Donor−Acceptor-Substituted Phenylethenyl Bithiophenes:  Highly Efficient and Stable Nonlinear Optical Chromophores

Abstract

For practical applications of poled electrooptic polymers, highly efficient and thermally stable nonlinear optical (NLO) chromophores are required. We describe here a concise synthesis and characterization of a series of donor−acceptor chromophores incorporating a bithiophene moiety in the conjugated bridge. They display a suitable thermal stability and significantly enhanced molecular nonlinearity as compared to their monothiophene analogues and are among the most efficient yet stable NLO chromophores prepared so far.

Single waveguide silicon-organic hybrid modulator

“…The second order nonlinear optical properties of the chromophore have been simulated using the CPHF (coupled perturbed Hartree-Fock) approach and also determined experimentally by electric field induced second harmonic generation (EFISH) measurements in dichloromethane solution (see Table 1). The theoretical data are in good accordance with the experimental data and both also lie in the range of known materials with comparable acceptors (Cai et al, 1999;Delgado et al, 2008). Time dependent density functional theory (TD-DFT) calculations reveal that the nonlinear optical (NLO) response seems to arise from the lowest energy allowed absorption.…”

Charge‐Transfer‐Chromophore durch Cycloaddition‐Retro‐Elektrocyclisierung: multivalente Systeme und Kaskadenreaktionen

“…[1,2] Unlängst fanden wir, dass ein breites Spektrum von 4-N,N-Dialkylanilin(DAA)-substituierten Alkinen glatt und oft quantitativ mit TCNE zu DAADonor-substituierten TCBDs reagiert. Diese neue Klasse von Chromophoren zeigt starke intramolekulare Charge-Transfer(CT)-Wechselwirkungen mit Absorptionsmaxima im sichtbaren Spektralbereich sowie vielversprechende optische Nichtlinearitäten dritter Ordnung.…”

An improved method for tricyanovinilation of aromatic amines under ultrasound irradiation

“…Another method involves the tricyanovinylation of thiazoles and thiophenes carried in DMF for 12 h at room temperature, after refluxing for 1 h [20]. Two other widely used synthetic routes use stepwise conversions starting from arylaldehydes where the aldehydes are first converted to dicyanovinyl compounds via condensation with malonodinitrile, then to tricyanovinyl by nucleophilic substitution of dicyanovinyl with sodium cyanide, followed by oxidation with lead tetraacetate [21] or by lithiation followed by quenching with tetracyanoethylene [22,23].…”