Structural, vibrational, electronic, NMR, NLO and reactivity analyses of (3Z)-3-(2-oxo-2-phenylethylidene)-1,3-dihydro-2H-indol-2-one (OPEDI) by ab initio HF and DFT calculations

This study represents the vibrational, electronic, NMR, NLO, reactivity and structural aspects of (3Z)-3-(2-oxo-2-phenylethylidene)-1,3-dihydro-2H-indol-2-one (OPEDI). A detailed interpretation of the FT-IR, FT-Raman, UV and NMR spectra were reported. Theoretical calculations were performed by ab initio HF and density functional theory (DFT)/B3LYP method using 6-311++G(d,p) basis sets. The most preferred Z isomer (cis-configuration) was confirmed through PES scan studies. The vibrational wavenumbers and potential energy distribution (PED) of various normal modes were calculated. The lower frontier orbital energy gap and high dipole moment of OPEDI illustrates the high reactivity. The stability and charge delocalization of the molecule was studied by natural bond orbital (NBO) analysis. OPEDI exhibited good nonlinear optical activity and was 13 times greater than that of urea. Molecular electrostatic potential (MEP) was carried out for predicting the reactive sites. The NMR results indicated that the observed chemical shifts depend not only on the structure of the molecule being studied, but also on the solvent used.

This study represents the vibrational, electronic, NMR, NLO, reactivity and structural aspects of (3Z)- 3-(2-oxo-2-phenylethylidene)-1,3-dihydro-2H-indol-2-one (OPEDI). Theoretical calculations were performed by ab initio HF and density functional theory (DFT)/B3LYP method using 6-311++G(d,p) basis sets. The stable isomer of OPEDI was calculated by PES scan. The electronic spectrum corresponding to electronic transitions are mainly π-π∗. NBO analysis and non linear optical activity (NLO) calculations shows intramolecular charge transfer interactions taking place in OPEDI. The NMR results indicated that the observed chemical shifts depend on solvent used.Figure optionsDownload as PowerPoint slideHighlights
► The vibrational, electronic, NMR, NLO and structural aspects of (OPEDI) was studied.
► PES scan results indicated that the most stable isomer of OPEDI is Z isomer.
► OPEDI exhibited good NLO activity.
► NMR chemical shifts and solvent effects of OPEDI were studied.