Preliminary approach to estimation and prediction of infrared spectroscopy for Mannich bases by atomic...

Systematical studies were made on infrared spectroscopy (IR) and its regularity of vibration frequency. By applying a novel molecular structural descriptor vector containing four elements, called atomic electronegativity (EN) distance vector (VAED) expressed in the form of force, to characterize the chemical environment of various atoms in Mannich bases, the quantitative relationship models of IR of Mannich bases were established with respect to their VAED descriptors, based on multiple linear regression (MLR) analysis. In order to demonstrate the modeling stabilities and predictive abilities of diverse models, a cross validation (CV) with the leave-one-out (LOO) procedure was performed for each modeling equation. For the first panel of the 17 examined analogous Mannich bases, the correlation coefficient (R) between the observed and estimated vibration frequencies and standard deviation (S.D.) both for the double covalent bonds, C, O ami Pz.sbnd;O are 0.9782, 0.9817, 9.1170 and 11.0649; and the corresponding R and S.D. obtained by the CV method are 0.9496, 0.8829, 14.1186 and 27.2829, respectively, which shows that the quantitative structure-spectrum relationship (QSSR) models are quite stable and have both good estimative results and fine predictive capabilities. For the second panel of the 16 examined Mannich bases, the results still seem satisfied since the QSSR model is stable and could roughly estimate and predict the vibration frequency of the Cz.dbnd6;O bond for the other related Mannich bases.