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6,7-Bis(hexylthio)-2-[(2-hydroxyethyl)thio]-3-methylthio-tetrathiafulvalene (TTF-2) is coupled with thiophene-3-carboxylic acid and thiophene-3,4-dicarboxylic acid by Steglich esterification, respectively, to afford 2-((4′,5′-bis(hexylthio)-5-(methylthio)-[2,2′-bi(1,3-dithiolylidene)]-4-yl)thio)ethyl thiophene-3-carboxylate (TTF-Th) and bis(2-((4′,5′-bis(hexylthio)-5-(methylthio)-[2,2′-bi(1,3-dithiolylidene)]-4-yl)thio)ethyl)thiophene-3,4-di-carboxylate (DTTF-Th). Their structures were characterized by ESI-MS, 1H NMR, and elemental analysis. Electropolymerization of TTF-Th and DTTF-Th was conducted with 0.1 M n-Bu4NPF6. The results indicated that both assemblies could rapidly form polymers via electrochemical deposition. In addition, their electrochromic performances illustrated that the color of P(TTF-Th) could switch from orange-yellow to dark blue, while P(DTTF-Th) changed its color from orange in the neutral state to dark blue in the oxidation state. Moreover, the electrochromic performances of P(DTTF-Th) were better than P(TTF-Th) due to the introduction of one extra TTF unit.

Although widely used in organic synthesis, pharmaceuticals and agrochemicals, thiophenol has brought about a series of ecological problems due to its high toxicity. Therefore, the development of efficient methods to discriminate thiophenols from aliphatic thiols is of great importance. In this work, a new reaction-based turn-on red fluorescence probe for the detection of thiophenols has been developed for the first time by employing dicyanomethylene-4H-pyran (DCM) as a fluorescence reporter and 2,4-dinitrobenzene-sulfonate (DNBS) as a recognition unit. The probe displayed a highly selective and sensitive (63 fold-fluorescence enhancement) response to thiophenols over aliphatic thiols. Additionally, the probe also exhibited a large Stokes shift (159 nm) and the detection limit reached as low as 8.3 nM. Moreover, this probe was also proved suitable for the quantification of thiophenol in real environmental water samples. [ABSTRACT FROM AUTHOR]

Sulfur-based heterocycles were one of appealing building blocks in functional materials, due to their outstanding optical/electronical performance. Assembled DTTF-BTh which combined from two different sulfur heterocycles was synthesized by condensation of 2-cyanoethylthio-3-methylthio-6, 7-bis (hexylthio) tetrathiafulvalene ( TTF-1), and 4, 4′-bis (2′-bromoethoxy)- 3, 3′-bithiophene ( DBE-BTh). The full structural and physical characterizations of novel DTTF-BTh were studied by H NMR, Mass, UV-Vis absorption, and electrochemical measurements. The two heterocycle moieties were connected successfully but inclined to perform individually. This could be explained as electron separation by alkyl chains. Electropolymerization was also conducted. The result indicated that DTTF-BTh could directly form polymeric films on prepared ITO glass via electrochemical deposition. Moreover, the deposited polymer film possessed an electrochromic performance. [ABSTRACT FROM AUTHOR]

A novel and simple fluorescence probe was synthesized from benzo[1,2- b:4,5- b′]dithiophene (BDT) and trimethylsilylethyne via Sonogashira reaction, and showed highly selective and sensitive fluorescence decreasing response towards F−. The probe molecule turned to a weakly fluorescent terminal alkyne moiety because its trimethylsilyl (TMS) group was cleaved by fluoride, which was proved by 1H NMR titration. Whereas no distinct fluorescent changes were observed with the addition of other anions, such as Cl−, Br−, I−, AcO− and H2PO4−. Upon the addition of F−, the maximum fluorescence emission wavelength shifted from 460 nm to 450 nm with a decrease of fluorescence intensity by 40% within 20 s. Moreover, the detection limit towards F− was calculated to be as low as 73.5 nmol/L. [ABSTRACT FROM AUTHOR]

Two copolymers, poly(1,1-dimethyl-3,4-diphenylsilole-alt- N-hexyl-3,6-diethynylcarbazole) (PS-DyCz) and poly(1,1-dimethyl-3,4-diphenylsilole-alt-2,7-diethynyl-9,9′-dihexylfluorene) (PS-DyF), were synthesized by Sonogashira coupling reaction of 2,5-dibromo-1,1-dimethyl-3,4-diphenylsilole and N-hexyl-3,6-diethynylcarbazole or 2,7-diethynyl-9,9′-dihexylfluorene, respectively. The chemical structures of the copolymers were characterized by NMR, FT-IR techniques. Their thermal and photophysical properties were evaluated by TGA, DSC, UV-Vis and fluorescence spectroscopy, respectively. The weight-averaged molecular weights ( Mw) of PS-DyCz and PS-DyF are 1.20×104 and 3.83×104 Da, respectively. The degree of polymerization is 8 and 22 units. These π-conjugated polymers exhibited lower band-gap of 2.25 and 2.70 eV due to the presence of silole rings and CC triple bonds in their backbone, the results were consistent with the density functional (DFT) calculations at the B3LYP/6-31G* level. [ABSTRACT FROM AUTHOR]

