Photodynamics of polyene-polymethine transformations and spectral fluorescent properties of merocyanine dyes.

摘要: Absorption and fluorescence spectrum band moments (center of gravity, width, asymmetry, excess, fine structure) have been determined in a wide range solvents with different polarities for inverse solvatochromic di-, tetra-, hexamethinemerocyanines derived from 1,3-diphenyl-2,3-dihydro-1H-benzimidazole. Juxtaposition the quantum-chemically calculated (by semiempirical AM1 method) charges, bond orders, dipole merocyanine molecules ground excited singlet states experimentally observed spectral fluorescent characteristics suggests that molecular electronic structure two can vary nonpolar polyene via polymethine to charge-separated polyene, depending on length chain medium polarity. As shown, solvatofluorochromism gives rise smaller shifts than those solvatochromism. This effect is attributable weaker intermolecular solute−solvent interactions st...