Reactions of the unsaturated triosmium cluster [(μ-H)Os 3(CO)8(Ph2PCH2P(Ph)C 6H4)

Article abstract of DOI:10.1016/j.jorganchem.2005.03.041

Treatment of the electronically unsaturated cluster [(μ-H)Os ₃(CO)₈(Ph₂PCH₂P(Ph)C ₆H₄)] (1) with HCl gas at ambient temperature in dichloromethane afforded (μ-H)Os₃(CO)₈(μ-Cl)(μ- dppm) (2) and [(μ-H)Os₃(CO)₇(η¹-Cl) (μ-Cl)₂(μ-dppm)] (3). Thermolysis of 2 at 110 °C led to an isomer of 2, 4. A similar reaction of 1 with HBr gas gave [(μ-H)Os ₃(CO)₈(μ-Br)(μ-dppm)] (5) as the only product which does not isomerize at 110 °C. In sharp contrast, treatment of 1 with HF gas gave the protonated species [(μ-H)₂Os₃(CO) ₈(Ph₂PCH₂P(Ph)C₆H₄)] ⁺ (6). Treatment of 1 with CF₃CO₂H also gave cation 6 whereas CH₃CO₂H yielded [(μ-H)Os ₃(CO)₈(μ-η²-CH₃CO ₂)(μ-dppm)] (7). Structures of 2, 3, 4 and 6 were established crystallographically. In 2, both the chloride and the hydride ligands simultaneously bridge the same Os-Os edge and the dppm spans another Os-Os bond whereas in 4, all the three ligands bridge the same Os-Os edge. Compound 3 is comprised of an open Os₃ arrangement in which one chloride bridges the open Os-Os edge, another chloride and a hydride mutually bridge an Os-Os bond and the third chloride is terminally coordinated to one of the Os atoms of the dppm bridged edge. The cation 6 consists of a triangle of osmium atoms in which the shortest Os-Os edge is bridged by a hydride and the metallated phenyl ring and the longest edge is bridged by another hydride and the diphosphine ligand.

Full text of DOI:10.1016/j.jorganchem.2005.03.041

Journal of Organometallic Chemistry 690 (2005) 3044–3053
www.elsevier.com/locate/jorganchem
Reactions of the unsaturated triosmium cluster
[(l-H)Os3(CO)8(Ph2PCH2P(Ph)C6H4)] with HX
(X = Cl, Br, F, CF3CO2,CH3CO2): X-ray structures
of [(l-H)Os3(CO)7(g1-Cl)(l-Cl)2(l-dppm)],
[(l-H)2Os3(CO)8(Ph2PCH2P(Ph)C6H4)]+[CF3O]À
and the two isomers of [(l-H)Os3(CO)8(l-Cl)(l-dppm)]
a,
a
a
b
Shariff E. Kabir *, Md. Arzu Miah , Nitai C. Sarker , G.M. Golzar Hossain ,
c
Kenneth I. Hardcastle , Dalia Rokhsana , Edward Rosenberg
d
d,
*
a
Department of Chemistry, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
Department of Chemistry, Cardiff University, P.O. Box 912, Park Place, Cardiff CF10 3TB, UK
b
c
Department of Chemistry, Emory University, Atlanta, GA 30322, USA
d
Department of Chemistry, The University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
Received 10 March 2005; revised 22 March 2005; accepted 22 March 2005
Available online 11 May 2005
Abstract
Treatment of the electronically unsaturated cluster [(l-H)Os3(CO)8(Ph2PCH2P(Ph)C6H4)] (1) with HCl gas at ambient temper-
ature in dichloromethane afforded (l-H)Os3(CO)8(l-Cl)(l-dppm) (2) and [(l-H)Os3(CO)7(g1-Cl)(l-Cl)2(l-dppm)] (3). Thermolysis
of 2 at 110 ꢀC led to an isomer of 2, 4. A similar reaction of 1 with HBr gas gave [(l-H)Os3(CO)8(l-Br)(l-dppm)] (5) as the only
product which does not isomerize at 110 ꢀC. In sharp contrast, treatment of 1 with HF gas gave the protonated species [(l-
H)2Os3(CO)8(Ph2PCH2P(Ph)C6H4)]+ (6). Treatment of 1 with CF3CO2H also gave cation 6 whereas CH3CO2H yielded [(l-
H)Os3(CO)8(l-g2-CH3CO2)(l-dppm)] (7). Structures of 2, 3, 4 and 6 were established crystallographically. In 2, both the chloride
and the hydride ligands simultaneously bridge the same Os–Os edge and the dppm spans another Os–Os bond whereas in 4, all the
three ligands bridge the same Os–Os edge. Compound 3 is comprised of an open Os3 arrangement in which one chloride bridges the
open OsÁ Á ÁOs edge, another chloride and a hydride mutually bridge an Os–Os bond and the third chloride is terminally coordinated
to one of the Os atoms of the dppm bridged edge. The cation 6 consists of a triangle of osmium atoms in which the shortest Os–Os
edge is bridged by a hydride and the metallated phenyl ring and the longest edge is bridged by another hydride and the diphosphine
ligand.
ꢁ 2005 Elsevier B.V. All rights reserved.
Keywords: Triosmium clusters; Electronically unsaturated; Protic acid; Thermolysis; X-ray structures
1. Introduction
*
Corresponding authors. Tel.: +1 406 243 2592; fax: +1 406 243
The reactions of triosmium carbonyl clusters with
protic acids have been thoroughly investigated and
found to exhibit a range of reactivity patterns [1–8].
4227.
E-mail addresses: skabir_ju@yahoo.com (S.E. Kabir), edward.
rosenberg@mso.umt.edu (E. Rosenberg).
0022-328X/$ - see front matter ꢁ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.03.041

S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
3045
Most common is simple protonation to give cationic
hydrido species in which the hydride adopts a bridging
coordination site [1–5] although cleavage of a metal–
carbon [6] or a metal–metal bond [7] are known to oc-
cur as well. For example, the parent compound
[Os3(CO)12] reacts with concentrated H2SO4 to give
the cationic species [(l-H)Os3(CO)12]+ [1]. The proton-
ation of electron rich mono- and diphosphine deriva-
tives occur more readily on treatment with weaker
acids such as CF3CO2H. The unsaturated cluster [(l-
H)2Os3(CO)10] and its tertiary phosphine substituted
derivatives [(l-H)2Os3(CO)9(L)] (L = PEt3, or PPh3) re-
act with CF3CO2H to give the cationic clusters [(l-
H)3Os3(CO)10]+ and [(l-H)3Os3(CO)9L]+, respectively
[8]. The cyclometallated compound [(l-H)2Os3(CO)9-
(l3-P(C6H4)Ph)] reacts with Brønsted acids HX via a
protonation followed by anion coordination to give
the addition products [(l-H)2Os3(X)(CO)9(l-PPh2)]
(X = F, Cl, Br or CF3CO2) but with HBF4 only the
protonated complex [(l-H)3Os3(CO)9(l3-P(C6H4)Ph)]+
is obtained [9]. In some cases, stable ploynuclear spe-
cies where the acidꢀs conjugate base has coordinated
to the cluster in place of an organic ligand or a me-
tal–metal bond can be isolated. For example, Shapley
and co-workers [6] reported that the triflate compound
[(l-H)2Os3(CO)9(O3SCF3)2] reacts with CF3CO2H and
CH3CO2H to afford the mixed oxyanion ligand clus-
ters [(l-H)2Os3(CO)9(l,g2-O2CCF3)2(g1-O3SCF3)] and
[(l-H)2Os3(CO)9(l,g2-O2CCH)2(g1-O3SCF3)]. We also
reported that protonation of l-vinyloxy ligand in
[(l-H)Os3(CO)10(l-OCH@CH2)] with HX leads to the
compounds [(l-H)Os3(CO)10(l-X)] (X = Cl, CF3CO2)
with liberation of aldehyde via the intermediate addi-
tion species [(l-H)Os3(CO)10(l-OCHXCH3)] [10]. Such
acid adducts of the general formula [(l-H)Os3-
(CO)10(l-X)] (X = RCO2, halogen, MeO) are also
available from the lightly stabilized cluster [Os3-
(CO)10(MeCN)2] [11,12]. A few years ago we reported
the first example of direct adduct formation not
accompanied by ligand displacement or metal–metal
bond cleavage from the reactions of the l3-imidoyl
[Au(PPh3)]PF6 [20], EtSH [21], CH3CH(CH3)SH [21],
PhSH [21], pySH [22], HSCH2CH2SH [23], HSCH2CH2-
CH2SH [23], and Se [24] that afford many interesting
and potentially useful compounds have been investi-
gated. Our recent studies of the reactivity of 1 toward
CH2CN2 [25] and silanes [26] have uncovered some
examples of its distinctly different reactivity patterns
compared with unsaturated benzoheterocyclic trios-
mium clusters [27]. Herein, we report our results on
the investigations of the reactions of 1 with a series of
Brønsted acids. It was of interest to examine whether
structurally diverse products would also be accessible
in these systems.
