CpCr(CO)3 ■-initiated N-N bond cleavage in a thiotetrazole ligand in a cyclopentadienylchromium complex

Abstract

The tetrazolylthiolato complex CpCr(CO)3(STz) (4a) was obtained from the facile reaction between [CpCr(CO)3]2 (Cp = C 5H5) (1) and 5,5′-dithiobis(1-phenyl-1H-tetrazole), (abbrev. (PhN4CS)2 or (STz)2). Further reaction of 4a with 1 under thermolytic conditions led to isolation of low yields of the cubane-like complexes Cp4Cr4S3(μ 3-N3Ph) (5), Cp4Cr4S 2(μ3-CO)(μ3-NC≡CrCp(CO) 2) (6), Cp4Cr4S2(μ3- N3Ph)(μ3-NC≡CrCp(CO)2) (7) and Cp 4Cr4SO2(μ3-NPh) (8), containing μ3-phenyltriazenido, imidocarbyne and phenylimido groups at the corners of cuboids, in addition to μ3-sulfide, oxo or carbonyl groups. The predominant products were the decarbonylation derivative of 1, i.e. [CpCr(CO)2]2(Cr≡Cr) (9), together with [CpCr(CO)2]2S (10) and its thermolytic cuboidal derivatives, mainly Cp4Cr4S2O2 (11) and Cp4Cr4S4 (13). 1-initiated homolytic fragmentation of the tetrazole ring was proposed to rationalize the formation of the derived cubanes. The structures of the complexes 4a, 6-8 and 11 have been determined by single X-ray diffraction analysis. © 2004 Elsevier B.V. All rights reserved.