Manganese(III) Complexes with Decolourization Ability

Some novel mixed ligand complexes of Mn(III) with glycine ligand, namely [Mn(gly)2Cl(en)], [Mn(gly)2Br(en)], [Mn(gly)2N3(en)] and [Mn(gly)2NCS(en)] have been synthesized, from starting from Mn(gly)2Cl, Mn(gly)2Br, Mn(gly)2N3 and Mn(gly)2NCS respectively. These complexes have been characterized by UV/Visible, FT-IR and Mass spectrometry. The spectroscopic data suggest distorted octahedral geometry for all these novel complexes. The max values for these complexes (5T2g 5Eg transitions) are 482 nm [Mn(gly)2N3(en)], 488 nm [Mn(gly)2NCS(en)], 486 nm [Mn(gly)2Br(en)] and 484 nm [Mn(gly)2Cl(en)], all these transitions show red shift in comparison to the parent complex. The ligand field parameters such as 10 Dq, B and have also been calculated and suggest a covalent metal ligand bonding. One peculiar finding in the FT-IR spectra of these complexes is that it shows stretching frequencies for both the free and coordinated NH2 group in all complexes indicating ethylenediamine ligand non bridging. The mass spectrometry results show molecular ion peaks at m/z 300, 345, 307 and 323 for [Mn(gly)2Cl(en)], [Mn(gly)2Br(en)], [Mn(gly)2N3(en)] and [Mn(gly)2NCS(en)] respectively. The coordination of ethylenediamine to Mn(III) enhances its efficiency towards decolourization of methyl red dye. The main objective of this study is to explore the catalytic properties of these complexes.