Major Research Projects:
Organometallic Chemistry of Main Group Elements and Cationic Organo-aluminum Complexes: Chemistry of highly reactive organo-main group ionic compounds and late transition metals supported by bulky iminophosphonamide ligands with N2P or N,3P2 skeleton is the major emphasis of this research. Recently discovered series of cationic aluminum complexes exhibit very strong Lewis acid character and have been useful in promoting/catalyzing organic reactions mediated by Lewis acids. The multiply bonded terminal boron-chalcogen complexes have been important breakthrough in field.
Low Valent Complexes of Group 13 and 14 Elements: Synthesis of novel germylene, stannylene chelate compounds stabilized by bis(phosphinimino)amide is under investigation. The successful synthesis of Ge(II) and Sn(II) compounds has opened up a new opportunity to explore not only reduction of these divalent species (to prepare zero valent species) but also the oxidation reactions (to new interesting derivatives of the unknown tetravalent metal centers).
N-heterocyclic Carbene Complexes of Transition Elements for Catalysis: We have synthesized novel pincer type/tripodal N-heterocyclic carbenes bearing chalcogens in their backbone. Transition metal complexes of these carbenes are being investigated for their structure and reactivity. Recently, we have also discovered that Au(III) and Pd(II) complexes prepared in this project show excellent activity for C-H activation in aromatic rings and promising C-C coupling reactions.
Inorganic Macrocycles and Cryptands: Synthesis of phosphazane based and boron-amide based organic-inorganic hybrid macrocycles and cryptands are major theme of this research area. We have successfully assembled a series of new pyridinophanes and cryptands. Study of host-guest complexation and use of cations, anions or neutral molecules as templates in assembling macrocycles and cryptands are important aspect of our work. The phosphazene templated macrocyclic arrangement of NaCl is a landmark in this area.
- Aluminum Containing Molecular Bowls and Pyridinophanes: Use of Pyridine Modules to Access Different Molecular Topologies. D. Bawari, C. Negi, V. K. Porwal, S. Ravi, K. R. Shamasundar and S. Singh, Dalton. Trans. 2019, 48, 7442-7450. Invited article for the themed issue of Dalton Transactions on New Talent Asia-Pacific 2019.
- Group 13 Element Containing Conformationally Rigid “N-E-N” Heteroatomic Bridged [3.3](2,6)Pyridinophanes (E = B, Al), D. Bawari, C. Negi, K. Jaiswal, B. Prashanth, A. R. Choudhury and S. Singh, Chem. Commun. 2018, 54, 8857-8860.
- Electronically Unsaturated Three Coordinated Aluminum Hydride and Organoaluminum Cations, B. Prashanth, M. Bhandari, S. Ravi, K. R. Shamasundar, S. Singh, Chem. Eur. J. 2018, 24, 4794-4799.
- Designing the Macrocyclic Dimension in Main Group Chemistry, H.-C. Niu, A. J. Plajer, R. Garcia-Rodriguez, S. Singh, D. S. Wright, Chem. Eur. J. 2018, 24, 3073-3082.