Geometry,Electronic Structure,and Related Properties of Dye Sensitizer： 3,4-bis[1- （carboxymethyl）-3-indolyl]- 1 H-pyrrole-2,5-dione

The geometry, electronic structure, polarizability and hyperpolarizability of dye sensitizer 3,4-bis[1-（carboxymethyl）-3-indolyl]-1H-pyrrole-2,5-dione （BIMCOOH） were studied using density functional theory （DFT） with hybrid functional B3LYP, and the electronic absorption spectra were investigated using semi-empirical quantum chemical method ZINDO-1 and time-dependent DFT （TDDFT）. The results of natural bond orbital suggest that the natural charges of the dione, indole, and acetic groups are about 0.15e, -0.29e, and 0.44e, respectively. The calculated isotropic polarizability, polarizability anisotropy invariant and hyperpolarizability are 305.4, 188.3, and 1155.4 a.u., respectively. The electronic absorption spectral features in visible and near-UV region were assigned to the π→π^＊ transition due to the qualitative agreement between the experiment and the TDDFT calculations, and the transitions of the excited states 9-11 related to photoinduced intramolecular charge transfer processes. The analysis of electronic structure and UV-Vis absorption indicates that the indole groups primarily contributed sensitization of photo-to-currency conversion processes, and the interracial electron transfer between semiconductor TiO2 electrode and dye sensitizer BIMCOOH are electron injection processes from excited states of the dyes to the semiconductor conduction band.     

Solvent-promoted chemiluminescent decomposition of a bicyclic dioxetane bearing a 4-(benzothiazol-2-yl)-3-hydroxyphenyl moiety

An aprotic polar solvent such as N-methylpyrrolidone (NMP) promoted the thermal decomposition of bicyclic dioxetane bearing a 4-(benzothiazol-2-yl)-3-hydroxyphenyl moiety 1 without the addition of any base. This solvent-promoted decomposition (SPD) gave light as effectively as the base-induced decomposition (BID) in an aprotic polar solvent. SPD caused intramolecular CT-induced chemiluminescence similar to BID, but, in contrast to BID, SPD proceeded through a pathway with a large negative entropy of activation. Dioxetane 1 was also shown to give light due to excited state intramolecular proton transfer (ESIPT) upon heating in p-xylene.     

Synthesis of 3,4-bis(2,5-dimethyl-3-thienyl)furan-2,5-dione from mucobromic acid

Palladium-catalyzed cross-coupling between 2,5-dimethyl-3-thienylboronic and mucobromic acids under phase transfer catalysis (PTC) conditions gave the expected 3,4-bis(2,5-dimethyl-3-thienyl)-5-hydroxyfuran-2-one in 32% yield. The by-product was 2,2’,5,5’-tetramethyl-3,3’-bithiophene. The oxidation of the obtained hemiacylal with potassium permanganate under PTC conditions afforded 3,4-bis(2,5-dimethyl-3-thienyl)furan-2,5-dione in high yield.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2238–2240, October, 2004.     

Organic superbase-induced chemiluminescent decomposition of a hydroxyaryl-substituted dioxetane: Unique effect of a bifunctional guanidine base on the chemiluminescence profile of a bicyclic dioxetane bearing a 4-(benzoxazol-2-yl)-3,5-dihydroxyphenyl moiety

Organic superbases represented by TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) effectively induced the decomposition of hydroxyaryl-substituted dioxetanes in acetonitrile to give bright light. The color of the chemiluminescence from a dioxetane bearing a 4-(benzoxazol-2-yl)-3,5-dihydroxyphenyl moiety varied depending on the base used. In addition to this change in the color of emission, TBD increased the chemiluminescence efficiency 2- to 5-fold compared to the results with other base systems and accelerated decomposition of the dioxetane. These unique effects of TBD may be due to its “bifunctional” character, which is different from those of other organic superbases. Chemiluminescent decomposition of the dioxetane was effectively induced by superbases even in apolar p-xylene.     

Chemiluminescent decomposition of a dioxetane bearing a 3-(1-cyanoethenyl)phenyl moiety induced by Michael addition of an anion of malonate

A thermally stable dioxetane bearing a 3-(1-cyanoethenyl)phenyl group (1) was synthesized. Michael addition of an anion of malonate (3a,b) to a dioxetane (1) substituted with a 3-(1-cyanoethenyl)phenyl moiety took place to give an intermediary dioxetane bearing a benzylic anion, which decomposes rapidly with accompanying emission of crimson light. When an anion of chloromalonate (3c) was used as a base, intramolecular cyclopropanation of 3c occurred concurrently with the Michael-addition-induced chemiluminescent decomposition.     

