Heterocycles with a bridging nitrogen atom. 15. The novel recyclization of dipyrido[1,2-<Emphasis Type="Italic">a</Emphasis>:1′,2′-<Emphasis Type="Italic">c</Emphasis>]-imidazolium salts to pyrido[1,2-<Emphasis Type="Italic">a</Emphasis>]-benzimidazole-8-carboxaldehydes

A previously unknown recyclization of an 11-acyldipyrido[1,2-a:1,2-c]imidazolium cation to 8-formyl-9-methyl(aryl)pyrido[1,2-a]benzimidazoles has been discovered. The proposed reaction mechanism includes a selective opening of one of the pyridinium rings and the formation of a benzaldehyde fragment via condensation of the intermediate with the participation of the acyl group.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 135–139, January, 2005.     

New strategies for the synthesis of partially fluorinated acrylic polymers as possible materials for the protection of stone monuments

The conservation of the cultural heritage requires the development of new materials having specific characteristics that encompass particular attention to durability and efficacy. We approached this problem by synthesizing polyacrylic esters containing variable amounts of fluorine in the α-position of the main chain. These products were obtained from the copolymerisation of ammonium 2-fluoroacrylate and acrylic acid. The polyacrylic acids were esterified using different procedures. The polyester characteristics vary in relation to the polymerisation procedures and degree of esterification. The best esterification results, were obtained using a reaction catalyzed by BF₃ or TMSCl. These materials show good properties and are of potential interest for their use as protective agents for stone conservation.     

Stabilization of Unusual Oxidation and Coordination States by the Ligands OSF5, OSeF5, and OTeF5

Compounds with the ligands OSF₅, OSeF₅, and OTeF₅ are now known for most of the chemical elements. The ability of these ligands to stabilize the highest valency levels of the central atoms to which they are bound is unsurpassed by any other polyatomic ligand. Examples are Xe(OTeF₅)₆, Te(OTeF₅)₆, W(OTeF₅)₆, and U(OTeF₅)₆ or I(OTeF₅)₅ and Br(OSeF₅)₃. Because of the ligands' size and internal bonding they hardly ever form bridges, and in this respect they differ from fluorine, although they do share the latter's high electronegativity.     

F2＋2HI=2HF＋I2反应机理的研究

根据氯离子型层状复合氢氧化物(LDH-Cl)制备过程中溶液浓度变化的监测结果和不同反应进程时产物的EDS、IR、XRD、TEM、TG-DTA表征结果,研究了合成LDH-Cl的共沉淀反应动力学特征及机理.实验结果表明, LDH-Cl的生成符合多核层表面反应动力学模型;反应过程中LDH的晶胞参数c从2.421 nm变为2.399 nm,通道高度h由0.3321 nm减小为0.3228 nm,粒子直径Da由6.40 nm增大为15.16 nm, Dc由7.43 nm增大到10.93 nm,纵横比由0.86增大为1.39; IR和TG-DTA特征变化表明了层板对阴离子作用的强度和层板的结构稳定性随反应进程而提高.     

双取代环戊二烯基卤化钼（Ⅳ）及钨（Ⅳ）化合物质谱

报道了一系列双环戊二烯基二卤化钼（Ⅳ）及钨（Ⅳ）化合物在７０ｅＶ电离能量下的电子轰击质谱（ＥＩ）及以甘油作底物的快原子轰击质谱（ＦＡＢ），分别总结了其谱图特征，讨论了其碎裂机理，为这类化合物结构鉴定提供了依据。     

煤烟对食物、饮水氟污染的研究

测定了云南滇东“燃煤污染型”氟病区新、陈玉米(皮、饭)、饮用水(自然井水、泉水、室内缸水、开水)的含氟量，并对玉米、豆娄、辣椒进行水洗脱氟试验，结果证明由于用煤方式不当，造成室内食物、饮水的污染，发生氟中毒。     

Synthesis of coil‐comb block copolymers containing polystyrene coil and poly(methyl methacrylate) side chains via atom transfer radical polymerization

A series of polystyrene‐b‐(poly(2‐(2‐bromopropionyloxy) styrene)‐g‐poly(methyl methacrylate)) (PS‐b‐(PBPS‐g‐PMMA)) and polystyrene‐b‐(poly(2‐(2‐bromopropionyloxy)ethyl acrylate)‐g‐poly(methyl methacrylate)) (PS‐b‐(PBPEA‐g‐PMMA)) as new coil‐comb block copolymers (CCBCPs) were synthesized by atom transfer radical polymerization (ATRP). The linear diblock copolymer polystyrene‐b‐poly(4‐acetoxystyrene) and polystyrene‐b‐poly(2‐(trimethylsilyloxy)ethyl acrylate) PS‐b‐P(HEA‐TMS) were obtained by combining ATRP and activators regenerated by electron transfer (ARGET) ATRP. Secondary bromide‐initiating sites for ATRP were introduced by liberation of hydroxyl groups via deprotection and subsequent esterification reaction with 2‐bromopropionyl bromide. Grafting of PMMA onto either the PBPS block or the PBPEA block via ATRP yielded the desired PS‐b‐(PBPS‐g‐PMMA) or PS‐b‐(PBPEA‐g‐PMMA). ¹H nuclear magnetic resonance spectroscopy and gel permeation chromatography data indicated the target CCBCPs were successfully synthesized. Preliminary investigation on selected CCBCPs suggests that they can form ordered nanostructures via microphase separation. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2971–2983     

Fluorescent oligo(N‐phenylmaleimide)s via aerobic radical telomerization initiated by benzylic hydrocarbons: Catalytic effect of CoII/N‐hydroxyphthalimide pair

Radical oligomerization of N‐phenylmaleimide (NPMI) was performed in benzylic hydrocarbons as the solvent. The thermally induced oligomerization occurred only above 130 °C, with the initiation attributed to autoxidation of benzylic hydrocarbons as well as formation and dissociation of charge‐transfer complexes between benzylic hydrocarbons and maleimides. The end‐group analysis on oligo(N‐ethylmaleimide) prepared under similar conditions confirmed that the chain transfer to benzylic hydrocarbons was the primary fashion in forming oligomeric chains, and radical telomerization underlaid the oligomerization with benzylic hydrocarbons as both the solvent, the initiator and the telogen. Co^II/N‐hydroxyphthalimide (NHPI) pairs could catalyze the telomerization at 110 °C. In such a catalytic process, Co^II‐based oxidative complexes oxidized benzylic hydrocarbons and NHPI into benzylic radicals and phthalimide N‐oxyl (PINO), and benzylic hydrocarbons underwent hydrogen atom transfer (HAT) to PINO. Oligo(NPMI)s were formed via HAT with benzylic hydrocarbons and NHPI. These oligo(NPMI)s exhibited fluorescent properties with excitation at 270–350 nm and 400–550 nm and emission at 530–750 nm. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3846–3857     

Recent trends in perfluorinated sulfoximines

The search for original perfluorinated moieties is a very modern and attractive challenge. Among the emergent groups, the S-perfluoroalkylated sulfoximines are very peculiar because of their structural diversity and promising properties. A literature survey shows that interest in these molecules is strongly increasing. This short review summarizes the recent works devoted to this topic.