Some Novel Manganese(III) Mixed Ligand Complexes and its Decolourization Studies

Abstract

Some novel mixed ligand complexes of Mn(III) with glycine ligand namely [Mn(gly)2 Cl(en)], [Mn(gly)2 Br(en)], [Mn(gly)2 N3 (en)] and [Mn(gly)2 NCS(en)] have been synthesized starting from Mn(gly)2 Cl, Mn(gly)2 Br, Mn(gly)2N3 and Mn(gly)2 NCS respectively. These newly synthesized complexes have been characterized by UV/Vis, FT-IR and Mass spectrometry. The spectroscopic data suggest distorted octahedral geometry for all these mixed ligand complexes. The λmax values of these complexes for 5T2g → 5Eg transitions are 482 nm for [Mn(gly)2N3(en)], 488 for [Mn(gly)2NCS(en)], 486 for [Mn(gly)2 Br(en)] and 484 for [Mn(gly)2Cl(en)], all these transitions are red shifted in comparison to their parent complexes. The ligand field parameters such as 10 Dq, B and β have also been calculated and suggest covalent metal ligand bonding. One peculiar finding is that the FT-IR spectra shows frequencies for both free and coordinated NH2 group in all complexes indicating that the ethylenediamine ligand present here is non bridging in nature. 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 methyl red dye.

Aqueous Medium Synthesis and Characterization of Mixed-Ligand Molecular Complexes of Manganese(III).

“…The IR spectrum of compound 2 shows characteristics absorptions due to coordinated ethylenediamine, coordinated fluoride and coordinated as well as lattice water. The major bands coming from coordinated ethylenediamine are observed at 1592, 1511, 1351 and at 1034 cm -1 assigned to d(NH 2 ), d(CH 2 ) and n(skeletal) modes of vibrations of coordinated ethylene diamine 21,22 . The observed frequencies and pattern originating from ethylenediamine suggest that ethylenediamine ligand occurs as bidentate one in the compound under discussion.…”