ChemInform Abstract: Quantum-Chemical Study of the Electronic Structure and Stability of Aluminum Fluorides.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Quantum-Chemical Study of the Structure and Stability of Gallium Hydride Oligomers.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Steric and Electronic Structure of Selenoanisole: A Quantum-Chemical Study

The potential functions of internal rotation around the C_sp2-Se bond in selenoanisole were ob- tained by quantum-chemical calculations in the approximations HF/3-21G(d), HF/6-31G(d), MP2(f)/6-31G(d), and B3LYP/6-31G(d). The calculations were performed in the range of variation of the torsion angle (between the planes of the benzene ring and C_sp2-Se-C_sp3 bonds) from 0° to 90° with 15° step. The energy minimum is in the region of the orthogonal conformation ( 90°), and the energy maximum, in the region of the planar form ( 0°). The rotation barriers (kJ mol^{- 1}) are as follows: HF/3-21G(d), 9.20; HF/6-31G(d), 13.13; MP2(f)/6-31G(d), 10.25; and B3LYP/6-31G(d), 6.41. The geometric parameters, Koopmans ionization potentials, and dipole moments are given. The energies, degrees of hybridization, populations of the lone electron pairs of Se, energies of their interaction with the antibonding * orbitals of the benzene ring, and electron density distributions were determined in terms of the natural bond orbital approach.     

壳聚糖季铵盐的合成及结构表征

用异相法合成了水溶性壳聚糖季铵盐衍生物，并用红外光谱及核磁共振谱进行结构表征。结果表明：在中性反应条件下，壳聚糖分子的季铵盐衍生化反应主要发生于亲该中心Ｃ２位的氨基上，所合成的壳聚糖季铵盐衍生物可直接溶解于水。其水溶液可以任意比例与乙醇、丙二醇、甘油等混溶。     

Quantum-Chemical Study of the Structure of Cyanophosphines and Their Oxides

The structure of cyanophosphines and their oxides was studied by ab initio (RHF/6-31G^**) and semiempirical (PM3) methods. Both methods predict that MeOP(CN)₂, (MeO)₂PCN, and (MeO)₂P(O)CN exist in noneclipsed antiperiplanar and synclinal conformations. The calculation results nicely agree with measured dipole moments and Kerr constants of these compounds. The phenyl and diphenyl derivatives PhP(CN)₂, Ph₂PCN, Ph(Et)PCN, and Ph₂P(O)CN prefer forms in which the phenyl ring plane is eclipsing the phosphorus lone electron pair or the phosphoryl bond. The interactions of the phosphorus lone electron pair with the phenyl ring and with the cyano group are lacking in the title compounds.     

Quantum-Chemical Study of the Relative Stability of N-Substituted Tetrazole Isomers

The enthalpies of formation and total energies of a series of 1- and 2-substituted tetrazoles in the gas phase and in solution were calculated by MNDO and AM1 semiempirical methods and by a set of nonempirical procedures. The effect of solvent on the relative stability of N-substituted tetrazoles was estimated in terms of the PCM, SM5, and SCRF models. The possibility for isomerization of N-substituted tetrazoles, depending on the substituent in position 1 or 2, was studied at the MP2/6-31G*//HF/6-31G* level. According to the results of nonempirical calculations, 2-substituted tetrazoles are more stable in the gas phase, in keeping with the experimental data for the corresponding isomers. The solvent nature is an important factor affecting isomerization of N-substituted tetrazoles: Rise in the solvent polarity leads to displacement of the equilibrium toward 1-substituted isomers.     

用于燃料电池的季铵基团的PVA/PAADDA碱性聚合物电解质膜的制备及稳定性

通过聚合物共混法成功地制备出了具有化学交联结构的聚乙烯醇/二甲基二烯丙基氯化铵和丙烯酰胺共聚物(PVA/PAADDA)碱性聚合物电解质膜。采用傅里叶红外分析（FTIR）、扫描电镜（SEM）、热重分析（TGA）和交流阻抗等方法详细考察了PVA/PAADDA膜的分子结构、微观形貌、热稳定性、耐碱稳定性、尺寸稳定性和电导率。红外分析结果表明,PAADDA成功地混入聚合物基体中。SEM分析结果表明,当m(PVA):m(PAADDA)=1:1时,膜可观察到明显的微相分离。TGA结果表明,混入PAADDA后膜的热稳定性没有明显降低,并且在210 oC之前能保持很好的热稳定性。PVA/PAADDA膜在经过高温、高浓度碱溶液（80 oC, 6 mol?L-1）处理后,仍表现出很好的耐碱稳定性。同时,由于膜内形成致密的内互交联网络结构,PVA/PAADDA膜在60 oC水中处理300 h后也能表现出优良的尺寸稳定性和电导率稳定性。此外,膜的甲醇吸收率随着温度的升高没有明显变化,90 oC时甲醇吸收率仅为同条件下Nafion115膜的1/5。     

