Chiral Discrimination in Hydrogen-Bonded Complexes of 2-Methylol Oxirane With Hydrogen Peroxide

摘要

A systematic quantum chemical study reveals the effects of chirality on the intermolecular interactions between two chiral molecules bound by hydrogen bonds. The methods used are second-order Moller-Plesset perturbation theory (MP2) with the 6-311 ++ g(d,p) basis set. Complexes via the O-H center dot center dot center dot O hydrogen bond formed between the chiral 2-methylol oxirane (S) and chiral HOOH (P and M) molecules have been investigated, which lead to four diastereomeric complexes. The nomenclature of the complexes used in this article is enantiomeric configuration sign corresponding to English letters. Such as: sm, sp. The relative positions of the methylol group and the hydrogen peroxide are designated as syn (same side) and anti (opposite side). The largest chirodiastaltic energy was Delta E-chir = -1.329 kcal mol(-1) [9% of the counterpoise correct average binding energy D-c(corr)] between the sm-syn and sp-anti in favor of sm-syn. The largest diastereofacial energy was -1.428 kcal mol(-1) between sm-syn and sm-anti in favor of sm-syn. To take into account solvents effect, the polarizable continuum model (PCM) method has been used to evaluate the chirodiastaltic energies, and diastereofacial energies of the 2-methylol oxirane center dot center dot center dot HOOH complexes. The chiral 2,3-dimethylol oxirane (S, S) is C-2 symmetry which offers two identical faces. Hence, the chirodiastaltic energy is identical to the diastereomeric energy, and is Delta E-chir = 0.563 kcal mol(-1) or 5.3% of the D-c(corr) in favor of s,s-p. The optimized structures, interaction energies, and chirodiastaltic energies for various isomers were estimated. The harmonic frequencies, IR intensities, rotational constants, and dipole moments were also reported. (C) 2008 Wiley Periodicals, Inc. Int J Quantum Chem 109:920-930,2009