Synthesis and reactivity of bis(1,4-diaryltetraazadiene)nickel complexes. Crystal and molecular structure of di[1,4-di(3,5-dimethylphenyl)tetraazadiene]nickel

Abstract

Bis(tetraazabutadiene)nickel complexes, [Ni(Ar,N4),], have been prepared by reactions of bis( 1,s-cyc1ooctadiene)nickel or bis(cyclopentadieny1)nickel with aryl azides (Ar = 4-MeC6H4, 4-MeOC6H4, 4-ClC6H4, and 3,5-Me). The reaction with bis(cyclopentadieny1)nickel proceeds via [Ni(Ar2N4)($-CSH5)]. The crystal and molecular structure of bis[ 1,4- bis(3,5-dimethylphenyl)tetraazabutadiene]nickel, which is the first example of a bis(tetraazabutadiene)metal complex, have been determined by a single-crystal X-ray diffraction study. Cr stals are tetragonal, space group P4,/n, with Z = 2 in a unit cell of dimensions a = b = 9.677 (1) and c = 16.601 (1) i.The final R value is 0.034 for 1307 reflections. The nickel atom has a pseudotetrahedral geometry with two planar Ar2N4 ligands orientated perpendicular to each other. Furthermore the three N-N bond distances are nearly equal with a mean value of 1.322 A. On the basis of these structural features the compounds are formulated as 18e Nio species. Bis[ 1,4-bis(4-tolyl)tetraazabutadiene]nickel reacts with rert-butyl isocyanide to give [Ni[1,4-(4-MeC6H4)2N4](r-BT~hNeC l)atzte]r. p roduct could also be prepared via the 1 / 1 reaction of [Ni[1 ,4-(4-MeC6H4)2N4]w2]it h [Ni(t-BuNC),] in the presence of excess t-BuNC.