Synthesis and Crystal Structure of Dicopper（II） Compound Containing Oxalate and Reduced Imino Nitroxide Radicals

A new dicopper(Ⅱ) compound with oxalate and reduced imino nitroxide radicals[Cu2(μ-C2O4)(Him2-py)2(H2O)2] (NO3)2 (Him2-py= l-hydroxy-2-(2'-pyridyl)-4,4,5,5-tetramethylimidazoline) has been synthesized and its crystal structure was determined by X-ray diffraction method. The complex crystallizes in monoclinic, space group P21/n with a = 9.913(4), b =19.057(8), c = 10.169(4)^°A,β = 114.292(7)°, V = 1751(1)^°A^3, C26H38Cu2N8O14, Mr = 813.72, Dc =1.543 g/cm^3,μ(MoKα) = 1.290 mm^-1， F(000) = 840, Z = 2, the final R = 0.0398 and wR = 0.0986 for 1878 observed reflections (1>2σ(I)). The imino nitroxide 2-(2'-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (im2-py) is reduced in the reaction to yield Him2-py which consists of oxalato-bridged centrosymmetric [Cu2(μ-C2O4)(Him2-py)2(H2O)2]^2+ ions and noncoordimated NO3^- anions. Each copper(Ⅱ) ion is in a distorted tetragonal pyramid environment two niuogen atoms from Him2-py and two oxygen atoms from the oxalate group are in the basal plane,and one water molecule at the axial position.