SYNTHESIS AND CATALYTIC ACTIVITY OF MANGANESE(II) COMPLEXES OF PENTANEDIOIC ACID - X-RAY CRYSTAL-STRUCTURE OF O2)(PHEN)(2)H2O](O2C(CH2)(3)CO2)CENTER-DOT-12H(2)O (PHEN = 1,10-PHENANTHROLINE)

Reaction of manganese(II) acetate tetrahydrate with pentanedioic acid gives [Mn(O2C(CH2)(3)CO2)]. H2O (1). Complex 1 reacts with 1,10-phenan throline (phen) (similar to 1:3 mol ratio) in ethanol giving the mono- phenanthroline complex [Mn(O2C(CH2)(3)CO2) (phen)] (2). Using less phe nanthroline (similar to 1 mol of 1:2 mol phenanthroline) in an ethanol -water solvent mixture gives the bis-phenanthroline complex [Mn(phen)( 2)(H2O)(2)] [Mn(O2C(CH2)(3)CO2) (phen)(2)H2O] (O2C(CH2)(3)CO2). 12H(2) O (3) which was characterised using X-ray crystallography. Complex 3 c ontains two independent mononuclear manganese(II) species, the dicatio n [Mn(phen)(2)(H2O)(2)](2+) and the neutral manganese pentanedioate co mplex [Mn(O2C(CH2)(3)CO2) (phen)(2)(H2O)], along with a non-coordinate d (O2C(CH2)(3)CO2)(2-) counter dianion. In the dication [Mn(phen)(2)(H 2O)(2)](2+) the manganese atom is coordinated to four nitrogen atoms f rom two chelating phenanthroline ligands and two oxygen atoms from two cisoid water molecules. In the neutral fragment [Mn(O2C(CH2)(3)CO2) ( phen)(2)(H2O)] the metal atom is coordinated to four nitrogen atoms fr om two chelating phenanthroline ligands, one oxygen atom from a uniden tate (O2C(CH2)(3)CO2)(2-) ligand and one oxygen atom from a water mole cule which is cis with respect to the coordinated carboxylate oxygen o f the pentanedioate ligand. IR, magnetic and conductivity data for the complexes are given. All three complexes are catalysts for the dispro portionation of H2O2 in the presence of added imidazole. (C) 1998 Else vier Science S.A. All rights reserved.