1-(2-螺二芴)-3,4-二[3-(2,5-二甲基呋喃)-2,5-二氢吡咯的合成及光致变色性质的研究

将螺二芴引入二芳基乙烯分子中,设计合成了一种新型的含螺二芴呋喃芳香杂环的二芳基乙烯光致变色分子7a.用FT-IR,NMR,MS和元素分析进行结构表征;研究了7a在正己烷溶液和乙腈溶液中的光致变色反应,结果表明7a在两种溶剂中均具有良好的光致变色性能.并且7a在正己烷溶液中变色速率和转化率比在乙腈溶液中大.还研究了7a光致变色过程中荧光光谱的变化,发现关环反应后荧光被淬灭,并且7a的荧光发射峰在极性溶剂中有很大的蓝移.研究了开环态7a,关环态7b的热稳定性,发现7a的热失重温度比未用螺二芴修饰的8a提高了100℃.7b的热稳定性也比8b高.     

Mass spectral fragmentation patterns of 2,5-bis(p-R2-phenyl)-(3,4)-R1-furans

The electron impact mass spectrometric fragmentation pathways for several 2,5-bis(p-R₂-phenyl)-(3,4)-R₁-furans, I, were investigated. Our investigation of the mass spectra of these compounds revealed interesting relationships between substitution pattern in the framework of I and the fragmentation patterns.     

Determination of copper(II) based on its catalytic effect on thiosemicarbazide-H(2)O(2)-CTMAB chemiluminescence reaction

A novel chemiluminescence (CL) reaction, thiosemicarbazide (TSC)–H₂O₂, for the determination of copper at nanogram per milliliter level in batch type is described. The method is based on the catalytic effect of copper(II) on the oxidation of TSC with hydrogen peroxide to produce light emission. The emitted light was observed by using a conventional fluorescence detector. In the optimum conditions, calibration graph was linear in the range of 0.1–1.3 ppm. The limit of detection was 10 ppb. The relative standard deviation for five determinations of 0.5 ppm copper(II) was 1.93%. The proposed method permitted the selective and sensitive determination of Cu(II) in human hair and wheat flour with sufficient precision. The possible mechanism for the new chemiluminescence reaction was also discussed.     

DFT investigation of the mechanism of CH2CO + O(3P) reaction

A detailed theoretical survey of the potential energy surface (PES) for the CH₂CO + O(³P) reaction is carried out at the QCISD(T)/6‐311+G(3df,2p)//B3LYP/6‐311+G(d,p) level. The geometries, vibrational frequencies, and energies of all stationary points involved in the reaction are calculated at the B3LYP/6‐311+G(d,p) level. More accurate energy information is provided by single‐point calculations at the QCISD(T)/6‐311+G(3df,2p) level. Relationships of the reactants, transition states, intermediates, and products are confirmed by the intrinsic reaction coordinate (IRC) calculations. The results suggest that P1(CH₂+CO₂) is the most important product. This study presents highlights of the mechanism of the title reaction. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Simple route to 3-(2-indolyl)-1-propanones via a furan recyclization reaction

A simple route to 1-R-3-(2-indolyl)-1-propanones has been elaborated based on recyclization of 2-(2-aminobenzyl)furan derivatives. Being a modification of the Reissert indole synthesis, our approach employs the furan ring as a source of carbonyl function. This approach is general and allows varying of substituents in aromatic ring as well as in 3-position of indole nucleus.     

UV absorption spectra of HO2, CH3O2, C2H5O2, and CH3C(O)CH2O2 radicals and mechanism of the reactions of F and Cl atoms with CH3C(O)CH3

Pulse radiolysis techniques were used to measure the gas phase UV absorption spectra of the title peroxy radicals over the range 215–340 nm. By scaling to σ(CH₃O₂)_{240 nm} = (4.24 ± 0.27) × 10^?18, the following absorption cross sections were determined: σ(HO₂)_{240 nm} = 1.29 ± 0.16, σ(C₂H₅O₂)_{240 nm} = 4.71 ± 0.45, σ(CH₃C(O)CH₂O₂)_{240 nm} = 2.03 ± 0.22, σ(CH₃C(O)CH₂O₂)_{230 nm} = 2.94 ± 0.29, and σ(CH₃C(O)CH₂O₂)_{310 nm} = 1.31 ± 0.15 (base e, units of 10^?18 cm² molecule^?1). To support the UV measurements, FTIR‐smog chamber techniques were employed to investigate the reaction of F and Cl atoms with acetone. The F atom reaction proceeds via two channels: the major channel (92% ± 3%) gives CH₃C(O)CH₂ radicals and HF, while the minor channel (8% ± 1%) gives CH₃ radicals and CH₃C(O)F. The majority (>97%) of the Cl atom reaction proceeds via H atom abstraction to give CH₃C(O)CH₂ radicals. The results are discussed with respect to the literature data concerning the UV absorption spectra of CH₃C(O)CH₂O₂ and other peroxy radicals. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 283–291, 2002     

Determination Co2+ in vitamin B12 based on enhancement of 2-(4-substituted-phenyl)-4,5-di(2-furyl) imidazole and H2O2 chemiluminescence reaction

