Recent advances in catalytic and electrocatalytic applications of half‐sandwich nickel(0/II) N–heterocyclic carbene complexes

Diverse structural and catalytic features of half‐sandwich nickel N–heterocyclic carbene (NHC) complexes provide an encouraging platform not only to address the drawbacks of other group X (palladium and platinum) metal NHC catalysts but also to bring about their superior performance. The chemistry of nickel NHC complexes has gained substantial interest from the organometallic community owing to their remarkable stability to air and moisture, easier preparation protocols, and availability of wide scope for structural fine tuning in order to achieve targeted applications. The recent progress in the field of half‐sandwich nickel(0/II) NHC complexes is covered in this review article with a special emphasis on the different synthetic strategies employed, structural characterization including spectral and X‐ray diffraction techniques, and surface morphology of the films of complexes. Both, homogeneous and electrocatalytic applications of half‐sandwich nickel NHC complexes are discussed with respect to their potential in various C–C and C–S bond constructions, targeted C–H bond activations, reductions using silylating agents, electrocatalytic glucose sensing, and electrocatalytic hydrogen evolution reactions. Donor functionalized complexes displayed improved catalytic potential in several C–C and C–S coupling reactions over non–functionalized counterparts. Overall, this assessment, from a comprehensive standpoint, affords evidence that is advantageous in the design of novel NHC ligands to access targeted half‐sandwich nickel(0/II) NHC complexes encompassing potential homogeneous catalytic and electrocatalytic applications.