Efficient Cellulose Solvent: Quaternary Ammonium Chlorides

Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N‐dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well‐established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

     

十聚钨酸季铵盐的合成

利用离子液体首次合成两种十聚钨酸季铵盐{[Bmim]_4W_(10)O_(32)(Bmin=N-甲基-N'-正丁基咪唑)和[Bu~nPy]_4W_(10)O_(32)},其结构经TG,~1H NMR,~(13)C NMR,IR和元素分析表征.     

Quantum-Chemical Study of Electronic Structure and Reactivity of Diphospha-1,3-Butadienes

Abstract

Quantum-chemical calculations of the electronic structure of 1,3-, 1,4- and 2,3-diphospha-1,3-butadienes (DPB) and their derivatives with different substituents were performed. The MNDO method was used to describe the electronic structure of phosphaalkenes. The frontier orbitals of all unsubstituted DPB are of π-type. The highest occupied molecular orbital (HOMO) is delocalized through both double phosphorus-carbon bonds; the next occupied MO is a combination of two phosphorus lone pairs (n-MO). The HOMO of 2,3-DPB differs markedly from those of 1,3- and 1,4-isomers: the contributions of phosphorus and carbon p-orbitals are nearly equal, and the energy gap between HOMO and n-MO is very small (0.008 eV). The introduction of the electron-withdrawing substituents results in the reverse order of these MO's. In contrast with 1,3- and 1,4-isomers, the double bonds of 2,3-DPB are almost non-polar. Effect of substituents upon the electron density distribution are considered. The results indicate that orbitally controlled 1,4-additions should be characteristic for the derivatives of 1,3- and 1,4-DPB, similar to 1,3-butadiene. In case of 2,3-DPB, tendency to 1,4-addition should be lower; for its derivatives the reaction type depends greatly upon the electronic effects of substituents. In particular, reactions involving phosphorus lone pairs should be typical for the derivatives of 2,3-DPB with electron-withdrawing substituents.     

两亲性季铵盐对钙钛矿太阳能电池效率和稳定性的影响

将廉价易得的两亲性季铵盐十六烷基三甲基溴化铵（CTMAB）加入到钙钛矿前驱体溶液中,通过调节添加量研究了CTMAB对钙钛矿太阳能电池效率和稳定性的影响.结果表明,加入CTMAB后制备的钙钛矿薄膜更加致密均匀,表面缺陷更少,钙钛矿晶体结晶性得到显著提高,从而提高了电池的光电转换效率及电池稳定性;含有CTMAB的钙钛矿太阳能电池的光电转换效率（PCE）为18.03%,明显高于未添加CTMAB的电池效率（17.05%）;含有CTMAB的电池稳定性有较大的提高,在一定湿度环境中保存40 d后效率仍达初始效率的95%,而未添加CTMAB的器件效率只有初始效率的70%.     

季铵盐型Gemini表面活性剂诱导囊泡结构改变机理研究

用动态光散射技术以及荧光探针方法, 研究了不同连接基长度的季铵盐型Gemini表面活性剂对卵磷脂囊泡结构改变的影响, 并借助理论模型和临界堆积参数理论探索了Gemini表面活性剂诱导囊泡结构改变的机理. 实验结果表明, 表面活性剂诱导囊泡结构改变的主要原因是表面活性剂嵌入到囊泡的双分子层中, 从而改变了囊泡的表面电荷强度以及嵌入后的表面活性剂在囊泡双分子层中分布的不均匀性. 此外, 表面活性剂分子的结构也会对其产生影响, 不同连接基长度的季铵盐型Gemini表面活性剂对囊泡结构改变的影响不完全相同, 但会呈现出一定的规律性.     

