电子等排体的噻吩多烯与苯多烯同系递变的比较Ⅰ.

为了进一步研究苯多烯化合物的电子等排体噻吩多烯化合物的结构与性能间的定量关系,确定噻吩基的端基当量,合成了三个末端带拉电子基团的噻吩多烯化合物(A_n,B_n,C_n),测定了它们在乙醇和环己烷中的电子光谱.结果表明,和相应苯多烯化合物的电子光谱相比,普遍红移25—30nm,即相差一个插烯双键引起的红移.以2-噻吩基的端基当量为3,噻吩多烯化合物的电子光谱波数与同系因子(1/2)~(2/N)形成良好的直线,相关系数r>0.99;并与相应苯多烯化合物的同系直线相距很近.其差距可用苯多烯系列增加一个烯链的增量△λ_E=λ_(n+1)—λ_n(Ph系列)与改换一个电子等排体2-噻吩基的增量△λ_(Th)=λ_(Th)-λ_(Ph)(在n处)之比△λ_(Th)/△λ_E作定量描述.△λ_(Th)/△λ_E在0.9左右,证明2-噻吩基的端基当量t=3,比苯基大1.     

电子等排体的噻吩多烯与苯多烯同系递变的比较Ⅱ

为了比较噻吩多烯和苯多烯三岔共轭体系的性能,合成了三个系列带两个拉电子基团的噻吩多烯三岔化合物(TDn,TEn,TFn),测定了它们在环已烷和乙醇中的电子吸收光谱。实验表明,带两个拉电子基团的噻吩多烯三岔共轭化合物的电子吸收光谱频率也都遵守同系线性规律,相关系数Υ>0.99。与相应的苯多烯化合物的电子光谱相比,吸收峰普遍地红移一个插烯双键所引起的红移数值。相应的同系直线相距很近。△λ_(th)/△λ_E值为0.83-1.10。第一个拉电子基团的引入,化合物的电子吸收峰红移30nm左右,但当第二个拉电子基团引入时,电子吸收峰仅红移3—17nm,其作用只相当于一个取代基。     

三岔共轭体系中的结构效应——分流型三岔多烯腈及多烯酸类

本文中研究了五个系列分流型三岔共轭体系,其中包括脂肪族多烯腈,芳香族多烯腈类和多烯酸类的电子吸收峰,以及二个系列的甲基氢—CH_3,次甲基氢—OCH_2及β-H的化学位移。所有这些性能都与同系因子形成良好线性关系。也研究了a-氰代羧酸酯的质谱,实验数据证明—COOEt基比—CN基容易断裂。失去COOEt的碎片比例值很大,未发现失掉CN基的碎片,表明CN基与烯链的共轭效应强于COOEt基。 虽然这些三岔体系中的各分支基团都是吸电子的,但与推电子的分支基团和代基一样,这些分支基团的引入都导致红移现象,因而三岔体系的同系直线都位于线型体系之下。而与后者形成一小夹角。 利用线型体系与三岔体系同系直线间的对比,根据其间的相似三角形的关系,可以准确地计算出分支基团的当量△Ns值。由于在各个三岔系列开头的化合物中分支基团的效应都小于一个链单位,可见分支基团不是端基而只起代基作用。同时还应用线型体系的扩大同系方程式,采用适当的代基当量计算了四个系列的电子吸收峰:所得结果与实验数据的偏差一般在±7毫微米以内。这也表明两个三岔分支基团中的一个可作为代基来处理。 随着三岔化合物共轭键的增长,分支基团的当量继续增大以致有时超过1,这表明在分流型三岔体系中,对分支基团的当量特别是在偕二氰基体     

苯多烯酮、酯类三岔共轭体系结构性能定量关系的研究 Ⅰ.电子吸收光谱

制备和合成了三个线性系列(A_n,K_n,T_n)和三个三岔系列(P_n,E_n,M_n)共34个化合物,其中14个为新化合物。测定了它们在环己烷、乙醇、氯仿中的电子吸收光谱。实验表明,三岔系列的电子吸收光谱频率也遵守同系线性规律,与同系因子之间的相关系数均在0.995以上。三岔体系与相应的线性系列的同系直线相比较表明,一个吸电子分岔的引入导致了红移。用同系直线间的相似三角形计算法,可计算出三岔体系中一个分岔的当量仅为一个链节的0.4～0.8;用同系线性规律的专一性证明,分岔端基的当量是2而不是3.这都表明,分岔端基中只有一岔起端基作用,而另一岔只起代基的作用。取起代基作用的分岔基团的代基当量,并考虑位置效应,则可用线性体系扩大的同系方程来计算三岔化合物的电子吸收光谱。计算值与实验值的误差在±5nm以内。这些结果都与前文的结论相符。三岔体系的溶剂效应比较显著,而且随链增长而增大;线性体系的溶剂效应不如三岔体系的明显,且随链增长变化不大(K_n,A_n)或变小(T_n)。所以,在比较三岔体系与线性体系的同系直线时,必须考虑溶剂的影响。若用溶剂效应较强的溶剂时,三岔同系直线与线性体系的同系直线几乎平行.     

