J. Kohout et al., Cyanamidonitrate-copper(II) complexes of imidazole ligands: X-ray crystallography and physical investigation, INORG CHIM, 287(2), 1999, pp. 186-192
New cyanamidonitrate-copper(II) complexes [Cu(NO2NCN)(2)L-n] (L = imidazole
(iz), n = 2; L = iz, 1-, 2- or 4-methylimidazole (meiz), n = 4) have been
isolated and characterised by IR, electronic and ESR spectroscopy. The crys
tal structures of 1- and 4-meiz complexes have been determined by X-ray cry
stallography; the structure of [Cu(NO2NCN)(2)(iz)(2)] is known (J. Kozisek,
J.G. Diaz, M. Hvastijova, L. Jager, Acta Crystallogr., Sect. C53 (1997) 70
3) The crystal structure of the first two compounds consists of [Cu(NO2NCN)
(2)L-4] units, in which the central Cu-II atoms are pseudo-octahedrally coo
rdinated by six nitrogen atoms. Four of them, in equatorial planes, origina
te from meiz molecules and two, in axial positions, are nitrile nitrogens f
rom the NO2NCN- anions. Influence of hydrogen bonds on equatorial-axial bon
d length correlation was ascertained. Tn the ESR spectra of the [Cu(NO2NCN)
(2)L-4] compounds copper hyperfine splitting is resolved. For all complexes
, weak lines corresponding to the Delta M-s = 2 transitions appear. The spe
ctrum of [Cu(NO2NCN)(2)(iz)(4)] in frozen methanolic solution shows 16-fold
nitrogen splitting of the perpendicular band. (C) 1999 Elsevier Science S.
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