Since Ardeungos report on the isolation of stable carbene, N-heterocyclic carbenes (NHCs) have been gaining a privileged status among ancillary ligands in homogeneous catalysis and organometallic chemistry.1 The unique strong σ-donor nature and ease of synthesis along with the possibility of modulation in stereoelectronics through back bone alteration make them an elite group of ligands.1 Recently, 1,2,3-triazol-5-ylidenes have emerged as a new subclass of abnormal/mesoionic carbenes (aNHCs/tzNHCs) and their specific structural and electronic features maintain their donor abilities between the normal imidazolin-2-ylidene and abnormal imidazolin-4-ylidene donors.2 It is well established that chelated ligands can attribute remarkable robustness to metal catalysts toward decomposition as well as enhanced activity in catalysis. Transition metal complexes of N-heterocyclic carbene ligands chelated analogues, having appropriate secondary donor with strong donor ability, show improved stability in various oxidation states.3 Unsymmetrical heteroditopic bis-NHC ligands having two distinct carbene donor of unique -donor/-acceptor characteristics represent a special class of chelating ligands. Transition metal complexes derived from these types of ligands can exhibit various topologies and are reported as excellent catalysts for diverse organic transformations.4 Inspired by these reports, the presentation will include the design of various NHC based new ligand systems for the synthesis of effective organometallic catalysts. Further, different approaches for fine-tuning the stereoelectronic properties of the ligands to tweak the catalytic activity of their metal complexes will be presented in detail. Real Money Rummy proposal and some preliminary results will also be discussed along with the future plans.

References:
1. (a) Herrmann, W. A. Angew. Chem. Int. Ed. 2002, 41, 1290. (b) Nelson, D. J.; Nolan, S. P. Chem. Soc. Rev. 2013, 42, 6723.
2. (a) Schuster, O.; Yang, L.; Raubenheimer, H. G.; Albrecht, M. Chem. Rev. 2009, 109, 3445. (b) Donnelly, K. F.; Petronilho, A.; Albrecht, M. Chem. Commun. 2013, 49, 1145.
3. Poyatos, M.; Mata, J. A.; Peris, E. Chem. Rev. 2009, 109, 3677.
4. (a) Mendoza-Espinosa, D.; Alvarez-Hernández, A.; Angeles-Beltrán, D.; Negrón-Silva, G. E.; Suárez-Castillo, O. R.; Vásquez-Pérez, J. M. Inorg. Chem. 2017, 56, 2092. (b) Monticelli, M.; Baron, M.; Tubaro, C.; Bellemin-Laponnaz, S.; Graiff, C.; Bottaro, G.; Armelao, L.; Orian, L. ACS Omega 2019, 4, 4192.