Reactions of [Os3(μ-H)2(CO)10] with [Rh(COD)(L)I] (COD=cycloocta-1,5-diene; L=2,2′-bipyridine, 1,10-phenanthroline and 4,4′-diphenyl-2,2′-dipyridyl): Crystal and molecular structures of [Os3Rh(μ-H)3(CO)10(η4-COD)]

Article abstract of DOI:10.1016/S0022-328X(98)00710-4

The co-ordinatively unsaturated dihydride cluster [Os₃(μ-H)₂(CO)₁₀] reacts with [Rh(COD)(L)I] (COD=cycloocta-1,5-diene; L=2,2′-bipyridine, 1,10-phenanthroline and 4,4′-diphenyl-2,2′-dipyridyl) to give a family of hydrido heterometallic clusters [Os₃Rh(μ-H)₃(CO)₁₀(η⁴-COD)] 1, [Os₃Rh(μ-H)₂(CO) ₈(μ-CO)(μ-I)(η⁴-COD)] 2, [Os₃Rh(μ-H)₂(CO)₈(μ-CO)(μ-I)(bipy)] 3, [Os₃Rh(μ-H)₂(CO) ₈(μ-CO)(μ-I)(1,10-phen)] 4, [Os₃Rh(μ-H)₂(CO) ₈(μ-CO)(μ-I)(4,4′-diphbipy)] 5 and [Os₃(CO)₁₂] in moderate yields. The crystal structures of 1-3 were established by X-ray diffraction method; 1 and 2 comprise a saturated tetrahedral Os₃Rh core in which the rhodium atom is η⁴-co-ordinated by a COD ligand. In structure 3-5, a bidentate N-donor ligand chelates to the rhodium metal centre instead of the COD ligand. Clusters 1-5 were fully characterized by IR and ¹H-NMR spectroscopy, mass spectrometry and elemental analysis.

Full text of DOI:10.1016/S0022-328X(98)00710-4

Journal of Organometallic Chemistry 566 (1998) 237–243
Reactions of [Os3(v-H)2(CO)10] with [Rh(COD)(L)I]
(COD=cycloocta-1,5-diene; L=2,2%-bipyridine, 1,10-phenanthroline
and 4,4%-diphenyl-2,2%-dipyridyl): crystal and molecular structures of
[Os3Rh(v-H)3(CO)10(p4-COD)],
[Os3Rh(v-H)2(CO)8(v-CO)(v-I)(p4-COD)] and
[Os3Rh(v-H)2(CO)8(v-CO)(v-I)(bipy)]
Sarah Yeuk-Wah Hung, Wing-Tak Wong *
Department of Chemistry, The Uni6ersity of Hong Kong, Pokfulam Road, Hong Kong, PR China
Received 16 April 1998
Abstract
The co-ordinatively unsaturated dihydride cluster [Os3(v-H)2(CO)10] reacts with [Rh(COD)(L)I] (COD=cycloocta-1,5-diene;
L=2,2%-bipyridine, 1,10-phenanthroline and 4,4%-diphenyl-2,2%-dipyridyl) to give a family of hydrido heterometallic clusters
[Os3Rh(v-H)3(CO)10(p4-COD)] 1, [Os3Rh(v-H)2(CO)8(v-CO)(v-I)(p4-COD)] 2, [Os3Rh(v-H)2(CO)8(v-CO)(v-I)(bipy)] 3,
[Os3Rh(v-H)2(CO)8(v-CO)(v-I)(1,10-phen)] 4, [Os3Rh(v-H)2(CO)8(v-CO)(v-I)(4,4%-diphbipy)] 5 and [Os3(CO)12] in moderate
yields. The crystal structures of 1–3 were established by X-ray diffraction method; 1 and 2 comprise a saturated tetrahedral Os3Rh
core in which the rhodium atom is p4-co-ordinated by a COD ligand. In structure 3–5, a bidentate N-donor ligand chelates to
the rhodium metal centre instead of the COD ligand. Clusters 1-5 were fully characterized by IR and 1H-NMR spectroscopy, mass
spectrometry and elemental analysis. © 1998 Elsevier Science S.A. All rights reserved.
Keywords: Osmium; Rhodium; Clusters; Hydrido-clusters
lytic processes while osmium clusters display rich chem-
istry and are kinetically stable.
