Xiaochuan Li

Electrochemical Study on Energy Potential Levels with Pyrene Molecule

Pyrene based molecule has been synthesized through the reaction of pyrene-1-carboxaldehyde and 4- phenylthiosemicarbazide in this research. The pyrene based molecule showed specific optical properties such as absorption and emission changes after mixing with fluoride in DMSO. The phenomenon is induced by the interaction of the molecule and fluoride. This interaction may affect to electron distributions and potential energy levels. In this regard, synthesized pyrene based molecule has been investigated for its electron distributions and HOMO/LUMO energy levels depending on interaction with fluoride. The absorption measurement, cyclicvoltammograms and computational method were investigated to calculate and compare energy potential levels.

Synthesis of Chemosensor Based on Pyrene and Study for Its Sensing Properties Toward Fluoride Ion

In this study, pyrene based chemosensor was synthesized by two step reaction. The chemosensor showed that high selectivity toward fluoride in DMSO. The fluorescence intensity was drastically increased by binding between chemosensor and fluoride ion. Absorption and fluorescence spectra were obtained by UV-Vis spectrometer and fluorescence spectrophotometer. The binding ratio between chemosensor and fluoride ion was also investigated by job’s plot method and Benesi-Hildebrand plot. The HOMO/LUMO energy levels and electron distribution were calculated and simulated by Material studio 6.0 Package.

C-H···π and C-H···O Interactions in Coumarin 6 : 3-(2-benzothiazolyl)-7-(diethylamino)-coumarin

Crystal structure of coumarin 6 has been solved by X-ray diffraction. The crystals are triclinic, space group P-1, with a=8.823(2) A, b=8.898(2) A, c=11.025(9) A, α=86.41(3)°, β=85.39(3)°, γ=76.23(3)°, Mr=350.42, V=837.1(3) A 3 , Z=2 and R=0.0516. The molecules are packed parallel to each other by weaker π···π and C-H···π interactions. The detailed geometry of C-H···π interactions were discussed. The hydrogen bonds and non-traditional C-H···O interactions join the no-parallel molecules together. All the molecules packed wall-like with the molecular brick.

Emission behavior of perimidine attached BODIPY and its response to acid/base

ABSTRACT A BODIPY based with perimidine attached derivative was developed and characterized. It was efficiently synthesized by condensation between aldehyde sited at β-position of BODIPY and 1,8-diamino-naphthalene. Owing to the electron-donor effect of N in heterocycle, emission was quenched completely. Upon protonation of N, the solution exhibited dramatic emission enhancement with emission peak locating at 510 nm, which is estimated to be 275-fold of initial emission. With OH− addition, it could be reverted to the emission to non-emisison state again and establish a fluorescence switch. The underlying mechanism of fluorescence “off-on” is based on the intramolecular PET, which was attested by quantum chemistry calculation approach.

Crystal structure of 4-(3,4-bis(2,5-dimethylthiophen-3-yl)- cyclopent-3-en-1-yl)benzaldehyde, C24H24OS2

C24H24OS2, monoclinic, P121/c1 (no. 14), a = 17.971(8) Å, b = 14.910(7) Å, c = 7.964(4) Å, ) = 93.453(6)°, V = 2130.1 Å, Z = 4, Rgt(F) = 0.087, wRref(F) = 0.247, T = 291 K. Source of material 4-(3,4-bis(2,5-dimethylthiophen-3-yl)cyclopent-3-en-1-yl)benzaldehyde was synthesized by multi-step reaction according to our early published method [1]. Chemicals used for the synthesis were commercially available of AR grade, and were used as received without further purification. The colorless crystals of the title compound were obtained by slow evaporation of a hexane solution at room temperature. Experimental details The hydrogen atoms were placed geometrically and refined using a riding model with d(C—H) = 0.93 Å (aromatic), 0.96 Å (–CH3), 0.97 Å (–CH2–) or 0.98 Å (–CH–), Uiso(H) = 1.2 Ueq(C) for CH and CH2 groups or Uiso(H) = 1.5 Ueq(C) for CH3 groups. The disordered two thiophene rings account for the large residual values mainly, for which the photosensitive molecules are easy to generate closed form (hexatriene structure). The structure was checked by PLATON [2]. Additional (disordered) solvent molecules were not found.

Synthesis and Optical Properties of (A)n-π-(Ph)3N Type Dyes

Two new (A)n-π-(Ph)3N type dyes were designed, synthesized and characterized. The optical properties and structures of them were studied, including UV-visible spectroscopy, photo-luminescence spectroscopy. The geometric structures of them were calculated theoretically based on the DFT level using BLYP/GGA basis set, the HOMO/LOMO levels were also measured and calculated.

Crystal structure of bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane)-9,9-dioctylfluorene, C41H64B2O4

Abstract C41H64B2O4, triclinic P1̅ (no. 2), a = 12.8189(8) Å, b = 13.4808(9) Å, c = 14.1592(12) Å, α = 110.394(3)°, β = 90.170(1)°; γ = 115.623(3)°; V = 2033.5(3) Å3, Z = 2, Rgt(F) = 0.0562, wRref(F2) = 0.1629 , T = 296 K.

Crystal structure of 5,5-difluoro-10-(4-fluorophenyl)-1,3,7,9-tetramethyl-5H-4l4,5l4-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinine - a Z′ = 3 structure, C19H18B2F3N2

Abstract C19H18B2F3N2, triclinic, P1̅ (no. 2), a = 10.8885(6) Å, b = 13.9767(8) Å, c = 18.1330(10) Å, α = 79.3484(19)°, β = 86.2213(9)°; γ = 73.461(2)°; V = 2599.6(3) Å3, Z = 6, Rgt(F) = 0.0450, wRref(F2) = 0.1105, T = 296 K.

Photochromic behavior of 2,3-bis(2,5-dimethylthiophene-3-yl)thiophene-5-carbaldehyde oxime

ABSTRACT Photochromic diarylethene oxime isomers were obtained by coupling between hydroxylamine hydrochloride and 2,3-bis(2,5-dimethylthiophene-3-yl)thiophene-5-carbaldehyde. The two isomers were confirmed by NMR. Photochromic behavior was investigated in THF. Reversible photochromism could be induced by alternated UV/Visible light. The solution color also can be toggled between colorless and light purple. Corresponding photo- and thermo-stability measurements indicate that they are stable in the dark at room temperature. However, the degradation of the two isomers is accelerated with the temperature rising and prolonged exposure to UV light. Optimized geometry structure and frontier molecular orbitals further supported their photochromic activity.

Photochromic behavior of triangle trithiophene with π-extension at the bridge unit

ABSTRACT A photochromic triangle terthiophene with phenylethynyl attached was synthesized under Sonogashira coupling condition and fully characterized. The photochromic behavior was investigated in typical solvents. In hexane, the reversibly photochromic process was induced by UV and Visible light. The solution color could be toggled between colorless and pink color. The photo- and thermo-stability were also investigated at 273 and 323 K. It is stable in the dark at the room temperature, while the degradation accelerated with the temperature rising. Correspondingly, the optimized geometry structure and frontier molecular orbitals were calculated. Both the distance between reactive carbon atoms and the HOMO distribution of ring-open form support the photo-cyclization reaction.