Relative Cooperative Effects of Non-Covalent Interactions on Hydrogen Bonds in Model Y…HCN/HNC…XF Trimers (Y = FB, OC, N2, CO, BF; XF = HF, LiF, BeF2, BF3, ClF, PH2F, SF2, SiH3F)

A computational study of model Y…HCN/HNC (Y = FB, OC, N2, CO, BF) dimers was undertaken to assess the effect on the Y…H hydrogen bond when the Lewis base Y is systematically varied, while another model study of HCN/HNC…XF (XF = HF, LiF, BeF2, BF3, ClF, PH2F, SF2, SiH3F) dimers was undertaken to compare the relative binding strengths of the various types of noncovalent interactions between HCN/HNC and the fluorinated Lewis acid XF. The X atoms represent elements that span Groups 1–2 and 13–17 of the periodic table. The optimized trimers Y…HCN/HNC…XF that result from the combined dimer pairs were then studied in order to assess the relative strengths of the cooperative effects of the noncovalent N…X or C…X interactions on the Y…H hydrogen bond. The properties computed for the dimers and trimers include interaction energies, intermolecular separations, bond length changes, vibrational frequencies and their infrared intensity enhancements.