Tri- and Tetranuclear Mixed-Metal Clusters Containing Alkyne Ligands: Synthesis and Structure of (Ru_3Ir(CO)_(11)(RCCR'))~-, (Ru_2Ir(CO)_9(RCCR'))~-, and (HRu_2Ir(CO)_9(RCCR'))

摘要

The tetrahedral cluster anion [Ru_3Ir(CO)_(13)]~- (1) reacts with internal alkynes RC ident to CR' to afford the alkyne derivatives [Ru_3Ir(CO)_(11)(RCCR')]~- (2: R = R' = Ph; 3: R = R'= Et; 4: R = Ph; R'= Me; 5: R = R'= Me) which have a butterfly arrangement of the Ru_3Ir skeleton in which the alkyne is coordinated in a #mu#_4-#eta#~2 fashion. Under CO pressure they undergo fragmentation to give the trinuclear cluster anions [Ru_2Ir(CO)_9(RCCR')]~- (6: R = R'= Ph; 7: R = R'= Et; 8: R = Ph; R'= Me; 8: R = R'= Me), in which the alkyne ligand is coordinated in a #mu#_3-#eta#~2 parallel fashion. Protonation of these trinuclear anions leads to the formation of the corresponding neutral hydrido clusters [HRu_2Ir(CO)_9(RC (ident to) CR')] (10: R = R'= Ph; 11: R = R'= Et; 12: R = Ph; R'= Me; 13: R = R'= Me). The protonation of the butterfly anions 2 and 3, however, gives rise to the formation of the neutral tetrahedral clusters [HRu_3Ir(CO)_(11)(RCCR')] (14: R = R'= Ph and 15: R = R'= Et), respectively. The analogous clusters [HRu_3Ir(CO)_(11)-(PbCCCH_3)] (16) and [HRu_3Ir(CO)_(11)(CH_3CCCH_3)] (17) are only accessible from the reaction of the neutral cluster [HRu_3Ir(CO)_(13)] with the corresponding alkynes. The complexes 2, 4, 5, 6, 10, 12 and 15 are characterised by X-ray structure analysis.