Abstract
Reaction of the hydroxyamine 7-chloro-4-(hydroxyamino)quinoline with the triosmium cluster Os 3 -(CO) 10 (NCMe) 2 gave the complex (μ-H)Os 3 (CO) 10 (μ 2 -η 1 -O-C 9 H 6 N 2 Cl) (3), in which a new mode of μ 2 -η 1 -O-oximato ligand bridged two osmium centers by an oxygen atom. This complex was slowly converted to (μ-H)Os 3 -(CO) 10 (μ 2 -η 2 ON-C 9 H 6 NCl) (4), where an aromatic C-H moiety in the μ 2 -η 2 -ON-oximatoquinoline group formed an unusual short intramolecular C-H⋯O-N hydrogen bond and an intermodular C-H⋯O=C hydrogen bond simultaneously. The formation of the intramolecular hydrogen bond may provide a stabilization effect for the generation of the η 2 -ON complex 4 and a driving force for the transformation of 3 to 4.