Synthesis and fungitoxic activity of manganese(II) complexes of fumaric acid: X-ray crystal structures of [Mn(fum)(bipy)(H2O)] and [Mn(Phen)(2)(H2O)(2)] (fum)center dot 4H(2)O (fumH(2) =fumaric acid; bipy=2,2 '-bipyridine; phen=1,10-phenanthroline)

The reaction of fumaric acid with Mn(CH3COO)(2). 4H(2)O gives the polymeric complex {Mn(fum)}(n) (1). Complex 1 reacts with 2,2'-bipyridine in ethanol to yield [Mn(fum) (bipy)(H2O)](n) (2). Reaction of 1 with 2 equiv. of 1,10 -phenanthroline produces [Mn-2(fum)(2)(phen)(2.5)]3H(2)O (3) and [Mn(phen)( 2)(H2O)(2)] (fum) . 4H(2)O (4). The molecular structures of 2 and 4 were de termined by X-ray crystallography. In 2 the fumarate anions link the mangan ese ions so that each is seven coordinate, being bonded to a bidentate bipy ridine, two bidentate carboxylates and one H2O molecule. In 4 the asymmetri c unit contains a [Mn(phen)(2)(H2O)(2)](2+) cation, half of each of two ind ependent fumarate anions and four lattice H2O molecules, The cations and an ions are interconnected by water molecules hydrogen bonded to both coordina ted water molecules and fumarate oxygens. The fumarate complexes, the metal free ligands and a number of simple manganese salts were each tested for t heir ability to inhibit the growth of Candida albicans. Only the 'metal fre e' 1,10-phenanthroline and its fumarate complexes exhibit fungitoxic activi ty (C) 2000 Elsevier Science Ltd All rights reserved.