Ab initio study of cooperative effects in complexes X:HBO:Z, with X, Z=LiH, HNC, HF, HCN, HCl, ClF, and HBO: Structures, binding energies, and spin-spin coupling constants across intermolecular bonds

Abstract

A systematic ab initio investigation has been carried out to determine the structures, binding energies, and spin-spin coupling constants of ternary complexes X:HBO:Z for X, Z=LiH, HNC, HF, HCN, HCl, ClF, and HBO. All complexes X:HBO:Z are linear with C∞v symmetry, except for HCl:HBO:Z and ClF:HBO:Z which have Cs symmetry, thereby reflecting the structures of the corresponding X:HBO and HBO:Z complexes. Cooperative effects on energies are synergistic in all ternary complexes. The enhanced binding energies of complexes X:HBO:Z correlate with the binding energies of the X:HBO and HBO:Z complexes. Coupling constants 1J(B-H) and 2hJ(B-A) across B-H⋯A hydrogen bonds correlate with the B-A distance, and exhibit synergistic effects due to the presence of Z. 1hJ(H-A) indicates that these bonds have little proton-shared character. Coupling constants across D-H⋯O hydrogen bonds, H-Li⋯O lithium bonds, and F-Cl⋯O halogen bonds are also sensitive to the synergistic effects arising from the presence of X. D-H⋯O hydrogen bonds in ternary complexes are traditional (normal) hydrogen bonds. © by Oldenbourg Wissenschaftsverlag, München.