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The structures,the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self|consistent %ab initio% Hartree|Fock and the second|order Mφller|Plesset correlation energy correction methods. The counterpoise procedure was used to check the basis set superposition error(BSSE) of the binding energies. There exist cyclic structures in a formamide dimer(Ⅰ),a HAN dimer(Ⅱ) and their heterodimer(Ⅲ). The corrected binding energies for dimers Ⅰ,Ⅱ and Ⅲ are respectively -45.53,-45.83 and -43.89 kJ/mol at the MP2/aug|cc|p VDZ//HF/{aug|cc|p VDZ} level. The change of the Gibbs free energies(Δ%G%) in the process of Ⅰ+Ⅱ→2Ⅲ was predicted to be -2.74 kJ/mol at 298.15 K. Dimer Ⅲ can be spontaneously produced in the mixture of formamide and HAN,which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo|His|Phe(CHP).
The structures, the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile (HAN) dimers have been studied by means of the self | consistent % ab initio % Hartree | Fock and the second | order M φφller | Plesset correlation energy correction methods. There are cyclic structures in a formamide dimer (I), a HAN dimer (II) and their heterodimers (III). The corrected binding energies for dimers I, II and III are respectively -45.53, -45.83 and -43.89 kJ / mol at the MP2 / aug | cc p VDZ // HF / {aug | cc | p VDZ } level. The change of the Gibbs free energies (Δ % G %) in the process of Ⅰ + Ⅱ → 2 Ⅲ was predicted to be -2.74 kJ / mol at 298.15 K. Dimer III can be spontaneously produced in the mixture of formamide and HAN, which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo | His | Phe ( CHP).