Nonlinear optical activity of push–pull indolizine-based chromophores with various acceptor moieties

Quadratic nonlinear optical response of composite polymer materials based on push–pull quinoxaline chromophores with various groups in the aniline donor moiety

“…3 Various attempts were made to improve chromophore properties; one of them is the modification of the donor moiety. Many D–π–A chromophores with donors based on the aniline structure: triarylamino-, 4 tetrahydroquinoline-, 5 julolidine-, 6 and phenothiazine-derivatives, 7 as well as aminothiophene or aminopyrrole structure 4 b ,8 and those based on various fused heterocycles and carbocycles: aminobenzothiophene-, 9 aminobenzofuran-, 10 indolizine- 11 and aminofluorene derivatives, 12 have been synthesized and the electrooptic (EO) and/or NLO properties of the composite materials containing these dyes as guests were studied. A new strategy exploited recently to improve the first hyperpolarizability of chromophores is focused on the modification and improvement of donors via the introduction of heteroatom-containing groups or the use of double donor structure to increase the electron-donating ability of the donors; the thienothiophene moiety was explored as a replacement for the phenyl unit in the donor part of the chromophore.…”

Accurate Nonlinear Optical Properties of Solvated para-Nitroaniline Predicted by an Electrostatic Discrete Local Field Approach

“…Organic molecular materials with enhanced nonlinear optical (NLO) properties remain an attractive subject of current research due to their broad application potential in communication, , signal processing, − data storage, , solar cells, − and other fields. − Compared to their inorganic counterparts, the NLO signal intensity and response times of the organic materials can be efficiently tuned by structural modifications. − Rational design of new efficient NLO materials should not rely on structure–property relationships for isolated chromophores but should also take environmental effects in the bulk into account. From a molecular structure point of view, the most common organic second-order NLO compounds are push-pull systems consisting of donor (D) and acceptor (A) groups linked by a π-conjugated bridge, thus ensuring a high susceptibility of the electron density to external electric fields and, at the same time, preserving the molecular asymmetry. ,,,− Examples of D-π-A systems include substituted benzenes, , stilbenes, , BODIPY derivatives, and aromatic heterocycles. , A popular D-π-A model molecule is para -nitroaniline (pNA), which has received an extensive attention both from experimentalists − and theoreticians. − The NLO properties of pNA and its substitutional derivatives have also been studied for bulk structures, ,− ,,,− e.g., molecular crystals,…”

“…5,13,14,18−23 Examples of D-π-A systems include substituted benzenes, 23,24 stilbenes, 24,25 BODIPY derivatives, 21 and aromatic heterocycles. 19,20 A popular D-π-A model molecule is para-nitroaniline (pNA), which has received an extensive attention both from experimentalists 26−32 and theoreticians. 33−48 The NLO properties of pNA and its substitutional derivatives have also been studied for bulk structures, 23,26−28,31,35,49−51 e.g., molecular crystals, 52 heterogeneous environments, 35 polymeric nanofibers, 28 O-dimeric aggregates, 27 and self-assembled polymeric films.…”