Effects of ligands and counterions on Mn(III) spin crossover phenomenon

Title : Effects of ligands and counterions on Mn(III) spin crossover phenomenon

Abstract:

Novel Mn(III) Spin crossover (SCO) complexes of new Schiff base ligands (L) are  reported.  Five Mn(III) complexes with different counterions (chloro (Cl), nitrate (NO₃)_,   hexafluoro phosphate (PF₆), perchlorate (ClO₄) and triflate (CF₃SO₃) were synthesized of which [Mn L(ClO₄)] complex with perchlorate counterion exhibits SCO phenomenon. All the complexes were characterised by X-ray diffraction analysis in exception with PF₆.  Magnetic susceptibility of the perchlorate complex shows a gentle SCO behaviour with χ_mT value of 1.9 cm³mol^-1K at 373K with high spin pollution of 63%, decreases gradually towards cooling and attains 1.0 cm³ mol^-1K at 95K and upon further cooling χ_mT decreases and reaches a maximum value of 0.8 cm³mol^-1K at 10K.   Mn(III) complexes with counterions Cl, NO₃ and PF₆ promoted low spin behavior whereas CF₃SO₃ shows high spin behavior. Our research results confirms that ligand design and counterions has a strong significance in promoting Mn(III) Spin crossover.

Keywords: Mn(III) Spin crossover, Schiff bases, Magnetic susceptibility

Biography:

Dr. Komala Pandurangan completed her M.Sc and M.Phil at MGAC, University of Madras, Chennai, India. She worked as a research assistant at the Department of Organic chemistry and Biochemistry at Indian Institute of Science, Bangalore, India from 2001-2006. She completed her PhD degree (chemistry) in 2011 at University College Dublin, Ireland. She pursued her postdoctoral research in Trinity College Dublin (Ireland), Jawaharlal Nehru Centre for Advanced Scientific Research (India) and Dublin City University (Ireland). Her area of expertise are  Organic Synthesis, Antimicrobial Drugs, Mn(III)  Spin crossover phenomenon,  Magnetic materials, Chemosensors and Supramolecular gels.