A Density Functional Theory Study on Electronic Structure and Second—order Nonlinear Optical Properties of Some Push—Pull Molecules

Time-dependent density-functional theory(TDDFT)has been applied to calculate the electronic structure and second-order nonlinear optical(NLO) properties of some organic molecules.The two-dimensional(2-D)charge transfer charateristics of calculated molecules were studied and compared with corresponding experimental results.All the theoretical results agree well with the measurement.For 2-D molecule with two-fold symmetry,the dominant charge transfer is off-diagonal,while for three-fold symmetry 2-D molecule,the dominant charge transfer is not only between branches and central group but also among branches.     

Peptide separation in hydrophilic interaction capillary electrochromatography

Separation of small peptides by hydrophilic interaction capillary electrochromatography (HI-CEC) has been investigated. The negative surface charge of a hydrophilic, strong-cation-exchange stationary phase (PolySULFOETHYL A) provided a substantial cathodic electroosmotic flow (EOF). The influence of acetonitrile content, ionic strength, mobile phase pH as well as applied voltage on the migration of the peptides was studied. Possible retention mechanisms of the peptides in HI-CEC were discussed. It was found that hydrophilic interaction between the solutes and the stationary phase played a major role in this system, especially when mobile phases with high acetonitrile content were used. However, an ion-exchange mechanism and electrophoretic mobility also affect the migration of the peptides in HI-CEC. Elution order and selectivity was proved to be different in HI-CEC and capillary zone electrophoresis (CZE), thus revealing the potential of HI-CEC as a complementary technique to CZE for the separation of peptides. Efficiency and selectivity of HI-CEC for the separation of peptides were demonstrated by baseline separating nine peptides in 6 min.     

共振光散射成像检测5,10,15,20-四(对三甲基氨基苯)卟吩诱导的DNA超螺旋聚集体

A resonance light scattering （RLS） imaging method was proposed based on imaging and measuring the RLS features of single suprahelical species of DNA, and its appfication to DNA assay was also investigated. In acidic medium, porphine-5,10,15,20-tetrakis（p-phenyltlimethylaminium） （PTPTMA）, could stack along the molecular surface of DNA with the mode of long-range assembly to induce the formation of suprahelical species of DNA, resulting in strong RLS signals in the range of 450-510 nm. Under the excitation of 488 nm fight beam of argon ion laser source, single suprahelical species could be observed with the aid of a common microscope due to the strong scattered fight emitted by the suprahelical species. By capturing the RLS images of the single suprahelical species with a cooled charge coupled device （CCD） camera, and analyzing the RLS data, herein an RLS imaging method of DNA was proposed based on the linear relationship between the counts of suprahelical species in the detection focus plane and the concentration of DNA in nanograms. When 1.8 μmol/L PTPTMA was employed, both calf thymus DNA （ct DNA） and fish sperm DNA （fs DNA） in the range of 25-1100 ng/mL could be detected with the limits of detection lower than 25 ng/mL （3a）. Four synthetic samples were detected satisfactorily with relative standard deviations less than 5.1%.     

[{Cu(phen)2}(μ‐malato){Cu(phen)(NO3)}](NO3)·4H2O: malate acting as a tetra­dentate and dibridging ligand in a dinuclear copper complex

The crystal structure of the title compound, μ‐2‐hydroxy­butane­dioato‐1κ²O⁴,O^4′:2κ³O¹,O²,O⁴‐nitrato‐2κO‐tris­(1,10‐phen­anthroline)‐1κ⁴N,N′;2κ²N,N′‐dicopper(II) nitrate tetra­hydrate, [Cu₂(C₄H₃O₅)(NO₃)(C₁₂H₈N₂)₃](NO₃)·4H₂O, contains an unsymmetrical dinuclear copper complex with Cu(phen)₂ and Cu(phen)(NO₃) moieties (phen is 1,10‐phenanthroline) bridged by a malate (2‐hydroxy­butane­dioate) ligand, which acts as a double‐bridging and tetra­dentate ligand. As a result of this double‐bridging action, especially the direct coordination of the O atom of one carboxyl­ate group of malate to the two Cu atoms, the Cu⋯Cu distance is only 4.199 (1) Å and the two phen planes are roughly parallel [the shortest inter­planar distance is 3.28 (1) Å], exhibiting an obvious intra­molecular π–π stacking inter­action.     

Crystal and Molecular Structure of a New Mono－substituted Titanocene Complex，｛（η~5－Cp）［η~5－（1－（4－OCH_3）C_6H_4）C_6H_（10）Cp］（TiCl_2）｝·0．3（n－C_6H_（14））

ＣｒｙｓｔａｌａｎｄＭｏｌｅｃｕｌａｒＳｔｒｕｃｔｕｒｅｏｆａＮｅｗＭｏｎｏ－ｓｕｂｓｔｉｔｕｔｅｄＴｉｔａｎｏｃｅｎｅＣｏｍｐｌｅｘ，｛（η~５－Ｃｐ）［η~５－（１－（４－ＯＣＨ_３）Ｃ_６Ｈ_４）Ｃ_６Ｈ_（１０）Ｃｐ］（ＴｉＣｌ_２）｝·０．３（ｎ－...     

