TERNARY COPPER(II) COMPLEXES OF THE ANTICONVULSANT DRUG VALPROATE WITH DIIMINES AS SUPEROXIDE-DISMUTASE MIMICS

Mononuclear complexes of the type [Cu(valp)(2)(2,2-bpy)]H2O (2), Cu(va lp)(2)(phen) (3), and Cu(valp)(2)(dmph) (4), and polynuclear complexes of the type [Cu(valp)(2)(mu-4,4(-)-bpy)](n) (5), and [Cu-2(valp)(4)(m u-4,4(-)-bpy)](n) (6) [valp=valproate ion, bpy = bipyridine, phen = 1, 10-phenanthroline, and dmph = 2,9-dimethyl-1,10-phenanthroline], were synthesized and characterized by magnetic and spectroscopic measuremen ts. Spectral and magnetic data for complexes 2, 3, and 4 and the preli minary x-ray measurements for complex 3 are consistent with mononuclea r structure. The copper atom in 2 and 3 is coordinated to two nitrogen atoms from diimine, two asymmetric carboxylic oxygen atoms from each of a bidentate valproate ions to give a tertragonally elongated CuN2O2 + O-2 chromophore. The copper atom in complex 4 is coordinated to two nitrogen atoms from dmph, two carboxylic oxygens of a bidentate valpr oate ion, and an oxygen atom of a monodentate carboxylic group of a se cond valproate ion to give a very distorted square pyramid or trigonal bipyramid CuN2O3 chromophore. The preceding data for 5 and 6 indicate that these complexes are polymeric in which the nitrogen atoms of 4,4 (-)-bpy ligands bridge mononuclear Cu(valp)(2) moities, coordinating e quatorially in complex 5, while bridge binuclear Cu(mu-valp)(4)Cu moit ies, coordinating axially in complex 6. The superoxide dismutase-mimet ic activity of the binary complex, Cu-2(valp)(4) (1), and of the previ ous ternary complexes was measured and found to be in the order: 2 app roximate to 3 > 6 > 4 > 1 > 5. (C) 1997 Elsevier Science Inc.