Syntheses, X-ray crystal structures and catalytic activities of the manganese(II) butanedioic acid complexes [Mn-2(O2C(CH2)(2)CO2)(2)(phen)(2) (H2O)(4)]center dot 2H(2)O and {[Mn(O2C(CH2)(2)CO2)(bipy)(H2O)(2)]center dot H2O}(n)

Manganese(II) acetate reacts with an ethanolic solution of butanedioic acid (ca 1 : 1 mol ratio) to produce the white complex [Mn(O2C(CH2)(2)CO2)(H2O)(2)] (1) ill high yield. Subsequent reaction of 1 with 1,10-phenanthroline (phen) and 2,2'-bipyridine (bipy) gives the yellow crystalline products [Mn-2(O2C(CH2)(2)CO2)(phen)(2)(H2O)(4)].(H2O (2) and {[Mn(O2C(CH2)(2)CO2)(bipy)(H2O)(2)]. H2O}(n) (3), respectively. Complexes and 3 have been structurally characterized. Complex 2 is a centrosymmetric dimeric complex in which the unique manganese(II) atom has distorted octahedral coordination geometry and is ligated by a chelating phenanthroline and two cisoid water molecules, A pair of butanedioic dianionic ligands bridge the two metals with each diacid using only one carboxylate oxygen from each end. Complex 3 consists of infinite zigzag chains of composition [Mn(O2C(CH2)(2)CO2)(bipy)(H2O)(2)], in which pairs of symmetry-related manganese(II) atoms are bridged by butanedioic dianionic ligands, the carboxylate functions of which coordinate to the metals in a unidentate fashion, Each manganese atom has a distorted octahedral coordination geometry and is ligated by a chelating bipyridyl ligand, two cisoid water molecules and two cisoid carboxylate oxygen atoms from separate bridging butanedioic ligands. IR, magnetic and conductivity data for the complexes are given. Complexes 2 and 3 are significantly better catalysts than 1 for the disproportionation of H2O2 in the presence of added imidazole. (C) 1997 Elsevier Science Ltd.