Effect of Excited-state Substituent Constant on the UV Spectra of 1,4-disubstituted Benzenes

A correlation equation between the UV absorption wavenumbers of 1,4-disubstituted benzenes and the excited-state substituent constant was obtained. For 80 sorts of 1,4- disubstituted benzenes, the correlation coefficient was 0.9805, and the standard deviation was only 672.27 cm^-1. The results imply that the excited-state substituent constant can be used productively for research on UV energy of 1,4-disubstituted benzenes. The present method provides a new avenue to study the UV absorption spectra of aromatic systems with the excited-state substituent constant, and it is helpful to understand the effect of substituent electrostatic effects on the chemical and physical properties of conjugated compounds with multiple substituents in excited state.

Substituent Effects on Reduction Potentials of Meta-substituted and Para-substituted Benzylideneanilines

Effects of meta-substituent of 3,4＇/4,3＇/3,3＇-substituted benzylideneanilines （XBAYs） on the electrochemical reduction potentials （E（Red）） were investigated, in which 49 samples of target compounds were synthesized, and their reduction potentials were measured by cyclic voltammetry. The substituent effects on the E（Red） of target compounds were analyzed and an optimality equation with four parameters （Hammett constant a of X, Hammett constant a of Y, excited-state substituent constant σexCC of X, and the substituent specific cross-interaction effect △σexCC2 between X and Y） was obtained. The results show that the factors affecting the E（Red） of 3,4＇/4,31/3,3P-substituted XBAYs are different from those of 4,4＇-substituted XBAYs. For 3,4＇/4,3＇/3,3＇-substituted XBAYs, σ（X） and σ（Y） must be employed, and the contribution of △σexCC2 is important and not negligible. Compared with 4,4＇-substituted XBAYs, X group contributes less to 3,4＇/4,3＇/3,3＇-substituted XBAYs, while Y group contributes more to them. Additionally, it was observed that either para-substituted XBAYs or meta-substituted XBAYs, the substituent effects of X are larger than those of Y on the E（Red） of substituted XBAYs.

取代苯甲腈类有机污染物水解行为的研究

研究了10种二取代苯甲腈类有机污染物的水解行为,用反相高效液相色谱测定了不同pH值和不同溫度下的水解速度常数。结果表明,含羟基的化合物在酸,碱和中性水介质中均不易水解;其它化合物仅在碱性介质中水解,其碱性催化水解速度常数与Hammett取代基常数以及酸常数之间呈近似线性关系。相关方程为:lgk_B=1.45σ-0.859和lgk_B=-1.34pK_(?)-4.83。

Recent progress in quantifying substituent effects

This paper summarizes significant progress in quantifying organic substituent effects in the last 20 years. The main content is as follows： （1） The principle of electronegativity equalization has gained wide acceptance, and has been used to calculate the intramolecular charge distribution and inductive effect of groups. A valence electrons equalization method was proposed to compute the molecular electronegativity on the basis of geometric mean method, harmonic mean method, and weighted mean method. This new calculation method further extended the application of the principle of electronegativity equalization. （2） A scale method was established for experimentally determining the electrophilic and nucleophilic ability of reagents, in which benzhydryliumions and quinone methides were taken as the reference compounds, and the research field was extended to the gas phase conditions, organometallic reaction and radicals system. Moreover, the nucleophilicity parameters N and electro- philicity parameters E for a series of reagents were obtained. The definition and quantitative expression of electrophilicity in- dex co and nucleophilicity index co were proposed theoretically, and the correlation between the parameters from experimental determination and the indexes from theoretical calculation was also investigated. （3） The polarizability effect parameter was initially calculated by empirical method and further developed by quantum chemistry method. Recently, the polarizability ef- fect index of alkyl （PEI） and groups （PEIx） were proposed by statistical method, and got wide applications in explaining and estimating gas-phase acidity and basicity, ionization energy, enthalpy of formation, bond energy, reaction rate, water solubility and chromatographic retention for organic compounds. （4） The excited-state substituent constant Crcc obtained directly from the UV absorption energy data of substituted benzenes, is different from the polar constants in molecular ground state and the radical spin-delocalization effects constants in molecular radical state. The proposed constant Crcc correlated well with the UV absorption energy of many kinds of organic compounds, such as 1,4-disubstituted benzenes, substituted stilbenes, and di- substituted N-benzylidenebenzenamine. （5） The establishment of the steric shielding effect distinguished the three traditional steric effects. The stereoselectivity index Ci was proposed to quantify the stereoselectivity of the addition reaction of carbonyl with nucleophilic reagent. The shielding parameter Rs was defined to quantitatively express the specific surface of the reac- tion center screened by a group. Further, the Topological Steric Effect Index （TSEI） of a group was proposed on the basis of the relative specific volume of reaction center screened by the atoms of substituents. These parameters can be applied in esti- mating the intramolecular dihedral angles, stereoselectivity of reaction, enthalpies of formation of alkenes and alkylbenzene, acidity of substitutedimidazolium ionic liquid, and the reaction rate of alkane and hydroxyl radical. In addition, some sugges- tions and prospects for further studies on quantifying the organic substituent effects were presented in this paper.

