受阻三芳基吡唑啉类化合物光物理行为的研究

1,3,5-三芳基-2-吡唑啉化合物因存在着广泛的应用前景,引起了人们极大的兴趣.吡唑啉类化合物不仅是良好的荧光增白剂,而且在静电复印中,它还是良好的光导材料.该类化合物具有强烈的荧光发射特性,因此许多研究都涉及其荧光光谱问题,在前人的报导中曾指出:芳基吡唑啉化合物所以具较强荧光,主要是由于其分子内存在着良好共平面性的“芳基—C=N—N—芳基”电荷转移发色团,而任何引起该发色团扭曲的效果都将对分子的发光能力带来影响.但对于这一看法,在对吡唑啉化合物发光行为的最近研究中已提出不     

2-芳基苯并噁唑衍生物与光物理行为研究

对2-芳基苯并噁唑衍生物的光谱及光物理行为进行了研究。结果表明,该系列化合物与常见分子内共轭电荷转移化合物的特性明显不同。分析了存在差异的原因,指出该类化合物的较强的荧光发射能力与其分子中的C=N双键的异构化受阻密切相关。     

含不同核心第一代π-共轭不对称树状化合物的合成

以3,5-二叔丁基苯酚、三氟甲基磺酸酐和4,5-二乙炔基-2-甲氧基苯酚为原料,合成了4,5-双（3′,5′-二叔丁基苯基乙炔基）-2-甲氧基苯酚（单分子枝）,单分子枝的酚羟基用三氟甲基磺酸酐酯化得到磺酸酯,后者再分别与偶氮苯、联苯、蒽和芘发色团偶联,得到含不同核心的第一代π-共轭不对称树状化合物。 目标化合物的组成和结构分别经1H NMR谱、13C NMR谱、IR光谱和元素分析予以表征。 其溶解性测试表明,相对于核（不同的发色团）,所有树状化合物均能溶于常用的有机溶剂,并显示出良好的热稳定性。 这将有利于其掺杂入其它材料和器件中。     

1,4-双(4-吡啶基甲基苯基醚)(C18H18N2O2)与SCN-形成的超分-子化合物[H2(C18H18N2O2)](SCN)2的合成、结构及其在溶液中的三阶非线性光学性质

超分子化合物[H2(C18H18N2O2)](SCN)由Fe(NO3)3·9H2O,KSCN和1,4-双(4-吡啶基甲基苯基醚)反应得到。通过X射线衍射仪测得该化合物是通过N┈H—N,S┈H—C(C5H5N)及S┈H—C(亚甲基CH2)三种氢键而形成的二维平面网状结构。用Z扫描法对该超分子在DMF溶液中的三阶非线性光学性质进行研究,发现它具有强的三阶非线性折射性能,三阶非线性超极化率X^(3)=6.27×10^-12esu.     

联苯基团引起的激发三重态重排活性增长

双发色团分子光化学研究兴趣与日俱增。我们在以前报道一个有趣的现象:基态发色团间的分子轨道交叠左右光反应机理。3-甲基-3-联苯基-1-丁烯(1),是有特殊意义的分子。与激发能高达(143 kcal/mol)的孤立双键相比,联苯基的激发能特别低(69 kcal/mool)。如此大的激发能差使乙烯基与联苯 p电子间的交叠通道更加畅通,基态1的稳定构象是 endo 型,1的光化学行为将不同于无环双π甲烷分子。1000 W 高压汞灯照射1的正已烷溶液,     

光致电子转移对Rhodamine 6G基态分子结构影响的非共振Raman光谱研究(英文)

基于非共振Raman光谱和量子化学计算,研究了在纯电子给体N,N-二乙基苯胺(DEA)溶剂中Rhodamine 6G(Rh6G+)基态分子结构的变化,这有利于理解该体系中的光致分子间电子转移(PIET).与PIET相耦合的所有振动模式已被确定和指认.结果表明:对应于氧杂蒽环且位于675 cm-1处最主要的振动模式对PIET有着至关重要的贡献;通过与电荷转移复合物(Rh6G/DEA+)的发色团芳香族环的C―C伸展振动模式作比较,C=C伸展振动对PIET的影响更敏感.本文的研究工作能为具有合适电子转移特性的光伏器件中分子结构或溶剂环境的设计提供新颖的观点.     

