Cleavage of P-X bond of phosphines by a dichromium complex containing a quintuple bond

Abstract

The reactivity of formally quintuply bonded bimetallic aminopyridinato chromium complex (1) towards various phosphines was investigated. Oxidative additions were observed in which the Cr[sbnd]Cr quintuple bond is inserted into P-X bond of the used phosphines to give the corresponding [Ap2Cr2(μ-PR2)(μ-X)] complexes (2a-2c) {where Ap = (2,6-diisopropylphenyl)-[6-(2,6-dimethylphenyl)pyridin-2-yl]amide, 2a: R = C6H5, X = H; 2b: R = C6H5, X = Cl; 2c: R = C2H5, X = Cl)}. The synthesized compounds are diamagnetic and 2a and 2c have been characterized by X-ray crystal structure analysis. The structures indicate a reduction of the bond order of the Cr2moiety to four. The bimetallic CrIIcomplexes 2a and 2c feature metal-metal distances of 1.856(11) and 1.867(7) Å, respectively.