In this paper, three kinds of imidazole derivatives, 2-(4-methylphenyl)-4,5-di(2-furyl) imidazole (MDFI), 2-(4-nitrophenyl)-4,5-di(2-furyl) imidazole (NDFI), and 2-(4-tert-butylphenyl)-4,5-di(2-furyl) imidazole (t-BDFI) were synthesized. In an alkaline medium, the chemiluminescence (CL) reaction of imidazole derivatives with H₂O₂ has been investigated. It was also found that MDFI/H₂O₂ and t-BDFI/H₂O₂ systems gave strong CL. When Co²⁺ was added into the two CL systems, the CL intensity was remarkably enhanced. In the optimum conditions, the CL intensity is linearly related to the logarithm of concentration of Co²⁺. The linear ranges are 5 × 10⁻⁹–2.5 × 10⁻⁷ mol/L for MDFI/H₂O₂ system and 5 × 10⁻⁹–2.5 × 10⁻⁷ mol/L for t-BDFI/H₂O₂ system, and the corresponding detection limits are 1.2 × 10⁻⁹ mol/L and 1.1 × 10⁻⁹ mol/L, respectively. The method was applied to the determination of Co²⁺ in vitamin B₁₂ injection. Furthermore, the CL mechanism was also discussed.     

Self-assembly of the octanuclear cluster [Cu8(OH)10(NH2(CH2)2CH3)12]6+ and the one-dimensional N-propylcarbamate-linked coordination polymer {[Cu(O2CNH(CH2)2CH3)(NH2(CH2)2CH3)3](ClO4)}n

The reaction of Cu(ClO4)2.6-H2O and n-propylamine in methanol gives two high-nuclearity products of well-defined compositions. At amine concentrations greater than seven equivalents compared to copper ion concentration, the system fixes carbon dioxide from air to form the one-dimensional carbamate-bridged coordination polymer, {[Cu(mu2-O,O'-O2CNH(CH2)2CH3)(NH2(CH2)2CH3)3](ClO4)}n ({1-ClO4}n). Lower relative amine concentrations lead to the self-assembly of an octanuclear copper-amine-hydroxide cluster [Cu8(OH)10(NH2(CH2)2CH3)12]6+ (2). Both compounds exhibit unique structures: {1-ClO4}n is the first mu2-O,O'-mono-N-alkylcarbamate-linked coordination polymer and 2 is the largest copper-hydroxide-monodentate amine cluster identified to date. The crystal structures indicate that the size of the n-propyl group is probably crucial for directing the formation of these compounds. Magnetic susceptibility studies indicate very weak antiferromagnetic coupling for 1. The octanuclear cluster 2 displays slightly stronger net antiferromagnetic coupling, despite the presence of a number of Cu-O(H)-Cu angles below the value of about 97 degrees that would normally be expected to yield ferromagnetic coupling.     

Temperature-dependent rate coefficients for the gas-phase OH + furan-2,5-dione (C4H2O3, maleic anhydride) reaction

Rate coefficients, k₁(T), for the gas-phase reaction of the OH radical with furan-2,5-dione (maleic anhydride (MA), C₄H₂O₃), a biomass burning related compound, were measured under pseudo–first-order conditions in OH using the pulsed laser photolysis–laser-induced fluorescence method over a range of temperature (283-374 K) and bath gas pressure (50-200 Torr; He or N₂). k₁(T) was found to be independent of pressure over this range with k₁(283-374 K) = (1.55 ± 0.20) × 10⁻¹² exp[(−410 ± 44)/T) cm³ molecule⁻¹ s⁻¹ and k₁(296 K) = (3.93 ± 0.28) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹, where the uncertainties are 2σ and the preexponential term includes the estimated systematic error. The atmospheric lifetime of MA with respect to OH reactive loss is estimated to be ∼15 days. The present results are compared with a previous room temperature relative rate study of the OH + MA reaction, and the significant discrepancy between the studies is discussed; the present results are approximately a factor of 4 lower. It is also noteworthy that the experimentally measured k₁(296 K) value obtained in this work is nearly a factor of 110 less than estimated by a structure activity relationship based on trends in ionization potential. Based in part on a computational evaluation, an atmospheric degradation mechanism of MA is proposed.     

1-(2-炔丙基)-7,8-二氢喹啉-2,5(1H,6H)-二酮的合成

以1,3-环己二酮为原料,依次经亚胺化反应、Michael加成-环化反应、烷基化反应合成了含有端基炔的喹啉酮衍生物——1-(2-炔丙基)-7,8-二氢喹啉-2,5(1H,6H)-二酮,其结构经1H NMR,HR-MS和2D NMR确证。     

2,5-二(邻羟苯基)-1,3,4-噻二唑与钴显色反应的研究

研究了在两性表面活性剂十二烷基二甲基氧化胺(OB-2)存在下,钴与新合成试剂2,5-二(邻羟苯基)-1,3,4-噻二唑的显色条件及应用,建立了测定钴的新方法。在pH 8.0 NH3-NH4Cl缓冲溶液中,钴与2,5-二(邻羟苯基)-1,3,4-噻二唑反应生成1∶3黄绿色螯合物,最大吸收波长为410 nm。加入OB-2后,使其最大吸收波长红移至470 nm,表观摩尔吸光系数为5.74×104L.mol-1.cm-1,钴质量浓度在0.2~2.4μg/mL范围内服从比耳定律,可用于维生素B12针剂和水样中钴的测定,回收率在97.7%~98.2%之间。