Distribution and Transfer of Gatifloxacin Between Two Microemulsion Phases with Different Structures in SDS/n-C5H11 OH/H2O System

At a weight ratio of n‐C₅H₁₁OH/H₂O=50/50, when the total content of sodium dodecyl sulfate (SDS) was less than 6.0%, the ternary mixture of SDS/n‐C₅H₁₁OH/H₂O coexisted in two immiscible microemulsions. The distribution and transfer of gatifloxacin (GTFX) between the two phases were studied using UV‐Vis and electrochemistry AC impedance spectra. The results show that GTFX transferred from the upper phase (W/O) to the lower phase (O/W or bicontinuous microemulsion), but a small amount of SDS transferred from the lower phase to the upper phase correspondingly with the increase of the total SDS content at a total GTFX concentration of 1.0×10^?5 mol/L. The addition of GTFX did not change the structures of the two different phases fundamentally, but resulted in the transfer and redistribution of GTFX and SDS, so the electric properties of the system were changed correspondingly.     

荷移反应分光光度法测定谷氨酸的含量

对谷氨酸与四氯对苯醌的荷移反应进行研究,确定了反应条件。在pH9.6硼砂缓冲溶液中,两者形成1∶1的络合物,其最大吸收波长为338nm,表观摩尔吸光系数为5.5×103L/mol.cm,线性范围为0～25μg/mL。该法用于测定味精中谷氨酸钠含量的测定,加标回收率为96.1%～101.8%,相对标准偏差不大于1.13%(n=6)。     

From Packed “Sandwich” to “Russian Doll”: Assembly by Charge‐Transfer Interactions in Cucurbit[10]uril

As the host possessing the largest cavity in the cucurbit[n]uril (CB[n]) family, CB[10] has previously displayed unusual recognition and assembly properties with guests but much remains to be explored. Herein, we present the recognition properties of CB[10] toward a series of bipyridinium guests including the tetracationic cyclophane known as blue box along with electron‐rich guests and detail the influence of encapsulation on the charge‐transfer interactions between guests. For the mono‐bipyridinium guest (methylviologen, MV ²⁺), CB[10] not only forms 1:1 and 1:2 inclusion complexes, but also enhances the charge‐transfer interactions between methylviologen and dihydroxynaphthalene ( HN ) by mainly forming the 1:2:1 packed “sandwich” complex (CB[10] ? 2 MV ²⁺ ?HN ). For guest 1 with two bipyridinium units, an interesting conformational switching from linear to “U” shape is observed by adding catechol to the solution of CB[10] and the guest. For the tetracationic cyclophane‐blue box, CB[10] forms a stable 1:1 inclusion complex; the two bipyridinium units tilt inside the cavity of CB[10] according to the X‐ray crystal structure. Finally, a supramolecular “Russian doll” was built up by threading a guest through the cavities of both blue box and CB[10].     

含Dawson结构杂多钨磷(砷)酸电荷转移配合物的合成、结构与性质

近年来,有机多金属氧酸盐电荷转移配合物由于有特殊的光、电、磁性质在催化、功能材料及药物化学等领域受到研究者的广泛关注［１］。自从１９８８年法国的Ｌ．Ｏｕａｈａｂ［２］首次报道（ＴＴＦ）６ＰＷ１２Ｏ４０（Ｅｔ４Ｎ）２的合成以来,已见报道的多金属氧酸盐仅限于ＡｎｄｅｒｓｏｎＥｖａｎｓｅ、ｌｉｎｄｑｕｉｓｔ和Ｋｅｇｇｉｎ结构的多阴离子,对它们功能性质的系统研究也未见文献报道。为了研究阴离子的大小和形状对标题化合物功能性质的影响,作者在以前工作的基础上［３,４］,首次以Ｄａｗｓｏｎ结构杂多钨磷（砷）…     

Reactivity Ratios for Microemulsion Copolymeriration of N-butyl Maleimide and Styrene

