A Heterobimetallic Superoxide Complex formed through O-2 Activation between Chromium(II) and a Lithium Cation

摘要

The reaction of 1,1,3,3-tetraphenyl-1,3-disiloxandiol (LH2) with n-butyllithium and CrCl2 results in a mononuclear chromium(II) complex (1) that further reacts with O-2 at low temperatures to yield a mononuclear chromium(III) superoxide complex [L2CrO2(THF)][Li-2(THF)(3)] (2). The crystal structure revealed that the chromium superoxido entity is stabilized by the coordination to an adjacent lithium cation. Complex 2 thus contains an unprecedented heterobimetallic [Cr-III(-O-2)Li+] core; beyond this it is the first chromium superoxide for which a temperature-dependent magnetic characterization could be achieved, and the first structurally characterized representative with chromium in an exclusive O-donor environment.