Formula omitted]-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 5H 5) ( 1) and 5,5′-dithiobis(1-phenyl-1H-tetrazole), (abbrev. (PhN 4CS) 2 or (STz) 2). Further reaction of 4a with 1 under thermolytic conditions led to isolation of low yields of the cubane-like complexes Cp 4Cr 4S 3(μ 3-N 3Ph) ( 5), Cp 4Cr 4S 2(μ 3-CO)(μ 3-NC CrCp(CO) 2) ( 6), Cp 4Cr 4S 2(μ 3-N 3Ph)(μ 3-NC CrCp(CO) 2) ( 7) and Cp 4Cr 4SO 2(μ 3-NPh) ( 8), containing μ 3-phenyltriazenido, imidocarbyne and phenylimido groups at the corners of cuboids, in addition to μ 3-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 Cp 4Cr 4S 2O 2 ( 11) and Cp 4Cr 4S 4 ( 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.