3-乙酰基-8-苯基辛三烯-3,5,7-酮-2的晶体结构

3-乙酰基苯多烯酮三岔共轭体系(Ⅰ)电子吸收光谱的研究,定量地表明在三岔端基中一个分岔起着端基的作用,另一岔仅起代基的作用,其代基当量仅相当于一个链节的0 .4一0.8。为了深人研究这种现象,我们对所合成的新化合物3一乙酚基一8一苯基辛三烯一3,5,7一     

有机硅活性中间体的研究 Ⅲ.含噻吩环硅烯的产生及其捕获

硅烯(两价的硅)和卡宾(两价的碳)一样,是一类基本的反应活性中间体,但含有杂环的硅烯,目前研究还不多.我们曾报道了含呋喃基苯基硅烯的产生.噻吩环的硫原子虽然和呋喃环的氧同属周期表中的第六族元素,但硫是第三周期,其最外层的3s和3p电子距原子核较远,估计将会有不同于呋喃基苯基硅烯的性质.因此,进行了含噻吩环硅烯的产生及捕获的研究. 产生噻吩基苯基硅烯的前体化合物是2-(α-噻吩基)-2-苯基六甲基三硅烷(1).首先由α-     

查耳酮类化合物的代基效应

查耳酮类化合物是一类合流型三岔共轭化合物。对于这类三岔共轭体系中的结构效应,前文中已在同系线性规律的基础上进行了比较系统的研究。但对于作为代基一岔的结构效应研究的不多,对于不同电性的取代基引入苯基后,所导致的同系直线斜率的变化是否与取代基的极性存在一定关系,尚待进行研究。本文合成了5个苯多烯基4＇-取代苯基酮系共20个化合物和一个相应的线型体系——苯多烯醛。研究了     

2-(P-取代基苯乙烯基)-3,3-二甲基-3 H-吲哚盐的合成及性能研究

2,3,3-三甲基-3H-吲哚氢溴酸盐分别与五种取代苯甲醛在乙醇介质中反应,可得 到五种新的2-(P-取代苯乙烯基)-3,3-二甲基-3H-吲哚氢溴酸盐(R=H(3a);Br(3b);MeO(3c);HO(3d);Me~2N(3e)].研究了化合物3a-e的紫外光谱和Hammett常数的定量关系.以位移增量△λ~p对△σ(△σ=α~p-σ~m)作图可得到一条直线,说明它们紫外光谱的取代基效应遵守Hammett方程,即随着取代基给电子能力的增强,吸收带向红移.五个化合物以3e的光谱增感性能最好.     

冠醚查耳酮类化合物的合成及其性能的研究

本文合成了四个4′-苯多烯酰基苯并15-冠-5和一个4′-苯酰基苯并15-冠一5等五个三岔共轭化合物。测定了它们的电子吸收光谱,红外光谱。并用同系因子(1/2)~(2/N)考查了这类三岔共轭体系的同系递变关系。用相似三角形法计算的较短分岔基团苯并15-冠-5的代基当量值△N_5为0.854。这表明苯并15-冠-5不权起代基作用而且它与羰基之间还有一定的共轭作用,约相当于一个双键。此外,还合成了四个3′,4′-二甲氧基苯多烯酮类化合物,将它们的电子光谱与冠醚查耳酮类化合物的进行了比较。     

芳杂环基苯基酮双重电子吸收峰结构基础的判别

为了判别芳杂环基苯基酮电子光谱中双重峰的结构基础,文中对(Ⅰ)(Ⅱ)(Ⅲ)三组六个三岔同系列的同系递变进行了研究,结果表明,所有这些系列的同系直线都分别在双重峰处通过。根据同系直线的相对位置及其通过双峰的长波点或短波点,即可判断各峰所属的基干体系,这就为确定双峰的结构基础提供了一种可靠的定量方法。并用同系直线间的相似三角形法,计算了各组三岔化合物中与羰基直接相连的各种芳杂环的当量△N_s,表明这些基团都只起代基作用。质谱实验结果,芳杂环羰基碎片的丰度都大于苯羰基碎片,而杂环基的碎片则较苯基的小,这表明杂环与羰基的共轭效应较苯基强,这与杂环羰基体系较苯环羰基体系有较长的电子吸收峰是一致的。     

