An Application of QM‐QSAR to Predict and Rationalize the Refractive Index of a Wide Variety of Simple Organic/Organosilicon Molecules
Andrew J. Holder, Lin Ye, J. David Eick, CECIL C. JUN. CHAPPELOW · QSAR & Combinatorial Science · 2006
Abstract The Refractive Index (RI) is a basic optical property of organic matter. In our research on dental restorative materials, RI values of monomers are important, since they affect the penetration of initiating light pulses into the forming matrix. This paper addresses the development of a general Quantum‐Mechanically based Quantitative Structure–Activity Relationship (QMQSAR) for the RI of small molecules. SAM1 is the semiempirical method used to calculate molecular properties. A training set of 75 varied molecules was used to derive the final QSAR model, which included descriptors quantifying the contributions of the relative numbers of carbon atoms and the α polarizability of the molecule. The coefficient of correlation was R2=0.924, and the other indicators of quality were within acceptable limits. The model demonstrated extensibility beyond the training set by predicting the refractive index of 29 molecules with an R2=0.913. The signed error, unsigned error and RMSE are −0.0049, 0.01412, and 0.0167 respectively. Comparison was made to existing models in the literature.