title: Conformational and Molecular Structures of α,β-Unsaturated Acrylonitrile Derivatives: Photophysical Properties and Their Frontier Orbitals.
abstract: We report single crystal X-ray diffraction (hereafter, SCXRD) analyses of derivatives featuring the electron-donor N-ethylcarbazole or the (4-diphenylamino)phenyl moieties associated with a -CN group attached to a double bond. The compounds are (2Z)-3-(4-(diphenylamino)-phenyl)-2-(pyridin-3-yl)prop-2-enenitrile (I), (2Z)-3-(4-(diphenylamino)phenyl)-2-(pyridin-4-yl)-prop-2-enenitrile (II) and (2Z)-3-(9-ethyl-9H-carbazol-3-yl)-2-(pyridin-2-yl)enenitrile (III). SCXRD analyses reveal that I and III crystallize in the monoclinic space groups P2/c with Z' = 2 and C2/c with Z' = 1, respectively. Compound II crystallized in the orthorhombic space group Pbcn with Z' = 1. The molecular packing analysis was conducted to examine the pyridine core effect, depending on the ortho, meta- and para-positions of the nitrogen atom, with respect to the optical properties and number of independent molecules (Z'). It is found that the double bond bearing a diphenylamino moiety introduced properties to exhibit a strong π-π-interaction in the solid state. The compounds were examined to evaluate the effects of solvent polarity, the role of the molecular structure, and the molecular interactions on their self-assembly behaviors. Compound I crystallized with a cell with two conformers, anti and syn, due to interaction with solvent. DFT calculations indicated the anti and syn structures of I are energetically stable (less than 1 eV). Also electrochemical and photophysical properties of the compounds were investigated, as well as the determination of optimization calculations in gas and different solvent (chloroform, cyclohexane, methanol, ethanol, tetrahydrofuran, dichloromethane and dimethyl sulfoxide) in the Gaussian09 program. The effect of solvent by PCM method was also investigated. The frontier HOMO and LUMO energies and gap energies are reported.
authors.affiliation: Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla, Mexico. judith.percino@correo.buap.mx.
authors.forename: María Judith
authors.initials: MJ
authors.lastname: Percino
authors.affiliation: Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla, Mexico. margarita.ceron@correo.buap.mx.
authors.forename: Margarita
authors.initials: M
authors.lastname: Cerón
authors.affiliation: Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla, Mexico. oscar.biome@gmail.com.
authors.forename: Oscar
authors.initials: O
authors.lastname: Rodríguez
authors.affiliation: Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla, Mexico. jesus.soriano@correo.buap.mx.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Soriano-Moro
authors.affiliation: Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla, Mexico. mareug.castro@correo.buap.mx.
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Castro
authors.affiliation: Laboratorio de Polímeros, Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), Complejo de Ciencias, ICUAP, Edif. 103H, 22 Sur y San Claudio, C.P. 72570 Puebla, Puebla, Mexico. victor.chapela@correo.buap.mx.
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Chapela
authors.affiliation: Department of Chemistry, Johns Hopkins University, New Chemistry Building, 3400 N. Charles St. Baltimore, MD 21218, USA. xray@jhu.edu.
authors.forename: Maxime A
authors.initials: MA
authors.lastname: Siegler
authors.affiliation: Centro de Investigaciones en Óptica (CIO), Loma del Bosque 115, Lomas del Campestre, León, Guanajuato 37000, Mexico. eperez@cio.mx.
authors.forename: Enrique
authors.initials: E
authors.lastname: Pérez-Gutiérrez
mesh_terms: D000181:Acrylonitrile / Q000138:chemical synthesis / Q000737:chemistry*; D002227:Carbazoles / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004583:Electrons; D008958:Models, Molecular; D015394:Molecular Structure; D011725:Pyridines / Q000737:chemistry
chemical_list: D002227:Carbazoles; D011725:Pyridines; C041514:carbazole; D000181:Acrylonitrile; C023666:pyridine
keywords: D-π-A type dyes and DFT calculations; charge transfer; electrochemical properties; structure-property relationships; supramolecular network