Fast estimation of hydrogen-bonding donor and acceptor propensities: a GMIPp study.

The suitability of the GMIPp energy functional as a fast, efficient method for estimating the hydrogen-bond donor and acceptor propensities of a wide variety of organic compounds is examined. Comparison of the GMIPp values is made with two experimental hydrogen-bond scales: i) the hydrogen-bond basicity scale for N-heteroaromatics in carbon tetrachloride, and ii) the hydrogen-bond acidities for NH/OH donors and hydrogen-bond basicities of N/O acceptors determined in 1,1,1-trichloroethane. Attention is paid to i) the reliability of semiempirical versus ab initio treatments of the quantum mechanical molecule, ii) the role of solvation, and iii) the effect of including the polarization energy component in the calculation of the GMIPp functional. The statistical analysis of the results reveals that the GMIP functional, which combines electrostatic and steric energy components, predicts with reasonable accuracy and computational efficiency the hydrogen-bond strength for a wide variety of compounds.