title: Helquat Dyes: Helicene-like Push-Pull Systems with Large Second-Order Nonlinear Optical Responses.
abstract: Helquat dyes combine a cationic hemicyanine with a helicene-like motif to form a new blueprint for chiral systems with large and tunable nonlinear optical (NLO) properties. We report a series of such species with characterization, including determination of static first hyperpolarizabilities β0 via hyper-Rayleigh scattering and Stark spectroscopy. The measured β0 values are similar to or substantially larger than that of the commercial chromophore E-4'-(dimethylamino)-N-methyl-4-stilbazolium. Density functional theory (DFT) and time-dependent DFT calculations on two of the new cations are used to probe their molecular electronic structures and optical properties. Related molecules are expected to show bulk second-order NLO effects in even nonpolar media, overcoming a key challenge in developing useful materials.
authors: School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.
authors: Benjamin J
authors: BJ
authors: Coe
authors: School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.
authors: Daniela
authors: D
authors: Rusanova
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: Vishwas D
authors: VD
authors: Joshi
authors: School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.
authors: Sergio
authors: S
authors: Sánchez
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: Jan
authors: J
authors: Vávra
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: Dushant
authors: D
authors: Khobragade
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: Lukáš
authors: L
authors: Severa
authors: Department of Inorganic Chemistry, Charles University , Hlavova 2030/8, 128 43 Prague 2, Czech Republic.
authors: Ivana
authors: I
authors: Císařová
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: David
authors: D
authors: Šaman
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: Radek
authors: R
authors: Pohl
authors: Department of Chemistry, University of Leuven , Celestijnenlaan 200 D, Leuven B-3001, Belgium.
authors: Koen
authors: K
authors: Clays
authors: Department of Chemistry, University of Leuven , Celestijnenlaan 200 D, Leuven B-3001, Belgium.
authors: Griet
authors: G
authors: Depotter
authors: Molecular Materials Research Center, Beckman Institute, MC 139-74, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States.
authors: Bruce S
authors: BS
authors: Brunschwig
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , v.v.i., Flemingovo n. 2, 166 10 Prague 6, Czech Republic.
authors: Filip
authors: F
authors: Teplý