Synthesis of new complexes of osmium and ruthenium containing the carboxylated group of 18 beta-glycyrrhetinic acid as ligand. Crystal structure of the complex [Os-3(mu-H)(mu-O2C-C29H45O2)(CO)(10)]

The reaction of Os-3(CO)(10)(MeCN)(2) with 18 beta -glycyrrhetinic acid (18 beta -GA) yielded the complex [Os-3(mu -H)(mu -O2C-C29H45O2)(CO)(10)] (1). An X-ray study of the complex indicated that the carboxylated group of 18 beta -GA is coordinated with the trinuclear cluster and the oleanic organic framework is oriented in exo form with respect to the plane defined by the osmium triangle. By contrast, the reaction of Ru-3(CO)(12) with 18 beta -G A yielded a dimeric complex characterized by H-1 NMR; FTIR and mass spectro scopy as [Ru-2(mu -O2C-C29H45O2)(2)(CO)(4)(THF)(2)] (2). (C) 2001 Published by Elsevier Science B.V.