1-苯基-5-(3,4-二甲氧基苯基)-3-羟基吡唑的合成和晶体结构

标题化合物(I)是由 1-苯基-5-(3, 4-二甲氧基苯基)-3-吡唑烷酮在 FeCl3催化下被氧气氧化得到的。它的结构经过了元素分析、IR、1H NMR 的表征,用 X-射线衍射法测定了化合物的晶体结构。C17H16N2O3(I)的晶体学参数分别为:三斜晶系,P1空间群,a = 6.6600(13),b = 8.4200(17),c = 14.060(3) ?,α= 85.61(3), β= 76.89(3), γ= 81.18(3)?, Z = 2, Dc= 1.298g/cm3, V = 758.1(3) ?3, Mr = 296.32,μ= 0.090 mm–1, F(000) = 312, R = 0.048,wR = 0.1231。结构测定表明化合物的吡唑环存在着一个大的共轭体系,含有一个稳定的烯醇结构,分子通过分子间的氢键形成了网状的结构。     

1,4-双(4-吡啶基甲基苯基醚)(C18H18N2O2)与SCN^-形 成的超分子化合物[H2 (C18H18N2O2)](SCN)2的合成、结构 及其在溶液中的三阶非线性光学性质

超分子化合物[H2(C18H18N2O2)](SCN)由Fe(NO3)3·9H2O,KSCN和1,4-双(4-吡啶基甲基苯基醚)反应得到。通过X射线衍射仪测得该化合物是通过N┈H—N,S┈H—C(C5H5N)及S┈H—C(亚甲基CH2)三种氢键而形成的二维平面网状结构。用Z扫描法对该超分子在DMF溶液中的三阶非线性光学性质进行研究,发现它具有强的三阶非线性折射性能,三阶非线性超极化率X^(3)=6.27×10^-12esu.     

4,4′-二[3-(3,4-二甲氧基苯基)-2-丙烯酰基]联苯的合成和光热性能研究

合成了一种双查尔酮衍生物4,4′-二[3-(3,4-二甲氧基苯基)-2-丙烯酰基]联苯(BBPAB),经IR、~1H NMR、~(13)C NMR、LC-MS等分析测试手段对其结构进行了确证。该化合物热稳定性良好,在可见光范围有高的线性透光率。利用Z扫描测试方法研究了BBPAB在190fs(515～700 nm)时域下的非线性光学吸收,其在飞秒脉冲下具有宽波段的反饱和吸收性质,并拟合得到了三阶非线性吸收系数和五阶非线性吸收系数。量子化学计算结果表明,BBPAB存在较强的分子内电荷转移现象和较大的极化率。     

含1,8-二甲氧基-9,10-二氢蒽和巴比妥酸的发色团化合物的合成和NLO性质

在哌啶和醋酸催化下,1,8-二甲氧基-4,5-二甲酰基-9,10-二氢蒽和异佛尔酮巴比妥酸衍生物经Knoevenagel缩合合成了具有NLO性质的发色团化合物。在这些发色团中,环锁定的三烯和9,10-二氢蒽用作共轭桥,巴比妥酸和甲氧其分别作为吸电子和给电子基, 组成非共轭的两个D-π-A单位。溶剂变色法和紫外光谱研究证实它们比相应的参考物有较大的NLO活性并能保持与参考化合物相同的透光性。     

Photochemical Properties of 1-(9-Phehanthryl)-2-(2-Quinolyl)ethylene

Spectral and photochemical properties of 1-(9-phehanthryl)-2-(2-quinolyl)ethylene (9Ph2QE) in neutral and protonated forms have been investigated. It has been found that both isomers of 9Ph2QE are photoactive. The quantum yield of trans–cis photoisomerization (? _tc = 0.47) in the neutral form is typical of the diabatic photoisomerization; on passing to the protonated form, ? _tc increases up to 0.70. Thus, the double annelation of the 2-styrylquinoline phenyl group to form 9Ph2QE makes it possible to conserve the α-effect, which consists in an increase in the quantum yield to ? _tc > 0.5 on passing from the neutral to protonated form, whereas the effect disappears for other types of annelation (naphthylquinolylethylenes, 1-(9-anthryl)-2-(2-quinolyl)ethylene).     

