Hooriye Yahyaei - Department of Chemistry, Zanjan Branch, Islamic Azad University, Zanjan, Iran
Neda Hasanzadeh - Department of Chemistry, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

In this research, Quantum-mechanical calculations were performed at the HF methodwith the ۶-۳۱+G*basis set and at the B۳LYP method with the ۶-۳۱+G* basis set in thegas phase and five solvents such as water, DMSO, methanol, ethanol anddichloromethane at six temperatures. According to these theoretical results of IR, weextracted thermo chemical parameters such as enthalpy (ΔH Kcal/mol), Gibbs freeenergy (ΔG Kcal/mol) and entropy (ΔS cal/molK). Important relationship have beenfound between solvent effect and structure of Calixarens with histidine L and Dstereochemistry. Also, nuclear shielding parameters of Calixarene, such as chemical shiftisotropic value (σiso) and the anisotropy shielding (σaniso, Δσ), have been taken intoaccount using GIAO method at the HF method with the ۶-۳۱+G* basis set and at theB۳LYP method with the ۶-۳۱+G* basis set in the gas phase and in different solvents suchas water, DMSO, methanol, ethanol and dichloromethane. The results were revealed thatthe NMR chemical shielding parameters are strongly affected by inducing differentsolvent media. According to these theoretical results,it can be drastically concluded thatthe dielectric permittivity of the solvent is a key factor that determines the chemicalbehavior of Calixarene with histidine L and D stereochemistry in solution. Also thenatural bond orbital (NBO) analysis has been performed at the six levels in the gas phaseand different solvent media which show some important atomic and structural features.Key words: Calixarene; IR; thermo chemical parameters; NMR chemical shieldingparameters; NBO; gas phase; solvent effect.