Theoretical assessment of the influences of aromatic bridges on molecular second order nonlinear optical responses of Donor-Bridge-Acceptor types of molecular organic chromophores

Planar in Brooker's mode and twisted in Reichardt's mode: defying the steric forces in biphenyl types of zwitterionic systems through metameric resonance stabilizations

“…From a thorough look at the numerous examples of biphenyl types of systems reported in the literature, I have observed one thing which is that when the biphenyls are para substituted (like donor–acceptor substituted or push–pull types of biphenyl systems), reduced values of twist angles are reported, compared to the unsubstituted biphenyl types of systems. 50,51 Hence, one can say that chemical perturbation induced by donor/acceptor substitutions is capable of reducing the twist angle to some extent. Based on this observation I can conjecture that if large chemical perturbations (for example, charged donor/acceptor systems like zwitterions) can be induced in the biphenyl types of systems, then one can possibly be able to achieve planarity or pseudo planarity types of conformations.…”

Synthesis, nonlinear optical analysis and DFT studies of D–π–D and A–π–A configured Schiff bases derived from bis-phenylenediamine

“…13 Charge transfer is improved in compounds containing delocalized electrons in a D-A conguration. 17,18 In optoelectronics and photonics, the demand for the production of new NLO materials has expanded dramatically in recent years. The intriguing photo-physical behavior of NLO materials, when exposed to strong laser light, is responsible for their wide range of applicability.…”

A theoretical comparison of the electrical and nonlinear optical properties ofGDY–π–TPA: The important role ofπ‐conjugated bridge

“…The β 0 values of our systems are comparable to the values (about 2.0 Â 10 4 a.u.) of some organic chromophores with hetero-aromatic bridges (diazine, tetrazine, pyrrole, furan, and thiophene) and conjugated bridges (ethylene and acetylene) [12,21].…”

“…Complexes with the donor-(π-conjugated bridge)-acceptor (D-π-A) or the X-π-X (X = D/A) framework can display considerable NLO responses, and evident charge transfer (CT) that occurs in such structures is responsible for their NLO properties [6][7][8][9]. NLO properties can be easily tuned by varying the nature of the donor/acceptor group and the π-conjugated part [9][10][11][12]. Various NLO molecules containing some aromatic heterocyclic rings (e.g., furan, phenyl, pyrrole, and thiophene) have been studied [13][14][15].…”

“…For example, at the CNDOVSB theoretical level, heterocycles (furan, pyrrole, and thiophene) decorated with donor/acceptor groups (NMe 2 /NO 2 ) have large first hyperpolarizabilities (β 0 ) in a range of 12.9 Â 10 À30 to 13.5 Â 10 À30 cm 5 e.s.u [20]. Sanyasi Sitha et al have performed computational studies to account for the roles of various bridges (such as aromatic rings, ethylene, and acetylene) on the β 0 values of D-bridge-A types of organic chromophores, with p-aniline as the donor and p-nitrobenzene as the acceptor [12,21]. Recently, it has been reported that some molecules containing -CH=CH) nbridges can exhibit large first hyperpolarizabilities [22,23].…”