9-(2-Oxo-1-azetidinyl)-10,10-dimethyl-9,10-dihydro-10-sila-2-azaanthracenes

9-(3-Methyl-3-bromo-2-oxo-1-azetidinyl)-10,10-dimethyl-9,10-dihydro-10-sila-2-azaanthracene was obtained in the form of a mixture of two diastereomers by intramolecular cyclization of the corresponding 9-(,-dibromoisobutyrylamino)dihydrosilaazaanthracene in the presence of sodium hydride, as well as Triton B. It was established by two-dimensional nuclear Overhauser effect (NOE) spectroscopy that the azetidinyl substituent in the 9 position has a pseudoaxial orientation vis-à-vis a boat conformation of the central silicon-containing ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 559–562, April, 1991.     

Azo polymers for reversible optical storage: 12. Poly{1-acryloyl-4-[4-(4-nitrophenylazo)phenyl] piperazine}

Two azo-containing vinyl monomers, 1-acryloyl-4-[4-(4-nitrophenylazo)phenyl]piperazine (ANPP) and 1-methacryloyl-4-[4-(4-nitrophenylazo)phenyl]piperazine (MNPP), were synthesized. MNPP did not polymerize in a few solvents, with a few free radical initiators and at a few temperatures. pANPP is amorphous with a T_g of 156 °C and decomposes above 230 °C. Birefringence can be induced by a polarized laser (514 nm) on a pANPP film to a level of 0.1 and is very stable. Comparison is made with poly{4′-[(2-(acryloyloxy)ethyl)ethylamino]-4-nitroazobenzene} (pDRIA). Biexponential curve fitting shows a lower writing rate for pANPP. Both the slow response to the laser and the higher stability of the photoinduced birefringence are due to the ‘rigid’ piperazine linkage between azobenzene groups and backbone which prevents the azo groups from rotating freely. pANPP decomposes under long term exposure to the laser.     

Biomimetic syntheses of (-)-gochnatiolides a-C and (-)-ainsliadimer B

We report the first biomimetic syntheses of (-)-gochnatiolides A-C and (-)-ainsliadimer B based on our proposed biogenetic pathway. Our synthesis features one-pot cascade transformations including Saegusa oxidation, intermolecular Diels-Alder cycloaddition, and radical-mediated allylic oxidation, which allow for the rapid generation of (-)-gochnatiolides A-C in a collective manner. We also disclose an unprecedented "copper effect" on the stereochemical outcome of the radical-mediated allylic oxidation. Our synthetic endeavors led to the structural reassignment of (-)-gochnatiolide B. Ultimately, a biomimetic transformation from gochnatiolide B to ainsliadimer B was achieved through a remarkable direct enone hydration.     

The stereodynamics of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane and 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane—an experimental and theoretical study

Multinuclear dynamic NMR spectroscopy of 3,5-bis(trifluoromethylsulfonyl)-1,3,5-oxadiazinane (3) revealed the existence of two conformers with differently oriented CF₃ groups with respect to the ring, and two dynamic processes: ring inversion and restricted rotation about the N-S bond. Two transition states connecting the two conformers and corresponding to clockwise and counterclockwise rotations about the N-S bond were found; the calculated activation barriers of about 12 kcal/mol are in excellent agreement with those measured experimentally for the related molecule 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane (1). X-ray analysis proved the existence of the symmetric isomer of 3, which is the minor isomer in solutions but the only one in the crystal due to packing effects. The normal Perlin effect (JCH_ax<JCH_eq) was observed for 2(6)-CH₂ in 3, whereas the reversed Perlin effect was found for the 4-CH₂ group in 3 as well as for all CH₂ groups in 1 both experimentally and theoretically. The latter effect in compounds 1, 3, and 1-(methylsulfonyl)-3,5-bis(trifluoromethylsulfonyl)-1,3,5-triazinane (2) can be considered as a genuine reverse Perlin effect since larger values of ¹J_CH are observed for longer C-H bonds.     