1. Introduction
In the course of the investigation, two novel high
The chemistry of mixed-metal carbonyl clusters re-
mains an active area of research interest [1]. The pres-
ence of the inherent polarity in the mixed-metal bonds
results in greater reactivity and selectivity in ligands
binding than the analogous homometal complexes [2–
4]. Besides the osmium–palladium cluster, [5] we are
recently interested in the chemistry of mixed-metal clus-
ters containing osmium-rhodium bonds. Rhodium, like
palladium ion, can attain either a 16- or 18-electron
configuration which is an important feature for cata-
nuclearity
clusters,
[Os12Rh9(CO)44(v3-Cl)]
and
[Os4Rh3(v3-H)(CO)14(p4-NBD)2] were obtained by the
redox condensation of [(Ph3P)2N][Os3(v-H)(CO)11] with
[Rh(NBD)Cl]2 (NBD=norbornadiene) in the presence
of AgPF6 [6].
Although a range of tetranuclear osmium-rhodium
mixed-metal clusters have been prepared previously by
the reaction of [Os3(v-H)2(CO)10] with some rhodium-
cyclopentadienyl reagents, [7–12] there is no example of
Os–Rh mixed-metal clusters containing N-donor lig-
ands reported. Herein we describe the preparation of
new osmium–rhodium hydrido carbonyl clusters gener-
* Corresponding author. Fax: +852 25 472933; e-mail: wtwong@
hkucc.hku.hk
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00710-4

238
S. Yeuk-Wah Hung, W.-T. Wong / Journal of Organometallic Chemistry 566 (1998) 237–243
Scheme 1. [Rh(COD)(L)I], reflux, CH2Cl2; (COD=cycloocta-1,5-diene; L=2,2%-bipyridine, 1,10-phenanthroline and 4,4%-diphenyl-2,2-dipyriyl).
ated from the reaction of the unsaturated triosmium
cluster [Os3(v-H)2(CO)10] with rhodium reagents con-
taining a labile COD group and N-donor ligand,
namely [Rh(COD)(L)I] (COD=cycloocta-1,5-diene;
L=2,2%-bipyridine, 1,10-phenanthroline and 4,4%-
diphenyl-2,2%-dipyridyl).
2.2. Spectroscopic analyses of the complexes 1–5
1
The spectroscopic (IR, H-NMR and mass) (Table 1)
and analytical data are fully consistent with the ob-
served structures in the solid-state. The solution IR
spectra of 2–5 indicate the presence of bridging CO
groups in the molecules. Mass spectra of 1–5 obtained
from positive FAB techniques show a parent ion envel-
ope and daughter ion envelope corresponding to suc-
2. Results and discussion
1
cessive CO losses. The H-NMR spectrum of 1 shows
two multiplets of integration 4:8 which are attributed to
the coordinated COD ligand. There are three upfield
resonance signals with an integral ratio of 1:1:1. The
two broad singlets at l −18.33 and l −19.08 were
assigned to hydrides bridging Os–Os edges and the
doublet at d −15.08, due to the coupling with 103Rh
(JRhH=13 Hz), was assigned to the hydride bridging an
Os–Rh edge. Although such broad signals normally
indicate some dynamic processes of the cluster may be
occurring in solution, the 1H-NMR properties of 1
remains unchanged even at low temperature (−50°C).
2.1. Synthesis
Attempts to synthesize triosmium-based mixed metal
clusters of rhodium were made by employing a rhodium
complex comprising a bidentate N-donor ligand to-
gether with a labile substituent such as cycloocta-1,5-di-
ene (COD). The bidentate N-donor ligands such as
2,2%-bipyridine (bipy), 1,10-phenanthroline (1,10-phen)
and 4,4%-diphenyl-2,2%-dipyridyl (4,4%-diphbipy) were
used instead of monodentate ligands so as to stablise
the products and allow ease of characterization [13].