3,4-(Hydroxymethyl-ethylenedioxy)thiophene ( 4) and 3,4-(2′-hydroxypropylenedioxy)thiophene ( 4'′) were synthesized from dimethyl 3,4-dihydroxythiophene-2,5-dicarboxylate ( 1), which were isomers and difficult to separate. When they were esterified with tetrathiafulvalene carried carboxylic acid group, only 3,4-(hydroxymethyl-ethylenedioxy)thiophene ( 4) could be esterified. No such selectivity was observed when the isomers were esterified by lauric acid and benzoic acid, respectively. [ABSTRACT FROM AUTHOR]

Two conjugated ethynyl-linked oligomers, oligo(benzodithiophene-ethynylene-benzothiadiazole) (O1) and oligo(benzodithiophene-ethynylene-carbazole) (O2), were synthesized by Sonogashira coupling reaction. Their degrees of polymerization were 7 and 10, respectively. Their photophysical and electrochemical properties were investigated. O1 exhibitd two strong absorption bands at 404 nm and 483 nm, and O2 at 401 nm and 429 nm. The results of UV-Vis, cyclic voltammetry (CV) and theoretical calculations showed that O1 has a narrower band gap than O2. The conductivities of O1 and O2 were 1.05×10−15 and 6.98×10−16 S/cm, respectively, and would increase to 1.23×10−10 and 1.05×10−10 S/cm after doping with iodine. [ABSTRACT FROM AUTHOR]

A new conjugated copolymer (PTST-DyOXD) derived from 1,1-dimethyl-3,4-diphenyl-2,5-bis(5-bromo-2-thienyl)-silole (TST) and 2,5-bis(4-ethynylphenyl)-1,3,4-oxadiazole (DyOXD) was synthesized by Pd(0)-catalyzed Sonogashira coupling reaction. For comparison, another copolymer without acetenyl group (PTST-OXD) was also synthesized by Pd(0)-catalyzed Suzuki coupling reaction. Chemical structures and optoelectronic properties of the copolymers were characterized by 1H NMR, 13C NMR, IR, UV-vis absorption, photoluminescence and cyclic voltammetry. The number-average molecular weight ( Mn) is 4010 Da for PTST-DyOXD and 3890 Da for PTST-OXD, respectively. The thermogravimetric analysis (TGA) measurements show that they have good thermal stability with decomposition temperature at 312 and 318°C, respectively. The optical band gap is 2.21 eV for PTST-DyOXD and 2.10 eV for PTST-OXD based on the absorption onset. CV analysis revealed the LUMO level of PTST-DyOXD is −3.04 eV, lower than that of PTST-OXD (about −2.89 eV), which is attributed to the introduction of acetylene group in PTST-DyOXD, increasing the system of the conjugate chain length. [ABSTRACT FROM AUTHOR]

Three 3,4-ethylenedioxythiophene (EDOT) derivatives, including an EDOT-tetrathiafulvalene (TTF) derivative, were synthesized by Steglich esterification of carboxylic acids with hydroxymethyl EDOT (3,4-ethylenedioxythiophene methanol). The UV spectra showed that there was no distinctive intramolecular interaction for the EDOT-TTF monomer between the EDOT and the TTF moieties in the ground state; however, the cyclic voltammetry responses implied that such intramolecular interaction occurred. Electropolymerization in excessive potential could bring in strong overoxidation effects and degradation in the polymer film. The polymers were simulated using density functional theory with Gaussian03 package and the optimized HOMO and LUMO state were figured out. The conductivity of TTF-polymer was 6 S·cm−1 obtained by galvano station and 4.8 × 10−3 S·cm−1 obtained by potentiostatic electropolymerization after doping with 7,7,8,8-tetracyanoquinodimethane. The results indicated that this polymer was a reasonable candidate for conducting materials and it was meaningful to increase the conductive dimensions of TTF polymers by chemical doping. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Three routes were designed to synthesize a π-conjugated aryleneethynylenesiloles dendron. With the desilylation of the disilole mono(silylethynyl) derivative in the presence of potassium carbonate (K2CO3), the silole-containing oligomer has been successfully synthesized without impact on the Si-(CH3)2 group. The disilole mono(silylethynyl) derivative was prepared by means of the Sonogashira heterocoupling reaction between the diacetylene compound and asymmetrical silole, catalyzed by the dichloro bis(triphenylphosphine)palladium, in a divergent synthesis. Due to their steric effect and triethynylbenzene self-coupling Glaser reaction, the endeavour to prepare the dendron by controlling the molar ratio of asymmetrical silole and 1,3,5-triethynylbenzene was failed. The another attempt to prepare the dendron by different desilylation condition of triisopropylsilyl group and trimethylsilyl group was also failed, the desilylation of Si-(CH3)2 group in silacyclopentadiene unit was also easily accomplished in the presence of tetrabutylammonium fluoride(Bu4NF), whereas no reaction occurred when K2CO3 was used instead of Bu4NF. [ABSTRACT FROM AUTHOR]