IntroductionReactivityratioscanofferthemessageofrelativereactivityofcomonomers.TWomonomerreactivityratioscanbeacquiredfromtheend-groupmodelproposedbyMayoandLewis,howevef,thereareonlyapparentreactivityratiosavailablefromthiskineticmodelwhencharge-transfercomplex(CTC)participatesinthecopolymerization.Therefore,thecopolymeriZationinwhichCTCexistsisworthyoffurtherresearch.Sofar,therearethreekineticmodelsofcopolymerizationwiththeparticipationofCTCinall,namely,SeinerandLittmodel',Shirotamodel…     

Synthesis and investigation of 4,5-dimethyl-1,3-dithiolylidene-(4-dimethylaminophenyl)acetonitrile

A method was developed for the synthesis of unsymmetrical strong electron donors. 4,5-Dimethyl-1,3-dithiolylidene(4-dimethylaminophenyl)acetonitrile was obtained, and its properties were investigated by electrochemica, spectroscopic, and quantum-chemical methods.Riga Technical University, Riga, Latvia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 22–25, January, 2000.     

Chemical Principles of Designing Organometallic Ferromagnets

The idea of designing ferromagnets chemically boils down to uniting paramagnetic atoms by means of a chemical reaction and “turning on” positive exchange interaction between them, which aligns the atoms'electron spins into ferromagnetic order. This general idea can be tested using organometallic polymers with metal paramagnetic atoms in the polymer chain. The metal atoms are isolated by organic fragments and are not bound by exchange interaction. Two ways can be used to turn on the exchange. The first is to remove the isolating fragments between the metal atoms or to replace them by electron-conductive fragments which allow the exchange interaction. The second is to build new molecular bridges able to turn it on.     

Synthesis,structural characterization,spectroscopic, thermal,dielectric and Hirshfeld surface analysis of 1-(2-methoxyphenyl)piperazinium chloranilate

The new compound 1-(2-methoxyphenyl)piperazinium chloranilate (MPP.CA) was synthesized and studied by the single crystal X-ray diffraction method. Its structure was confirmed by infrared spectroscopy. The crystal structure consists of ribbons of chloranilate anions and 1-(2-methoxyphenyl)piperazinium cations linked together by NH…O hydrogen bonds. Two protons are transferred from a chloranilic acid molecule to the nitrogen of the piperazine in this structure. Measurements of AC conductivity as a function of frequency at different temperatures indicated the hopping conduction mechanism; in addition, the variation of dielectric constant as a function of T confirmed the transition phase indicated by the differential scanning calorimetry (DSC). The physico-chemical properties, UV-Vis, DSC and dielectric properties are described. Hirshfeld surface analyzes all the intermolecular interactions involved within the structure, which are important to stabilize the structure.     

Ce4+离子在Ca2SnO4一维结构基质中的电荷迁移光谱研究

利用高温固相反应法制备了Ca₂Sn_1-xCe_xO₄和Ca_2-ySr_ySn_1-xCe_xO₄一维结构发光体. XPS结果显示 Ca₂SnO₄拥有两种结合能分别为5277 eV和5293 关键词： 2Sn_1-xCe_xO₄')" href="#">Ca₂Sn_1-xCe_xO₄ 2-ySr_ySn_1-xCe_xO₄')" href="#">Ca_2-ySr_ySn_1-xCe_xO₄ 一维结构 电荷迁移光谱     

Dependence of negative ion formation on inhomogeneous electric field strength in atmospheric pressure negative corona discharge

The dependence of negative ion formation on the inhomogeneous electric field strength in atmospheric pressure negative corona discharge with point-to-plane electrodes has been described. The distribution of negative ions HO^-, NO_x ^- and CO_x ^- and their abundances on the plane electrode was obtained with a mass spectrometer. The ion distribution on the plane was divided into two regions, the center region on the needle axis and peripheral region occurring the dominant NO_x ^- and CO_x ^- ions and HO^- ion, respectively. The calculated electric field strength in inhomogeneous electric field established on the needle tip surface suggested that the abundant formation of NO_x ^- and CO_x ^- ions and HO^- ion is attributed to the high field strength at the tip apex region over 10⁸ Vm^-1 and the low field strength at the tip peripheral region of the order of 10⁷ Vm^-1, respectively. The formation of HO^-, NO_x ^- and CO_x ^- has been discussed from the standpoint of negative ion evolution based on the thermochemical reaction and the kinetic energy of electron emitted from the needle tip.