咔唑磺酸基铜酞菁的合成与其二阶非线性光学性能的研究

合成了具有潜在非线性光学性能的咔唑磺酸基铜酞菁,用红外光谱,元素分析进行了表征,采用溶剂化变色估算了其二阶非线性光学性能。结果表明,其二阶非线性光学系数与基态偶极距的复合量的值为37．1×10^-30esu．D。     

Synthesis and crystal structure determination of 2,6-di-tert-butyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate and its corresponding perchlorate salt

2,6-Di-tert-butyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate belongs to the class of negatively solvatochromic dyes commonly used for the empirical determination of solvent polarities. By way of exception, it crystallizes without any solvent of crystallization due to the presence of two bulky tert-butyl groups in the phenolate moiety. The synthesis of this hydrophobic betaine dye has been improved and an X-ray crystal structure analysis of this solventless zwitterionic dye and its protonated form (as a perchlorate salt) has been carried out.     

New diaminomaleonitrile-based azo-azomethine dyes; synthesis, characterization and spectral properties

New diaminomaleonitrile-based azo-azomethine dyes were synthesized via a condensation between 2,6-bis(N-(2-amino-1,2-dicyanoetheneimino))-4-methylphenol and 5-(4-substituted-phenyl)-azo-salicyladehyde. FT-IR and ¹H NMR spectroscopy and mass spectrometry studies as well as elemental analysis data revealed the symmetrical bis-iminated structures of the dyes. The electrochemical behavior of the dyes has been investigated by cyclic voltammetry. The effect of various solvents with different polarities on the UV-Vis spectra of the dyes was also studied. The thermal analysis data indicated that the framework of the dyes was stable up to 285 °C.     

Synthesis and properties of novel aziridinyl azo dyes from 2-aminothiophenes—Part 1: Synthesis and spectral properties

A series of yellow to greenish-blue aziridinyl azo dyes and their azo precursors containing a thienyl coupling moiety has been prepared from 2-aminothiophenes. The 2-aminothiophenes were readily obtained by using the Gewald reaction. It was found that cyclisation of the precursor dyes to the corresponding aziridinoazo dyes brought about bathochromic shifts in absorption maxima. Further spectral comparisons with N-phenylazo dyes derived from other terminal cyclic groups, such as four-, five-, six-, seven- and eight-membered rings, showed that the N-thienylaziridinoazo dyes are relatively bathochromic. From the viewpoint of solvatochromism, a clear contrast existed between λ_max values in different solvents; thus, a positive solvatochromism was observed in aprotic solvents, whereas a hypsochromic shift was brought about in polar protic solvents. PPP–MO calculations provided reliable predictions of absorption maxima for the various aziridinyl azo dyes and their precursor dyes.     

Negative solvatochromism of merocyanine dyes: Application as water content probes for organic solvents

Two new merocyanine dyes derived from 7-hydroxycoumarin were prepared, and their signaling ability to detect water content in organic solvents was investigated. The dyes exhibited a pronounced negative solvatochromism, and dramatic changes in absorption spectra and λ_max as a function of water content were observed. Solvatochromic behavior was pronounced in regions of less than 5% water content; therefore, these dyes could be used as chromogenic probes for detecting water in common water miscible organic solvents.     

Synthesis of 6-(4-diethylamino)phenyl-2-oxo-2H-pyran-3-carbonitorile derivatives and their fluorescence in solid state and in solutions

One-pot synthesis of a new 2-pyrone dye (3a) by the reaction of 4-diethylamino-acetophenone (1) with methyl 2-cyano-3,3-bis(methylsulfanyl)acrylate (2) in the presence of sodium hydroxide as the base was carried out in DMSO. Compound 4a was synthesized by the replacement of methylsulfanyl group of 3a with dimethylamine at 4-position of pyrone ring. Similarly, compound 5a was prepared via the reaction of 3a with diethyl malonate. Compounds 3a-5a exhibited the following fluorescence in the solid state: red (3a), green (4a), and orange (5a). In addition, it was revealed that 2-pyrone dyes exhibit fluorescence in various solvents and show positive solvatochromism. Compounds 3a and 5a exhibited intense fluorescence in chloroform and dichloromethane (fluorescence quantum yield Φ: 0.94-0.95). In contrast, compound 4a exhibited intense fluorescence in polar solvents (methanol: Φ = 0.92). These 2-pyrone dyes have the potential for applications in various fields.     