Quantum-Chemical Study of the Electronic and Steric Structure of Vinyltetrazoles: II. 2-Vinyltetrazoles

The total Mulliken charges on the C and N atoms, populations of the S-trans-(N¹) conformers, and rotation barriers in the molecules of 2-vinyl-5-R-tetrazoles (R = H, CH₃, CH = CH₂, C₆H₅, CH₂Cl, CF₃) were calculated ab initio (HF/6-31G**, MP2/6-31G**). The results were compared with the ¹H and ¹³C NMR data for these compounds.     

Synthesis of Chitosan Quaternary Ammonium Salts

Chitosan has a wide scale of applications1-3. Interestingly, some antibacterial and antifungal activities have been described with chitosan and modified chitosan derivatives4-6. In polycationic biocides, generally, it is reasonably assumed7 that the charge density of the polyelectrolyte increases with increase in the molecular weight of its single coil, which leads to the enhanced adsorption of polycations onto the negatively charged cell surface. This is also favorable for the binding of t…     

Hydroxyl Ammonium and Diethyl Ammonium Glutaratouranylates: Synthesis and Structure

The structures of two new coordination polymers, namely, hydroxyl ammonium glutaratouranylate NH₃OH[UO₂(C₅H₆O₄)(C₅H₇O₄)] · H₂O (I) and diethyl ammonium glutaratouranylate NH₂(C₂H₅)₂[UO₂(C₅H₆O₄) (C₅H₇O₄)] · 2H₂O (II), have been characterized by single-crystal X-ray diffraction. It has been established that the structures of complexes I and II contain [UO₂(C₅H₆O₄)(C₅H₇O₄)]–infinite chains with the crystallochemical formula AQ⁰²B⁰¹ (\(\rm{A = UO_2^{2+}}, Q^{02} = C_5H_6O_4^{2-}, B^{01} = C_5H_7O_4^{-}\)). Despite the identical compositions, uranyl glutarate chains in the studied structures appreciably differ from each other by their geometry and linking. The specific features of nonbonded interactions in the structures of complexes I and II have been characterized by the Voronoi–Dirichlet method of molecular polyhedra.     

四苯基硼季铵盐的合成和光引发性能

自由基聚合;四苯基硼季铵盐的合成和光引发性能     

金刚烷基甜菜碱型和季铵盐阳离子型表面活性剂的合成研究

以金刚烷胺为起始反应物,首先在过量甲酸存在下,与甲醛发生埃斯韦勒-克拉克甲基化反应合成了N,N-二甲基金刚烷叔胺,在此基础上通过N,N-二甲基金刚烷叔胺与氯乙酸钠、溴代正丁烷、溴代正辛烷、溴代十二烷、溴代十六烷等一系列季铵化试剂的季铵化反应,分别合成了N,N-二甲基金刚烷甜菜碱型表面活性剂及N-(1-金刚烷基)-N,N-二甲基正丁基溴化铵、N-(1-金刚烷基)-N,N-二甲基辛基溴化铵、N-(1-金刚烷基)-N,N-二甲基十二烷基溴化铵、N-(1-金刚烷基)-N,N-二甲基十六烷基溴化铵等金刚烷季铵盐阳离子型表面活性剂,产率分别为75%,75%,61%,44%,54%.采用元素分析,IR,1H NMR等分析手段对5种产物进行了结构鉴定,测试了各种金刚烷表面活性剂水溶液的表面张力.     

Quantum-Chemical Study of Electronic and Steric Structure of Vinyltetrazoles: I. 2-Substituted 5-Vinyltetrazoles

The total Mulliken charges on the carbon atoms of the vinyl group, populations of S-trans-(N¹)conformers, and internal rotation energies were calculated ab initio (HF/6-31G**, MP2/6-31G**, and MP2/6-31G**//AM1) for a series of 2R-5-vinyltetrazoles (R = CH₃, C₂H₅, i-C₃H₇, t-C₄H₉, C₆H₅). The calculation results were compared to the available experimental data.     

新型吡咯季铵盐的合成

以乙酰乙酸乙酯为原料,经缩合、氧化、还原和氯代等反应合成了3-甲基-5-碘甲基-1H-吡咯-2,4-二(甲酸乙酯)(5);5分别与乌洛托品,吡啶和三甲胺经取代反应合成了3个吡咯季铵盐6a~6c,其中5和6a~6c均为新化合物,其结构经1H NMR,IR和ESI-MS表征。