金属卟啉的电化学性质与其催化氧化α-蒎烯性能的关系

采用循环伏安法对一系列四苯基金属卟啉的电化学氧化还原性质进行了研究,考察了四苯基金属卟啉的第一还原电位与其催化氧化α蒎烯性能的关系.结果表明,各四苯基金属卟啉催化空气氧化α蒎烯转化率的大小顺序为TPPMnⅢCl >TPPCoⅢCl>TPPFeⅢCl>TPPCuⅡ≈TPPNiⅡ≈TPPZnⅡ,除TPPCoⅢCl外,基本与其第一还原电位的大小顺序一致.随着卟啉环上取代基供电子能力的减弱,各取代基铁卟啉和锰卟啉的第一还原电位E1值均逐渐减小,表现在催化体系中是它们越容易被还原而引发反应,催化氧化α蒎烯的转化率逐渐升高.

农药分配系数测定方法比较研究

施入农田的农药通过各种分配过程分布在空气、土壤、水和生物体中,进而对生态环境造成污染。农药在环境中的分配过程主要表现有:农药在土壤和水体中的吸附与解吸;从土壤和水体向空气中的挥发;从环境介质向生物体的富集。这些过程都与农药在正辛醇/水相中的分配系数有着一定的关系。近年来,分配系数已成为评价有机农药对生态环境影响的一个重要参数,而且还被用于结构活性的预测研究。我们以甲基对硫磷、敌草隆、伏草隆、呋喃丹、非草隆、绿麦隆6种农药为对象,参考经济联合与发展组织(OECD)制订的化学品试验指南及其它资料。

苯乙酮类化合物的碳谱研究

本文分析了九个被羟基和（或）甲氧基取代的苯乙酮类化合物的碳谱数据，首次提出了理论计算这类化合物芳环碳化学位移的计算公式以及羟基和甲氧基的取代参数。羟基的取代参数分别为：３０．４（Ｚ＿ｉ），－１３．２（Ｚ_０），２．３（Ｚ_ｍ）和－７．８（Ｚ_ｐ），甲氧基的取代参数分别为：３０．５（Ｚ＿ｉ），－１４．１（Ｚ＿０），０．６（Ｚ＿ｍ）和－７．２（Ｚ＿ｐ）。计算公式分别为：δ＿Ｃ１＝１３７．３＋∑Ｚ，δ＿Ｃ４＝１３３．０＋∑Ｚ和δ＿Ｃ２，３，５，６，＝１２８．５＋∑Ｚ。当用这组取代参数和计算公式来计算这类化合物芳环碳的化学位移时，求得的理论值比用简单苯衍生物的取代参数和相应计算公式求得的值更接近实测值；从而能够准确地指导这类化合物的碳谱解析及实测碳谱数据的指认。同时，这组取代参数也适用于被羟基和（或）甲氧基取代的黄酮类化合物芳环碳的化学位移计算，对这类化合物的碳谱解析亦有指导意义。另外，本文还纠正了文献中对３－羟基－４－甲氧基苯乙酮碳谱的某些错误指认。

双环磷酸酯类化合物NMR结构效应研究

用现有理论说明不了双环磷酸酯类化合物^(31)P NMR化学位移的变化。本文在我们提出的核外电子云球对称效应原理基础上,用量子化学和分子力学计算的参数,表达了这类化合物^(31)P化学位移变化的规律,同时还研究了它们的^(13)C NMR化学位移和偶合常数的取代基效应。

结晶紫和结晶紫母体的~1H NMR溶剂效应的研究及与取代基常数间的关系

结晶紫和结晶紫母体在强有机酸中,其甲基峰都移向低场。在取代的芳烃溶剂中,甲基峰都移向高场,而且彼此间的化学位移有线性关系,并与Hammett取代基常数及改正的Hammett取代基常数间有线性关系。讨论了电子移动度的应用以及取代基常数σ与σ^-间的线性关系。

