Rational design of the benzothiazole-based fluorescent scaffold for tunable emission

The 2-(2-hydroxyphenyl)-benzothiazole (HBT) fluorophore has attracted considerable attention due to its excited-state intramolecular proton transfer (ESIPT) based emission and its large Stokes shift. However, this fluorophore possesses several disadvantages including low quantum yield and short emission in the blue range. In this study, by coupling HBT at the ortho-, meta-, and para-positions to the hydroxyl group with different heterocycles to extend the conjugation system, we have successfully obtained new fluorophores with tunable emissions both in solution and in the solid-state (409–652?nm). Notably, all of the derivatives demonstrated improved quantum yields compared with the parent HBT structure. Moreover, selected compounds have been shown to shine brightly in live cells, indicating promising potential for bioimaging.     

Synthesis and fluorescent properties of bis-salicyloyl hydrazide metal complexes of some group IV ions

Four novel organometallic compounds containing tin(IV), titanium(IV) and zirconium (IV) ions were synthesized and strong fluorescent emission was observed from two tin(IV) complexes.     

Synthesis and characterization of new fluorescent nanoparticles

A novel kind of fluorescent nanoparticles（FNPs）has been prepared using a precipitation polymerization method.Methacrylic acid,trimethylolpropane trimethacrylate and azobisisobutyronitrile were used as functional-monomer,cross-linker and initiator, respectively.Compared with other fluorescent nanoparticles,the FNPs have the characteristics including low dye leakage and good photostability.The fluorescence microscopy imaging indicates that the FNPs can be used as fluorescent labels in bioanalysis.     

Synthesis of multisubstituted furans, pyrroles, and thiophenes via ynolates

An efficient synthetic method for the preparation of multisubstituted furans, thiophenes, and pyrroles using ynolates was developed. This novel formal [4 + 1] annulation by C2-C3 and C3-C4 bond formations includes cycloaddition, cyclization, decarboxylation, and dehydration as key steps.     

Synthesis and properties of new poly(arylene thiophenes)

Soluble poly(arylene thiophenes) containing amide bridge bonds and free nitrile groups have been synthesized through polycondensation of new arylene-bis(2-aminothiophene-3-carbonitrile)s with arylene- dicarboxylic acid dichlorides, and their physical and photochemical properties have been studied. Thermostable and acid-resistant poly(thiene pyrimidones) co ntaining main-chain thiophene, arylene, and pyrimidone fragments have been obtained via the isomerization polycyclomerization of the poly(arylene thiophenes).     

Synthesis and photophysical properties of lead phthalocyanines

This work reports on the synthesis and photophysical parameters of tetra-and octa-substituted new lead phthalocyanines. The complexes synthesized are: 1,4-(tetraphenoxyphthalocyaninato)lead (7a), 1,4-(tetra-tert-butylphenoxyphthalocyaninato)lead (7b), 2,3-(tetraphenoxyphthalocyaninato)lead (8a), 2,3-(tetra-tert-butylphenoxyphthalocyaninato)lead (8b), 2,3-octaphenoxyphthalocyaninatolead (9a) 2,3-[octakis(4-t-butylphenoxyphthalocyaninato)]lead (9b). Photophysical properties were studied for these complexes in a dimethylsulfoxide, dimethylformamide, toluene, tetrahydrofuran and chloroform. The fluorescence spectra were different from excitation spectra due to demetallation upon excitation. High triplet quantum yields ranging from 0.70 to 0.88 (in DMSO, DMF and toluene) and low triplet lifetimes (20–50 μs in DMSO, and <10 μs in the rest of the solvents) were observed due to the presence of heavy atom.     

Synthesis, structure and photo-physical properties of phosphorus-supported fluorescent probes

Various phosphorus-supported fluorescent probes have been synthesized by the condensation reaction of multi-functional phosphorus hydrazides with various fluorophore-containing carboxaldehydes. Compounds, thus prepared, in this study are (PhO)₂P(O)[N(Me)-NCH-R] (1a, 1b), Ph₂P(O)[N(Me)-NCH-R] (2b, 2c, 2d), PhP(O)[N(Me)-NCH-R]₂ (3b, 3c), P(S)[N(Me)-NCH-R]₃ (4b, 4c), P(O)[N(Me)-NCH-R]₃ (5a, 5b, 5c), N₃P₃(O₂C₁₂H₈)₂[N(Me)-NCH-R]₂ (6a, 6b, 6c), N₃P₃(O₂C₁₂H₈)[N(Me)-NCH-R]₄ (7a, 7b, 7c, 7d) and N₃P₃[N(Me)-NCH-R]₆ (8b, 8c), where R=1-pyrenyl (a), 9-anthracenyl (b), 9-phenanthryl (c) and 7-(N,N′-diethylamino)-3-coumarinyl (d). All of these compounds have been characterized by various analytical techniques including ³¹P{¹H} NMR spectroscopy. Compounds 1b, 2b, 3b, 4b, 5b, 5c and 6d have also been characterized by single crystal X-ray analysis. All of these phosphorus-supported compounds exhibit excellent fluorescence properties in aqueous solution at near physiological conditions.     

