Dicyano and pyridine derivatives of β-carotene: synthesis and vibronic, electronic, and photophysical properties.
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.
Department of Chemistry, Wichita State University, Wichita, Kansas 67260, USA.
A J
AJ
Cruz
K
K
Siam
D P
DP
Rillema
D000042:Absorption; D002338:Carotenoids / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004579:Electron Transport; D004581:Electronics; D004735:Energy Transfer; D008958:Models, Molecular; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D019265:Spectroscopy, Near-Infrared; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*
D011725:Pyridines; C110652:beta-apo-8'-carotenal; D019207:beta Carotene; D002338:Carotenoids