Theoretical studies on the nature and strength of an intermolecular non-covalent Te•••π interaction

ABSTRACT

DFT and MP2 calculations were used to determine the nature of non-covalent tellurium–π interactions in R₂Te???C₆H₆ (R = H, F, Cl, CH₃) and C₄H₄Te???C₆H₆ systems. The results showed that the strength of Te···π interaction follows the order F₂Te > Cl₂Te > tellurophene > H₂Te > Me₂Te. Also, the F₂X···π system complexes (X = Te or Se, π system = C₆F₆, C₆(CH₃)₆, Cr(C₆H₆)₂ and coronene) were studied for investigating the direction of charge flow in Te···π interaction. The obtained data expressed that the existence of electron withdrawing group on Te atom increases the strength of Te???π interaction while the fluorine atoms on benzene ring decrease it. The breakdown of ΔE_int in the R₂Te···C₆H₆ (R = H, F, Cl, CH₃) and C₄H₄Te···C₆H₆ systems using two dispersion corrected DFT methods showed that when the R group on divalent tellurium atom is an electron withdrawing substituent, the contribution of ΔE_elstat and ΔE_orb in total interaction energy increases and the value of ΔE_int is relatively large. The present data also showed that the intermolecular Te···π interactions are slightly stronger than corresponding Se···π interactions.