~ ) Pergamon PII: S0277-5387(97)00037-5 Po(vhedron Vol. 16, No. 16, pp. 2741--2748, 1997 © 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0277-5387/97 $17.00+0.00 Manganese(ll) complexes of hexanedioic and heptanedioic acids: X-ray crystal structures of [Mn(O2C(CH2)4CO2) (phen)2H20] • 7H20 and [Mn(phen)2(H20)2] [Mn(O2C(CH2)sCO2) (phen)2H20] (O2C(CH2)5CO2) • 12.5H20 Malachy McCann, a* Michael T. Casey, a Michael Devereux, b Martin Curran b and Vickie McKee c "Chemistry Department, St Patrick's College, Maynooth, Co. Kildare, Ireland b Dublin Institute of Technology, Cathal Brugha Street, Dublin, Ireland c School of Chemistry, Queen's University Belfast, Belfast BT9 5AG, Northern Ireland (Received 2 December 1996 ; accepted 16 January 1997) Abstract--Mn(CH3CO2)2 "4H20 reacts with ethanolic solutions of hexanedioic and heptanedioic acids (ca 1 : 1 mol ratio) to produce the respective manganese(II) complexes [Mn(O2C(CH2)4CO2)H20] (1) and [Mn(O2C- (CH2)5CO2)] (2). Subsequent reaction of 1 and 2 with 1,10-phenanthroline (phen) (ca I : 2 mol ratio) in aqueous ethanol gives [Mn(O2C(CH2)4CO2)(phen)2H20]'7H20 (3) and [Mn(phen)2(H20)2][Mn(O2C(CH2)sCO2 (phen)2H20](O2C(CH2)sCO2)" 12.5H20 (4), respectively. Complexes 3 and 4 have been structurally charac- terised. The asymmetric unit in 3 has a manganese(II) atom coordinated to four nitrogen atoms from two chelating phenanthroline ligands, one oxygen atom from a unidentate (O2C(CH2)4CO2) -2 ligand and one oxygen atom from a water molecule which is in a cisoid position with respect to the diacid ligand. The asymmetric unit in 4 contains two mononuclear manganese(II) species, the dication [Mn(phen)2(H20)2] 2+ and the neutral manganese heptanedioate complex [Mn(O2(CH2)sCO2)(phen)(H20)], along with a non-coordinated (O2C(CHz)sCO2) 2- counter dianion. In the dication [Mn(phen)2(H20)2] 2+ the manganese atom is coordinated to four nitrogen atoms from two chelating phenanthroline ligands and two oxygen atoms from two cisoid water molecules. In the neutral fragment [Mn(O2C(CH2)sCO2)(phen)2(H20)] the metal atom is coordinated to four nitrogen atoms from two chelating phenanthroline ligands, one oxygen atom from a unidentate (O2C(CH2)5CO2) 2- ligand and one oxygen atom from a water molecule which is cis with respect to the coordinated carboxylate oxygen of the heptanedioate ligand. IR, magnetic and conductivity data for the complexes are given. All four complexes are catalysts for the disproportionation of H202 in the presence of added imidazole. © 1997 Elsevier Science Ltd Keywords: hexanedioic acid; heptanedioic acid; phenanthroline; manganese(II); hydrogen peroxide; dis- proportionation. As part of our ongoing efforts to synthesise and struc- turally characterise molybdenum(II) [1], copper(II) [2,3] and manganese(II) [4] complexes of ~t,o~-dicar- boxylic acids we report here the preparation and properties of manganese(II) complexes of hexanedioic acid (HO2C(CHz)4CO~H) and heptanedioic acid (HOzC(CH2)sCO2H). X-ray crystallographic details for two complexes are given along with results for the catalytic disproportionation of hydrogen peroxide by all of the new complexes. RESULTS AND DISCUSSION *Author to whom correspondence should be addressed. Mn(CH3CO2)2"4H20 reacted with ethanolic solu- tions of hexanedioic and heptanedioic acids (ca 1 : 1 2741