Estimation of intramolecular hydrogen bond energy via molecular tailoring approach

A novel method, based on the molecular tailoring approach for estimating intramolecular hydrogen bond energies, is proposed. Here, as a case study, the O-H center dot center dot center dot O bond energy is directly estimated by addition/ subtraction of the single point individual fragment energies. This method is tested on polyhydroxy molecules at MP2 and B3LYP levels of theory. It is seen to be able to distinguish between weak (similar to 1 kcal mol(-1)) and moderately strong (similar to 5 kcal mol(-1)) hydrogen bonds in polyhydroxy molecules.