title: Geometric description and electronic properties of the principal photosynthetic pigments of higher plants: a DFT study.
abstract: The geometric parameters, local and global chemical reactivity parameters (such as the ionization potential, electron affinity, electronegativity, hardness, softness, chemical potential, and electrophilicity index), as well as the energy levels (HOMO/LUMO) and HOMO-LUMO energy gaps have been determined for the principal carotenoids in higher plants. DFT calculations performed using the B3LYP functional in combination with the 6-31G(d,p) (for geometric parameters) and 6-31 + G(d,p) (for energy parameters) basis sets were carried out to study these structures. The HOMO-LUMO energy gaps obtained with the TPSSh functional were compared with the corresponding energy gaps obtained with B3LYP (when both functionals were used with the 6-31 + G(d,p) basis set). Upon analyzing all of the calculated parameters of the studied molecules, both carotenes were found to be the most reactive, followed by β-cryptoxanthin, zeaxanthin, lutein, violaxanthin, and finally neoxanthin, the least reactive molecule. The results reveal that all of the carotenoids show very high coplanarity in the photochemically active region, resulting in small HOMO-LUMO energy gaps. The calculated local and global chemical reactivity parameters indicate that all of the studied molecules may be classified as soft, as they are good electron donors/acceptors, making these molecules good candidates for use in artificial photosynthetic systems.
authors.affiliation: Centro de Investigación en Alimentación y Desarrollo, A.C. Unidad Delicias. Av. 4ª Sur 3820, Fracc. Vencedores del Desierto. Cd., Delicias Chih, México, 33089.
authors.forename: Francisco
authors.initials: F
authors.lastname: Torres-Rivas
authors.affiliation: Facultad de Ciencias Químicas, Universidad Juárez del Estado de Durango, Ave. Veterinaria s/n, Circuito Universitario, 34120, Durango, México.
authors.forename: Manuel Alberto
authors.initials: MA
authors.lastname: Flores-Hidalgo
authors.affiliation: Centro de Investigación en Materiales Avanzados, S.C., M. de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua Chih, México, 31109.
authors.forename: Daniel
authors.initials: D
authors.lastname: Glossman-Mitnik
authors.affiliation: Centro de Investigación en Alimentación y Desarrollo, A.C. Unidad Delicias. Av. 4ª Sur 3820, Fracc. Vencedores del Desierto. Cd., Delicias Chih, México, 33089. dianabarraza@ujed.mx.|Facultad de Ciencias Químicas, Universidad Juárez del Estado de Durango, Ave. Veterinaria s/n, Circuito Universitario, 34120, Durango, México. dianabarraza@ujed.mx.
authors.forename: Diana
authors.initials: D
authors.lastname: Barraza-Jimenez
mesh_terms: D008956:Models, Chemical; D008962:Models, Theoretical; D015394:Molecular Structure; D010788:Photosynthesis; D010860:Pigments, Biological / Q000737:chemistry* / Q000378:metabolism; D010944:Plants / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010860:Pigments, Biological
keywords: Carotenes; Condensed Fukui functions; Electron affinity; Electrophilicity index; Ionization potential; Xanthophylls