An ab initio simulation of the UV/Visible spectra of substituted chalcones

Abstract

a An ab initio simulation of the UV/Visible spectra of substituted chalcones Abstract:The electronic absorption spectra of 29 phenyl-ring substituted chalcones have been investigated with the time-dependent density functional theory (TD-DFT) and polarizable continuum TD-DFT (PCM-TD-DFT). It turns out that the hybrid PBE1PBE functional with the 6-31G basis set provide reliable λ max when the solvent effects are included in the model. Comparisons with experimental values lead to a mean absolute error of 12 nm (0.136 eV). Moreover, the observed substituent effects are reproduced by calculation qualitatively. The λ max of substituted chalcone in phenyl ring A is less sensitive to substitution than that in ring B. The linear correlation of Hammett's substituent constants (σ P ) with LUMO energies is better with respect to HOMO energies. The calculation reveals that the maximum absorption band mainly results from the π→π* transition from HOMO to LUMO. The analysis of the electron density plots of frontier molecular orbitals show that most transitions should be of valence excitation nature.

Photophysical Properties and Electronic Structure of Bacteriochlorin–Chalcones with Extended Near‐Infrared Absorption

“…The inherent color yet relatively small size of chalcones has prompted a large number of synthetic , photophysical and computational studies, predominantly of “push‐pull” chalcones. As one relatively recent example, Rurack et al .…”

Luminescent properties of chalcone and its aminoderivatives

“…Substituents in the phenyl ring conjugated with À CQCÀ group affect the absorption maximum with a greater extent than those in the phenyl ring conjugated with -C(QO)-group [9]. Both electron-donor and electron-acceptor (except highly polar CF 3 and Cl) substituents cause a decrease in the energy of the S state − ππ ⁎ .…”

“…Chalcone and its derivatives are widely used as fluorescent probes [20,21], materials with significant nonlinear responses [22] and typical chromophore components for photochemical sensors [23]. Charge transfer character of the low-lying ππ ⁎ transition from the phenyl ring to the polyene chain allows one to vary the energy of the intense transition introducing substituents in the phenyl ring [9].…”

“…Electronic structure of chalcone derivatives was explored mostly in their singlet ππ ⁎ states in order to analyze the absorption spectra of substitued chalcones [9,[17][18][19]28]. Substituents in the phenyl ring conjugated with À CQCÀ group affect the absorption maximum with a greater extent than those in the phenyl ring conjugated with -C(QO)-group [9].…”

“…However, it hardly be said about the properties of chalcone and its amino-derivatives. Due to the flexible -CQC-C(-)QO chain and non-planar structure [8,9] they have distinguishing features, such as fluorescence quenching in protic solvents [4,[10][11][12][13][14].…”