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 spectrum
1 shows the presence of terminal carbonyl ligands,
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
UV/Vis spectrum 1 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-