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

Article abstract of DOI:10.1021/ic00136a051

Bis(tetraazabutadiene)nickel complexes, [Ni(Ar₂N₄)₂], have been prepared by reactions of bis(1,5-cyclooctadiene)nickel or bis(cyclopentadienyl)nickel with aryl azides (Ar = 4-MeC₆H₄, 4-MeOC₆H₄, 4-ClC₆H₄, and 3,5-Me₂C₆H₃). The reaction with bis(cyclopentadienyl)nickel proceeds via [Ni(Ar₂N₄)(η⁵-C₅H₅)]. 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. Crystals are tetragonal, space group P4₂/n, with Z = 2 in a unit cell of dimensions a = b = 9.677 (1) and c = 16.601 (1) A?. 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 Ni⁰ species. Bis[1,4-bis(4-tolyl)tetraazabutadiene]nickel reacts with tert-butyl isocyanide to give [Ni[1,4-(4-MeC₆H₄)₂N₄](t-BuNC) ₂]. The latter product could also be prepared via the 1/1 reaction of [Ni[1,4-(4-MeC₆H₄)₂N₄]₂] with [Ni(t-BuNC)₄] in the presence of excess t-BuNC.