New Coordinaiton Modes of an Oxime Ligand in a Triosmium Cluster. Stabilization by Intra- and Intermolecular C-H...O Hydrogen Bonds

摘要

Reaction of the hydroxyamine 7-chloro-4-(hydroxyamino)quinoline with the triosmium cluster Os_3(CO)_10(NCMe)_22 gave the complex (#mu#-H)Os_3(CO)_10(#mu#_2-#eta#~1-O-C_9H_6N_2Cl) (3), in which a new mode of #mu#_2-#eta#~1-O-oximato ligand bridged two osmium centers by an oxygen atom. This complex was slowly converted to (#mu#-H)Os_3(CO)_10(#mu#_2-#eta#~2-ON-C_9H_6NCl) (4), where an aromatic C-H moiety in the #mu#_2-#eta#~2-ON-oximatoquinoline group formed an unusual short intramolecular C-H...O-N hydrogen bond and an intermolecular C-H...O=C hydrogne bond simultaneously. The formation of the intramolecular hydrogne bond may provide a stabilization effect for the generationl of the #eta#~2-ON complex 4 and a driving force for the transformation of 3 to 4.