Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

Hard and soft acids and bases: structure and process

Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Syntheses and structures of P-anilino-P-chalcogeno- and P-anilino-P-iminodiazasilaphosphetidines and their group 12 and 13 metal compounds

The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Preparation and photolysis of poly-p-ethylacrylophenone and poly-p-chloroacrylophenone and their copolymers with styrene and methyl methacrylate

Poly-p-ethylacrylophenone (PPEtAP) and poly-p-chloroacrylophenone (PPClAP) and their copolymers with styrene (PEtAP/S) and (PClAP/S) and with methyl methacrylate (PEtAP/MMA) and (PClAP/MMA) were prepared. Quantum yields of main-chain scissions at 366 nm at room temperature in benzene solution are of the same order as those of the unsubstituted polyacrylophenone and its copolymers. Substitution with chlorine and ethyl group in the para position compared to the unsubstituted polyacrylophenone and its copolymers leads to an increase of the lifetime for the n–π^* excited triplet state, as is evident from the measured quenching constants of photolysis. The low-temperature emission spectra of the copolymers are similar to the spectra of the model compounds in a polymer film. For the homopolymer, however, the character of the emission spectrum changes considerably.     

Concentrations and distributions of trace and minor elements in Chinese and Canadian coals and ashes

A total of 35 trace and minor elements including some of environmental significance were determined in each of a selection of 15 Chinese and 6 Canadian thermal coals and their ashes by using the SLOWPOKE-2 nuclear reactor facility of the University of Toronto. The concentrations and distributions of these constituents among the coals and their combustion products (viz. ash and volatile matter) are presented together with an interpretation of their significance in relation to the large scale combustion of these coals as thermal fuels in industrialized countries such as China and Canada. The detailed results showed wide variations in trace impurity concentrations (up to a factor of 100 and more) among the coals studied with few large differences between those of Chinese and Canadian origin except that the rare earths, Sc, Th, U, I, and Se were much higher in the former, other halogens, As and Na were lower. Values for elemental enrichment factors (EF) relative to normal crustal abundances indicated that only As(EF=13), Br(5.7), I(16), S(230), Sb(11) and Se(320) were appreciably enriched in coal. During static ashing at 750°C most of the halogens, S and Se were volatilized whereas most other inorganic constituents were highly retained and concentrated in the ash by factors of 6 to 11.     

Electronic structures and reactivities of methyl-substituted thienothiazoles and thieno- and furopyridines

The electronic structures of a number of methyl-substituted heterocyclces containing a thiophene or furan ring condensed with a thiazole or pyridine ring and of their quaternary salts and methylene bases were calculated by the Pariser-Parr-Pople method. The features of the electronic structures of the investigated molecules were ascertained. It is shown that methyl-substituted thienothiazoles and thieno- and furopyridines and their quaternary salts are appreciably inferior to the corresponding benzothiazoles and quinoline derivatives used for the synthesis of polymethine dyes with respect to the reactivity of the methyl group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1202–1206, September, 1976.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。