title: Nonlinear optical and two-photon absorption properties of octupolar tris(bipyridyl)metal complexes.
abstract: The linear (absorption and emission) and nonlinear optical (NLO) properties of a series of D(3) [(Fe(II), Ru(II), Ni(II), Cu(II), Zn(II)] octupolar metal complexes featuring the 4,4'-bis[(dibutylamino)styryl]-2,2'-bipyridine ligand are reported. Zinc(II), nickel(II), and copper(II) complexes exhibit similar absorption spectra in the visible region (lambda(ILCT) = 474-476 nm) which are assigned to intraligand charge-transfer (ILCT) bands. The quadratic and cubic NLO properties are strongly influenced by the nature of the metallic center. Harmonic light scattering studies at lambda = 1.91 microm reveal that these chromophores display large first hyperpolarizabilities beta(1.91) in the range of (211-340) x 10(-30) esu; replacing the Zn(II) metal ion by Ni(II) or Cu(II) results in a decrease of the static beta(0) coefficient by a factor of 1.5-1.6. Z-scan measurements at 765 and 965 nm reveal relatively large two-photon absorption cross-sections [650 < sigma(2) < 2200 GM], showing that both beta and sigma(2) values can be tuned by simple modification of the metal ion.
authors.affiliation: UMR 6226 CNRS-Université de Rennes1, Campus de Beaulieu, 35042 Rennes Cedex, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Feuvrie
authors.forename: Olivier
authors.initials: O
authors.lastname: Maury
authors.forename: Hubert
authors.initials: H
authors.lastname: Le Bozec
authors.forename: Isabelle
authors.initials: I
authors.lastname: Ledoux
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Morrall
authors.forename: Gulliver T
authors.initials: GT
authors.lastname: Dalton
authors.forename: Marek
authors.initials: M
authors.lastname: Samoc
authors.forename: Mark G
authors.initials: MG
authors.lastname: Humphrey