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.

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 (M_w) 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 CC triple bonds in their backbone, the results were consistent with the density functional (DFT) calculations at the B3LYP/6-31G* level.

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.

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 (M_n) 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.

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.

Silole-core phenylacetylene dendrimers were designed and synthesized, among them, the model compound (n = 0) and the first generation of the dendrimer (n = 1) were obtained by the reaction of 2,5-dibromosilole with corresponding terminal alkynes, the second generation of the dendrimers (n = 2) was synthesized from 2,5-diiodosilole. These compounds indicated the absorptions of both phenylacetylene dendrons (250–350 nm) and silole core (400–500 nm). The first generation displayed efficient energy transfer from phenylacetylene dendrons to silole core, whose energy transfer efficiency was as high as 80%. These compounds were used as chemical sensors to probe explosive, for picric acid (PA), the Stern–Volmer constants of model compound and the first generation are 7120 and 5490M⁻¹, respectively. J. Heterocyclic Chem., (2012).

Seven lower odor benzophenone (BP) derivatives (2a, 2b, 2c, 2d, 3a, 3b, 3c) based on 4-hydroxybenzophenone(1) were synthesized and characterized by ¹H NMR, Mass, UV–Vis absorption spectroscopy. electron spin resonance (ESR) spectroscopy was carried out to research the photopolymerization mechanism. The kinetics of photopolymerization was studied by differential scanning photocalorimetry (photo-DSC). The results showed that 2a–d with uni-BP moiety were more effective photoinitiators (PIs) than 3a–c with bi-BP moieties, and 2c was the most effective one which could be a promising candidate for BP alternative in practical application. Copyright © 2009 John Wiley & Sons, Ltd.

Phenylacetylene dendrimers 9–11 containing fluorene as the core with a larger HOMO-LUMO energy gap were synthesized and characterized. Their structure and properties were studied by UV, FL, ¹H NMR, MS etc. These novel phenylacetylene dendrimers exhibit unique photophysical properties. They exist a new absorption band around 340 nm whose molar coefficient decreases with increasing generation. The band-gaps of 9–11 are 3.54, 3.43 and 3.02 respectively. The fluorescence quantum yield of 10 is as high as 0.61.

Novel porphyrin-perylene diimide dyad (TPP-PDI) and porphyrin-perylene diimide-porphyrin triad (TPP-PDI-TPP) were synthesized and characterized. Their structure and properties were studied by UV, FL, ¹H NMR, MS, elemental analysis, etc. The variation of fluorescence feature and UV spectra of TPP-PDI-TPP triad were investigated at different concentration of CF₃COOH in THF. The incorporation of CF₃COOH leads to the closure of the efficient charge transfer decay. After protonation of porphyrin units, the fluorescence intensity of TPP-PDI-TPP triad increased greatly. The fluorescence intensity of TPP-PDI-TPP triad restored after addition of triethylamine into the solution. Thus, TPP-PDI-TPP triad was a proton-type fluorescence switch based on acid-base control. Moreover, different from porphyrin-perylene type molecular switches reported before, this TPP-PDI-TPP triad has wonderful solubility in organic solvents.