Computational Study of Geometry, Solvation Free Energy, Dipole Moment, Polarizability, Hyperpolarizability and Molecular Properties of 2-Methylimidazole

Abstract

Ab initio calculations were carried out to study the geometry, solvation free energy, dipole moment, molecular electrostatic potential (MESP), Mulliken and Natural charge distribution, polarizability, hyperpolarizability, Natural Bond Orbital (NBO) energetic and different molecular properties like global reactivity descriptors (chemical hardness, softness, chemical potential, electronegativity, electrophilicity index) of 2-methylimidazole. B3LYP/6-31G(d,p) level of theory was used to optimize the structure both in the gas phase and in solution. The solvation free energy, dipole moment and molecular properties were calculated by applying the Solvation Model on Density (SMD) in four solvent systems, namely water, dimethylsulfoxide (DMSO), n-octanol and chloroform. The computed bond distances, bond angles and dihedral angles of 2-methylimidazole agreed reasonably well with the experimental data except for C(2)-N(1), C(4)-C(5) and N(1)-H(7) bond lengths and N(1)-C(5)-C(4) bond angle. The solvation free energy, dipole moment, polarizability, first order hyperpolarizability, chemical potential, electronegativity and electrophilicity index of 2-methylimidazole increased on going from non-polar to polar solvents. Chemical hardness also increased with increasing polarity of the solvent and the opposite relation was found in the case of softness. These results provide better understanding of the stability and reactivity of 2-methylimidazole in different solvent systems.

Photo-accelerated Hydrolysis of Metal Organic Framework ZIF-8

“…Ligand-based photo-absorption is often used to explain the excitation spectra of photoluminescence (PL) in many MOFs. , In ZIF-8, PL excitation by UVA, UVB, and near-UV visible light was reported in the literature. ,,, It is believed that the PL of MOFs is fundamentally the PL of ligands, except the intensity is enhanced due to strong interactions between ligands and also between ligands and metals. , The ligand, HmIm, in ZIF-8 has the energy separation between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) about 6.8 eV according to ab-initio calculation, and an experimental optical bandgap of 5 eV . Nonetheless, HmIm is reported to have low-energy absorption bands in the wavelength range of 250–400 nm, , similar to ZIF-8.…”

Theoretical B3LYP Study on Electronic Structure of Contrast Agent Iopamidol

“…According to Parr and co-workers, global molecular electrophilicity (ω mol ) and global molecular nucleophilicity (ε mol ) index were defined and they were calculated based on molecular hardness and molecular electronegativity of the studied compounds with the help of the following equations, respectively. (7) The electrophilicity index measures the property of a molecule to accept electrons. Nucleophile molecule is characterized by a lower value of μ, ω; and conversely electrophile molecule is characterized by a high value of μ, ω. Organic molecules having a value of more than 1.5 is classified as strong electrophiles, the value between 0.8 and 1.5 eV is classified as moderate electrophiles, smaller than 0.8 eV is said as marginal electrophiles.…”

“…So, Iopamidol commonly used for CT, may be also considered as a contrast agent for Magnetic resonance imaging (MRI) applications. 4 The geometry, dipole moment, polarizability, hyperpolarizability, and other molecular properties can be affected by the polarity of the solvent due to variable interactions with the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO) 6,7 and so the polarity of the solvent can influence the stability and reactivity of the molecule. 8 They can be obtained by quantum chemical calculation without laboratory measurements, thus saving time and equipment, reducing safety and disposal concerns.…”