2. Results and discussion
When HCl gas was bubbled through a dichlorometh-
ane solution of the electron-deficient cluster 1 at ambient
temperature for 2 min, the initial green solution immedi-
ately turned orange and two compounds [(l-H)Os3-
(CO)8(l-Cl)(l-dppm)] (2) and [(l-H)Os3(CO)7(g1-Cl)-
(l-Cl)2(l-dppm)] (3) were isolated in 85% and 10%
yields, respectively, after chromatographic separation.
Both compounds 2 and 3 have been characterized by a
combination of spectroscopic data and single-crystal
X-ray diffraction analysis. An ORTEP diagram of the
molecular structure of 2 is depicted in Fig. 1, crystal
data are given in Table 1 and selected bond distances
and bond angles are listed in Table 2. The molecule con-
sists of a triangular cluster of osmium atoms with eight
terminal carbonyl groups, one bridging chloride, one
bridging hydride and a bridging dppm ligand. Three
CO ligands are bound to Os(1) and Os(2) atom while
Os(3) bears two carbonyls. The chloride and hydride
cluster
with
[(l-H)Os3(CO)9(l3-g2-C@NCH2CH2CH2–)]
HX to afford
[(l-H)2Os3(CO)9(l3-g2-
C@NCH2CH2CH2–)]X (X = Cl, Br, CF3CO2, CF3SO3)
[13]. We have recently reported [14] that the electron-
deficient quinoline triosmium clusters [(l-H)Os3(CO)9-
(l3-g2-XC9H6N)] (X = H, 5-NH2, 6-NH2, 3-NH2,
5-Br, 5-CH3) all undergo simple protonation with both
coordinating (CF3CO2H) and non-coordinating acids
(HBF4).
The reactions of the coordinatively unsaturated trios-
mium cluster [(l-H)Os3(CO)8(l3-g3-Ph2PCH2P(Ph)-
C6H4)] (1) with a wide variety of small inorganic and
organic ligands such as CO [15], H2[16], PR3 [17],
P(OR)3 (R = Me, Et, Pri, Bu or Ph) [17], PPh2H
[18], RC„CR (R = Ph, C6H4Me, Me or CF3) [19],
Fig. 1. Molecular structure of [(l-H)Os3(CO)8(l-Cl)(l-dppm)] (2)
showing the atom-labeling scheme. Thermal ellipsoids are drawn at the
50% probability level.

3046
S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
Table 1
Crystallographic data and structure refinementa for 2, 3, 4 and 6
Compound
Formula
2
3 Æ 0.25CH2Cl2
4
6 Æ 2CH2Cl2
C33H23ClO8Os3P2
C32H23O7Cl3Os3P2 Æ
0.25CH2Cl2
1279.63
C33H22ClO8Os3P2
C34H23F3O9Os3P2 Á
2CH2Cl2
1434.92
Formula weight
Crystal system
Space group
1215.50
monoclinic
P21/n
1214.50
monoclinic
P21/n
triclinic
ꢀ
orthorhombic
P212121
P1
˚
a (A)
15.6579(3)
12.7532(3)
17.1996(3)
90
10.8505(2)
11.7011(3)
16.4839(4)
89.3461(12)
86.4453(12)
66.0351(8)
1908.53(8)
2
16.32200(10)
10.8817(2)
20.6814(3)
90.0000(6)
109.1381(5)
90.0000(9)
3479.23(8)
4
9.9064(10)
15.9284(14)
26.663(2)
90
˚
b (A)
˚
c (A)
a (ꢀ)
b (ꢀ)
c (ꢀ)
96.0695(8)
90
90
90
3
˚
V (A )
3415.32(14)
4
2.364
4207.2(7)
4
2.265
Z
Dcalc (mg mÀ3
)
2.227
10.333
1181
2.325
11.175
2236
l (Mo Ka) (mmÀ1
F(000)
Crystal size (mm)
)
11.355
2240
9.432
2672
0.20 · 0.15 · 0.15
3.05–27.49
À19 6 h 6 19,
À16 6 k 6 16,
À22 6 l 6 22
28876
0.16 · 0.12 · 0.10
3.10–27.53
À14 6 h 6 14,
À15 6 k 6 15,
À21 6 l 6 21
33332
0.25 · 0.22 · 0.20
2.97–27.51
À21 6 h 6 21,
À14 6 h 6 14,
À26 6 l 6 26
53072
0.40 · 0.24 · 0.03
1.49–28.38
À13 6 h 6 13,
À21 6 k 6 21,
À35 6 l 6 35
56672
h Range (ꢀ)
Limiting indices
Number of reflections collected
Number of indepedent reflections (Rint
Maximum and minimum transmission
Data/restraints/parameters
)
7747 (0.1045)
0.343 and 0.176
7747/0/424
1.032
8683 (0.0774)
0.552 and 0.356
8683/6/451
1.031
7941 (0.1146)
0.2134 and 0.1666
7941/0/424
1.018
10502 (0.0610)
1.00 and 0.302505
10502/0/319
1.058
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R1 = 0.0445,
wR2 = 0.1021
R1 = 0.0445,
wR2 = 0.1021
2.138 and À2.355
R1 = 0541,
wR2 = 0.1349
R1 = 0.0678,
wR2 = 0.1436
9.631 and À3.216
R1 = 0.0568,
wR2 = 0.1486
R1 = 0.0746,
wR2 = 0.1555
11.522 and À6.132
R1 = 0.0408,
wR2 = 0.0968
R1 = 0.0445,
wR2 = 0.0985
2.141 and À1.348
2
R indices (all data)
À3
˚
Largest differecne in peak and hole (e A
)
a
˚
Details in common: X-radiation, Mo Ka (k = 0.71073 A), temperature (K) 150(2) except 6, refinement method: full-matrix least-squares on F .
