Dr. Kuduva R. Vignesh
Assistant Professor, Chemical Sciences

Research Focus

Molecular Magnetism: Our group research work mainly deals with the synthesis and modeling of spin-Hamiltonian parameters in transition metal, lanthanide and radical-bridged metal complexes using both experimental and computational tools to understand their molecular magnetic behavior. Certain mononuclear/polynuclear complexes are capable of retaining their magnetization even in the absence of magnetic field which gives rise to magnetic hysteresis at a molecular level and an ability to act as magnets below their blocking temperature and these molecules are termed Single-Molecule Magnets (SMMs) or Single-Ion Magnets (SIMs). These SMMs have the intriguing potential applications in memory storage devices, quantum computing, and spintronic devices. We also focus on Single-Molecule Toroics (SMTs), which are defined as molecules that display a toroidal magnetic state which can potentially be used in multiferroic materials.

We use X-ray diffractometer and SQUID magnetic instrumentation to characterise these magnetic complexes. To further understand the observed magnetic behaviour of synthesised molecules, we employ both density functional theory (DFT) and ab initio methods using various quantum mechanics programs.

Heterogeneous catalysis: The main areas of catalysis are focusing on minimizing the environmental impacts while combusting fuels from the automobile engines. Our group is searching for the three-way catalyst (TWC) of a car exploits three reactions which include NO reduction, CO oxidation and oxidation of unburnt hydrocarbons. We are adopting computational approach to understand the CO and NO adsorption and to intensively seek the suitable metal oxide surface for the investigation of NO-CO reaction mechanism. We perform slab model calculations by spin polarized DFT methods using VASP program.

• "Strategies to Design Single-Molecule Toroics Using Triangular {Ln3}n Motifs"  K. R. Vignesh, G. Rajaraman ACS Omega, 2021, 6, 32349–32364.
  
• "Six-Coordinate Mononuclear Dysprosium (III) Single-Molecule Magnets with the Triphenyl-phosphine oxide ligands"  K. R. Vignesh, D. I. Alexandropoulos, H. Xie, K. R. Dunbar, Dalton Trans., 2020, 49, 4694–4698. 
  
• "Rare Janus-Faced {FeII7} Single-Molecule Magnet Exhibiting Intramolecular Ferromagnetic Interactions"  D. I. Alexandropoulos, K. R. Vignesh, T. C. Stamatatos, K. R. Dunbar, Chem. Sci., 2019, 10, 1626–1633. 
  
• "Lanthanide Triangles Supported by Radical Bridging Ligands"  B. S. Dolinar, D. I. Alexandropoulos, K. R. Vignesh, Tia’Asia James, K. R. Dunbar, J. Am. Chem. Soc., 2018, 140, 908–911. 
  
• "Slow Magnetic Relaxation and Single-Molecule Toroidal Behaviour in a Family of Heptanuclear {CrIIILnIII6} (Ln = Tb, Ho, and Er) Complexes"  K. R. Vignesh, S. K. Langley, A. Swain, B. Moubaraki, M. Damjanovic, W. Wernsdorfer, G. Rajaraman, K. S. Murray, Angew. Chem. Int. Ed., 2018, 57, 779–784. 
  
• "Ferrotoroidic Ground State in a Heterometallic {CrIIIDyIII6} Complex Displaying Slow Magnetic Relaxation"  K. R. Vignesh, A. Soncini, S. K. Langley, K. S. Murray, W. Wernsdorfer, G. Rajaraman, Nat. Comm., 2017, 8, 1023
• "Exploring the Influence of Diamagnetic Ions on the Mechanism of Magnetization Relaxation in {CoIII2LnIII2} (Ln = Dy, Tb and Ho) Butterfly Complexes"  K. R. Vignesh, S. K. Langley, K.S. Murray, G. Rajaraman, Inorg. Chem., 2017, 56, 2518−2532.
• "Quenching the Quantum Tunneling of Magnetization in Heterometallic Octanuclear {TMIII4DyIII4} (TM=Co and Cr) Single-Molecule Magnets by Modification of the Bridging Ligands and Enhancing the Magnetic Exchange Coupling"  K. R. Vignesh, S. K. Langley, K.S. Murray, G. Rajaraman, Chem. Eur. J, 2017, 21, 1654−1666 (Hot Paper).