TD-M06-2X insights into the absorption and emission spectra of dichlorvos and its molecularly imprinted recognition by methacrylic acid

Abstract

The absorption and emission spectra of dichlorvos and the dichlorvos-MAA complex in methanol, water, and chloroform in the molecularly imprinted recognition were investigated systematically. The M06-2X results revealed that: 1) the hydroxyl groups in polar solvents such as methanol and water may markedly influence the weak interactions, and then alter the adsorption and emission spectra; 2) the electronic excitation in absorption spectra of dichlorvos is dominated by the configuration HOMO → LUMO, but in the most stable dichlorvos-MAA it becomes the ππ* excitation of HOMO → LUMO + 1; 3) Mulliken charges reveal that dichlorvos almost dissociates to Cl and a cation in its S excitation state; 4) the phosphorescence spectra of dichlorvos-MAA are relatively weak. Graphical Abstract The absorption and emission spectra of dichlorvos and the dichlorvos-MAA complex in the molecularly imprinted recognition of dichlorvos were investigated systematically in methanol, water, and chloroform as solvents.

DFT and TD-DFT study on quadratic NLO response and optoelectronic activity in novel Y-shaped imidazole-based push-pull chromophores

“…The detailed information, namely, the maximum absorption wavelength (labs), electronic absorption energies (Ege), oscillator strengths (fge), transition dipole moments (μge) and the major MO contributions for the most relevant singlet-singlet excited states are gathered in Table 5. It is well-recognized that the CAM-BLYP and M06-2X functionals are suitable for calculating the electronic transition energies [41,42]. Indeed, the calculated absorption wavelength λabs value of D3 agrees well with the experimental value and the deviations are 38(30) nm at the CAM-B3LYP(M06-2X) level.…”

“…The S0 and S1 optimized states were used for the calculation of absorption and fluorescence characteristics, respectively. These two functionals are found to be appropriate for calculating the absorption and fluorescence spectra of p-conjugated organic chromophores [41,42]. For instance, the calculated absorption λabs and emission λflu wavelengths of D3 agree well with the available experimental data [28] (see Tables 4-5).…”