73440-09-2Relevant academic research and scientific papers
Synthesis, reactivity, and crystal structure of [1,4-bis(4-tolyl)tetraazabutadiene](η5-cyclopentadienyl)nickel
Overbosch, Peter,Van Koten, Gerard,Spek, Anthony L.,Roelofsen, Gerrit,Duisenberg, Albert J. M.
, p. 3908 - 3913 (2008/10/08)
The complex [1,4-bis(4-tolyl)tetraazabutadiene](η5-cyclopentadienyl)nickel has been prepared by reaction of bis(η5-cyclopentadienyl)nickel with 4-tolyl azide. The crystal and molecular structures have been determined by a single-crystal X-ray diffraction study. Crystals are monoclinic, space group P21/c, with Z = 4 in a unit cell of dimensions a = 10.277 (4) A?, b = 15.139 (6) A?, c = 11.455 (3) A?, and β = 102.31 (3)°. The final R value is 0.032 for 3150 reflections. The structure comprises mononuclear units with each central nickel atom coordinated to an η5-bonded cyclopentadienyl group and, via two nitrogen atoms at the 1- and 4-positions, to the tetraazabutadiene system. The resultant NiN4 ring is planar with the aryl substituents twisted 45° out of this plane. The tetraazabutadiene moiety has a short central N(2)-N(3) distance (1.278 (2) A?) and two longer adjacent N-N bonds (1.345 (2) A? average). This complex can be reacted further either with aryl azides to produce bis(tetraazabutadiene)nickel complexes or with tert-butyl isocyanide to yield bis(tert-butyl isocyanide)[1,4-bis(4-tolyl)tetraazabutadiene]nickel. The title complex is paramagnetic. The ESR spectrum shows hyperfine coupling of the unpaired electron with two nitrogen atoms (g1 = 1.97, g2 = 2.01, g3 = 2.08, AN(g2) = 12 G). XPS spectra of the Ni(2p) and N(1s) bands exhibit a shake-up satellite in the latter. The bonding in this compound is discussed on the basis of the crystal structure and the spectral data.
