Chalcogen bonding in complexes based on electrophilic tellurium

Chalcogen bonding (ChB), defined as the non-covalent interaction between an electrophilic chalcogen atom and a Lewis base, is now recognized as a powerful tool across a wide range of chemical applications. The strength of the ChB depends on the nature of the chalcogen atom; consequently, tellurium species exhibit the strongest ChB, compared to their sulfur and selenium analogues. This review aims at providing the readers with an overview of systems involving electrophilic tellurium atoms engaged in ChBs with Lewis bases, both in the solid state and in solution. In early studies–predating the widespread adoption of the σ-hole concept–the presence of ChBs was proposed on the basis of the geometrical parameters obtained from the X-ray single crystal structures. Specifically, interatomic distances below the sum of van der Waals radii and the near-linearity of the interactions were considered key indicators of ChB formation. This review is organized in sections highlighting the ability of tellurium to participate in ChBs at different oxidation states (0, +1, +2, +4 and + 6). Beyond structural analysis and characterization, the aim of this review is to underscore the different roles of ChB, ranging from the stabilization of reactive or unstable species to their involvement in catalytic processes and crystal engineering. • ChB involving tellurium at different oxidation states (0, +1, +2, +4, +6). • Role of ChB in tellurium complexes: stabilization, catalysis, crystal engineering. • ChB as a new mode of interaction in the coordination chemistry of electrophilic tellurium. • Electrophilic tellurium is considered as a “coordination center”.