Table 2
Selected bond lengths (A) and bond angles (ꢀ) for 2
[28]. The osmium–chloride bond distances are slightly
˚
˚
asymmetrical, with Os(3)–Cl(1) = 2.450(2)
A
and
˚
Os(1)–Os(2)
Os(2)–Os(3)
Os(1)–P(1)
Os(3)–Cl(1)
2.8298(4)
2.8572(5)
2.325(2)
2.450(2)
Os(1)–Os(3)
Os(2)–Cl(1)
Os(3)–P(2)
2.8390(4)
2.482(2)
2.324(2)
Os(2)–Cl(1) = 2.482(2) A; the angle Os(2)–Cl(1)–Os(3)
is quite acute, 70.82(5)ꢀ, which is similar to that ob-
served in [(l-H)Os3(CO)10(l-Cl)] (70.83(9)ꢀ) [28]. The
˚
Os–P bond distances {2.325(2) and 2.324(2) A} are com-
Os(2)–Os(1)–Os(3)
P(2)–Os(3)–Os(2)
P(1)–Os(1)–Os(3)
P(2)–Os(3)–Cl(1)
Os(2)–Cl(1)–Os(3)
Cl(1)–Os(1)–Os(2)
C(7)–Os(3)–Os(2)
60.5333(11)
136.84(5)
94.93(5)
P(2)–Os(3)–Os(1)
P(1)–Os(1)–Os(2)
Os(1)–Os(2)–Os(3)
Os(1)–Os(3)–Os(2)
P(1)–C(33)–P(2)
Cl(1)–Os(2)–Os(3)
C(6)–Os(2)–Os(3)
86.09(5)
parable to the corresponding distances in [Os3(CO)10(l-
dppm)] [29]. The spectroscopic data for 2 are in accord
with the solid-state structure. In agreement with the
presence of the bridging hydride ligand on one of the
155.45(5)
59.893(11)
59.574(11)
112.3(4)
101.70(7)
70.82(5)
54.07(5)
1
55.11(5)
115.6(3)
Os–Os edges not bridged by the dppm ligand, the H
117.9(3)
NMR spectrum of 2, in the hydride region, shows a dou-
blet at d À12.88 with an H–P coupling constant of 31.6
Hz. The aliphatic region of the 1H NMR spectrum con-
tains two multiplets at d 6.05 and 4.46 due to the two
diastereotopic methylene protons of dppm ligand. Con-
sistent with this, the 31P{1H} NMR spectrum exhibits
two doublets at d À18.1 and À22.5 (J = 25.5 Hz) due
to two magnetically non-equivalent 31P nuclei of the
dppm ligand (see Scheme 1).
An ORTEP diagram of the molecular structure of 3 is
shown in Fig. 2, crystal data are given in Table 1 and se-
lected bond distances and bond angles are listed in Table
3. The molecule consists of an open cluster of three
ligands bridge the same Os(2)–Os(3) edge but are lo-
cated above and below the Os3 plane (Fig. 1). The bridg-
ing hydride ligand was located but not refined. The Os–
Os distances are very similar being in the range of
˚
2.8298(4)–2.8572(5) A. The dppm bridges the Os(1)–
Os(3) vector with an angle of P(1)–C(33)–P(2) of
˚
112.3(4)ꢀ. The Os(2)–Os(3) edge (2.8572(5) A) which is
mutually bridged by the chloride and the hydride li-
gands is comparable to the corresponding doubly
˚
bridged edge in [(l-H)Os3(CO)10(l-Cl)] {2.846(1) A}

S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
3047
Ph2
P
Ph2
P
(CO)4
Os
CH2
CH2
(CO)
Os
Os (CO)3
Cl
3
Cl
PPh2
PPh2
H
110oC
H
+
(OC)2Os
Ph2P
(OC)3Os
Os(CO)2
Os(CO)2
PPh2
(OC)2Os
Os(CO)2
Cl
Cl
H
2
Cl
C
3
H2
CH2Cl2
HCl
4
Ph
Ph2
P
+
CH2
H
]
Ph
P
P
CH2
CH2
(CO)
Os
3
(OC)
3 Os
(CO)
Os
3
PPh2
PPh2
H
PPh2
HX
CH2Cl2
HBr
CH2Cl2
(OC)3Os
Os(CO)2
Os(CO)2
(OC)3Os
Os(CO)2
(OC)3Os
Br
H
H
X= F, CF3COO
5
6
1
110oC
CH3COOH
Ph2
P
CH2
No reaction
Os
H
(CO)3
PPh2
Os(CO)2
O
(OC)3Os
O
C
CH3
7
Scheme 1.
Table 3
˚
Selected bond lengths (A) and bond angles (ꢀ) for 3
Os(1)–Cl(2)
Os(3)–P(2)
Os(1)–Os(3)
Os(2)–Os(3)
Os(2)–Cl(1)
2.470(3)
2.334(3)
2.9039(5)
2.9613(6)
2.447(3)
Os(2)–Cl(3)
Os(1)–P(1)
Os(2)–Cl(2)
Os(3)–Cl(1)
2.384(3)
2.307(3)
2.405(3)
2.484(3)
Cl(2)–Os(1)–Os(3)
Cl(3)–Os(2)–Cl(2)
P(2)–Os(3)–Os(1)
P(2)–Os(3)–Os(2)
Os(1)–Os(3)–Os(2)
Cl(1)–Os(3)–Os(1)
Os(2)–Cl(2)–Os(1)
P(2)–C(32)–P(1)
84.55(6)
173.10
P(1)–Os(1)–Cl(2)
P(1)–Os(1)–Os(3)
Cl(3)–Os(2)–Cl(1)
Cl(3)–Os(2)–Os(3)
Cl(1)–Os(2)–Os(3)
Cl(1)–Os(3)–Os(2)
Os(2)–Cl(1)–Os(3)
C(6)–Os(3)–Os(2)
176.35(9)
92.05(6)
87.64(11)
90.78(8)
53.66(6)
52.52(7)
73.82(8)
115.0(3)
86.87(6)
153.79(7)
83.853(15)
67.35(6)
106.99(10)
113.1(6)
84.44(6)
Cl(2)–Os(2)–Os(3)
atoms Os(2) and Os(3) each have two terminal CO li-
gands but Os(1) has three. The Os(2)–Os(3) bond dis-
Fig. 2. Molecular structure of [(l-H)Os3(CO)7(g1-Cl)(l-Cl)2(l-dppm)]
(3) showing the atom-labeling scheme. Thermal ellipsoids are drawn at
the 50% probability level.
