title: Three-dimensional nonlinear optical chromophores based on metal-to-ligand charge-transfer from ruthenium(II) or iron(II) centers.
abstract: In this article, we describe a series of new complex salts in which electron-rich transition-metal centers are coordinated to three electron-accepting N-methyl/aryl-2,2':4,4' ':4',4' ''-quaterpyridinium ligands. These complexes contain either Ru(II) or Fe(II) ions and have been characterized by using various techniques, including electronic absorption spectroscopy and cyclic voltammetry. Molecular quadratic nonlinear optical (NLO) responses beta have been determined by using hyper-Rayleigh scattering at 800 nm and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d --> pi* metal-to-ligand charge-transfer bands. The latter experiments reveal that these putatively octupolar D(3) chromophores exhibit two substantial components of the beta tensor which are associated with transitions to dipolar excited states. Computations involving time-dependent density-functional theory and the finite field method serve to further illuminate the electronic structures and associated linear and NLO properties of the new chromophoric salts.
authors.affiliation: School of Chemistry, University of Manchester, Manchester, UK. b.coe@man.ac.uk
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Coe
authors.forename: James A
authors.initials: JA
authors.lastname: Harris
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Brunschwig
authors.forename: Inge
authors.initials: I
authors.lastname: Asselberghs
authors.forename: Koen
authors.initials: K
authors.lastname: Clays
authors.forename: Javier
authors.initials: J
authors.lastname: Garín
authors.forename: Jesús
authors.initials: J
authors.lastname: Orduna
mesh_terms: D007501:Iron / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D015394:Molecular Structure; D009905:Optical Rotatory Dispersion; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D012428:Ruthenium; D007501:Iron