TY - JOUR
T1 - Preparation, X-ray structural analysis, and method of interconversion of two isomeric forms of [os6(CO)16{P(OMe)3}2]
AU - Johnson, Brian F. G.
AU - Kamarudin, Rose A.
AU - Lahoz, Fernando J.
AU - Lewis, Jack
AU - Raithby, Paul R.
PY - 1988/12/31
Y1 - 1988/12/31
N2 - Treatment of the labile cluster [Os6(CO)16(NCMe)2] (1) with excess trimethyl phosphite, at room temperature, affords two isomers of [Os6(CO)16{P(OMe)3}2] (2a) and (2b) as the major products, together with small amounts of [Os6(CO)15{P(OMe)3}3] (3). The 1H n.m.r. spectrum of (2a) indicates that the two P(OMe)3 groups are equivalent, and an X-ray analysis of this product shows that these two ligands occupy equivalent sites on the two capping Os atoms of the bicapped tetrahedral metal framework, as has been observed previously in other disubstituted derivatives of [Os6(CO)18]. In isomer (2b), 1H n.m.r. data show that the two phosphite environments are inequivalent. This is confirmed by the X-ray crystal structure in which the bicapped tetrahedral hexaosmium framework is retained, but while one P(OMe)3 group occupies a site on one of the capping Os atoms, the other is co-ordinated to one of the Os atoms in the central tetrahedron. In solution isomer (2b) converts to (2a). Possible mechanisms by which this interconversion may take place are discussed.
AB - Treatment of the labile cluster [Os6(CO)16(NCMe)2] (1) with excess trimethyl phosphite, at room temperature, affords two isomers of [Os6(CO)16{P(OMe)3}2] (2a) and (2b) as the major products, together with small amounts of [Os6(CO)15{P(OMe)3}3] (3). The 1H n.m.r. spectrum of (2a) indicates that the two P(OMe)3 groups are equivalent, and an X-ray analysis of this product shows that these two ligands occupy equivalent sites on the two capping Os atoms of the bicapped tetrahedral metal framework, as has been observed previously in other disubstituted derivatives of [Os6(CO)18]. In isomer (2b), 1H n.m.r. data show that the two phosphite environments are inequivalent. This is confirmed by the X-ray crystal structure in which the bicapped tetrahedral hexaosmium framework is retained, but while one P(OMe)3 group occupies a site on one of the capping Os atoms, the other is co-ordinated to one of the Os atoms in the central tetrahedron. In solution isomer (2b) converts to (2a). Possible mechanisms by which this interconversion may take place are discussed.
UR - http://www.scopus.com/inward/record.url?scp=37049084144&partnerID=8YFLogxK
U2 - 10.1039/DT9880001205
DO - 10.1039/DT9880001205
M3 - Article
AN - SCOPUS:37049084144
SN - 1472-7773
SP - 1205
EP - 1211
JO - Journal of the Chemical Society, Dalton Transactions
JF - Journal of the Chemical Society, Dalton Transactions
IS - 5
ER -