Crystal structure and ESR study of a nitridochromium(V) complex

The crystal structure of the nitridochromium(V) complex [CrN(salen)] (H(2)salen = N,N'-bis(salicylidene) ethylenediamine) has been determined. This complex crystallizes in the monoclinic system, space group P2(1)/c, a = 9.575(1), b = 12.322(3), c = 12.999(2) Angstrom, beta = 103.57(1)degrees, V = 1490.8(5) Angstrom(3), Z = 4; final R2 = 0.059 (R = 0.054), wR2 = 0.082 (wR = 0.044) for 1935 observed reflections (I greater than or equal to 1.5 sigma(I)). The coordination geometry is square pyramidal with an N2O2 donor set (L-N202) in the basal plane and the nitride ion at the apex. The UV-Vis spectra of the complex have been re-measured in several solvents and exhibited a d-d band maximum around 540 nm (epsilon approximate to 200 M-1 cm(-1)). This is the first example of an observed d-d band among the nitridochromium(V) complexes isolated so far. The ESR spectra have been also re-measured in more detail. The ESR parameters have been compared with those of the [CrN(L-N4)] complexes and a remarkable nephelauxetic effect of the 3d sub-shell in comparison with the 3s sub-shell is indicated for the nitridochromium(V) complexes. (C) 1997 Elsevier Science S.A.