Simultaneous occurrence of the Lewis acid-base interactions in chalcogen∙∙∙chalcogen contacts.

BURALLI, GABRIEL J.; DUARTE, DARÍO JORGE R.; BURALLI, GABRIEL J.; DUARTE, DARÍO J. R.; PERUCHENA, NÉLIDA M.

Montevideo

Congreso; Congreso de Químicos Teóricos de Expresión Latina (QUITEL); 2016

Quitel

Recently Guo et al. has been reported that, chalcogen atoms covalently bonded can act both as donors and acceptors of charge density at the same time, that is Lewis bases and acids respectively [1,2]. In these works it has been studied the dual role of chalcogen atoms covalently linked facing to various Lewis bases and acids. Moreover, in the framework of the halogen bonds, we have explained through hole-lump concept the simultaneous occurrence of the Lewis acid-base interactions in halogen∙∙∙halogen contacts [3]. In the present work, we study the chalcogen∙∙∙chalcogen contacts, where each chalcogen atom simultaneously acts as Lewis acid and base. The geometries of all the monomers and complexes were fully optimized using the Moller-Plesset second-order perturbation theory with the aug-cc-pVTZ basis set. The intermolecular distribution of both the electronic charge density and that the function L(r)= -2ρ(r) has been studied within the framework of the atoms in molecules (AIM) theory [4]. The natural bond orbital (NBO) method [5] has been used to analyze the stabilizing charge-transfer interactions in the complexes. Theoretical calculation show that, formation of the unusual chalcogen∙∙∙chalcogen interactions leads to a significant increase of electron charge density in the bonding region between the two chalcogen atoms. The geometry and stability of these complexes is mainly due to electrostatic interactions and the charge transfers, as in conventional halogen bonds.