73432-46-9Relevant academic research and scientific papers
Synthesis and reactivity of bis(1,4-diaryltetraazabutadiene)nickel complexes. Crystal and molecular structure of bis[1,4-bis(3,5-dimethylphenyl)tetraazabutadiene]nickel
Overbosch, Peter,Van Koten, Gerard,Overbeek
, p. 2373 - 2378 (2008/10/08)
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.
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.
Inter- and Intra-molecular Ligand-exchange and -rearrangement Reactions of Tetra-azadiene Complexes of Nickel, Platinum, and Cobalt
Overbosch, Peter,Koten, Gerard van,Vrieze, Kees
, p. 1541 - 1548 (2007/10/02)
Tetra-azadiene-exchange and -rearrangement reactions have been observed for both and 5-C5H5)> (R2=1,4-diaryl) complexes.The reactions of or 5-C5H5)> with aryl azides lead to substitution of the tetra-azadiene ligands.Reactions of or 5-C5H5)> with aryl azides R'N3 produced platinium and nickel complexes with non-symmetrical RN4R' ligands.All products arising from these reactions were identified by field desorption mass spectrometry and/or h.p.l.c.Four mechanisms which can account for the nature of the observed products, the product distributions, and reaction times are discussed.Transient aryl-nitrene species are proposed as key intermediates in these reactions.
