Abstract: Owing to the presence of unique bonding and propensity to undergo hydroboration, C-H functionalization and dehydro-genation reactions, the transition metal (TM) σ-borane/borate complexes are very appealing for various organic reactions.1 Based on the interaction types between the metal and boron, these TM-boron complexes with boron in tricoordinated (σ-borane) and/or tetracoordinated (Lewis base stabilized borane or borate complex) surroundings are classified into two categories. For example, i) presence of only primary σ(B–H) interaction(s) with metal, e.g., I-II (Chart 1)2 and ii) primary σ(B–H) as well as secondary interaction(s) with metal, e.g., III-IV (Chart 1)3. Complexes in the first category (I-II) have been synthesized by reacting metal precursors with a borane/borate species. The second-category of complexes (III-IV) are typically synthesized from the chelation of a metal by a scorpionate type borane/borate ligand. The growth of this chemistry featuring these complexes was initially aided primarily by the introduction of Trofimenko’s scorpionate ligands4 and further investigations have been carried out the role of the scorpionate ligands in stabilization of TM σ-borate complexes. In this research proposal seminar, a thorough literature on the synthesis, bonding and application of σ-Borane & σ-Borate species will be presented along with some preliminary results in this area.

Chart 1: Examples of σ-borane/borate complexes of transition metals.
References:
[1] a) Saha, K.; Roy, D. K.; Dewhurst, R. D.; Ghosh, S.; Braunschweig, H. Acc. Chem. Res. 2021, 54, 1260–1273; b) Alcaraz, G.; Sabo-Etienne, S. Angew.Chem. Int. Ed. 2010, 49, 7170 –7179.
[2] a) Montiel-Palma, V.; Lumbierres, M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B. J. Am. Chem. Soc. 2002, 124, 5624–5625; b) Lenczyk, C.; Roy, D. K.; Ghosh, B.; Schwarzmann, J.; Phukan, A. K.; Braunschweig, H. Chem. Eur. J. 2019, 25, 8585–8589.
[3] a) Wagler, J.; Hill, A. F. Organometallics 2008, 27, 2350–2353; b) Lin, T. P.; Peters, J. C. J. Am. Chem. Soc. 2013, 135, 15310–15313.
[4] Trofimenko, S. Scorpionates: The Coordination of Poly(pyrazolyl)-borate Ligands, Imperial College Press, London. 1999.