tance of 2.9613(6) A is significantly longer than the
˚
˚
Os(1)–Os(3) bond distance of 2.9039(5) A but both are
substantially longer than that of the corresponding Os–
˚
Os distances in 2 {2.8298(4)–2.8572(5) A}. The Os(1)–
˚
Os(2) distance is very long at 3.919(4) A and is clearly a
osmium atoms with two metal–metal bonds, seven termi-
nal carbonyl groups and three chloride ligands, one edge
of which is bridged by both a chloride and a hydride and
other is bridged by the dppm ligand. The position of the
hydride ligand was located but not refined. Osmium
non-bonding interaction. This open edge is asymmetri-
cally bridged by a chloride ligand with Os–Cl bond dis-
tances of Os(1)–Cl(2) = 2.470(3) and Os(2)–Cl(2) =
˚
2.405(3) A. Another chloride ligand is terminally

3048
S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
Table 4
coordinated to Os(2) with Os(2)–Cl(3) bond distance of
˚
2.384(3) A which is seen to be the shortest Os–Cl bond
˚
Selected bond lengths (A) and bond angles (ꢀ) for 4
Os(1)–Os(2)
Os(2)–Os(3)
Os(1)–P(1)
Os(2)–Cl(1)
2.81498(5)
2.8276(6)
2.350(3)
Os(1)–Os(3)
Os(2)–Cl(1)
Os(2)–P(2)
2.8241(6)
2.489(2)
2.354(3)
among the five. The Os(2)–Os(3) edge is spanned both
by the chloride and hydride ligands lying above and be-
low the Os3 plane, respectively. The osmium–chloride
bond distances are almost equal (Os(2)–Cl(1) = 2.497(3)
2.485(2)
Os(2)–Os(1)–Os(3)
Cl(1)–Os(2)–Os(1)
P(1)–Os(1)–Os(2)
C(2)–Os(1)–Os(2)
Os(1)-Os(3)–Os(2)
P(2)–Os(2)–Os(1)
Os(1)–Os(2)–Os(3)
P(2)–C(21)–P(1)
60.190(14)
55.48(6)
94.01(6)
P(2)–Os(2)–Cl(1)
P(1)–Os(1)–Os(3)
P(1)–Os(1)–Cl(1)
Cl(1)–Os(1)–Os(2)
C(3)–Os(1)–Os(2)
P(2)–Os(2)–Os(3)
Os(1)-Cl(1)–Os(2)
C(1)–Os(1)–Os(2)
85.27(9)
153.92(6)
83.16(8)
55.59(6)
119.3(3)
154.71(6)
68.93(6)
142.6(3)
˚
and Os(3)–Cl(1) = 2.484(3) A). The Os(2)–Cl(1)–Os(3)
angle is quite acute {73.82(8)ꢀ} and is significantly smal-
ler than the Os(2)–Cl(2)–Os(1) angle (106.99(10)ꢀ), but
similar to the corresponding angle in [(l-H)Os3-
(CO)10(l-Cl)] (70.83(9)ꢀ) [28]. The Os–P distances
121.2(3)
59.744(13)
95.23(6)
60.067(14)
119.9(10)
˚
(2.307(3) and 2.334(3) A) are similar to those in 2. The
spectroscopic data for 3 are in accord with the solid-state
1
structure. The H NMR spectrum in the hydride region
shows a doublet of doublets at d À12.66, indicating that
the hydride is coupled to both non-equivalent 31P nuclei.
The aliphatic region of the spectrum contains two equally
intense multiplets at d 4.83 and 4.28 due to the methylene
protons of the dppm ligand. Consistent with this the
31P{1H} NMR spectrum exhibits two doublets at d
À16.5 and À28.5 (J = 35.5 Hz) due to two magnetically
non-equivalent 31P nuclei of the dppm ligand. Com-
pound 3 is a rare example of a structurally characterized
triosmium cluster containing two bridging and one termi-
nal chloride ligands. Most probably, this compound is
formed from a further reaction of 2 with two moles of
HCl followed by elimination of H2 and rupture of a
metal–metal bond.
of osmium atoms bearing eight terminal carbonyl
groups, one bridging chloride, one hydride and a dppm
ligand. The Os–Os distances lie in the close ranges
˚
2.8149(8)–2.8276(6) A and do not show any differences
between the bridged and unbridged edges. Two carbo-
nyls are bonded to Os(1) and Os(2) whereas Os(3) is
bonded to four carbonyls. An interesting feature of the
structure of 4 is that the chloride and hydride span
the same Os–Os vector as the dppm ligand. Although
the position of the hydride ligand was not determined
crystallographically, its presence in the same Os–Os edge
as the chloride and dppm ligands was unambiguously
1
verified by the H NMR spectrum in the hydride region
which contains a triplet at d À12.74 with a H–P coupling
constant of 12.8 Hz due to coupling to two equivalent
31P nuclei. This conclusion is further supported by the
arrangement of the carbonyl ligands, in particular the
large C(2)–Os(1)–Os(2) angle of 121.2(3)ꢀ and C(3)–
Os(1)–Os(2) angle of 119.3(3)ꢀ to accommodate the
bridging hydride ligand. The feature of interest in 4 is
the chloride ligand which symmetrically spans the
Os(1)–Os(2) edge compared to that in 2. Another exam-
ple of a triosmium cluster having three bridging ligands
on the same Os–Os edge is [(l-H)Os3(CO)8(l-OH)(l-
dppm)] [30]. A notable feature of 4 is that the P(1)–
C(21)–P(2) bite angle is opened up considerably
(120.0(6)ꢀ) compared to 112.3(4)ꢀ in 2 in order to make
for room to accommodate the hydride and the chloride
ligands inside the five-membered (Os(1)–Os(2)–P(2)–
C(21)–P(1)) metallacycle during this transformation.
That 4 is more thermodynamically stable than 2 proba-
bly reflects the net electron withdrawing effect of the
HCl moieties on the Os(2)–Os(3) edge in 2. The fact that
2 is the kinetic product suggests that its formation re-
sults from initial electrophillic attack on the Os–C bond
of the l-phenyl followed by nucleophillic attack by ClÀ
on the same Os(2)–Os(3) edge.
Thermolysis of 2 in refluxing toluene at 110 ꢀC re-
sulted in a color change from orange to yellow and 4
was isolated in 60% yield after chromatographic separa-
tion. An ORTEP diagram of the molecular structure of
4 is shown in Fig. 3, crystal data are given in Table 1 and
selected bond distances and bond angles are listed in
Table 4. The molecule consists of a triangular cluster
A similar treatment of 1 with HBr gave [(l-H)Os3-
(CO)8(l-Br)(l-dppm)] (5) as the single product in almost
quantitative yield. The structure of 5 is proposed from
the spectroscopic data by analogy with 2. The FAB mass
spectrum shows the molecular ion peak at m/z 1260
Fig. 3. Molecular structure of [(l-H)Os3(CO)8(l-Cl)(l-dppm)] (4)
showing the atom-labeling scheme. Thermal ellipsoids are drawn at the
50% probability level.

S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
3049
Table 5
corresponding to the formulation of [(l-H)Os3(CO)8(l-
˚
Selected bond lengths (A) and bond angles (ꢀ) for 6
Br)(l-dppm)]. The infrared spectrum of 5 is similar to
that of 2 indicating that they have similar distribution
Os(1)–P(2)
Os(2)–P(1)
Os(1)–Os(2)
Os(2)–Os(3)
Os(1)–Os(3)
F(3)–C(3S)
F(2)–C(3S)
Os(1)–C(9)
2.370(2)
2.364(2)
3.0040(5)
2.8684(5)
2.7673(5)
1.495(10)
1.456(10)
2.271(9)
Os(1)–H(1H)
Os(1)–H(2H)
Os(2)–H(2H)
Os(3)–H(1H)
F(1)–C(3S)
C(3S)–O(1S)
F–C(av.)
1.8506
1.8574
1
of the carbonyl ligands. The H NMR spectrum in the
1.8357
1.8516
hydride region shows a doublet at d À13.74 with a H–
P coupling constant of 39.5 Hz. The resonance of the
methylene protons of dppm is observed as two doublets
of double doublets at d 3.13 and 3.73, each integrating
for 1 H. This arrangement of the ligands in 5 is strongly
supported by the 31P{1H} NMR spectrum which shows
two doublets at d À19.1 and À22.9 (J = 39.5 Hz) due to
the inequivalent phosphorus nuclei of the dppm ligand
It is interesting that thermolysis of 5 in refluxing toluene
at 110 ꢀC does not convert it into an isomer in which the
bromide and the hydride bridge the same Os–Os edge as
the dppm ligand most probably because of steric reasons
and the lower electronegativity of Br relative to Cl.
