NOVEL RED LIGHT-EMITTING POLYMERS BASED ON 2,7-CARBAZOLE AND THIOPHENE DERIVATIVES

A series of conjugated copolymers derived from 9-ethylhexyl-2,7-carbazole(Cz)and 4,7-di(4-hexylthien-2-yl)- 2,1,3-benzothiadiazole(DHTBT)was synthesized by Suzuki polycondensation.The photo-and electro-luminescent properties of these polymers were investigated.Efficient energy transfer from the Cz segment to the DHTBT unit occurs even if the DHTBT content as low as 1 mol%.PL emission was red-shifted significantly from 645 nm to 700 nm with the increase in DHTBT content by 1-50 mol%.PL efficiencies decreased...

Theoretical Study on Electronic and Charge Transfer Properties of Oligo[8]thiophene and Its Circular,Hooped,and Helical Derivatives

The novel linear, circular, hooped, and helical molecules based on oligo[8]thio- phene were theoretically studied for the applications of charge transfer devices. To investigate the influence of topology for oligo[8]thiophene derivatives, the geometry structures, frontier molecular orbital （FMO） energies, charge transport properties, and stability property were predicted by density functional theory methods. The calculated results reported herein show that the oligo[8]thiophene derivative with linear structure has smaller energy gap, and fused oligo[8]thiophene derivative with circular structure has the smallest reorganization energy among the designed molecules. We have also studied the stability properties of the designed molecules, and oligo[8]thiophene derivatives are more stable tharJ the fused oligo[8]thiophene derivatives.

Effect of Substituting Group on the Calculated Nonlinear Second－Order Optical Susceptibilities of Substituted Thiophene Derivatives with Quinoidlike Conformation

alculations of the nonlinear second-order optical susceptlbilities(β_(ijk))for sub- stituted tl1iophene derivative;with quinoidlike conformation are reported.These systetems possess small dipole moment;and large differences between dipole mo- ments of ground and first-excited states.Geometry optimizations of the molecules investigated were carried out using AM 1 method.The calculations were performed using INDO/CI method comboned with a sum-over-states expression for β_(jik). The calculated results sbw that the second-order susceptibility is a function of the na- ture and location of substituents and is larger for disubstituted molecules than monosubstituted molecules. Bipolymeric thiophenemetmne with NH_2/NO_2 groups was calctilated to have a β_μof 79. 920 × 10￣(-30) esu. It was found that the NH_2 and NO_2 groups in above disubstituted molecules are pull-pull groups in ground states,but are usual push-pull groups in the first excited states.

ZINDO-SOS Studies on Second-order Nonlinear Optical Properties of Thiophene S,S-Dioxide Chromophores

The second-order nonlinear optical properties of thiophene S,S -dioxides derivatives were studied by using the ZINDO-SOS method. The computed results show that the thiophene S,S -dioxide derivatives exhibit larger second-order polarizabilities than their thiophene precursors. In order to clarify the origin of the different NLO responses among these chromophores, their electron properties and frontier orbital properties were investigated as well. These thiophene S,S -dioxides derivatives are good candidates for their application in electro-optical device due to their high nonlinearities, good thermal and photo stabilities.

Recent advances in the synthesis of benzo[b]thiophene fused polycyclic derivatives:Strategies and reactions

Benzo[b]thiophene fused compounds with a unique active heterocyclic skeleton have wide applications in the fields of medicinal chemistry,organic synthesis,and organic functional materials,which resulted in rapid development of many efficient methods for the construction of benzo[b]thiophenefused heterocycles in recent years.Among these methods,the domino reaction of benzo[b]thiophene derivatives is a practical and powerful synthetic route to access benzo[b]thiophene-fused heterocycles by virtue of the particularity of sulfur atom.This review summarizes the latest developments in the construction of benzo[b]thiophene-fused heterocycles by ring formation at the C2-C3-position of benzo[b]thiophene derivatives in the past decade.Additionally,this review is divided into four parts according to the four kinds of benzo[b]thiophene derivatives used,including thioaurone,thioisatin,substituted benzo[b]thiophene,and azadiene.

Study on the Biological Activity of 3-Aroyl-5-substituted Thiophene Derivatives Based on the CoMFA Method

A three-dimensional quantitative structure-activity relationship(3 D-QSAR) study was conducted to analyze the A1 AR density(Bmax) of 56 3-aroyl-5-substituted thiophene derivatives(ASTDs) in human A1 Chinese hamster ovary(hA1 CHO) membranes by the comparative molecular field analysis(CoMFA) method. A training set of 45 compounds was used to establish the predictive model, which was verified by the test set of 17 compounds containing template molecule and 5 newly designed molecules. The cross-validation(R2 cv) and non-cross-validation(R2) coefficients of the training set were 0.655 and 0.959, respectively. The model was used to predict the activities of the compounds of the training and test sets, and the results indicated that the models had strong stability and good prediction ability. According to model analysis, the contribution of steric and electrostatic fields was 51.4% and 48.6%, respectively. Based on the 3 D contour maps, five excellent ASTDs agonists were designed, which need to be further verified by biomedical experiments.

Visible Light Excitable SCN^- Selective Fluorescence Probe Derived from Thiophene

An efficient fluorescence probe, 4-methyl-2,6-bis（（thiophen-2-ylmethylimino）methyl）phenol （DFPTMA） and its SCN adduct has been synthesized and characterized by different spectroscopic techniques like ^1H NMR,^13C NMR, QTOF-MS ES^＋, UV-Vis and FTIR spectroscopy. Single crystal X-ray structure of DFPTMA is reported. In presence of SCN-, DFPTMA exhibits significant fluorescence enhancement （λEx, 455 nm, λEm, 504 nm） in aqueous methanol （water-methanol, 1 ： 4, V/V, 0.1 mol/L HEPES buffer, pH 7.4）. Common bio-relevant anions viz. CH3COO^-, NO2, NO7, Cl^-, Br^-, I^-, SO4^2-, HSO4^-, N3^-, HAsO4^2-, Cr2O7^2-, H2PO4, ClO4^-, NCO^-, CN^-, CO3^2-, F^-, PO4^3-, S2-, HS- do not interfere in the recognition of SCN-. Lowest detection limit for SCN^- is 0.88 μmol/L with response time 〈5 min. The SCN assisted enhancement in emission intensity may be attributed to the formation of H-bond which enhances the rigidity of the molecular assembly.