New MnII Complexes with an N/O Coordination Sphere from TripodalN-Centered Ligands − Characterization from Solid State to Solution and Reaction with Superoxide in Non-Aqueous and Aqueous Media

Abstract

The crystal structure of a dimeric bis(µ-carboxylato)Mn II Mn II complex (2) with a tetradentate N-centered tripodal ligand, N,N-bis [(1-methylimidazol-2-yl)methyl]glycinate, is presented. The carboxylates are bridging monodentate. This complex shows some striking differences to the previously published parent compound 1 obtained with the closely related ligand N- [(1-methylimidazol-2-yl)methyl]-N-(2-pyridylmethyl)glycinate. The carboxylato bridges in both structures are shown to be disrupted in solution. The reactivities in solution of compounds 1 and 2 toward superoxide were

Role of carboxamido nitrogen in mononuclear manganese complex: Superoxide scavenging activity and nuclease activity

“…Moreover, the IC 50 values calculated for 1 and 2 were higher than the values calculated for Mn(ClO 4 ) 2 Á6H 2 O [26]. It is clear from the electrochemical data that the Mn II /Mn III redox couples are not in the proper range for 1 and 2 and hence some other mechanism similar to that of SOD activity of Mn(ClO 4 ) 2 Á6H 2 O could be involved for the scavenging of superoxide ions [26,27]. The DNA binding properties of complexes were studied by UVvisible, circular dichroism and fluorescence spectroscopy.…”

“…The inhibition study for 1 and 2 gave rise to a curve similar to the curve found by Biencenue et al [25] and the curve did not go beyond 65-70% inhibition. Moreover, the IC 50 values calculated for 1 and 2 were higher than the values calculated for Mn(ClO 4 ) 2 Á6H 2 O [26]. It is clear from the electrochemical data that the Mn II /Mn III redox couples are not in the proper range for 1 and 2 and hence some other mechanism similar to that of SOD activity of Mn(ClO 4 ) 2 Á6H 2 O could be involved for the scavenging of superoxide ions [26,27].…”

Stabilization of Mn(II) and Mn(III) in mononuclear complexes derived from tridentate ligands with N2O donors: Synthesis, crystal structure, superoxide dismutase activity and DNA interaction studies

“…Several reports [20,60,[65][66][67][68][69][70][71] are there by which one can select a manganese complex that could mimic SOD activity considering the electrochemical properties. Our electrochemical data showed the Mn(II)/Mn(III) couple, responsible for the catalytic activity, was within the proper range [60,69].…”

Hydrothermal synthesis and crystal structure of a novel 2-D polymeric manganese (II) complex with mixed ligands

“…Mn complexes containing carboxylato ligands are of interest, because of their intriguing structures [1][2][3][4][5][6][7][8][9][10][11][12][13] and potential applications in catalysis etc. [7][8][9][10][11]; e.g., some 'highly efficient Mn catalase mimics' with dinuclear Mn structures were reported recently [12,13].…”

“…[7][8][9][10][11]; e.g., some 'highly efficient Mn catalase mimics' with dinuclear Mn structures were reported recently [12,13].…”