TRIOSMIUM CLUSTERS CONTAINING THIAZOLIDE LIGAND - CRYSTAL-STRUCTURES OF [(MU-H)OS-3(CO)(10)(MU-3,4-ETA(2)-HC=NC=CHS)] AND [(MU-H)OS-3(CO)(9)(MU-3,4-ETA(2)-HC=NC=CHS)(PPH3)]

The reaction of [Os-3(CO)(10)(MeCN)(2)] with thiazole at ambient tempe rature affords two isomeric isolable compounds [(mu-H)Os-3(CO)(10)(mu- 2,3-eta(2)-C=NCH=CHS)] 2 and [mu-H)Os-3(CO)(10)(mu -3,4-eta(2)-HC=NC=C HS)] 3 in 20 and 60% yields, respectively. Compound 3 reacts with PPh3 at 110 degrees C to give [(mu-H)Os-3(CO)(9)(mu-3,4-eta(2)-HC=NC=CHS)( PPh3)] 4, which exists as two isomeric forms in solution. Reaction of 3 with trimethyl phosphite at 110 degrees C gives the substitution pro duct mu-H)Os-3(CO)(9)(mu-3,4-eta(2)-HC=NC=CHS){P(OMe3}] 5, which is st ructurally analogous to 4 in solution. Similarly compound 2 reacts wit h PPh3 at 110 degrees C to afford (mu-H)Os-3(CO)(10)(mu-2,3-eta(2)-C=N CH=CHS)(PPh3)] 6, which also exists as two isomers in solution. The co mpounds have been characterised by IR,H-1-NMR and elemental analysis t ogether with single crystal X-ray analysis for 3 and 4. (C) 1998 Elsev ier Science S.A, All rights reserved.