香豆素酮类化合物的磷光光谱

研究了在不同溶剂中测定和在不同波长时激发的香豆素酮类化合物的荧光光谱, 结果明显地指出, 在溶液中呈现出由位阻旋转引起的许多不同的旋光异构体.     

Electronic properties of thienylene vinylene oligomers: synthesis and theoretical study

(E)-1,2-bis(2-thienyl)vinylene (TV), (E)-1,2-bis(3-octyl-2-thienyl)vinylene (TOV), (E)-1,2-bis(3-(2-ethylhexyl)-2-thienyl)vinylene (T2EHV), and (E)-1,2-bis-[2,2??-bithienyl] vinylene (BTV) have been synthesized by a combination of formylation reaction and Mc Murry dimerization. UV?CVis spectra of BTV showed the longest wavelength absorption, TOV and T2EHV showed a bathochromic shift to the red compared with TV, due to an increment of delocalization of the conjugated ??-system as the result of the weakening of the carbon?Ccarbon double bonds of the thienyl rings due to the substitution of one hydrogen by the alkyl group. Based on optical data, the effect of linear and branched alkyl chain and extension of conjugation length on the electronic properties is discussed. ¹H, ¹³C-NMR, UV?CVisible, Fluorescence data are discussed and theoretical DFT and TD-DFT calculations of ground state and excited states have been also considered in the analysis and explanation of results.     

羰桥双共轭体系结构效应的研究 I. 羰桥两边支链的共轭竞争

为了定量地研究桥双共轭体系中的结构效应, 制备了TmBn、BmBn和TmTn系列共32个羰桥化合物, 测定了电子吸收光谱。发现: 电子光谱频率与由总双键数所构成的同系因子不成直线关系, 而是不规则的散布点, 表明分子中没有贯通的共轭基干, 羰基对整个分子的共轭极化有隔断作用。羰桥两边两个分支对羰桥的共轭作用是互相竞争的, 当共轭竞争的优势从一分支转移到另一分支时, 同系直线就分为斜率不同的两段, 其间出现转折点。随着两个共轭分支链长的改变, 拐点出现有规则的移动, 在羰桥化合物的同分异构体中, 两个分支的共轭竞争也很明显, 其电子吸收峰与一定的m+n值表现为V形曲线。     

反-1,2-双[2-(5-取代苯基恶唑基)]环丙烷的合成与光性能的研究

合成了8个反 -1,2-双[2-(5-取代苯基恶唑基)]环丙烷和2个1,2-双[2-取代苯基恶唑基)]乙烷,其中9个为新化合物.讨论了化合物的结构与其电子光谱及荧光量子产率间的关系.发现恶唑环与三元环间存在一定程度的共轭,并解释了上述化合物荧光量子产率较低的现象.     

Base cleavage of substituted [phenyl(2-thienyl)methyl]- and [phenyl(2-furyl)methyl]-trimethylsilane. Stabilization of carbanionic centres by 2-thienyl and 2-furyl groups

Rates of cleavage by NaOMEMeOH at 25°C have been determined for (2-thienyl)₂CHSiMe₃ and for the compounds Ph(2-thienyl)CHSiMe₃ and Ph(2-furyl)CHSiMe₃ and some of their derivatives with a substituent in the m- or p-position of the phenyl group or the 5-position of the heterocyclic group. The results indicate that the 2-thienyl and 2-furyl groups stabilize a carbanionic centre more effectively than a phenyl group, and the following approximate pK_a values can be derived: Ph₂CH₂, 33.4; Ph(2-thienyl)CH₂, 30.0; Ph(2-furyl)CH₂, 29.6; (2-thienyl)₂CH₂, 27.1. The effect of the 2-Cl substituent in the thiophen ring is close to that of the p-Cl substituent in the benzene ring, and the effects of the p-Me substituents on the benzene ring are very close to those of the 2-Me substituents on the thiophen or furan rings. The product and rate isotope effects (determined by use of MeOD) are consistent with separation of the carbanion in the rate-determining step.     