立体拥挤二苯基卡宾分子结构的电子效应

通过对二苯基重氮甲烷的光照射产生了一系列具有对称对位取代基的三线态二 (2 ,6 二甲苯基 )卡宾 .用电子顺磁共振波谱对其进行了研究 .通过对不同粘度的基质 (matrix)中零磁场分裂参数D和E的测定 ,依据电子自旋离域取代基常数σ 对三线态二苯基卡宾的分子结构的取代基效应进行了分析 .并通过对卡宾的热消失温度及其室温脱气苯溶液中寿命的测定 ,对三线态二 (2 ,6 二甲苯基 )卡宾的稳定性进行了定量考察 .结果表明 ,对卡宾中心的自旋电子具有离域效应的取代基使三线态二 (2 ,6 二甲苯基 )卡宾采取低能稳定的直线型结构 ,且显示了更好的热稳定性和更长的寿命 .

芳基取代戊二烯-1,3(E、E)类化合物的色谱保留指数与分子结构参数的相关性

本文考察了芳基取代戊二烯-1,3(E、E)类化合物的气相色谱保留值与分子结构参数之间的关系,结果表明色谱的保留指数可以用分子的体积和取代基常数的方程式表示;I=aΓ_(?)-bδp+c,并讨论了它们之间的关系。

3(或)4—取代苯甲亚氨酸酯中取代基效应的^(13)C—NMR研究

本文测定了三个3(或4)-取代苯甲亚氨酸乙酯(1)和八个N-氰甲基-3(或4)-取代苯甲亚氨酸乙酯(2)的^(13)C-NMR谱。归属了1 和2和各碳化学位移。求得了的取代基化学位移(substituent Chemical Shift,SCS)。碳-13化学位移与单取代苯的取代基化学位移(SCS)的相关分析表明:4-取代苯甲亚氨酸酯1 b～g和2b～e中,除C_(2,6)外,其他各芳碳的化学位移值与加和规则基本相符;3-取代苯甲亚氨酸酯1h～j和2f～h中,除C_1外,其他各芳碳的化学位移值与加和规则基本相符。另外,本文还进行了碳-13化学位移与σ_(I)/σ_(R)~O和F/M的双参数相关分析。

苯甲亚氨酸乙酯及N—乙氧基羰基亚甲基苯甲亚氨酯乙酯的~1H和^(13)C NMR的研究

本文测定了苯甲亚氨酸乙酯(Ⅰ)和N-乙氧基羰基亚甲基苯甲亚氨酸乙酯(Ⅱ)的~1H和^(13)C NMR谱,归属了共振谱线,得到了这两类化合物的官能团在苯衍生物中的经验增量,讨论了化学位移与Hammett常数的相关性.

小分子化合物与DNA结合的研究——取代基电性因素的影响

通过NMR及粘度测定,本文研究了7个具有不同取代基的萘并噻吩系列化合物与DNA结合的方式。认定无论取代基的电性如何,此系列化合物均以嵌插络合的方式与DNA结合。通过光谱及热力学测量,比较了取代基的电性效应对本系列化合物与DNA结合强度的影响,发现Hammett取代基常数σ与小分子—DNA络合物的表观稳定常数K(LogK)值有一定的相关性,并据此初步探讨了其反应机制。

取代基对硫代磷酰胺酯摩擦磨损的影响

采用四球机和SRV试验机研究了3类不同结构的硫代磷酰胺酯(TPA)的抗磨有效性,包括硫代磷酰单胺酯(TPMA)、硫代磷酰双胺酯(TPDA)和二硫代磷酰单胺酯(DPMA)。结果表明,TPA通常有较好的抗磨性和承载能力。其润滑性取决于酯基和胺基的结构、取代基的电负性和摩擦条件。在单向滑动和往复运动中性能都较佳的是硫脲基上连接有强烈吸电子作用的取代基的O-乙基、N-烷基和硫脲基单硫代磷酰胺酯(EAPTUT)。某些TPA的性能优于ZDTP、MoDTP、硫代磷酸酯、膦酸次膦酸胺盐、T305和T307等商品化的抗磨剂。1个TPA分子中同时含有S、P、N基团,分子内相互牵制作用使每个功能团都不会过度活泼,摩擦过程中的腐蚀磨损和磨粒磨损很易平衡,总磨损最小。SRV试验中每次往复运动磨出新鲜金属表面仅费时百分之几秒,而活性不够的抗磨剂可能无法及时生成新表面保护膜。

