IMPROPER HYDROGEN BONDS - A THEORETICAL STUDY ABOUT THE MOLECULAR STRUCTURE OF INTERMOLECULAR SYSTEMS FORMED BY H3C-H+Δ...X AND H3C+Δ...H-Y WITH X = CL- OR F- AND Y = CL OR F

In this work is presented a theoretical study of the molecular properties of the H3C-H...X and H3C+&#948;...H-Y intermolecular systems with X = CL- or F- and Y = Cl or F. In the H3C-H...X complex, it is formed a traditional hydrogen bond between the CL- or F- anions and the hydrogen atom of the methyl. About the H3C+&#948;...H-Y complex, it was observed an improper hydrogen bond because the carbon atom of the methyl cation function as a proton acceptor. In this insight, the capacity of methane to interact with halogen anions (CL- or F-) and molecular acids (HCl or HF) was examined at the B3LYP/6-311++G(3df,3dp) level of calculation. Moreover, the interaction strengths of the H3C-H...X and H3C+&#948;...H-Y complexes was evaluated by computing their intermolecular distances and binding energies. Finally, QTAIM calculations also were executed with the purpose to examine the intermolecular interactions through the quantification of their electronic densities (p) as well as by the interpretation of the Laplacian operators (<img border=0 width=25 height=17 src="http://fbpe/img/jcchems/v54n1/form10-01.jpg">).