51%) as yellow crystals after recrystal-
lization from CH2Cl2/hexane at −20°C (Anal. Calc.
for C35H28O7Os3P2S2·1/2H2O; C, 33.19; H, 2.31.
Found: C, 33.32; H, 2.48%). IR (wCO, CH2Cl2): 2049
3.5. Thermolysis of [(v-H)Os3(CO)8(v-SCH2CH2S)-
{Ph2PCH2P(Ph)C6H4}] (9)
3.5.1. At 110°C
A toluene solution (20 cm3) of 9 (0.070 g, 0.054
mmol) was refluxed at 110°C for 3 h. The solvent was
removed under reduced pressure and the residue was
chromatographed by TLC on silica gel. Elution with
hexane/CH2Cl2 (3:2, v/v) gave a single band which
afforded [Os3(CO)8(m-SCH2CH2S)(Ph2PCH2PPh2)] (10)
(0.039 g, 55%).
vs, 2033 s, 1987 m, 1973 vs, 1943 m, 1869 w cm−1
;
1H-NMR (250 MHz, CDCl3): l 7.21, (m, 20H), 4.22
(m, 1H), 3.73 (m, 1H), 3.27 (m, 1H), 3.07 (m, 1H), 2.63
(m, 1H), 2.41 (m, 1H), 2.17 (m, 1H), −15.91 (t, 1H,
J=6.7 Hz); 31P{1H}-NMR (CDCl3): l 14.1 (d), 2.6 (d),
J=102.6, Hz; mass spectrum (m/z): 1256 [M]+.
3.5.2. At 128°C
3.3. Thermolysis of
[Os3(CO)8(v-SCH2CH2CH2S)(Ph2PCH2PPh2)] (13)
A similar thermolysis of 9 (0.100g, 0.079 mmol) in
refluxing octane (20 cm3) at 128°C for 3 h followed by
similar chromatographic work separation a single band
An octane solution (20 cm3) of 13 (0.100 g, 0.078
mmol) was heated to reflux at 128°C for 3.5 h. A
similar chromatographic separation to that above de-
veloped two bands. The faster moving band gave too
small an amount for complete characterization while
the second band yielded 14 (0.052 g, 53%).
which
afforded
[(m-H)Os3(CO)7(m3-h3-SCH2CHS)-
(Ph2PCH2PPh2)] (11) (0.042 g, 43%) as yellow crystals
after recrystallization from hexane/CH2Cl2 at −20°C
(Anal. Calc. for C34H26O7Os3P2S2: C, 32.84; H, 2.11.
Found: C, 32.62; H, 2.02%). IR (wCO,CH2Cl2): 2048 vs,
2032 vs, 1987 m, 1971 s, 1944 m, 1867 w, cm−1
;
1H-NMR (250 MHz, CDCl3): l 7.20 (m, 20H), 4.28 (m,
1H), 3.71 (m, 1H), 3.04 (m, 1H), 2.65 (m, 1H), 2.45 (m,
1H), −15.88 (t, 1H, J=6.8 Hz); 31P{1H}-NMR
(CDCl3): l 12.9 (d), 2.2 (d), J=98.2 Hz; mass spectrum
(m/z): 1242 [M]+.
3.4. Reaction of 1 with 1,2-ethanedithiol
A similar reaction to that above of 1 (0.150 g, 0.127
mmol) and 1,2-ethanedithiol (0.024 g, 0.254 mmol) in

S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
119
3.6. Thermolysis of
3.9. X-ray crystallography
[Os3(CO)8(v-SCH2CH2S)(Ph2PCH2PPh2)] (10)
Crystallographic measurements for compounds 13·1/
2CH2Cl2 and 14·1/2H2O were made at 150 using a
FAST area detector diffractometer by following previ-
ously described procedures [36]. Both data sets were
corrected for absorption using the program DIFABS
[37]. The structures were solved by direct methods
An octane solution (20 cm3) of 10 (0.100 g, 0.078
mmol) was refluxed at 128°C for 3.5 h. A similar
chromatographic separation to that above gave 11
(0.049 g, 50%).
(
SHELX-S) [38] and refined by full-matrix least squares
on F2 using all unique data with intensities \0
SHELXL-96) [39]. Crystals of 14 contained two identical
3.7. Photolysis of [(v-H)Os3(CO)8-
(v-SCH2CH2CH2S){Ph2PCH2P(Ph)C6H4}] (9)
(
A benzene solution (90 cm3) of 9 (0.100 g, 0.079
mmol) was photolyzed by a 250 W medium pressure
mercury lamp for 1.5 h. The solvent was removed in
vacuo and the residue was chromatographed by TCL
on silica gel. Elution with hexane/CH2Cl2 (3:2, v/v)
gave three bands. The faster moving band gave 10
(0.035 g, 35%). The second band gave small quantity of
an uncharacterized compound while the third band
afforded unconsumed 9 (0.015 g).
