Synthesis and Crystal Structure of a Novel Co（II）-Nitronyl Complex [Co（IM2-Py）(PCA)（N3）2]

The title compound [Co(IM2-Py)(PCA)(N3)2] (IM2-Py = 2-(2?-pyridyl)-4,4,5,5-te- tramethylimidazoline-1-oxyl, PCA = 2-pyridine carboxylic acid) has been prepared and structurally characterized by elemental analysis, IR spectra and X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 13.169(3), b = 11.235(2), c = 15.596(3) ?, β = 104.70(3)o, V = 2232.0(8) ?3, C18H21CoN10O3, Mr = 484.38, Z = 4, Dc = 1.441 g/cm3, μ(MoKα) = 0.811 mm-1, F(000) = 1000, the final R = 0.0563 and wR = 0.1010. The nitronyl nitroxide (NIT2Py) was reduced to IM2-Py, and another NIT2Py oxidated to PCA. The self-redox reaction between the radicals was observed. The cobalt(II) ion is six-coordinated into a distorted octahedral geometry. Meanwhile, the intermolecular hydrogen bonds result in the dimer.