Spectral-luminescent and solvatochromic properties of 2-(3-coumarinyl)-5-(2′-(R-amino)-phenyl)-1,3,4-oxadiazoles

Spectral-luminescent properties of the newly synthesized 2-(3^′-coumarinyl)-5-(2′-(R-amino)-phenyl)-1,3,4-oxadiazoles has been investigated in solvents of various polarity and hydrogen-bonding ability. It has been found that for all the studied compounds no excited state intramolecular proton transfer occurs despite the presence of coumarinyl fragment - electron acceptor effect of the coumarinyl fragment is not sufficient to increase the excited state acidity of the amino group. It has been found that the absorption spectra of the studied compounds shift to higher energy with increase in solvent polarity, whereas corresponding fluorescence spectra shift to lower energy with solvent polarity increase. It has been suggested that long-wavelength shifts of the fluorescence spectra of the studied compounds with increase in solvent polarity is caused by the solvent relaxation. The observed solvent relaxation effect allow us to propose some of the studied compounds as potential probes to monitor changes in solvent relaxation in low-polar media and as potential probes for rigidochromic effect.     

Fluorescence probe studies on the complexation between poly(methacrylic acid) and poly(N, N-diethylacrylamide)

The complexation between poly(methacrylic acid) (PMAA) and poly(N, N-diethylacrylamide) (PDEAM) in aqueous phase was studied by UV-vis and fluorescence probe techniques. It was demonstrated that the complexation of PMAA with PDEAM occurs within a pH range of 1-6.5 and along with the complexation, the conformation of PMAA changed from a hypercoiled to a loose coiled form. The complex ratio between the two polymers is 1:1 (PMAA:PDEAM, in monomer unit). Salt effect studies showed that the complexation occurred due to formation of hydrogen bonds between the two polymers. Based upon these conclusions and the "compact micelle-like structure" for PMAA at low pH, a "ladder" model was proposed for the structure of PMAA-PDEAM complex formed at low pH.     

Structure of 9-(4-pyridylmethylene)fluorene and 9-(E)-benzylidene-1-azafluorene. Oxidation of 9-(4-pyridylmethylene)fluorene and its condensation with acetylenedicarboxylic acid diester

It was found by x-ray diffraction analysis that in the fulvenes studied, the aromatic rings of the condensed tricyclic fragment are not in the same plane. The angle between them is approximately 4°. The exocyclic carbon atom is at the same angle relative to the plane of the five-membered ring. Starting from 9-(4-pyridylmethylidene)fluorene, there were obtained 3-(4-pyridyl)spirooxirane[2,9]fluorene and 1,2,3,4-trimethoxycarbonyl-8-(fluorylidene-9-methylene)-9a-H-quinolizine.Russian University of Peoples' Friendship, Moscow 117923. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 962–966, July, 1998.     

Synthesis of 3-alkyl(aryl)-3-aminoquinuclidines

A series of 3-alkyl(aryl)-3-aminoquinuclidines was synthesized by means of the interaction between 3-alkyl(aryl)-3-oxyquinuclidines and acetonitrile in the presence of concentrated sulfuric acid with subsequent hydrolysis of the 3-alkyl(aryl)-3-acetaminoquinuclidines. It was shown that in addition to acetamino derivatives 3-alkyl-²-dehydroquinuclidines and 3-alkylidenequinuclidines are formed, the structure of which was established by the method of NMR.