Abstract:

Polychlorinated biphenyls(PCBs), an important kind of toxic pollutant, are persistent in the environment and accumulative in many species. Ab initio calculations have been performed for all 209 PCB congeners at the HF/6-31G* level. Electrostatic potentials and subsequently derived statistically based structural descriptors have been obtained. Linear relationships between aqueous solubility(lgS_W), n-octanol/water partition coefficient (lgK_OW),n-octanol/air partition coefficient (lgK_OA), soil sorption (lgK_OC), aqueous activity coefficient(lgY_W), 298 K supercooled liquid vapour pressures(lgp_L), total molecular surface area (TSA), gas-chromatographic relative retention time (RRT), enthalpy of sublimation (ΔH_subl), enthalpy of vaporization (ΔH_vap), enthalpy of fusion (ΔH_fus), Aryl hydrocarbon receptor biding affinity (pEC50),biodegradability (Biodeg％) and Microbial elimination rate constant(－lgk) of PCBs and theoretical descriptors have been established by multiple regression method. It appears that the quantities derived from electrostatic potentials, V_min, V_s,min, V_s,max, V_s, Π,σ²_tot,ΣV_s⁺,>,ΣV_s^-, together with the molecular surface area and some popular quantum chemical descriptors (e.g. E_HOMO and E_LUMO) can be well used to express the quantitative structure-property (activity) relationships of PCBs. Although the correlation equations for some physicochemical properties and biological activities are not superior to those previously established with other types of structural parameters, the parameter set used in the present systematic quantitative structure-property relationship (QSPR)/quantitative structure-activity relationship (QSAR) study was proven to have more general applicability.

Key words: QSPR, QSAR, Molecular electrostatic potential, Ab initio;　Polychlorinated biphenyl