羧酸衍生物水解活性的直观理解

有机化学中羧酸衍生物水解活性受到离去基团的电子效应和离去能力的影响,其活性顺序及引起该活性顺序的原因,是学习过程中最难理清的地方。采用Hammett电子效应常数σ和离去基团共轭酸的离解常数p Ka,对问题进行深入剖析,可以使抽象的理论变得更直观,减少理解难度,利于学生从本质上把握和理解羧酸衍生物水解活性的内在原因。

间位基团激发态取代基常数的扩展及应用

合成了七个系列含间位取代基X的二苯乙烯m-XArCH=CHArY-p(简称m-XSBY-p),其中X为NO_2、I、CHCH_2、Ph、Et、NMe_2和CCH。在无水乙醇中测定它们的紫外(UV)吸收光谱,得到紫外吸收最大波长λ_(max)(nm)。对λ_(max)的波数ν_(max)(cm^(-1))进行定量相关,采用曲线拟合方法,得到上述7个间位基团的激发态取代基常数σ_(CC(m))^(ex)。将对位基团和间位基团的σ_(CC)^(ex)与Hammett常数σ进行对比,表明σx_(CC)^(ex)与σ分别表达取代基不同的电子效应。另外,合成了含上述间位基团的二芳基希夫碱(10个)和二苯乙烯(14个),用所得σ_(CC(m))^(ex)预测它们的λ_(max),并用实验测定它们的λ_(max),结果表明预测值与实验值相吻合,验证了所得σ_(CC(m))^(ex)常数的可靠性。收集了225个化合物(涉及二取代苯及二苯乙烯)的ν_(max),建立了一个统一的定量方程来表达这些化合物ν_(max)的变化规律。

Effects of substituent and solvent on the UV absorption energy of 4,4'-disubstituted stilbenes

Twenty five samples of 4,4'-disubstituted stilbene derivatives were synthesized, and their UV absorption max wavelengths were determined in over 10 kinds of solvents including cyclohexane, ether, chloroform, acetonitrile and ethanol, in which 242 experimental data were recorded. The effects of substituents and solvents on the energy of their UV absorption max wavelengths were discussed. The research results showed: the energy of UV absorption max wavelengths of 4,4'-disubstituted stilbenes was mainly affected by their intramolecular structure (substituent effect) in a given solvent, that is, the energy is dominated by both of excited-state substituent parameter o-~c and polar substituent constant crp. While their energy was dominated by the substituent effect and solvent effect in different kinds of solvents. An equation quantifying the energy of UV absorption max wavelengths of 4,4'-disubstituted stilbenes was developed. In addition, it is found that the n-octanol/water partition coefficient (logP) is more effective than the solvatochromic dye (ET(30)) in scaling the solvent effect. The equation employed the parameter logP has a better correlation and more specific physical meaning. Further, the energies of UV absorption max wavelengths of some reported compounds were predicted by the obtained equation, which are in agreement with their experimental values.

6,7-(1′,4′-亚丁基)-8-(4″-取代苯基)-10,10-二甲基-10H-吡啶并[1,2-α]吲哚盐的合成及波谱性质

前文报道了2,3,3-三甲基-3 H-吲哚高氯酸盐与1-苯基-3-取代苯基丙烯酮和1,5-二取代苯基-1,4-戊二烯-3-酮的反应。为了进一步探讨吡啶并吲哚盐类化合物的光谱特性与结构之间的内在关系,以获得具有应用前景的光敏染料和有机光导体的增感剂。

过渡金属-二芳基希夫碱配位稳定常数的QSPR研究

金属离子与有机配体形成配合物的稳定性与金属离子的特性和有机配体的分子结构密切关系。为了探讨席夫碱与金属离子配位的稳定性规律,本文以二芳基希夫碱为模型配体化合物,选用部分过渡金属离子(Ni^2+、Mn^2+、Fe^3+、Cu^2+、Cr^3+)为配位对象,将金属离子的特性参数和配体中取代基X的电子效应参数Hammett常数作为变量,对模型化合物与金属离子形成的配合物的稳定常数logβ2进行定量构效关系研究,得到具有良好相关性的定量方程并通过实验验证了方程的可靠性。结果表明,金属离子的能量密度(XP/PM+)是影响配合物稳定性的主要因素;对同一金属离子,取代基的吸电子效应增强配合物的稳定性;而金属离子电荷Q和离子半径R需在一个合适的范围内,才利于配合物的稳定。