Treatment of [Os3(v-H)2(CO)10] with one equivalent
[Rh(COD)(bipy)I] in refluxing CH2Cl2 gave a series of
clusters with a common tetrahedral Os3Rh core. These
complexes were fully characterized by both spectro-
scopic and crystallographic techniques. The formulae of
cluster 1 was first established by FAB MS and 1H-
NMR to be [Os3Rh(v-H)3(CO)10(p4-COD)] and confi-
rmed by X-ray crystallography. In fact, 1 had been
previously prepared from the substitution reaction of
[Os3Rh(v-H)3(CO)12] with an excess of COD in the
presence of Me3NO [10]. The major products of the
title reaction were iodide-bridged clusters [Os3Rh(v-
1
However, the H-NMR spectroscopic properties of 2
are more complicated. Two sets of resonances corre-
sponding to two isomers in an approximate ratio of 1:2
are observed. The multiplets centred at l 5.43, l 5.09,
l 4.79 and l 4.61 with integral ratio of 1:1:1:1, are
attributed to the olefinic CH of the coordinated COD
ligand of the major isomer. The resonances due to
methylene hydrogens are observed as three multiplets
centred at l 2.62, l 2.38 and l 1.98 with a total of
integral of 8. The signals due to the minor isomer are
found at l 5.61 (olefinic CH) and l 2.86 (methylene
CH). In the upfield region, the resonance signals due to
the hydrides in the major isomer are observed at l
−18.2 as a doublet (JRhH=21 Hz) and at l −19.15 as
a singlet while the minor isomer shows a singlet at l
H)2(CO)8(v-CO)(v-I)(p4-COD)]
2
and [Os3Rh(v-
H)2(CO)8(v-CO)(v-I)(bipy)] 3. Similar reactions
between [Os3(v-H)2(CO)10] and rhodium cyclooctadiene
complexes containing other bidentate N-donor ligands
[Rh(COD)(L)I] also resulted in the formation of 1, 2,
[Os3Rh(v-H)2(CO)8(v-CO)(v-I)(L)] L=1,10-phenan-
throline 4 and 4,4%-diphenyl-2,2%-dipyridyl 5, see Scheme
1.
1
−17.5. The H-NMR signals due to the major isomer
are consistent with the observed solid-state structure of
2 as it contains a hydride bridging an Os–Rh edge. The
occurrence of the minor isomer may be due to the
rearrangement of the hydride ligands on the cluster

S. Yeuk-Wah Hung, W.-T. Wong / Journal of Organometallic Chemistry 566 (1998) 237–243
239
Table 1
Spectroscopic data for complexes 1–5
c
Complex
IR spectra, aw/cm−1
Mass spectra,b
1065(1065)
1H-NMR spectra,
1
2091m, 2070s, 2045s, 2030w, 2012s, 2005s, 1993w,
1979m, 1972w
5.24 (m,4H, CH), 2.45 (m, 8H, CH2), −15.18 (d, 1H,
RhH=13, RhHOs), −18.33 (s, 1H, OsHOs), −19.08
J
(s, 1H, OsHOs)
2
2082m, 2064m, 2053m, 2033s, 1997s, 1976m, 1960w, 1163(1164)
1933w, 1815w, 1742w
Isomer A: 5.43 (m, 1H, CH), 5.09 (m, 1H, CH), 4.99
(m, 1H, CH), 4.61 (m, 1H, CH), 2.62 (m, 2H, CH2),
2.38 (m, 4H, CH2), 1.98 (m, 2H, CH2), −18.20 (d,
1H, JRhH=21Hz, RhHOs), −19.5 (s, 1H, OsHOs).
Isomer B: 5.61 (m, 4H, CH), 2.86 (m, 8H, CH2),
−17.50 (s, 2H, OsHOs)
3
4
2099w, 2068s, 2030s, 2015s, 1966m, 1916w, 1781m
2070s, 2030s, 2015s, 1991m, 1966m, 1918w, 1783m
1210(1213)
1234(1235)
8.89 (d, 1H, JHH=6, Hd/Hd’), 8.76 (d, 1H, JHH=6,
Hd/Hd%), 8.09 (m, 4H, Ha, Ha%, Hc & Hc%), 7.59 (m,
1H, Hb/Hb%), 7.34 (m, 1H, Hb/Hb%), −19.43 (s, 1H,
OsHOs), -22.56 (d, 1H, JRhH=34, RhHOs)
9.18 (d, 1H, JHH=5, Ha/Ha%), 9.01 (d, 1H, JHH=5,
Ha/Ha%), 8.64 (d, 1H, JHH=5, Hb/Hb%), 8.49 (d, 1H,
J
HH=6, Hb/Hb’), 8.03 (m, 2H, Hc & Hc%), 7.91 (m,
1H, Hd/Hd%), 7.67 (m, 1H, Hd/Hd%), −19.42 (s, 1H,
OsHOs), −22.18 (d, 1H, JRhH=25, RhHOs)
5
2070s, 2029s, 2015s, 1991m, 1966m, 1916w, 1781m
1362(1363)
8.82 (d, 1H, JHH=5, Ha/Ha’), 8.67 (d, 1H, JHH=5,
Ha/Ha%), 8.27 (m, 4H, Hb, Hb’, Hc & Hc’), 7.66 (m,
4H, Hd, Hd%, Hh & Hh%), 7.53 (m, 4H, He, He%, Hg
&
Hg%), 7.42 (m, 2H, Hf/Hf%), −19.50 (s, 1H, OsHOs),
−22.39 (d, 1H, JRhH=24, RhHOs)
a 1,2 in n-hexane, 3-5 in CH2Cl2.
