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oxime and 9-anthracenecarbonitrile were used directly as
received. The compound [Os3ðCOÞ11ðMeCNÞ] was
prepared by the literature method [7]. Infrared spectra
were recorded on a Bio-Rad FTS-135 IR spectrometer,
2.4. Photoreaction of cluster 1
A CH2Cl2 solution of 1 (50 mg, 0.046 mmol) was
irradiated by means of a 300 W high-pressure mercury
lamp for 1/2 h. Evaporation of the solvent and separa-
tion of products by TLC, using n-hexane–CH2Cl2 (3:1,
v/v) as eluent, gave ½Os3ðCOÞ12 ðRf ꢀ 0:80, 8 mg, 0.009
mmol, 20%) as the major product accompanied by a
small amount of unchanged 1.
1
using 0.5 mm calcium fluoride solution cells. H NMR
spectra were recorded on a Bruker DPX 300 NMR
spectrometer using CD2Cl2 with reference to SiMe4ðd0Þ.
Mass spectra were obtained on a Finnigan MAT95 mass
spectrometer by fast atom bombardment techniques,
using m-nitrobenzyl alcohol as the matrix solvent. Elec-
tronic absorption spectra were obtained with a Hewlett-
Packard 8453 diode array UV/Vis spectrophotome-
ter, using quartz cells, with 1 cm path length at room
temperature. Routine purification of products was car-
ried out in air by thin layer chromatography (TLC) on
plates coated with Merck Kiesegel 60 GF254. Elemental
analyses were conducted by Butterworth Laboratories,
UK.
2.5. Hydrogenation of cluster 1
Cluster 1 (50 mg, 0.046 mmol) was dissolved in
CHCl3 (30 ml). Hydrogenation of the bright yellow
solution at atmospheric pressure was then attempted at
room temperature. The reaction was monitored by spot
TLC until complete consumption of 1 (2 h). Chroma-
tography on silica with n-hexane–CH2Cl2 (4:1, v/v) af-
forded ½H2Os3ðCOÞ10 ðRf ꢀ 0:75, 18 mg, 0.021 mmol)
with 45% yield.
2.1. Reaction of ½Os3ðCOÞ ðMeCNÞ with 9-anthra-
11
ldehyde oxime
The cluster [Os3ðCOÞ11ðMeCNÞ] (100 mg, 0.109
mmol) and 9-anthraldehyde oxime (24 mg, 0.109 mmol)
were stirred at refluxing chloroform (30 ml) for 5 h. The
colour gradually turned dark yellow. The reaction
mixture was evaporated to dryness. The residue was fi-
nally redissolved in CH2Cl2 (ca. 2cm3) and separated by
preparative TLC with an eluent of n-hexane–CH2Cl2
(3:1 v/v) to give yellow complex 1 (Rf ꢀ 0:55, 54 mg,
0.050 mmol, 46%). Anal. found for 1: C, 28.8; H, 0.8;
N, 1.5; calc. for C26H9NO11Os3: C, 28.9; H, 0.8; N,
1.3%.
3. Results and discussion
3.1. Reaction of ½Os3ðCOÞ ðMeCNÞ with 9-anthra-
11
ldehyde oxime
Heating [Os3ðCOÞ11ðMeCNÞ] with 1 equivalent of 9-
anthraldehyde oxime in refluxing chloroform for 5 h
afforded [Os3ðCOÞ11ðC14H9CNÞ] 1 in moderate yield
upon TLC separation. On the other hand, cluster 1 can
be prepared in a higher yield (ꢁ70%) by stirring
[Os3ðCOÞ11ðMeCNÞ] with 9-anthracenecarbonitrile in
CH2Cl2 for 1 h (Scheme 1). The acetonitrile group in the
parent cluster is shown to be labile and can be easily
replaced by the anthracenecarbonitrile. The IR spec-
2.2. Reaction of ½Os3ðCOÞ ðMeCNÞ with 9-anthracene-
11
carbonitrile
1
trum shows the presence of terminal carbonyl ligands,
To a CH2Cl2 solution of [Os3ðCOÞ11ðMeCNÞ] (100
mg, 0.109 mmol) 9-anthracenecarbonitrile (22 mg, 0.109
mmol) was added at room temperature. Reaction was
completed after stirring for 1 h, as monitored by TLC
and IR spectroscopy. The reaction solution was con-
centrated in vacuo and separated by TLC using n-hex-
ane–CH2Cl2 (3:1, v/v) to give complex 1 (Rf ꢀ 0:55, 85
mg, 0.079 mmol, 72%).
and the mass spectrum exhibits molecular ion envelopes
that agree with the formula of the compound, with ion
peaks corresponding to CO loss also being present. The
1H NMR spectrum of 1 consists of proton signals
ranging from d 7.6 to 8.8, which are due to the aromatic
ring system; no metal hydride could be detected. In the
1
UV/Vis spectrum of 1, six absorption bands are seen,
whilst that of free 9-anthracenecarbonitrile exhibits five
absorption bands at 259, 348, 365, 383 and 404 nm. To
elucidate the molecular structure of cluster 1, a single
crystal X-ray analysis was carried out on a yellow crystal
that was obtained by slow evaporation from a n-hex-
2.3. Carbonylation of cluster 1
Cluster 1 (50 mg, 0.046 mmol) was dissolved in
CHCl3 (30 ml). The bright yellow solution was then
carbonylated. The reaction was monitored by spot
TLC until complete consumption of 1 (1/2 h). The
solvent was removed under reduced pressure and
TLC purification (eluent: n-hexane–CH2Cl2 (3:1, v/v))
afforded ½Os3ðCOÞ12ðRf ꢀ 0:80, 13 mg, 0.014 mmol,
30%).
1
Spectroscopic data of 1: IR [m(CO), CH2Cl2]: 2105w, 2053vs,
2039vs, 2008vs, 1979m; [m(CBN), KBr]: 2237w. Positive FAB MS: m/z
1082 (calc. 1082 ). 1H NMR (CD2Cl2) at 298 K: d 8.79 (s, 1H), 8.15 (m,
4H), 7.80 (m, 2H), 7.68 (m, 2H). kmax (nm) (e; dm3 molÀ1 cmÀ1) in
CH2Cl2 at 298 K: 259 (140 000), 350 (11 000), 368 (13 000), 392
(13 000), 413 (15 000)and 436 (11 000).