title: 2,2'-Bipyridine-based dendritic structured compounds for second harmonic generation.
abstract: Parallel alignment of dipolar electron-donor-π-bridge-electron-acceptor entities can strongly enhance their nonlinear optical properties. This favorable arrangement can be in principle achieved by linking these units covalently or through metal coordination. Four dipolar single-strand chromophores decorated with a 5-electron-donor-5'-electron-acceptor-modified 2,2'-bipyridine functionality were synthesized. For two of these chromophores triple-stranded dendritic structures were successfully formed. All of the compounds were characterized with respect to their linear and nonlinear optical properties. For the aldehyde derivatives an enhancement of the first hyperpolarizability of 4.5 rather than 3 was obtained when going from single to triple strands. Theoretical calculations with density functional theory suggest that interstrand transitions contribute to the optical properties of the dendritic structures.
authors.affiliation: Department of Chemistry, Institute for Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 146 Hamburg (Germany).
authors.forename: Marina
authors.initials: M
authors.lastname: Büchert
authors.forename: Torben
authors.initials: T
authors.lastname: Steenbock
authors.forename: Christian
authors.initials: C
authors.lastname: Lukaschek
authors.forename: Marie C
authors.initials: MC
authors.lastname: Wolff
authors.forename: Carmen
authors.initials: C
authors.lastname: Herrmann
authors.forename: Jürgen
authors.initials: J
authors.lastname: Heck
keywords: amino compounds; bipyridine ligand; dendrimers; hyper-Rayleigh scattering; nonlinear optics