b Positive FAB, simulated values in parenthese.
c in CDCl3, J values in Hz.
core. A process is proposed in Scheme 2 which may
account for the observed spectroscopic data. The sug-
gested isomer B contains a mirror symmetry so that
two hydride ligands are equivalent.
The profile of the IR spectra of cluster 3, 4 and 5 in
the region 1600–2200 cm−1 (wCO) are almost identical
and suggests that their structures are similar (Table 1).
Their 1H-NMR spectra contain a set of multiplets
arising from the bidentate N-donor ligands and two
resonances due to hydride ligands. As in the case of 2,
the singlet should be due to the hydride bridging Os–
Os bond while the doublet is assigned to the hydride
bridging Os–Rh bond.
2.3. Crystallographic analyses of complexes 1–3 ·0.5
C6H6
Single crystals suitable for X-ray analysis of 1 and 2
were obtained from pure n-hexane solutions at room
temperature (r.t.) whereas crystals of 3 were grown in a
CH2Cl2 and benzene solution at room temperature.
Perspective drawings of complexes 1 and 2 are shown in
Fig. 1 and Fig. 2, respectively, with selected bond
lengths and angles given in Table 2 and Table 3. X-ray
analyses of 1 and 2 revealed that the metal frameworks
constitute distorted Os3Rh tetrahedra with COD lig-
ands coordinated to the rhodium atoms in a p4-co-ordi-
nation mode; the co-ordinating double bonds in COD
are situated in a plane parallel to the basal plane
defined by three osmium metals of the tetrahedron.
Similar mixed-metal clusters have been found in the
platinum analogues [Os3Pt(v-H)2(v-CO)(CO)9(COD)]
[14] and [Os3Pt(v-H)2(CH2)(CO)9(COD)] [15]. All car-
bonyl ligands in 1 are coordinated in a terminal mode.
For cluster 1, three hydrides are believed to bridge
Os(1)–Os(3), Os(2)–Os(3) and Os(1)–Rh(1) based on
the spectroscopic data (1H-NMR) and further sup-
ported by the elongated metal–metal bonds. For com-
plex 2, the Os(1)–Rh(1) bond is coordinated by an
asymmetrically bridging carbonyl ligand [Rh(1)–
˚
˚
C(3)=2.30(3) A, Os(1)–C(3)=1.89(3) A] and Os(3)–
Scheme 2.
Rh(1) is bridged by a hydride with the Os(2)–Rh(1)

240
S. Yeuk-Wah Hung, W.-T. Wong / Journal of Organometallic Chemistry 566 (1998) 237–243
Table 2
˚
Selected bond distances (A) and angles (°) for cluster 1
˚
Bond length (A)
Os(1)–Os(2)
Os(2)–Os(3)
Os(2)–Rh(1)
Os(1)–C(1)
Rh(1)–C(11)
Rh(1)–C(15)
C(11)–C(12)
C(12)–C(13)
C(14)–C(15)
C(16)–C(17)
2.7951(8) Os(1)–Os(3)
2.9189(8) Os(1)–Rh(1)
2.733(1) Os(3)–Rh(1)
2.9735(8)
2.920(1)
2.739(1)
1.92(2)
2.39(1)
2.39(2)
1.49(2)
1.51(3)
1.34(2)
1.49(3)
1.92(2)
2.36(1)
2.39(2)
1.35(2)
1.52(2)
1.49(2)
1.52(3)
Os(3)–C(3)
Rh(1)–C(12)
Rh(1)–C(16)
C(11)–C(18)
C(13)–C(14)
C(15)–C(16)
C(17)–C(18)
Bond angle (°)
Os(2)–Os(1)–Os(3) 60.70(2)
Os(2)–Rh(1)–C(10) 82.9(5)
Os(1)–Rh(1)–Os(3) 63.30(3)
C(10)–Rh(1)–C(15) 117.3(7)
and structural analyses. The molecular geometry with
atomic labelling of 3 is depicted in Fig. 3 and selected
bonding parameters in Table 4. Complex 3 also con-
tains a rhodium atom face capping on the triangular
osmium metal framework with the bidentate bipyridine
group chelating to the rhodium apex of the tetrahe-
dron. A bridging iodide and carbonyl ligand are found
to coordinate across the Os(1)–Os(2) and Os(2)–Rh(1)
bonds, respectively. The structures of 2 and 3 are very
similar except the chelating ligands on the rhodium
atom are different.