New solvatochromic merocyanine dyes based on Barbituric acid and Meldrum's acid

Two new types of solvatochromic merocyanine dyes derived from either Meldrum's acid or Barbituric acid have been synthesized by the condensation of 4-((2-hydro xyethyl)(methyl)amino) benzaldehyde with 5-(2,6-dimethyl-4H-pyran-4-ylidene) Meldrum's acid and 5-(2,6-dimethyl-4H-pyran-4-ylidene) Barbituric acid, respectively. The solvatochromic responses of the merocyanine dyes in 22 solvents of widely different polarities were measured; positive solvatochromism, with a large absorption bathochromic shift, was observed on moving from xylene to DMSO, corresponding to their maximum fluorescence emission with a large bathochromic shift. The dyes have the potential for the development of efficient probes for the detection of volatile organic compounds.     

ADJUSTMENT OF THE SELECTIVITY OF A DIELS-ALDER REACTION NETWORK USING SUPERCRITICAL FLUIDS

The thermodynamic pressure effect on rate constants is reported in supercritical fluid carbon dioxide for a homogeneous reaction network over a wide density range. The selectivity, or ratio of rate constants, has been controlled over a continuum for the parallel Diels-Alder additions of methyl acrylate and cyclopentadiene by adjusting the pressure at constant temperature. This reaction network is well-suited to provide fundamental insight into the nature of supercritical solvent effects since three simplifications arise: the pressure effect on the selectivity is independent of the partial molar volumes of the reactants, the temperature effect on the selectivity is independent of the partial molar enthalpies of the reactants, and the ratio of the endo- to exo-rate constants based on mole fraction units is the same as that based on concentration units. The selectivity for the more polar product, the endo-adduct, increases as the pressure or density increases, which indicates that it has a more negative partial molar volume in the transition state due in part to stronger induction forces. The slope of the logarithm of the selectivity is shown theoretically to increase as a function of the isothermal compressibility at constant temperature. At constant pressure, the selectivity decreases with temperature which indicates that the magnitude of the partial molar enthalpy is greater for the more polar endo-transition state than the exo-state. Solvatochromic polarity scales may be used to correlate quantitatively the solvent on this reaction network at supercritical fluid conditions.     

Chromism and molecular weight of polyaniline derivatives

The striking solvatochromic shift observed in polyaniline derivatives correlates with two solvent polarity scales, donor number (DN) and hydrogen bond acceptor scale (Taft's β-scale). The large shift is caused by conformational changes in solution that result in dramatic differences in relative molecular weight values obtained by gel permeation chromatography (MW_GPC) in different solvents. For example, for poly-o-toluidine base in the emeraldine oxidation state, a low transition energy solvent like NMP (excitonic transition, λ_max 608 nm) yields a very high molecular weight value (M_w  15,000 g mol⁻¹) whereas a high transition energy solvent like CHCl₃ (excitonic transition, λ_max 570 nm) yields an absurdly low value (M_w  650 g mol⁻¹). An absolute molecular weight value, M_w  4700 g mol⁻¹, was obtained for the first time using laser light scattering (MW_LS) suggesting that CHCl₃ promotes a highly coiled chain conformation whereas NMP promotes a more expanded, rod-like conformation. A similar trend is observed for poly-o-toluidine base in the fully oxidized pernigraniline oxidation state (Pierels transition). This suggests that even though the Pierels and excitonic transitions have different molecular origins their conformation driven solvatochromic shifts trend in a similar fashion which is different from thermochromic trends reported in previous studies.     

Spirobifluorene and biphenylaminophenyl fluorene with dimesitylboron as multifunctional electroluminescent materials

By introducing triarylamino and dimesitylboron groups into fluorene derivatives, two symmetric compounds 2,7-bis(dimesitylboryl)-9,9-spirobifluorene (SFMB) and 2,7-bis(dimesitylboryl)-9,9-bis(4-diphenylaminophenyl)fluorene (PAFMB) were prepared. SFMB and PAFMB exhibited solvatochromism in the different polarities of solvents. Devices A1, A2, A3 and A4 based on SFMB displayed emissions at 444, 448, 528, and 444 nm with current efficiencies of 1.06, 1.41, 0.84, and 1.52 cd/A, respectively. The blue light was close to the National Television Standards Committee standard blue color (x = 0.14, y = 0.08). Devices B1, B2, B3 and B4 based on PAFMB emitted lights centered at 484, 472, 513 and 472 nm, their current efficiencies were 1.80, 0.1, 1.23 and 1.93 cd/A, respectively. The results demonstrated that SFMB and PAFMB were multifunctional materials acted as emitters, and hole- and electron-transporting materials.