Nucleophilic reactivities of tributylstannyl-substituted furans and thiophenes

Kinetic investigations of the reactions of benzhydryl cations with stannylated furans and thiophenes suggest that 2-(tributylstannyl)furan and -thiophene are preferentially attacked at the 5-position (k(rel), FcPhCH(+), 20 degrees C, CH(2)Cl(2)).     

三氮唑类席夫碱的合成及其荧光性能

近年来,Schiff碱因其结构的多样化以及具有光、电、磁等物理材料性能[1-3]的配位化学性能[4-5]等引起人们的关注,同时一些特殊结构的Schiff碱的合成和性质研究具有更为重要的理论意义和应用价值.     

High-yield syntheses of 2,3-disubstituted furans and thiophenes

The course of lithiation of furan- and thiophene-2-carboxylic acids is critically dependent on the identity of the lithium base allowing high-yielding syntheses of 2,3- and 2,5-disubstituted thiophenes: the proposed use of a trimethylsilyl blocking group to control metallation in the furan acid provides a useful route to 2,3-disubstituted furans.     

Synthesis and properties of new non-symmetric 2,5-bis(4-alkylphenylethynyl)thiophenes

The synthesis and characterisation of new non-symmetric 2,5-bis(4-alkylphenylethynyl)thiophenes are described. Phase transition properties of these non-symmetric homologues are compared to those of the corresponding symmetric analogues. Furthermore, optical, dielectric and elastic data of investigated compounds and nematic mixture are provided. Compounds are characterised by ¹H NMR spectroscopy and mass spectrometry (electron ionization) analysis. They show an enantiotropic nematic behaviour in broad temperature ranges, confirmed by a polarising thermomicroscopy and differential scanning calorimetry. Detailed synthetic procedures are attached, showing a great synthetic versatility of the thiophene ring substitution. Synthesised compounds stand as promising components of highly birefringent liquid crystalline mixtures.     

Synthesis and properties of some new polyazomethine-urethanes

Two new bisazomethine diols were prepared from terephthalaldehyde and aromatic or aliphatic aminoalcohols. The structure of the diols with bisazomethine moieties was confirmed by ¹H-NMR, IR, UV spectroscopy and elemental analysis. Bisazomethine aliphatic diol exhibited a smectic phase that has been identified by means of polarizing microscopy and differential scanning calorimetry. By using these diols as partners in polyaddition reaction between poly(tetramethylene oxide)diol of 2000 average molecular weight, tolylene-2,4-diisocyanate (as 2,4- and 2,6-TDI, 80:20 v/v isomers mixture) and bisazomethine diol (1:3:2 molar ratio), two polyazomethine-urethanes were synthesized. Polyazomethine-urethanes with a higher concentration of poly-Schiff's base units were also obtained by reacting the above bisazomethine diols with the same diisocyanate (1:1 molar ratio). All polymers were characterized by viscometry, elemental analysis, IR, UV, ¹H-NMR spectroscopy and TGA techniques.     

Synthesis and optical properties of tetraphenylmethane-based tetrahedral fluorescent compounds and their water-soluble PEG-linked polymers

The synthesis and optical properties of tetrahedral fluorescent compounds comprising of tetraphenylmethane as the core and oligothiophenes as the chromophoric arms, and their water-soluble poly(ethylene glycol)-linked polymers are reported.     

Pd-catalyzed olefination of furans and thiophenes with allyl esters

A direct Pd(II)-catalyzed olefination of furans and thiophenes with allyl esters is demonstrated. Under the typical conditions, the dehydrogenative Heck coupling reactions of heteroarenes with allylic esters proceeded via a β-H elimination rather than a β-OAc elimination to give the corresponding γ-substituted allylic esters.     

Synthesis and fluorescent properties of some heterobifunctional and rigidized 7-aminocoumarins

Heterobifunctional fluorescent reagents of coumarin type are synthesized. They possess, in position 7 , a rigidized or un-rigidized amino group and, in position 3 or 4 , a carboxylic function. The fluorescence characteristics of these compounds are described and compared with the 7-amino-4-methylcoumarin. The influence of the relative freedom of rotation of the amino group or the position of the acid function on the fluorescence properties are also studied.