We have not been able to obtain suitable single
crystals of 4 and 5 for X-ray analysis. However, they
are proposed to be isostructural to 3 according to the
spectroscopic and elemental analyses. As far as the
electron counting rule is concerned, all the clusters 1–5
possess 60 cluster valence electrons (c.v.e.) count which
is consistent with the tetranuclear clusters with six
metal-metal bonds. Hence the rhodium atoms in these
clusters adopt 18-electron configuration.
Fig. 1. Molecular structure of cluster 1 showing the atomic labelling
scheme for non-hydrogen atoms.
vector being unsupported. Besides, there is an iodide
bridge across the Os(1)–Os(3) bond and a hydride
ligand bridging the Os(1)–Os(2) edge.
Complex 3 is the only bipyridine-containing product
from the reaction as confirmed by both spectroscopic
This work showed that nitrogen donor ligands can be
incorporated on the cluster core by simple coupling
Table 3
˚
Selected bond distances (A) and angles (°) for cluster 2
˚
Bond length (A)
Os(1)–Os(2)
Os(2)–Os(3)
Os(2)–Rh(1)
Os(1)–I(1)
Os(1)–C(3)
Rh(1)–C(10)
Rh(1)–C(14)
C(10)–C(11)
C(11)–C(12)
C(13)–C(14)
C(15)–C(16)
2.963(2) Os(1)–Os(3)
2.714(2) Os(1)–Rh(1)
2.908(2) Os(3)–Rh(1)
2.714(2) Os(3)–I(1)
2.842(2)
2.778(2)
2.902(2)
2.744(2)
2.32(3)
2.19(3)
2.17(3)
1.54(4)
1.51(5)
1.34(4)
1.48(4)
1.91(3)
2.22(3)
2.11(3)
1.31(4)
1.54(5)
1.54(5)
1.53(4)
Rh(1)–C(3)
Rh(1)–C(11)
Rh(1)–C(15)
C(10)–C(17)
C(12)–C(13)
C(14)–C(15)
C(16)–C(17)
Bond angle (°)
Os(2)–Os(1)–Os(3) 57.31(4)
Os(1)–I(1)–Os(3) 62.75(5)
Os(1)–Rh(1)–Os(3) 59.99(5)
Os(1)–C(3)–Rh(1) 81(1)
Fig. 2. Molecular structure of cluster 2 showing the atomic labelling
scheme for non-hydrogen atoms.

S. Yeuk-Wah Hung, W.-T. Wong / Journal of Organometallic Chemistry 566 (1998) 237–243
241
[16] and [Rh(COD)(L)I]13; L=2,2%-bipyridine, 1,10-
phenanthroline and 4,4%-diphenyl-2,2%-dipyridyl) were
prepared using the method from the literature. IR
spectra were recorded on Bio-Rad FTS-7 IR spectrom-
eter, using 0.5 mm calcium fluoride solution cells. Pro-
ton NMR spectra were recorded on a Bruker DPX 300
NMR spectrometer using CDCl3 and referenced to
SiMe4 (l 0). Mass spectra were recorded on a Finnigan
MAT 95 instrument by the fast atom bombardment
technique, using m-nitiobenzyl alcohol or h-thioglyc-
erol as the matrix solvents. Microanalyses were per-
formed by Butterworth Laboratories, UK. Routine
purification of products was carried out in air by
thin-layer chromatography (TLC) on plates coated with
Merck Kieselgel 60 GF254
.
