Research Projects

Nickel, unlike other transition metals, does not typically form high-valent species in biological systems. However, high-valent Ni species have been implicated in various cross-coupling, C-H activation, and oxidative coupling reactions. Recently, a Ni(IV)-σ-aryl group in the axial position supported by CNN pincer ligand scaffold has been claimed as the active intermediate to cause functionalization of robust C-H bonds. A Ni(IV) species has also been claimed to be responsible for highly selective Csp3-O, Csp3-N, and Csp3-S coupling reactions with exogenous nucleophiles and C-H trifluoromethylation reactions. The prevalence of such high-valent Ni intermediates in synthetic catalytic processes makes it difficult to find well-characterized spectroscopic evidences for their occurrence. The current proposal aims to synthesize non-innocent biologically relevant pseudopeptides that enable the formation and trapping of high valent Ni(IV) and Ni(V) species spectroscopically. Preliminary experiments suggest the sequential generation of one, two, and three oxidizing species starting from Ni(II) complex. Once these high-valent species are characterized and their formulation is unravelled, they will be tested for halogenation, nitration, and hydroxylation reaction towards C-H bonds. Investigating higher-valent nickel species is crucial as it could result in the creation of novel synthetic techniques and materials with distinctive features. High-valent nickel species also show greater reactivity and selectivity for some chemical transformations, enabling more effective and focused chemical synthesis.