In sharp contrast, the reaction of 1 with HF results in
an immediate color change from green to orange and
only the cationic species [(l-H)2Os3(CO)8(Ph2PCH2P-
(Ph)C6H4)]+[CF3O]À (6) was isolated in almost quantita-
tive yield after recrystallization from hexane/CH2Cl2 at
room temperature. The molecular structure of cation 6
is shown in Fig. 4, crystal data are given in Table 1
and selected bond distances and bond angles are listed
in Table 4. The structure consists of an Os3 triangle
with two shorter metal–metal bonds (Os(1)–Os(3) =
1.399(10)
1.277(13)
1.45(10)
2.318(9)
Os(3)–C(9)
P(2)–Os(1)–Os(3)
Os(3)–Os(1)–Os(2) 59.437(12) H(1H)–Os(1)–H(2H) 106.4
133.60(5)
P(2)–Os(1)–Os(2)
90.65(5)
P(1)–Os(2)–Os(3)
87.02(5)
P(1)–Os(2)–Os(1)
Os(3)–Os(2)–Os(1) 56.171(11) Os(1)–Os(3)–Os(2)
75.42(5)
64.392(13)
110.9(7)
103.2(7)
100.5(6)
104.86(7)
O(1S)–C(3S)–F(1)
O(1S)–C(3S)–F(2)
O(1S)–C(3S)–F(3)
O–C–F(av.)
118.8(8)
112.7(8)
108.6(8)
113.36(7)
111.5(4)
F(1)–C(3S)–F(2)
F(1)–C(3S)–F(3)
F(2)–C(3S)–F(3)
F–C–F(av.)
P(1)–C(15)–P(2)
The Os(1)–Os(3) edge is comparable to the correspond-
˚
ing edge in 1 (2.747(1) A) and is indicative of the unsat-
urated, 46-electron character of these triosmium clusters
[15]. The Os(1) is ligated by two CO groups, while each
of Os(2) and Os(3) is coordinated to three carbonyl li-
gands. The disposition of the metallated phenyl ring
forces the phosphorus atoms of the diphosphine ligand
to occupy axial co-ordination sites. A noticeable feature
in the structure is that the metallated phenyl group
forms asymmetric bridges across the Os(1)–Os(3) edge
˚
2.7673(5) and Os(2)–Os(3) = 2.8684(5) A) and one sig-
nificantly longer metal–metal bond (Os(1)–Os(2) =
˚
(Os(1)–C(9) = 2.271(9) and Os(3)–C(9) = 2.318(9) A),
˚
3.0040(5) A). The hydrides were located by using the
in contrast to the parent cluster 1 in which there is no
significant difference in the Os–C bond lengths for the
bridging carbon atom of the metallated phenyl ring
and probably reflects the electron withdrawing effect of
protonation on the Os(1)–Os(2) edge [15]. The Os–P dis-
tances (Os(1)–P(2) = 2.370(2) and Os(2)–P(1) = 2.364(2)
program WinGX [31] and found to bridge Os(1)–Os(3)
and Os(1)–Os(2) edges. The Os(1)–Os(2) edge is also
bridged by the diphosphine ligand while the Os(1)–
Os(3) edge is bridged by the metallated phenyl ring.
˚
A) are comparable to the corresponding distance in 1
˚
(2.362(10) and 2.360(10) A) [15]. The X-ray structure
of this anion was first determined by Farnham et al.
[32] as part of the complex [(CH3)2N]3S+CF3OÀ. Impor-
tant bond lengths and angles of this anion are listed in
Table 5. The average C–O and C–F distances
˚
(1.277(13) and 1.45(10) A, respectively) and O–C–F
and F–C–F angles (1.133(8) and 104.86ꢀ, respectively)
are comparable to those reported previously [32]. This
anion is most likely formed by the stepwise fluorination
and hydrolysis (by trace moisture) of CH2Cl2. The con-
version of chlorinated methanes to fluorinated alcohols
by HF and water is well known [33].
Treatment of 1 with excess CF3CO2H in an NMR
tube led to the formation of the protonated species
[(l-H)2Os3(CO)8(Ph2PCH2P(Ph)C6H4)]+. Its IR, 1H
and 31P NMR spectroscopic data are very similar to
those of the isolated 6 and [(l-H)2Os3(CO)8(Ph2PCH2P-
(Ph)C6H4)]+[BF4]À. The latter was briefly described by
Smith and co-workers [20] from the reaction of 1 with
HBF4 and characterized by spectroscopic data.
Fig. 4. Molecular structure of [(l-H)2Os3(CO)8(Ph2PCH2P(Ph)-
C6H4)]+ (6) showing the atom-labeling scheme. Thermal ellipsoids
are drawn at the 50% probability level.

3050
S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
Since CF3CO2H and CH3CO2H are structurally sim-
bridging modes for the acid anion. This is in sharp
contrast to the previously reported acid adducts of
the imidoyl species [(l-H)Os3(CO)9(l3-g2-C@NCH2-
CH2CH2–)X] (X = Cl, Br, CF3CO2, CF3SO2) where
the anions are all terminally bonded to the cluster
[13]. This is due to the facile reversibility of the ortho-
metallation in 1 whereas CO loss (a much higher en-
ergy process) would be required to form l-X adducts
in the case of the imidoyls. This reversal of the ortho-
metallation takes place even in the presence of rela-
tively weak electron-donor, i.e., lone pairs on Cl, Br,
and acetate.
ilar but have different acidities, we investigated the reac-
tion of 1 with CH3CO2H to see if 6 or an acid adduct is
formed. Treatment of 1 with excess CH3CO2H for 15
days gave [(l-H)Os3(CO)8(l-g2-CH3CO2)(l-dppm)] (7)
in 65% yield. Compound 7 has been characterized on
the basis of spectroscopic data. The infrared spectrum
of 7 in the terminal CO region is similar to that of 2
and 5 but it also exhibits two low energy absorption
bands at 1964, and 1445 cm1, which can be attributed
to the –l-g2-CH3CO2 group [6]. Agreement between
antisymmetric and symmetric carboxylate vibrations in
7 and those observed in [(l-H)- Os3(CO)10(l-g2-
CH3CO2)] and [(l-H)Os3(CO)10(l-g2-HCO2)], whose
structure have been determined by X-ray diffraction
4. Experimental
1
studies, is excellent [34,35]. Its H NMR in the hydride
region shows a doublet of doublets at À9.18 with P–H
coupling constants of 33.6 and 1.2 Hz, indicating that
the hydride is bridging one of the Os–Os edges not
bridged by the dppm ligand. The hydride chemical shift
appears to be similar in related triosmium clusters
containing bridging bidentate carboxylate moieties,
[(l-H)Os3(CO)10(l-g2-X)] (d ꢀ À10) [34,35]. The 31P
chemical shifts of 7 (d À27.1 and À31.5; J = 39.2 Hz)
are very similar to those of 2 and 5 indicating that they
have related structures.
