Evidence for and evaluation of fluorine-tellurium chalcogen bonding

In the field of noncovalent interactions, chalcogen bonding (ChB) involving the tellurium atom is currently attracting much attention in supramolecular chemistry and in catalysis. However, as a prerequisite for its application, the ChB should be studied in solution to assess its formation and, if possible, to evaluate its strength. In this context, new tellurium derivatives bearing CH2F and CF3 groups were designed to exhibit TeMIDLINE HORIZONTAL ELLIPSISF ChB and were synthesized in good to high yields. In both types of compounds, TeMIDLINE HORIZONTAL ELLIPSISF interactions were characterized in solution by combining F-19, Te-125 and HOESY NMR techniques. These TeMIDLINE HORIZONTAL ELLIPSISF ChBs were shown to contribute to the overall J(Te-F) coupling constants (94-170 Hz) measured in the CH2F- and CF3-based tellurium derivatives. Finally, a variable temperature NMR study allowed us to approximate the energy of the TeMIDLINE HORIZONTAL ELLIPSISF ChB, from 3 kJ mol(-1) for the compounds with weak Te sigma-holes to 11 kJ mol(-1) for Te sigma-holes activated by the presence of strong electron withdrawing substituents.

Automated summary

In the field of noncovalent interactions, chalcogen bonding (ChB) involving the tellurium atom is currently of great interest in supramolecular chemistry and catalysis. The formation and strength of ChB should be studied in solution before its application. New tellurium derivatives with CH2F and CF3 groups were synthesized to demonstrate Te...F ChB and their interactions were characterized using various NMR techniques. The energy of Te...F ChB was estimated to be 3-11 kJ mol(-1) depending on the substituents.