SYNTHESIS, STRUCTURE, AND SPECTROSCOPIC PROPERTIES OF (NITRITO-O,O') [2-(1-METHYL)IMIDAZOLYL]METHOXYMETHANE]COPPER(II), CU(II)(TIMM)(NO2)(2)

The nitrito-O,O' complex, Cu(II)(TIMM)(NO2)(2), (1) has been character ized by X-ray crystallography, UV-vis, IR, and EPR spectroscopy. CuC14 H18N8O5 crystallizes in the monoclinic space group P2(1)/n, with a = 7 .7068(6), b = 17.933(1), c = 13.615(1) Angstrom, beta = 95.334(8)degre es and Z = 4. The structure was refined to an R value of 0.031 based u pon 2150 observed reflections. The distorted tetragonal N2O4 coordinat ion is supplied by two TIMM imidazole groups and two anisobidentate ni trito-O,O' groups, resulting in a dx(2) - y(2) ground state for the Cu (II). Methanolic 1 exhibits an electronic absorption at 352 nm (should er, epsilon approximate to 900) assigned as the lowest energy nitrite --> Cu(II) CT absorption (it obscures the weak (epsilon similar to 30) lowest energy localized nitrite absorption at similar to 360 nm). The nitrite --> Cu(II) CT absorption appears as a shoulder (similar to 40 5 nm) in the mineral oil mull spectra of polycrystalline 1. The relati onship between the observed bond distances and nitrite stretching freq uencies is discussed.