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  • Title: Dicyano and pyridine derivatives of β-carotene: synthesis and vibronic, electronic, and photophysical properties.
    Author: Cruz AJ, Siam K, Rillema DP.
    Journal: J Phys Chem A; 2011 Feb 17; 115(6):1108-16. PubMed ID: 21244068.
    Abstract:
    Density functional theory and time-dependent density functional theory calculations provide pictures of the molecular orbitals involved in the ground and excited states of two cyano derivatives of 8'-apo-β-caroten-8'-al synthesized via an acid-base-catalyzed Knoevenagel condensation reaction. Population analysis shows that the symmetry-allowed transition, S(0) ((1)A(g)) → S(2) ((1)B(u)) based on the C(2h) symmetry is a HOMO (highest occupied molecular orbital) to LUMO (lowest unoccupied molecular orbital) π → π* transition with electron densities located mostly on the polyene chain. Calculated and actual steady-state absorption spectra show similar features with low-energy peak maxima between 550 and 600 nm.
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