Structures of four types of novel high-valent manganese complexes obtained by the reactions of KMnO4 with tridentate Schiff base ligands

X-ray structure analysis revealed that four types of novel manganese complexes, Mn-IV(N-EtO-sal)(2), Mn-III(N-PhO-sal)(L), [Mn-IV(5,6-Benzo-L)(2)(mu-O)](2) and Mn-III(L-4-Me)(3) have been found to be obtained by the reactions of KMnO4 with various tridentate Schiff base ligands (N-EtOH-salH, N-PhOH-salH and its derivatives) in dry MeCN, where N-EtOH-salH, N-PhOH-sales, LH, 5,6-Benzo-LH and L-4-MeH denote N-2-hydroxyethyl-salicylideneamine, N-2-hydroxyphenyl-salicylideneamine, 2-(2-hydroxyphenyl)benzoxazole 2-(2-hydroxynaphthyl)-benzoxazole and 2-(2-hydroxyphenyl)-5-methylbenzoxazole, respectively. The reactions of KMnO4 and N-PhOH-sales and its derivatives have especially been found to afford benzoxazole derivatives which may be formed by intramolecular oxidative coupling between the phenolic oxygen atom of aminophenol moiety and the carbon atom of imine moiety. (C) 2002 Elsevier Science Ltd. All rights reserved.