A QSPR Study for the Prediction of the pKaof N-Base Ligands and Formation ConstantKcof Bis(2,2′-bipyridine)Platinum(II)-N-Base Adducts Using Quantum Mechanically Derived Descriptors

摘要

Quantitative structure-property relationship (QSPR) study on the acid dissociation constant, pKaof various 22 N-base ligands including pyridines, pyrimidines, purines, and quinolines has been carried out using Codessa Pro methodology and software. In addition, the formation constant,Kcof these ligands with Pt(II)(bpy)2 2+(bpy = 2,2′-bipyridine) ion has also been modelled with the same methodology. Linear regression QSPR models of pKaandKcwere established with descriptors derived from AM1 calculations. Among the obtained QSPR models of pKapresented in the study, statistically the most significant one is a four parameters linear equation with the squared correlation coefficient,R2values of ca. 0.95 and the squared cross-validated correlation coefficient,Rcv2values of ca. 0.89, and external the squared correlation coefficient,Rext.2values of ca. 0.97. Statistically the most significant QSPR model ofKcis also a four parameters linear equation with the squared correlation coefficient,R2values of ca. 0.75 and the squared cross-validated correlation coefficient,Rcv2values of ca. 0.55, and external the squared correlation coefficient,Rext.2values of ca. 0.81. An analysis of descriptors that involved in the pKamodels indicate that reactivity index and charge distribution related descriptors play major roles to model acid dissociation constant of ligands of N bases.