QSAR Study Of Capacity Factor Of Indole Compounds

Quantitative structure-activity/property relationship (QSAR/QSPR) for organic compounds aims at investigation of the intercorrelation between their molecular structures and physiochemical properties such as activity, so as to get a comprehensive knowledge about their bioactivity and other behaviors. On the other hand, quantitative structure-retention relationship (QSRR) has been a hot spot in the science of chromatography, by which some valuable structural parameters for solutions can be determined to interpret partitioning mechanism of chromatography, estimating physiochemical characteristics of solutes and predicting bioactivity of solute substances. However, the necessity of establishing QSRR models is to explore sufficient information about structural parameters.Quantum chemical calculation has been an important way to obtain the molecular structural parameters. With necessary computation, the required information about electronic and spatial structures of molecules can be achieved. This sort of information may include molecular orbital energy, atomic charge density, polarizability, and the electrostatic charge of molecules. In addition, the quantum chemical parameters possess an advantage of non-experimental dependence and significant physical interpretations. As widely known, ab initio calculation method is theoretically strict due to precise computation results. With the improvement of the efficiency of computers in recent years, it has become a main stream in international quantum chemical computation.In the present paper, the Hartree-Fock(HF) and density functional theory(DFT) methods in the field of ab inito were used for optimized calculation of 16 indole derivatives, in which the bases sets of 6-31G* and 6-311G** were chosen and result in a series of structural parameters including dipole moment(μ), the highest occupied molecular orbital(E_HOMO), the lowest unoccupied molecular orbital(E_LUMO), the most negative partial charge in molecule(q^-), the most positive partial charge on a hydrogen atom (q⁺), molecular volume(V_i), mean poarizability from vibrational analisis(α), as well as thermodynamic parameters including total energy(TE), zero point vibrational energy (ZPE), standard enthalpy(H°), standard free energy(G°), heat energy correction(E_th), heat capacity at constant volume(C_V°) and standard entropy(S°).