All the reactions were performed under a nitrogen
atmosphere using standard Schlenk techniques. Solvents
were dried and distilled prior to use by standard meth-
ods. Hydrogen fluoride and hydrogen bromide gas were
purchased from Matheson gas products, Inc. while
hydrogen choloride gas was purchased from Aldrich
Chemical Company, Inc. The starting cluster [(l-
H)Os3(CO)8(Ph2PCH2P(Ph)C6H4)] (1) was prepared
according to the literature method [15]. Infrared spectra
were recorded on a Shimadzu FT-IR 8101 spectropho-
1
tometer. H and 31P{1H} NMR spectra were recorded
on a Varian Unity Plus 400 and a Bruker DPX 400 spec-
trometers. Chemical shifts for the 31P{1H} NMR spec-
tra are relative to 85% H3PO4.
3. Conclusion
In this paper, we have demonstrated that the
electronically unsaturated cluster 1 reacts with HCl
gas to give two compounds, [(l-H)Os3(CO)8(l-Cl)(l-
dppm)] (2) and [(l-H)Os3(CO)7(g1-Cl)(l-Cl)2(l-dppm)]
(3), whereas with HBr it gives exclusively [(l-H)Os3-
(CO)8(l-Br)(l-dppm)] (5). In sharp contrast, HF reacts
with 1 to give the protonated species [(l-H)2Os3-
(CO)8(Ph2PCH2P(Ph)C6H4)]+ (6). This probably re-
flects the expected weaker l-Os–F bond relative to
4.1. Reaction of [(l-H)Os3(CO)8(Ph2PCH2P(Ph)-
C6H4)] (1) with hydrogen chloride
HCl gas was bubbled through a CH2Cl2 solution (25
mL) of 1 (0.115 g, 0.098 mmol) at room temperature for
2 min during which time the color changed from green
to orange. The solvent was removed under reduced pres-
sure and the residue was chromatographed by TLC on
silica gel. Elution with hexane/CH2Cl2 (1:1, v/v) gave
two bands. The faster moving band afforded [(l-H)-
Os3(CO)8(l-Cl)(l-dppm)] (2) (0.101 g, 85%) as red crys-
tals after recrystallized from hexane/CH2Cl2 at À4 ꢀC.
(Anal. Calc. for C33H23ClO8Os3P2: C, 32.60; H, 1.91.
Found: C, 32.81; H, 2.05%.) IR (m(CO), CH2Cl2): 2078
the l-Os–Cl and l-Os–Br. Reaction of
1 with
CF3CO2H also gives the cation 6 while reaction
with CH3CO2H gives the adduct [(l-H)Os3(CO)8(l-
g2-CH3CO2)(l-dppm)] (7) indicating that the basicity
of the conjugate base also plays a role in determining
the relative stability of simple protonation versus ad-
duct formation. When refluxed in toluene at 110 ꢀC
both the hydride and chloride in 2 undergo edge migra-
tion to give 4 in which all the three ligands span the the
same Os–Os edge. The formation of 2, 5, and 7 from 1
involves oxidative addition of HX followed by demet-
allation of the phenyl ring of the diphosphine ligand.
It was not possible to convert 5 into the corresponding
isomer of 4 suggesting that most probably the small
bite of the dppm cannot accommodate the relatively
large bromide ligand compared to chloride in 4. Most
interestingly, the acid adducts reported here all involve
s, 2029 m, 2004 vs, 1980 s, 1960 m, 1929 m cmÀ1; H
1
NMR (CD2Cl2): d 7.56 (m, 20H), 6.05 (m, 1H), 4.46
(m, 1H), À12.88 (d, 1H, J = 31.6 Hz); 31P{1H}
(CD2Cl2): d À18.1 (d), À22.5 (d, J = 45.5 Hz); mass
spectrum: (m/z) 1214 [M]+. The slower moving band
afforded [(l-H)Os3(CO)7(g1-Cl)(l-Cl)2(l-dppm)] (3) as
pale yellow crystals (0.009 g, 7%) after recrystallization
from hexane/CH2Cl2 at À4 ꢀC. (Anal. Calc. for
C32H23O7Cl3Os3P2: C, 30.54; H, 1.85. Found: C,
30.71; H, 1.98%.) IR [m(CO), CH2Cl2]: 2093 w, 2049
1
m, 2029 m, 2010 vs, 1977 m, 1946 w cmÀ1; H NMR

S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
3051
(CD2Cl2): d 7.46 (m, 20H), 4.03 (m, 1H), 4.80 (m, 1H),
À12.57 (dd, 1H, J = 31.6, 4.8 Hz).
(J = 12.8, 4.4, 2.0 Hz). 31P{1H} (CDCl3): d À9.1 (d,
J = 41.9 Hz), À18.3 (d, J = 41.9 Hz).
4.2. Thermolysis of 2
4.5. Reaction of 1 with CF3CO2H
A toluene solution (30 mL) of 2 (0.075 g, 0.062 mmol)
was heated to reflux for 6 h. The solvent was removed
under reduced pressure and the residue chromato-
graphed by TLC on silica gel. Elution with hexane/
CH2Cl2 (3:2, v/v) gave two bands. The first band gave
unreacted 2 (0.012 g). The second band gave [(l-H)Os3-
(CO)8(l-Cl)(l-dppm)] (4) (0.045 g, 60%) as yellow crys-
tals after recrystallized from hexane/CH2Cl2 at À4 ꢀC.
(Anal. Calc. for C33H23ClO8Os3P2: C, 32.60; H, 1.91.
Found: C, 32.75; H, 2.03%). IR [m(CO), CH2Cl2]: 2080
CF3CO2H (one drop from a pauster pipette) was
added to a CD2Cl2 solution (0.75 mL) of 1 (0.0.027 g,
0.106 mmol) in an NMR tube. The color immediately
1
changed from green to orange. The H and 31P NMR
indicated the formation of the protonated species [(l-
H)2Os3(CO)8(Ph2PCH2P(Ph)C6H4)]+ (6). 1H NMR
(CD2Cl2): d 9.07 (m, 1H), 8.17 (m, 1H), 7.75–7.49 (m,
10H), 7.40–7.29 (m, 3H), 7.04 (m, 1H), 6.96 (m, 1H),
6.74 (m, 2H), 4.47 (m, 1H), 3.34 (m, 1H) À13.74 (dd,
1H, J = 29.6, 8.0 Hz), À14.27 (J = 12.4, 4.0, 1.6 Hz).
31P{1H} NMR (CD2Cl2): d À9.1 (d, J = 41.9 Hz),
À18.3 (d, J = 41.9 Hz); 31P{1H} (CDCl3): d À8.7 (d,
J = 41.9 Hz), À17.9 (d, J = 41.9 Hz).
1
s, 2006 vs, 1964 vw, 1943 w cmÀ1; H NMR (CDCl3):
d 7.45–6.98 (m, 20H), 3.53 (m, 1H), 3.02 (m, 1H),
À12.83 (t, 1H, J = 13.2 Hz); 31P{1H} NMR (CDCl3):
d À10.4 (s).
4.6. Reaction of 1 with CH3CO2H
4.3. Reaction of 1 with hydrogen bromide
Glacial acetic acid (five drops from a pauster pipette)
was added to a CH2Cl2 solution of 1 (0.022 g, 0.019 mmol)
and allowed to stir at room temperature for 15 days dur-
ing which time the color changed from green to yellow.
