连接性指数与Kováts指数的相关性研究

在分子拓扑理论的基础上,提出一种新的拓扑指数--连接性指数mG,其中0G=∑Ai,1G=∑(Ai@Aj).计算了12个系列94种分子的0G、1G值,发现0G或1G与这些化合物的Kovats指数具有很好的相关性.该模式计算方法简单,使用方便,预测结果理想.     

无机物晶格能及其它理化性质的定量构效关系研究

于邻接矩阵和原子或离子的极化力参数（gi)建立新的连接性指数（^mG)，其中^0G,^1G的定义式为：^0G=∑（gi)^0.5,^1G=∑(gi.gj)^0.5。涉及14种离子（如X^-,O^2-,S^2-,Se^2-,Te^2-,PO4^3-,SiO4^4-,N^3-等）的192种无机物晶格能与^0G,^1G的线性性回归方程为：U＝－381.11 310.20^1G 354.45^0G,R=0.9975其估算值与实验值基本吻合，^1G不仅计算简单，对无机分子结构差异具有很强的区分能力，而且而碱金属卤化物的理化性质（如晶格能、熔点、磁化主、M－X键长，反应微分截面等）显著相关。     

连接性指数与Kov(a)ts指数的相关性研究

在分子拓扑理论的基础上,提出一种新的拓扑指数——连接性指数~mG,其中。计算了12个系列94种分子的~0G、~1G值,发现~0G或~1G与这些化合物的Kovts指数具有很好的相关性。该模式计算方法简单,使用方便,预测结果理想。     

连接性指数及其逆指数对-元醇折光指数的拓扑研究

定义了原子特征值βi和βi＇，由βi建构连接性指数^mXA，由βi＇建构其逆指数^mXB，运用定量结构-性质相关技术研究了42个-元醇分子的折光指数与分子结构间的定量关系。通过多元回归的方法建立了^mXZ和^mXB与折光指数的定量结构性质模型，回归方程为：nD=0．1419^0XA^-1＋0．0434^1XA^-1-0．2534^0XB^-1-0．1460^1XB^-1＋1．4659。对醇折光指数的计算结果表明，预测值与实验值的一致性令人满意，平均相对误差为0．15％。研究表明连接性指数及其逆指数在一起使用可以更好地反映出醇的构效关系。     

一种改进的分子连接性指数

通过修正分子连接性指数中的点价,使分子轨道理论与分子拓扑理论有机地结合起来,将分子连接性指数改进成为一种量子拓扑指数．实际计算表明,改进后的指数不但保留了原分子连接性指数的优点,而且还弥补了量化指数和分子拓扑指数的一些缺陷。     

无机氢化物pK_(a1)与拓扑指数~mT的关系

在Randic分子价连接性拓扑指数的基础上,构建了价电子轨道平均能量拓扑指数mT 用其0,1阶指数0T,0T和1T以及Pauling电负性差的平方分别与P区无机氢化物的pKa1值关联,拟合成3个回归方程,其相关系数分别为0.9958,0.9960和0.9965,结构选择性达到唯一性表征 预测取得了较好的结果     

离子极化力连接性拓扑指数的应用

本文提出离子极化力连接性拓扑指数，定义为：mX=∑(gixgi……）^-0.5,gi为原子的极化力值，其0、1阶指数公式分别为：0X=∑(gixgj)^-0.5,0X,1X与56种金属卤化物的晶格能（U）呈优级线性关系，回归方程为：U=-631.58 1061.65^oX 1719.59^1X r=0.9996，另外，0X,1X与碱金属卤化物的磁化率，M-X键长等亦显著相关。     

改进的分子连接性方法

通过用Mulliken键级来加权分子连接性指数中的点价,使分子轨道理论与分子连接性指数有机地结合起来,将分子连接性指数改进成为一种量子拓扑指数。对比发现,分子连接性指数的点价与Mulliken键级具有相近的物理意义,而Mulliken键级更具有独特的优越性。利用改进的分子连接性指数对几种具有代表性的烃类与其体积、疏水常数以及热力学性质进行了关联,得到了满意的结果。     

新拓扑指数A_m在有机物气相色谱法中光离子化灵敏度的分析中的应用

本文把Am拓扑指数与分子连接性指数首次用于有机化合物气相色谱分析的光离子化灵敏度的结构-性能相关性研究中，在与相应体系的光离子化灵敏度进行相关分析时发现，Am指数、分子连接性指数均能较好地反映化合物的结构特征，将二者组合，得到了更为满意的构效关系的数学模型。     

价电子轨道能量拓扑指数mZ及其应用

受Randic分子连接性拓扑指数^mZ的启发,本文构建了价电子轨道能量拓扑指数^mZ。用^mZ的0、1阶指数分别与无机氢化物的pKa1值、20种碱金属卤化物的晶格能U、生成焓△rHm、水化能△rG^0m和气态碱金属卤化物核间距R0关联,拟合的回归方程的相关系(指)数,满足优级或良级标准。预测取得较好的结果。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).