3.2. Reaction of [Rh(COD)(bipy)I]
(COD=cycloocta-1,5-diene); bipy=2,2%-bipyridine)
with [Os3(v-H)2(CO)10]
A solution of [Os3(v-H)2(CO)10] (30 mg, 0.035 mmol)
and [Rh(COD)(bipy)I] (17 mg, 0.035 mmol) in CH2Cl2
(20 cm3) was refluxed under an dinitrogen atmosphere
for 1 h (TLC monitoring). The solution gradually
turned from bright–red to brown. The solvent was
removed in vacuo and the residue was chro-
matographed on silica gel using n-hexane-CH2Cl2 (1:3)
as eluent. The first yellow band was found to be
[Os3(CO)12] (as confirmed by IR spectroscopy). Three
consecutive bands were then eluted, namely complex, 1
(Rf 0.70; 10, 0.010, 22), 2 (Rf 0.55; 16, 0.014, 38), 3 (Rf
0.30; 12 mg, 0.009 mmol, 24%) (Found: C, 20.2; H, 1.4.
Calc. for C18H15IO10Os3Rh 1: C, 20.3; H, 1.4. Found:
C, 17.4; H, 1.2. Calc. for C17H15IO9Os3Rh 2: C, 17.6;
H, 1.3. Found: C, 18.8; H, 0.8; N, 2.1. Calc. for
C19H10IO9N2Os3Rh 3: C, 18.8; H, 0.8; N, 2.2%.).
Fig. 3. Molecular structure of cluster 3 showing the atomic labelling
scheme for non-hydrogen atoms.
reaction from a metal reagent containing the nitrogen
donors although the yields are not high.
3. Experimental
3.1. Materials
All reactions and manipulations were carried out
under an inert atmosphere of dinitrogen using standard
Schlenk techniques. Solvents were purified by standard
procedures and freshly distilled prior to use. All chemi-
cals, except where stated, were purchased commercially
and used as received. The complexes [Os3(v-H)2(CO)10]
3.3. Reaction of [Rh(COD)(L)I]; L=1,10-phen or
4,4%-diphbipy) with [Os3(v-H)2(CO)10]
The same treatment with [Os3(v-H)2(CO)10] using
equal molar [Rh(COD)(1,10-phen)I] or [Rh(COD)(4,4%-
Table 4
˚
Selected bond distances (A) and angles (°) for cluster 3
diphbipy)I] afforded same products, 1,
2
and
[Os3(CO)12] (confirmed by IR and 1H-NMR spec-
troscopy); however, instead of 3, cluster 4 (ca. 20%) and
5 (ca. 25%) were isolated, respectively. (Found: C, 20.5;
H, 0.9; N 2.2. Calc. for C21H11IO9N2Os3Rh 4: C, 20.4;
H, 0.8; N, 2.3. Found: C, 27.4; H, 1.2; N, 2.0. Calc. for
C31H19IO9N2Os3Rh 5: C, 27.3; H, 1.3; N, 2.1%).
˚
Bond length (A)
Os(1)–Os(2)
Os(2)–Os(3)
Os(2)–Rh(1)
Os(1)–I(1)
Os(2)–C(6)
Rh(1)–N(1)
N(1)–C(10)
N(2)–C(15)
C(10)–C(11)
2.8833(7) Os(1)–Os(3)
2.9870(7) Os(1)–Rh(1)
2.788(1)
2.803(1)
1.99(1)
2.7947(7)
2.897(1)
2.899(1)
2.7840(9)
1.99(1)
2.081(9)
1.37(1)
1.33(2)
Os(3)–Rh(1)
Os(2)–I(1)
Rh(1)–C(6)
1.074(10) Rh(1)–N(2)
1.32(2)
1.35(2)
1.39(2)
N(1)–C(14)
N(2)–C(19)
C(11)–C(12)
3.4. X-ray data collection and structural determination
of complexes 1–3
1.36(2)
Bond angle (°)
Os(2)–Os(1)–Os(3) 63.46(2)
Os(1)–I(1)–Os(2) 62.14(2)
N(1)–Rh(1)–N(2) 78.8(4)
Os(1)–Rh(1)–Os(2) 60.91(2)
Os(2)–C(6)–Rh(1) 89.0(5)
C(10)–N(1)–C(14) 117(1)
All pertinent crystallographic data and other experi-
mental details are summarised in Table 5. Data were
collected at ambient temperature either on a Rigaku

242
S. Yeuk-Wah Hung, W.-T. Wong / Journal of Organometallic Chemistry 566 (1998) 237–243
Table 5
Crystallographic data and data collection parameters for compounds 1–3
Compound
1
2
3
Empirical formula
M
Os3RhC18H15O10
1064.82
Red, block
0.14×0.18×0.21
Monoclinic
C2/c (no. 15)
32.311(2)
10.111(1)
−15.997(1)
—