Synthesis of 4-[(1,3-diaminopyrrolo[3′,4′:4,5]pyrido[2,3-d]-pyrimidin-8-yl)benzoyl]-L-glutamic acid as a potential antifolate

This paper is dedicated to the memory of Professor Roland K. Robins The synthesis of 4-[(1,3-diaminopyrrolo[3′,4′:4,5]pyrido[2,3-d]pyrimidin-8-yl)benzoyl]-L-glutamic acid ( 18 ), a potential antifolate and anticancer agent, has been achieved starting from 1,4-dibromobutan-2-ol with alkyl p-aminobenzoic acids. Condensation of these two agents gave 1-(4-alkoxycarbonylphenyl)pyrrolidin-3-ols 7a,b , which were oxidized to the corresponding pyrrolidin-3-one derivatives 8a,b . Compounds 8a,b were converted into 1,3-diamino-8-(4-alkoxycarbonylphenyl)-7,8-dihydro-9H-pyrrolo[3′,4′:4,5]pyrido[2,3-d]pyrimidines 12a,b in 4 steps. Saponification of 12b the benzoate ester and coupling with di-tert-butyl glutamate afforded a mixture of 7,8-dihydro product 16 and its aromatized derivative 17 . Finally hydrolysis of esters 16 or 17 gave only the title compound 18 . The 7,8-dihydro tricyclic derivatives were easily air-oxidized to form their fully aromatized compounds. The title compound 18 was one tenth less active than MTX against HL-60 cells in culture.     

Reinforcement of Self‐Healing Polyacrylic Acid Hydrogel with Acrylamide Modified Microcrystalline Cellulose†

Self‐healing hydrogel such as polyacrylic acid (PAA) hydrogel has attracted increasing attention based on its promising potential applications. However, it usually suffers from low strength especially as mechanical device. Herein, a commercial microcrystalline cellulose (MCC) was modified with acrylamide to graft polyacrylamide (PAM) chains on the particle surface. The acrylamide‐modified MCC (AM‐MCC) was then dispersed in monomer solution of acrylic acid to prepare composite hydrogel. The mechanical properties of the obtained composite hydrogels and the self‐healed hydrogels were carefully measured by compressive and tensile tests, and by dynamic mechanical analysis. Our results demonstrate that introduction of a small amount of AM‐MCC such as 3 wt% can not only reinforce the original hydrogel and the healed hydrogel markedly, but also improve self‐healing efficiency obviously. The analyses indicate that in addition to the reversible multi‐interactions such as hydrogen bonding and ionic interactions, the entanglements between the PAA chains of the hydrogel matrix and the PAM chains grafted on the MCC particles have also played an important role on the improvement in mechanical performances and the healing ability of the hydrogel. Moreover, the responsiveness to exterior ion has been tested to indicate potential application of the composite hydrogel as self‐healable sensor.     

Determination of Tiopronin in Human Plasma by SPE then Reversed-Phase HPLC–UV

An accurate, simple and sensitive method based on reversed-phase high-performance liquid chromatography with UV detection has been developed for determination of tiopronin (TP) in human plasma. TP in plasma was reacted with p-bromophenacyl bromide (p-BPB) to give the TP-p-BPB adduct and this derivative was then extracted from the plasma on a silica gel cartridge. Potential interfering compounds were removed by washing with water, and the TP-p-BPB adduct was then eluted with acetonitrile. The organic phase obtained was evaporated to complete dryness under a stream of nitrogen. The residue was dissolved in acetonitrile and this solution was injected on to a reversed-phase ODS HPLC column. The mobile phase was usually the ternary mixture acetonitrile–water–trifluoroacetic acid, 40:59.88:0.12 (v/v). The retention times of TP-p-BPB and the internal standard adduct were 14.4 and 17.9 min, respectively. No interfering peaks were encountered in several blank plasma samples examined. The limit of detection for TP was 12 ng mL^?1. Extraction recovery exceeded 70%. The calibration plot for the TP derivative was linear in the range 40?4000 ng mL^?1, regression coefficient 0.9989, and the coefficient of the variation of the points of the calibration plot was below 10%. The method was validated appropriately and successfully applied to the determination of TP in human plasma.     

Syntheses and Crystal Structures of Cadmium Complexes with Thiophenedicarboxylate and Bipyridine‐like Ligands

Two new coordination polymers [Cd(tdc)(bpy)(H₂O)]_n ( 1 ) and [Cd(tdc)(phen)]_n ( 2 ) (H₂tdc = thiophene‐2,5‐dicarboxylic acid, bpy = 2,2′‐bipyridine and phen = 1,10‐phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X‐ray single‐crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) Å, V = 7044(6) ų, Z = 16; 2 in the monoclinic space group P2₁/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) Å, β = 105.01(1)°, V = 1548.8(2) ų, Z = 4. Both of them are double‐stranded chains and further assembled into three‐dimensional networks by π‐π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.     

用ATRP法构筑核壳型梯度极性的多羟基多臂星状超支化聚合物及聚合物刷——三层聚合物刷的合成与表征

设计并通过原子转移自由基聚合方法 (ATRP)合成了核壳型具有梯度极性的多羟基多臂星状聚合物刷 .端羟基超支化聚 (3 乙基 3 羟甲基氧杂环丁烷 )与 2 溴 异丁基酰溴反应制得大分子引发剂 (HP Br) ,以Cu(I)Br和N ,N ,N′ ,N′ ,N″ 五甲基二乙基三胺 (PMDETA)为催化体系 ,进行甲基丙烯酸甲酯 (MMA)的ATRP反应 ,得到以甲基丙烯酸甲酯为臂的多臂星状超支化聚合物 (HP g PMMA) .又以HP g PMMA为引发剂 ,进行甲基丙烯酸羟乙酯 (HEMA)的ATRP聚合 ,得到核壳型具有梯度极性的多羟基多臂星状超支化聚合物 (HP g PMMA b PHEMA) ,继续将其羟基官能团溴代化 (与 2 溴 异丁基酰溴反应 ) ,引发HEMA的ATRP溶液聚合 ,得到了多臂星状超支化聚合物刷 .产物的结构用1 H NMR、FTIR、GPC等进行了表征和测试 .