cluster and one H2O molecules per asymmetric unit. In
13, a half-occupied CH2Cl2 solvate was present, which
,
was refined with C–Cl lengths constrained to 1.75 A
and an ISOR=0.01 restraint being used for the carbon
and three partially occupied chlorine atoms. The qual-
ity of the crystals for 14 were rather poor, but the data
enabled us to solve and refine the structure without any
ambiguity. For this structure, group values were refined
for the Os–C and C–O bonds (involving the carbonyl
ligands) and ISOR=0.01 restraints were used for a
number of carbon and oxygen atoms. The bridging
hydride in 14 could not be experimentally located, but
its presence along the dppm bridged Os(2)–Os(3) edge
was suggested from spectroscopic data and also consis-
tent with carbonyl ligand distribution on the metal
atoms.. The hydrogen atoms of the H2O and CH2Cl2
solvates in the two structures were ignored. All other
hydrogen atoms were included in calculated positions
(riding model). The phenyl rings were refined as ide-
3.8. Photolysis of [(v-H)Os3(CO)8-
(v-SCH2CH2CH2S){Ph2PCH2P(Ph)C6H4}] (12)
A similar photolysis of 12 (0.100 g, 0.078 mmol)
followed by similar chromatographic separation to that
above gave 13 (0.040 g, 40%) and 12 (0.013 g).
Table 3
Crystal data and refinement results for 13 and 14
,
alised hexagons (C–C 1.390 A, C–C–C=120.0°). Per-
tinent crystallographic data for the two complexes are
presented in Table 3.
Compound
13
14
Empirical formula
C36H28O8Os3P2S,
12(CH2Cl2)
1327.71
C35H28O7Os3P2S2,
12H2O
Formula weight
Crystal system
1266.24
Triclinic
Triclinic
4. Supplementary material
Unit cell dimensions
,
a (A)
10.072(2)
11.306(2)
20.606(3)
81.621(13)
77.26(2)
12.956(3)
16.332(4)
20.754(4)
73.76(2)
74.96(2)
68.03(3)
3851(2)
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 146216 for compound 13 and
CCDC no. 146217 for compound 14. Copies of this
information may be obtained from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
67.079(14)
2103.3(6)
3
,
(
(
Space group
Z
P1
2
P1
4
(fax:
+44-1233-336033;
e-mail:
deposit@ccdc.
v (Mo–Ka) (mm−1
Crystal size (mm)
)
8.986
10.113
cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
0.20×0.10×0.05
Yellow/plate
1.96–25.04
0.26×0.16×0.10
Yellow/prism
1.78–25.08
Crystal colour/shape
q Range for data
collection (°)
Acknowledgements
Reflections collected
Unique reflections (Rint
Data/restraints/
parameters
8803
5720 (0.0565)
5720/27/448
11590
9282 (0.0889)
9282/328/798
The support of this research by the Ministry of
Science and Technology, Bangladesh Government is
gratefully acknowledged. We are also grateful to Pro-
fessor M.B. Hursthouse (Southampton) for access to
the EPSRC supported National X-ray Data Collection
Service. ER acknowledges the National Science Foun-
dation (CHE 9625367) for partial support of this
research.
)
Goodness-of-fit on F2
Final R1/wR2 indices
(all data)
0.933
0.908
R1=0.0619/0.1142 R1=0.0727/0.1421
R1/wR2 indices
[I\2|(I)]
R1=0.0426/0.1110 R1=0.0515/0.1364

120
S.E. Kabir et al. / Journal of Organometallic Chemistry 625 (2001) 112–120
[19] R.D. Adams, J.H. Yamamoto, J. Cluster Sci. 7 (1996) 643.
References
[20] A. Shaver, P.J. Fitzpatrick, K. Steliou, I.S. Butler, J. Am. Chem.
Soc. 101 (1979) 1313.
[21] R.D. Adams, I. Chen, J.H. Yamamoto, Inorg. Chim. Acta 229
(1995) 47.
[22] H.D. Holden, B.F.G. Johnson, J. Lewis, P.R. Raithby, G. Uden,
Acta Crystallogr. Sect. C 39 (1983) 1203.
[23] K.M. Hanif, M.B. Hursthouse, S.E. Kabir, K.M.A. Malik, M.A.
Mottalib, E. Rosenberg, Polyhedron 19 (2000) 1073.
[24] S.E. Kabir, K.M.A. Malik, E. Rosenberg, T.A. Siddiquee, Inorg.
Chem. Commun. 3 (2000) 140.
[25] M.R. Churchill, B.G. DeBoer, Inorg. Chem. 16 (1977) 878.
[26] F.W.B. Einstein, T. Jones, K.G. Tyers, Acta Crystallogr. Sect. B
38 (1982) 1272.