The volatiles were removed under reduced pressure and
the residue chromatographed by TLC on silica gel. Elu-
tion with hexane/CH2Cl2 developed a single band which
afforded [(l-H)Os3(CO)8(l-g2-CH3CO2)(l-dppm)] (7)
(0.015 g, 65%) as yellow crystals from hexane/CH2Cl2at
À4 ꢀC. IR (m(CO), CH2Cl2): 2073 s, 2024 m, 1998 vs,
1975 s, 1948 s, 1922 m cm1; (m(COO), CH2Cl2): 1964 m,
HBr gas was bubbled through a CH2Cl2 solution
(35 mL) of 1 (0.125 g, 0.106 mmol) at room tempera-
ture for 2 min during which time the color changed
from green to orange. The solvent was then removed
under reduced pressure and the residue chromato-
graphed by TLC on silica gel. Elution with hexane/
CH2Cl2 (1:1, v/v) gave one orange band which afforded
[(l-H)Os3(CO)8(l-Br)(l-dppm)] (5) (0.127 g, 95%) as
red crystals after recrystallization from hexane/CH2Cl2
at À4 ꢀC. (Anal. Calc. for C33H23BrO8Os3P2: C, 31.45;
H, 1.84. Found: C, 31.61; H, 1.96%.) IR (m(CO),
CH2Cl2): 2075 s, 2028 m, 2001 vs, 1982 s, 1958 s,
1
1445 m cm1; H NMR (CDCl3): d 7.66-7.17 (m, 20H),
6.42 (ddt, 1H, J = 15.2, 10.0, 1.2 Hz), 4.64 (dt, 1H,
J = 15.2, 12.0 Hz), À9.18 (dd, 1H, J = 33.6, 1.2 Hz);
31P{1H} (CDCl3): d À27.1 (d, J = 39.2 Hz), À31.5 (d,
J = 39.2 Hz); mass spectrum: (m/z) 1238 [M]+.
1929 m cmÀ1 1H NMR (CDCl3): d 7.71–7.09 (m,
;
20H), 5.85 (m, 1H), 4.50 (m, 1H), À13.74 (d, 1H,
J = 21.2 Hz); 31P{1H} (CDCl3): d À19.1 (d, J = 39.5
Hz), À22.9 (d, J = 39.5 Hz); mass spectrum: (m/z)
1260 [M]+.
4.7. X-ray structure determination of 2, 3, and 4
4.4. Reaction of 1 with hydrogen fluoride
Single crystals of 2, 3 and 4 suitable for X-ray diffrac-
tion were grown by slow diffusion of hexane into a
dichloromethane solution at À4 ꢀC. Crystallographic
data were collected at 150 K, using a FAST area detec-
tor diffractometer and Mo Ka radiation (k = 0.71073
HF gas was bubbled through a CH2Cl2 solution (35
mL) of 1 (0.106 g, 0.099 mmol) at room temperature
for 2 min. The color immediately changed from green
to orange. The solvent was removed under reduced pres-
sure and the residue recrystallized from hexane/CH2Cl2
by slow evaporation of the solvent at room temperature
to give [(l-H)2Os3(CO)8(Ph2PCH2P(Ph)C6H4)]+[CF3O]À
(6) (0.108 g, 99%) as orange crystals. (Anal. Calc. for
C33FH23O8Os3P2: C, 33.05; H, 1.94. Found: C, 33.21;
H, 2.10%.) IR (m(CO), CH2Cl2): 2101 s, 2072 m, 2061 s,
˚
A). Data collection and processing were carried out
using the programs COLLECT [36] and DENZO [37]. Empir-
ical absorption corrections were applied to the data set
using multiple and symmetry-related data measurements
via the program SORTAV [38,39]. The unit cell parameters
were determined from all observed reflections in a /
range of 3–10ꢀ and refined using the entire data set.
The structures were solved by direct methods (SHELXS-
97) [40] and refined on F2 by full-matrix least-squares
(SHELXL-97) [41] using all unique data. The bridging hy-
drides in 2 and 3 were located from a difference map but
2031 m, 1999 s cmÀ1 1H NMR (CD2Cl2): 9.07 (m,
;
1H), 8.19 (m, 1H), 7.73–7.56 (m, 10H), 7.37-7.28
(m, 3H), 7.03 (m, 1H), 6.81 (m, 2H), 4.68 (m, 1H), 3.47
(m, 1H) À13.75 (dd, 1H, J = 28.8, 7.1 Hz), À14.22

3052
S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
not refined. All non-hydrogen atoms were refined aniso-
tropically. The hydrogen atoms were included in calcu-
lated positions (riding model) with Uiso set at 1.2 times
the Ueq of the parent atom. The crystals of compounds
3 and 4 grew as needles and although absorption correc-
tions were made to the data, there were still large resid-
Data Centre, CCDC Nos. 265868 for compound 2,
265869 for compound 3, 265870 for compound 4, and
265871 for compound 6. Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road Cambridge CB2 1EZ, UK
(fax: +44 1223 336 033; email: deposit@ccdc.cam.ac.uk
or www: http://www.ccdc.cam.ac.uk). Supplementary
data associated with this article can be found, in the on-
line version, at doi:10.1016/j.jorganchem.2005.03.041.
À3
˚
ual electron density peaks, 9.631 e A in 3 which is
located very close to the Os(2) atom with a distance
À3
˚
˚
1.00 A and 11.522 e A in 4 which is located close to
˚
the Os(1) atom with a distance of 0.95 A and have no
chemical sense. We are as yet unable to obtain better
quality crystals of 3 and 4.
References
4.8. X-ray structure analysis of 6
[1] (a) A.A. Koridze, O.A. Kizas, N.M. Astakhova, P.V. Petrovskii,
Y.K. Grishin, J. Chem. Soc., Chem. Commun. (1981) 853;
(b) J. Knight, M.J. Mays, J. Chem. Soc. A (1970) 711;
(c) A.J. Deeming, B.F.G. Johnson, J. Lewis, J. Chem. Soc. A
(1970) 2967.
Suitable crystals of 6 were coated with Paratone N
oil, suspended in a small fiber loop, and placed in a
cooled nitrogen gas stream at 173 K on a Bruker D8
SMART APEX CCD sealed tube diffractometer with
[2] A.J. Deeming, S. Donovan-Mtunzi, S.E. Kabir, M.B. Hursthouse,
K.M.A. Malik, N.P.C. Walker, J. Chem. Soc., Dalton Trans.
(1987) 1869.
˚
graphite monochromated Mo Ka (0.71073 A) radiation.
[3] A.J. Deeming, S.E. Kabir, J. Organomet. Chem. 340 (1988) 359.
[4] A.J. Deeming, K.I. Hardcastle, S.E. Kabir, J. Chem. Soc., Dalton
Trans. (1988) 827.
A hemisphere of data was measured using a series of
combinations of phi and omega scans with 10 s frame
exposures and 0.3 frame widths. Data collection, index-
ing, and initial cell refinements were all carried out using
SMART [42] software. Frame integration and final cell
refinements were done using SAINT [43] software. The fi-
nal cell parameters were determined from least-squares
refinement on 7310 reflections. The SADABS [44] program
was used to carry out absorption corrections.
[5] A.J. Deeming, S. Donovan-Mtunzi, K.I. Hardcastle, S.E. Kabir,
K. Henrick, M. McPartlin, J. Chem. Soc., Dalton Trans. (1988)
579.
[6] G.R. Frauenhoff, S.R. Wilson, J.R. Shapley, Inorg. Chem. 30
(1991) 78.
[7] R.D. Adams, N.M. Golembeski, J.P. Selegue, Organometallics 1
(1982) 240.
[8] E.G. Bryan, W.G. Jackson, B.F.G. Johnson, J.W. Kelland, J.
