Syntheses and X-ray crystal structures of cis-[Mn(bipy)2Cl2]•-2H2O•EtOH and cis-[Mn(phen)2Cl2] (bipy = 2,2′-bipyridine; phen = 1,10-phenanthroline); catalysts for the disproportionation of hydrogen peroxide

MnCl2. 4H(2)O reacts with 2,2'-bipyridine (bipy) to give cis-[Mn(bipy)(2)Cl-2] (1), and recrystallisation of 1 from ethanol gives cir[Mn(bipy)(2)Cl-2] . 2H(2)O . EtOH(2). MnCl2. 4H(2)O and 1,10-phenanthroline (phen) react to form cis-[Mn(phen)(2)Cl-2] (3), In each case, the X-ray crystal structures of 2 and 3 show the manganese(II) atom to have a similar distorted octahedral geometry, and in both cases there is extended pi-pi stacking of the conjugated ring systems. Compared with MnCl2 . 4H(2)O, 1 and 3 an much more efficient catalysts for the disproportionation of hydrogen peroxide. The catalytically active species are believed to be [Mn(bipy)(2)(H2O)(2)](2+) and [Mn(phen)(2)(H2O)(2)](2+), respectively. (C) 1998 Elsevier Science S.A. All rights reserved.