[27] R.D. Adams, N.M. Golembeski, Inorg. Chem. 18 (1979) 1909.
[28] M.R. Churchill, B.G. Deboer, Inorg. Chem. 16 (1977) 1141.
[29] K.A. Azam, M.B. Hursthouse, S.E. Kabir, K.M.A. Malik, M.A.
Mottalib, J. Chem. Crystallogr. 29 (1999) 813.
[30] R.D. Adams, M.P. Pompeo, Organometallics 11 (1992) 103.
[31] M. Day, W. Freeman, K.I. Hardcastle, M. Tsomaki, S.E. Kabir,
T. McPhillips, E. Rosenberg, L.G. Scott, E. Wolf, Organometal-
lics 11 (1992) 3376.
[32] K.L. Lu, H.J. Chen, P.Y. Lu, S.Y. Li, F.E. Hong, S.M. Peng,
G.H. Lee, Organometallics 13 (1994) 585.
[1] E.G. Bryan, B.F.G. Johnson, J. Lewis, J. Chem. Soc. Dalton
Trans. (1977) 1328.
[2] V.F. Allen, R. Mason, P.B. Hitchcock, J. Organomet. Chem. 140
(1977) 297.
[3] M. Tachikawa, J.R. Shapely, J. Organomet. Chem. 124 (1977)
C19.
[4] K.A. Azam, S.E. Kabir, A. Miah, M.W. Day, K.I. Hardcastle,
E. Rosenberg, A.J. Deeming, J. Organomet. Chem. 435 (1992)
157.
[5] S.R. Hodge, B.F.G. Johnson, J. Lewis, P.R. Raithby, J. Chem.
Soc. Dalton Trans. (1987) 931.
[6] S.M.T. Abedin, K.A. Azam, M.B. Hursthouse, S.E. Kabir,
K.M.A. Malik, M.A. Mottalib, E. Rosenberg, J. Cluster Sci. in
press.
[7] S.E. Kabir, K.M.A. Malik, E. Molla, M.A. Mottalib, J.
Organomet. Chem. 616 (2000) 157.
[8] H. Kawaguchi, K. Tatsumi, J. Am. Chem. Soc. 117 (1995) 3885.
[9] K. Tatsumi, H. Kawaguchi, I. Matsubara, A. Nakamura, K.
Miki, N. Kasai, Inorg. Chem. 32 (1993) 2534.
[10] K.A. York, K. Folting, G. Christou, J. Chem. Soc. Chem.
Commun. (1993) 1563.
[11] J.L. Martin, J. Takats, Can. J. Chem. 67 (1989) 1914.
[12] J.K. Money, J.C. Huffman, G. Christou, Inorg. Chem. 27 (1988)
507.
[13] B. Kang, M. Hong, T. Wen, H. Liu, J. Lu, J. Cluster Sci. 6
(1995) 379.
[33] C. Bergounhou, J.-J. Bonnet, P. Fompeyrine, G. Lugan, F.
Mansilla, Organometallics 5 (1986) 60.
[34] K.A. Azam, M.B. Hursthouse, M.R. Islam, S.E Kabir, K.M.A.
Malik, R. Miah, C. Sudbrake, H. Vahrenkamp, J. Chem. Soc.
Dalton Trans. (1998) 1097.
[14] D. Sellman, M. Wille, F. Knoch, Inorg. Chem. 32 (1993) 2534.
[15] F. Jiang, Z. Huang, D. Wu, B. Kang, M. Hong, H. Liu, Inorg.
Chem. 32 (1993) 4971.
[16] F. Jiang, X. Xie, M. Hong, B. Kang, R Cao, H. Liu, J. Chem.
Soc. Dalton Trans. (1993) 1447.
[17] A. Elduque, L.A. Oro, M.T. Pinillos, A. Tiripicchio, F Ugozzoli,
J. Chem. Soc. Dalton. Trans. (1994) 385.
[18] M. Mckenna, L.L. Wright, D.J. Tanner, R.D. Haltiwanger, M.
Rakowski DuBois, J. Am. Chem. Soc. 105 (1993) 5329.
[35] J.A. Clucas, D.F. Foster, M.M. Harding, A.K. Smith, J. Chem.
Soc. Chem. Commun. (1984) 949.
[36] J.A. Darr, S.R. Drake, M.B. Hursthouse, K.M.A. Malik, Inorg.
Chem. 32 (1993) 5704.
[37] N.P.C. Walker, D. Stuart, Acta Crystallogr. Sect. A 39 (1983)
1587.
[38] G.M. Sheldrick, Acta Crystallogr. Sect. A 46 (1990) 467.
[39] G.M. Sheldrick, SHELXL-96 Program for crystal structure refine-
ment, University of Go¨ttingen, Germany, 1996.
.