Chalcogen Bonding Catalysis: Tellurium, the Last Frontier?

Abstract

: Chalcogen bonding (ChB) is the non‐covalent interaction occurring between chalcogen atoms as Lewis acid sites and atoms or groups of atoms able to behave as Lewis bases through their lone pair or p electrons. Analogously to its sister halogen bonding, the high directionality of this interaction was implemented for the precise structural organization in the solid state and in solution. Regarding catalysis, ChB is now accepted as a new mode of activation as demonstrated by the increased number of examples in the last five years. In the family of ChB catalysts, those based on tellurium rapidly appeared to overcome their lighter sulfur and selenium counterparts. In this review, we highlight the Lewis acid properties of tellurium‐based derivatives in solution and summarize the start‐of‐the‐art of their applications in catalysis.

Affinity of Telluronium Chalcogen Bond Donors for Lewis Bases in Solution: A Critical Experimental‐Theoretical Joint Study

“…[39] Nevertheless, the presence of three σ-holes makes the study in solution rather challenging due to 1) three possible stoichiometries of the adducts with a Lewis base, 2) possible competing interactions between the chalcogen center and interfering Lewis bases (solvent, counterion), and 3) the hardly predictable effects of solvation, such as competing coordination. Being involved these last years in XB [40][41][42] and ChB catalysis, [19,43,44] we have recently reported the high catalytic efficiency of methyldiaryltelluronium salts in various reactions. [28] Herein, in order to gain insight into the interacting ability of diarylmethyltelluroniums in solution, the interaction of various σ-hole acceptors (Lewis bases) with a series of tellurium cations bearing different functional groups and associated with anions of different coordinating ability were addressed by NMR spectroscopy and ITC, complemented by structural XRD analyses and underpinned by state-of-the-art theoretical tools (Figure 2).…”

Chalcogen- and Halogen-Bond-Donating Cyanoborohydrides Provide Imine Hydrogenation

“…Although some of the σ-hole carriers − similarly with well-studied HB donorswere tested in the reaction of hydrogenation of the imine moiety by the Hantzsch esters (Scheme ), no examples were known for their applications involving simple inorganic reducing agents, such as hydrides, which might be explained by possible redox side reactions between the cationic σ-hole carrier and the reducing agent …”

Te⋯I secondary-bonding interactions in crystals containing tellurium(ii), tellurium(iv) and iodide atoms: supramolecular aggregation patterns, nature of the non-covalent interactions and energy considerations

“…44) contacts in solution, and the gas-phase (Te⋯N). 45 With such persistence, it is not surprising that chalcogen-bonding finds applications 46 beyond the solid-state 47 such as in coordination chemistry, 48 catalysis, 49,50 molecular recognition 51 and materials science. 52 While less numerous, chalcogen-bonding has many parallels with the ubiquitous halogen-bonding.…”