title: Study of Model Systems for Bilirubin and Bilin Chromophores: Determination and Modification of Thermal and Photochemical Properties.
abstract: Bilin chromophores and bilirubin are involved in relevant biological functions such as light perception in plants and as protective agents against Alzheimer and other diseases. Despite their extensive use, a deep rationalization of the main factors controlling the thermal and photochemical properties has not been performed yet, which in turn hampers further applications of these versatile molecules. In an effort to understand those factors and allow control of the relevant properties, a combined experimental and computational study has been carried out for diverse model systems to understand the interconversion between Z and E isomers. In this study, we have demonstrated the crucial role of steric hindrance and hydrogen-bond interactions in thermal stability and the ability to control them by designing novel compounds. We also determined several photochemical properties and studied the photodynamics of two model systems in more detail, observing a fast relaxation of the excited state shorter than 2 ps in both cases. Finally, the computational study allowed us to rationalize the experimental evidence.
authors.affiliation: Unidad Docente de Química Física, Universidad de Alcalá , Alcalá de Henares, E-28871 Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: García-Iriepa
authors.affiliation: Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT) , 76128 Karlsruhe, Germany.
authors.forename: Hanna A
authors.initials: HA
authors.lastname: Ernst
authors.affiliation: Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT) , 76128 Karlsruhe, Germany.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT) , 76128 Karlsruhe, Germany.
authors.forename: Andreas-Neil
authors.initials: AN
authors.lastname: Unterreiner
authors.affiliation: Unidad Docente de Química Física, Universidad de Alcalá , Alcalá de Henares, E-28871 Madrid, Spain.
authors.forename: Luis Manuel
authors.initials: LM
authors.lastname: Frutos
authors.affiliation: Departamento de Química, Centro de Investigación en Síntesis Química (CISQ), Universidad de La Rioja , Madre de Dios 53, E-26006 Logroño, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Sampedro
mesh_terms: D001654:Bile Pigments / Q000737:chemistry*; D001663:Bilirubin / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D009154:Mutation; D055668:Photochemical Processes; D012984:Software; D013237:Stereoisomerism
chemical_list: D001654:Bile Pigments; D001663:Bilirubin