Lewis, K.T. Schorpp, J. Organomet. Chem. 108 (1976) 385.
[9] S.B. Colbran, P.T. Irele, B.F.G. Johnson, P.T. Kaye, J. Lewis,
P.R. Raithby, J. Chem. Soc., Dalton Trans. (1989) 2033.
[10] A.J. Arce, A.J. Deeming, S. Donovan-Mtunzi, S.E. Kabir, J.
Chem. Soc., Dalton Trans. (1985) 2479.
The structures were solved using direct methods and
difference Fourier techniques (SHELXTL-V6.12) [45].
Hydrogen atoms were placed in their expected chemical
position using the HFIX command and were included in
the final cycles of least squares with isotropic Uijꢀs re-
lated to the atoms ridden on. The hydrides were posi-
tioned by using the XHYDEX program in the WinGX
suite of programs [31]. All non-hydrogen atoms were re-
fined anisotropically. Scattering factors and anomalous
dispersion corrections are taken from the International
Tables for X-ray Crystallography [46]. Structure solu-
tion, refinement, graphics, and generation of publication
materials were performed by using SHELXTL-V6.12 soft-
ware. The crystals of compound 6 grew as thin plates
and although absorption corrections were made to the
data, there were still large residual electron density
[11] E.J. Ditzel, B.F.G. Johnson, J. Lewis, J. Chem. Soc., Dalton
Trans. (1989) 2033.
[12] M. Day, S.E. Kabir, E. Wolf, E. Rosenberg, K.I. Hardcastle, J.
Cluster Sci. 9 (1990) 355.
[13] S.E. Kabir, E. Rosenberg, J. Stetson, M. Yin, J. Ciurash, K.
Mnatsakanova, K.I. Hardcastle, H. Noorani, N. Movesesian,
Organometallics 15 (1996) 4473.
[14] E. Rosenberg, Md.J. Abedin, D. Rokhsana, A. Viale, W. Dastru,
R. Gobetto, L. Milone, K.I. Hardcastle, Inorg. Chim. Acta 334
(2002) 343.
[15] J.A. Clucas, D.F. Foster, M.M. Harding, A.K. Smith, J. Chem.
Soc., Chem. Commun. (1984) 949.
[16] J.A. Clucas, M.M. Harding, A.K. Smith, J. Chem. Soc., Chem.
Commun. (1985) 1280.
À3
˚
[17] M.P. Brown, P.A. Dolby, M.M. Harding, A.J. Mathews, A.K.
Smith, J. Chem. Soc., Dalton Trans. (1993) 1671.
[18] 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.
peaks, ꢀ2 e A next to the osmium atoms. The other
significant residual electron density in 6 was due to dis-
order of the CF3O moiety which was not modeled.
Additional details of data collection and structure
refinement are given in Table 1.
[19] M.P. Brown, P.A. Dolby, M.M. Harding, A.J. Mathews, A.K. ;
Smith, D. Osella, D.M. Arbrun, R. Gobetto, P.R. Raithby, P.
Zanello, J. Chem. Soc., Dalton Trans. (1993) 827.
[20] M.M. Harding, B. Kariuki, A.J. Mathews, A.K. Smith, P.
Braunstein, P. J. Chem. Soc. Dalton Trans. (1994) 33.
[21] 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. 12
(2001) 5.
Appendix A. Supplementary material
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic

S.E. Kabir et al. / Journal of Organometallic Chemistry 690 (2005) 3044–3053
3053
[22] S.E. Kabir, K.M.A. Malik, E. Mollah, M.A. Mottalib, J.
Organomet. Chem. 616 (2000) 157.
[33] G. Kloter, K. Seppelt, J. Am. Chem. Soc. 101 (1979) 347.
[34] P.M. Lausarot, G.A. Vaglio, M. Valle, A. Tiripicchio, M.T.
Camellini, P.J. Gariboldi, J. Organomet. Chem. 291 (1985)
221.
[23] S.E. Kabir, C.A. Johns, K.M.A. Malik, M.A. Mottalib, E.
Rosenberg, J. Organomet. Chem. 625 (2001) 112.
[24] S.E. Kabir, S. Pervin, N.C. Sarker, A. Yesmin, A. Sharmin, T.A.
Siddiquee, D.T. Haworth, D.W. Bennett, K.M.A. Malik, J.
Organomet. Chem. 681 (2003) 237.
[35] E.G. Bryan, B.F.G. Johnson, J. Lewis, J. Chem. Soc., Dalton
Trans. (1977) 1328.
[36] R. Hooft, COLLECT: Data Collection Software, Nonius B.V., Delft,
The Netherlands, 1998.
[25] S.M.T. Abedin, K.I. Hardcastle, S.E. Kabir, K.M.A. Malik,
M.A. Mottalib, E. Rosenberg, M.J. Abedin, Organometallics 19
(2000) 5623.
[37] Z. Otwinowski, W. Minor, in: C.W. CarterJr., R.M. Sweet (Eds.),
Macromolecular Crystallography, Academic Press, New York,
1997, pp. 307–326.
[26] A.J. Deeming, M.M. Hassan, S.E. Kabir, E. Nordlander, D.A.
Tocher, J. Chem. Soc., Dalton Trans. (2004) 3079.
[38] R.H. Blessing, Acta Crystallogr., Sect. A 51 (1995) 33.
[39] R.H. Blessing, J. Appl. Crystallogr. 30 (1997) 421.
[40] G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990) 467.
[41] G.M. Sheldrick, SHELXL-97: Program for Crystal Structure
Refinement, University Go¨ttingen, Go¨ttingen, Germany, 1997.
[42] SMART Version 5.628, Bruker AXS, Inc., Madison, WI, 2003.
[43] SAINT Version 6.36, Bruker AXS, Inc., Madison, WI, 2002.
[44] G. Sheldrick, SADABS Version 2.10, University of Go¨ttingen,
Go¨ttingen, Germany, 2003.
[27] (a) S.E. Kabir, K.M.A. Malik, H.S. Mandal, M.A. Mottalib,
M.J. Abedin, E. Rosenberg, Organometallics 21 (2002) 2593;
(b) S.M.T. Abedin, T. Akter, N. Begum, S.E. Kabir, M.A. Miah,
M.A. Mottalib, D. Rokhsana, E. Rosenberg, G.M.G. Hossain,
K.I. Hardcastle, Organometallics (in preparation).
[28] M.R. Churchill, R. Lashewycz, Inorg. Chem. 18 (1979) 1926.
[29] K.A. Azam, M.B. Hursthouse, S.E. Kabir, K.M.A. Malik, M.A.
Mottalib, J. Chem. Crystallogr. 29 (1999) 813.
[30] S.R. Hodge, B.F.G. Johnson, J. Lewis, P.R. Raithby, J. Chem.
Soc., Dalton Trans. (1987) 931.
[45] SHELXTL-V6.12, Bruker AXS, Inc., Madison, WI, 2003.
[46] A.J.C. Wilson (Ed.), International Tables for X-ray Crystallog-
raphy, vol. C, Kynoch Press/Academic Publishers, Birmingham/
Dordrecht, 1992, Tables 6.1.1.4 (pp. 500–502) and 4.2.6.8 (pp.
219–222).
[31] L.J. Farrugia, J. Appl. Crystallogr. 32 (1999) 837.
[32] W.R. Farnham, B.G. Smart, W.J. Middleton, W.J. Calabrese,
D.A. Dixon, J. Am. Chem.. Soc. 107 (1985) 4565.