The reactions of cysteine ethyl ester with a series of triosmium clust
ers have been studied. Enantiomeric (mu-H)Os3{mu-SCH2CH(CO2Et)NH2}(CO)
10 and diastereomeric (mu-H)Os3{mu-eta2-SCH2CH(CO2Et)NH2}(CO)9 forms o
f the optically active cluster complexes have been obtained. Diastereo
meric clusters have been separated by TLC on Silufol plates. The treat
ment of the enantiomeric complex (mu-H)Os3{mu-SCH2CH(CO2Et)NH2}(CO)10
with the trimethylamine oxide yields the diastereomeric pair (mu-H)Os3
{mu-eta2-SCH2CH(CO2Et)NH2}(CO)9. The structures of the complexes obtai
ned have been established on the basis of IR, H-1 NMR and mass spectro
metry as well as X-ray analysis data.