Synthesis, crystal structures and magnetic properties of copper(II) complexes with nitronyl nitroxide

Two novel adducts of formula [Cu(pfpr)(2)(NITmNO2)](2) (I) and Cu(hfac)(2)( NITmNO2) (II), where pfpr=pentafluoropropionate, hfac=hexafluoroacetylaceto nate and NITmNO2 = 2-(3-nitrophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl- 3-oxide have been synthesized. Compound (I) is the first example of copper (II)-nitroxide complexes bridged by pfpr. Its structure consists of binucle ar units with the tetrakis(pentafluoropropionate) bridging two copper ions. Each copper ion has a distorted trigonal-bipyramidal coordination. Compoun d (II) is a mononuclear complex with a five-coordinated distorted square-py ramidal environment. The variable temperature magnetic susceptibilities sho w that there are antiferromagnetic interactions between copper ions and rad icals for compound (I), and compound (II) is diamagnetic. (C) 1999 Elsevier Science Ltd. All rights reserved.