Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Difluoroamine Complex

Introduction　　ApplicationsofabinitiocalculationstointermolecularinteractionsincludingeitherweakvanderWaalsorstrongerhydrogenbondinghavedrawnmuchattentioninthepastdecadesbecausetheyareimportantinawiderangeofphysical,chemicalandbiologicalfields .1 5Inre centyears ,wehaveappliedtheintermolecularinteractionstoenergeticsystemsandobtainedsomemeaningfulinfor mationthatisvaluableforthestudyofenergeticmateri als .6 14 Thebehaviorofmolecularcomplexesisusuallybe tweentwoextremes :thegasphaseandthecrys…

Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Difluoroamine Complex

Ab initio calculations were carried out for difluoroamine complexes at the HF and MP2 levels with different basis sets. The BSSE correction was included with counterpoise procedure. The dimer, trimer and tetramer were all found to exhibit two minima. The corrected binding energies are ‐8.87, ‐19.19 and ‐33.81 kJ · mol^?1 at the MP2/6–311G* *//HF/6–311G* * level for the more stable dimer, trimer and tetramer, respectively. At the G2 level, the binding energy for the cyclic dimer is ‐10.86 kJ · mol^?1. There are two types of complexes: cyclic and chain. The contribution of cooperative effect to the interaction energy is up to 12.9% of the binding energy in the cyclic complexes, but negligible in the chain ones. There exist weak hydrogen bonds which involve six and eight F H contacts at ca. 0.23–0.24 nm in the cyclic trimer and cyclic tetramer, respectively. The intermolecular interaction is an exothermic process under 400.0K accompanied by a decrease in the probability.