Study of spectroscopic properties, thermodynamic, NBO, quantum chemical calculations and Curie plot of 3'-(triflouromethyl)acetophenone

Abstract

The experimental spectra 3'-(triflouromethyl)acetophenone have been assigned based on DFT calculations at B3LYP level of theory using the standard 6-31+G(d) and 6-311++G(d, p) basis sets and scaling of the calculated frequencies. In fitting the calculated wavenumbers to the experimental ones, two different scaling procedures called “scaling wavenumbers with dual scale factors” and “uniform scaling procedure”, were preceded. These procedures have yielded results in very good agreement with the experiment and thus proved the necessity for an efficient scaling procedure over the calculated harmonic wavenumbers for performing a correct vibrational spectroscopic analysis on the basis of B3LYP calculations. The HOMO−LUMO energy gap of the molecule has been calculated and used for predicting the site for electrophilic and nucleophilic attack. The presence of the flouro-methyl group has a strong effect on the physical structure of the compound. The NBO and Mulliken population analysis have been performed on the molecule for understanding the charge distribution, molecular geometry, hybridization and the strength of different bonds forming the molecule. The thermodynamic and paramagnetic susceptibility variations with temperature are recorded for different temperature ranges.