双(1,2-二苯基环戊二烯基)二氯化锆化合物发光光谱行为及取代基效应

以干燥的正己烷为溶剂, 在N2气保护下, 研究了金属有机化合物双(1,2-二苯基环戊二烯基)二氯化锆(2)、 双(4-甲基-1,2-二苯基环戊二烯基)二氯化锆(3)和双(1,2,4\|三苯基环戊二烯基)二氯化锆(4)的发光光谱行为. 研究结果表明, 该系列化合物具有良好的发光性能, 且荧光光谱的发射波长可通过改变环戊二烯基4位上的取代基R进行调节. 发射光波长大小顺序为Ph>CH3>H.     

噻吩多烯基噻吩酮系列化合物的气相紫外光电子能谱研究

本文提供了噻吩多烯基噻吩酮系列化合物的气相HeI光电子能谱(UPS), 并进行了每个研究分子的MNDO量子化学计算。 表明乙烯基基团的数目与其分子的HOMO实验电离能(L~p)呈线性递降关系。MNDO计算结果不但很好地指认了每个研究分子UPS谱的归属, 而且从分子轨道特性上提供了该类化合物分子为三岔共轭体系的理论基础。     

Theoretical studies on the electronic and optical properties of two new alternating fluorene/carbazole copolymers

Poly(fluorene)-type materials are widely used in polymer-based emitting devices. During operation there appears, however, an additional emission peak at around 2.3 eV, leading to both a color instability and reduced efficiency. The incorporation of the carbazole units has been proven to efficiently suppress the keto defect emission. In this contribution, we apply quantum-chemical techniques to investigate two series of alternating fluorene/carbazole oligomers and copolymers poly[2,7-(N-(2-methyl)-carbazole)-co-alt-2,7-m(9,9-dimethylfluorene)], namely, PFmCz (m = 1,2) and gain a detailed understanding of the influence of carbazole units on the electronic and optical properties of fluorene derivatives. The electronic properties of the neutral molecules, HOMO-LUMO gaps (Delta(H-L)), in addition to the positive and negative ions, are studied using B3LYP functional. The lowest excitation energies (E(g)s) and the maximal absorption wavelength lambda(abs) of PFmCz (m = 1,2) are studied, employing the time-dependent density functional theory (TD-DFT). The properties of the two copolymers, such as Delta(H-L), E(g), IPs, and EAs were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero (1/n = 0). The outcomes showed that the carbazole unit is a good electron-donating moiety for electronic materials, and the incorporation of carbazole into the polyfluorene (PF) backbone resulted in a broadened energy gap and a blue shift of both the absorption and photoluminescence emission peaks. Most importantly, the HOMO energies of PF1Cz and PF2Cz are both a higher average (0.4 eV) than polyfluorene (PF), which directly results in the decreasing of IPs of about 0.2 eV more than PF, indicating that the carbazole units have significantly improved the hole injection properties of the copolymers. In addition, the energy gap tends to broaden and the absorption and emission peaks are gradually blue-shifted to shorter wavelengths with an increase in the carbazole content in the copolymers. This is due to the interruption of the longer conjugation length of the backbone in the (F1Cz)(n) series.     

One- and two-photon absorption of three-coordinate compounds with different centers (B,Al,N) and a 2,2'-dipyridylnitrogen functional group

A series of three-coordinate octupolar compounds with varied centers (boron, aluminum, and nitrogen), which exhibit very large effective two-photon absorption cross sections have been theoretically studied. The ground state geometries and electronic structures are obtained using the density functional theory with the B3LYP functional and 6-31G(d) basis set, and the results are comparable to the available experimental determinations. Based on the correct geometrical and electronic structures, the one- and two-photon absorptions are predicted by the ZINDO-SOS method. Among these compounds, the boron (B) and aluminum (Al) centers act as acceptors, while the nitrogen center acts as donor according to the net charge changes during the excitation. It is found that (i) the compounds with boron and aluminum centers show two large two-photon absorption peaks, while the molecule with nitrogen center show only one two-photon absorption peak; (ii) the cross sections of the molecules with B or Al as centers are larger than that of the molecule with nitrogen as center; furthermore, the two-photon absorption cross section of the molecule with Al center is larger than that of the molecule with B center, from this point of view, our theoretical prediction provides for the experiment a good new candidate with large two-photon absorption cross section for further research; (iii) lengthening the conjugation bridge by inserting a benzene ring on the organoborane compounds (forming the investigated molecule B-2) enhances the two-photon absorption cross section, and keeping good transparency at the same time.