Large nonlinear optical activity of chromophores with divinylquinoxaline conjugated π-bridge

Composing NLO Chromophore as a Puzzle: Electrochemistry‐based Approach to Design and Effectiveness

“…The notable mixing of CT state in IIaz compared to Iaz results in the reduction of ΔE el and corresponding increase of β tot values: 941 ⋅ 10 −30 esu and 875 ⋅ 10 −30 esu, respectively [42,43] . However, passing to IIIaz results in further growth of ΔE el (up to 1.32 eV) and decrease of β tot to 844 ⋅ 10 −30 esu.…”

“…Among various kinds of D‐π‐A chromophores, recent studies have focused on the modification of the π‐conjugated linkers, [42–55] which can modulate E HOMO and E LUMO , facilitate light harvesting, and hence play a vital role in the intramolecular electron density redistribution process. Various five‐ and six‐membered heterocycles, as well as polyenes were utilized as suitable π‐conjugated chromophore backbones.…”

“…In this respect, benzene, five‐membered thiophene, diazoles, and diazines, including quinoxalines and quinoxalinones seem to be suitable parent π‐conjugated backbones [42–55] . However, comparison of the effectiveness of bridges of different nature with each other was carried out rarely.…”

Electronic structure and second-order nonlinear optical properties of lemniscular [16]cycloparaphenylene compounds

“…One method is to insert an electron-donor and/or electron-acceptor substituted unit into organic compounds with an extended pconjugated backbone at appropriate positions. [11][12][13][14][15][16][17] The other method is to use chiral compounds, which have intrinsic asymmetric electronic structures. [18][19][20][21] Numerous studies have shown that chiral compounds can be a valuable alternative for excellent second-order NLO materials.…”

Characterization of Conjugation Effects in the Series of Quinoxaline-2-ones by Means of Vibrational Raman Spectroscopy

“…The role of the π bridge is fundamental to ensure an optimal electron mobility through the system, and hence, to optimize its functions, a broad range of aromatic heterocyclic moieties have been considered as π-linkers including thiazole, − thiophene, − phenothiazine, pyrrole, , and various diazines . In a recent contribution we have shown that quinoxalinones/quinoxalines possess interesting properties in this regard − and can be proposed as π-bridging fragments of NLO-phores − and as novel luminophores. , Indeed, due to their highly π-deficient character, these units can play a dual role acting simultaneously as electron-withdrawing (A) and π-bridging motifs in D-π-A structures. The extent of the conjugation induced by the presence of the π-bridge is indeed fundamental in modulating not only the optical properties of such compounds but also their response to external stimuli and in many instances their photophysical properties.…”