CRYSTAL STRUCTURE OF COPPER(II) COMPLEX WITH 4-TETRAZOLYL-3-IMIDAZOLINE-1-OXYL NITROXIDE

V.A. Reznikov¹, A.B. Burdukov², N.V. Pervukhina³, V.I. Ovcharenko²

¹Institute of Organic Chemistry, Sib. Branch of RAS, Akad Lavrentiev Av., 7, 630090 Novisibirsk, Russia
²International Tomography Center, Sib. Branch of RAS, Institutskaya St., 3a, 630090 Novisibirsk, Russia
³Institute of Inorganic Chemistry, Sib. Br. of RAS, Akad Lavrentiev Av., 7, 630090 Novosibirsk, Russia

A copper complex of 4-tetrazolyl-3-imidazoline-1-oxyl nitroxide (L) has been synthesized and isolated as CuL₂Py₂.CHCl₃. (triclinic, sp.gr. P(-1), a=8.611(2), b=11.182(2), c=12.169(2) A, a =102.88(1), b =98.60(1), g =111.127(1) deg, Z=2, 2262 I_hkl >2/304 params, R=0.046) The copper atom is hexacoordinated with four nitrogens of two nitroxides and two nitrogens of two pyridines. It manifests a pronounced Jahn-Teller distortion with elongated copper-imine nitrogen bonds (2.562(3) A), the lengthening of this chelate bond beeing observed for the first time among copper - 3-imidazoline nitroxide chelates. The compound incorporates chloroform molecules which fill the channels running along the c axis. Each chloroform molecule makes a short Cl-O contact (3.114 A) with the nitroxide oxygen, and the chloroform hydrogen weakly interacts with the tetrazole ring (H-N 2.48 A).