Os3RhC17O9H14
1162.70
Brown, cubic
I
Os3RhC19N2O9H10I.0.5C6H6
1210 (1249.76 with solvent)
Orange, block
0.19×0.23×0.24
Triclinic
Crystal colour, habit
Crystal size/mm
Crystal system
Space group
0.12×0.14×0.18
Monoclinic
P21/c (no. 14)
9.200(6)
10.915(5)
23.057(6)
—
92.02(4)
—
2314(1)
4
(
P1 (no. 2)
˚
a (A)
10.825(1)
12.253(1)
12.318(1)
74.97(2)
71.18(2)
70.26(2)
1434.8(4)
2
˚
b (A)
˚
c (A)
h (°)
i (°)
116.32(2)
—
4684.4(9)
8
k (°)
U/A
3
˚
Z
D
calc./g cm−3
3.019
3.337
2.893
F(000)
3808
169.52
—
51.1
0.0
19887
4598
3021
2056
184.88
0.94+0.35 tan q
2-45
16.0
3450
3218
2416
0.020
1114
149.22
—
51.2
0.0
20542
4774
3134
0.028
v(Mo–Kh)/cm−1
ꢀ-Scan width/°
2q Range collected/°
Scan speed/° min−1
Reflections collected
No. unique reflections
Reflections observed [I\3|(I)]
p in weighting scheme w=[|2c(Fo)+p2/4(Fo2)]−1
R indices (observed data)
0.024
R=0.042, R%=
0.052
R=0.065, R%=
0.081
R=0.035, R%=0.042
Goodness of fit S
Maximum D/|
1.70
0.02
289
2.23
1.45
195
1.05
0.09
328
No. of parameters
Maximum, minimum density in DF map/eA−3, close to Os or Rh 1.32 to −1.83
1.45 to −1.51
0.89 to −1.29
˚
AFC7R diffractometer (complex 2) or a MAR research
image plate scanner (complex 1 and 3), using Mo–Kh
positions whilst all the metal hydrides were estimated
by potential energy calculations [20]. All the hydrogen
atoms were included in the structure factors but the
parameters were not refined. Calculations were per-
formed on a Silicon-Graphics computer, using the pro-
gram package TEXSAN [21].
Atomic coordinates, thermal parameters, and bond
lengths and angles have been deposited at the Cam-
bridge Crystallographic Data Centre (CCDC).
˚
radiation (u=0.71073 A) with
a graphite-crystal
monochromator in the incident beam. For 2, the data
were collected using the (ꢀ-2q) scan technique with an
exposure time of 5 min per frame used. The diffracted
intensities were corrected for Lorentz and polarization
effects. The „-scan method was employed for semi-em-
pirical absorption corrections for 2 [17], while an ap-
proximation to absorption correction by inter-image
scaling was made for 1 and 3. Scattering factors were
taken from reference ([18]a) and anomalous dispersion
effects ([18]b) were included in Fc.
Acknowledgements
The space group of all structures were determined
from their systematic absences and the Laue symmetry
check. We realized that 3 can be transformed into a
C-centered cell. However, the required 2/m Laue sym-
metry is not observed. Therefore, the triclinic cell is
used for structure solution and refinement. All struc-
tures were solved by direct methods (SIR 88) [19] and
expanded by Fourier-difference techniques. The solu-
tions were refined on F by full-matrix least-squares
analysis with all non-hydrogen atoms refined anisotrop-
ically except carbon atoms in 2. The hydrogen atoms of
all the organic moieties were generated in their idealised
We gratefully acknowledges financial support from
the Hong Kong Research Grants Council and the
University of Hong Kong. S.Y.-W. Hung acknowledges
the receipt of a postgraduate studentship and Hung
Hing Ying scholarships administered by the University
of Hong Kong.
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