Al替代和烧结温度对NiZn铁氧体磁性能的影响

采用陶瓷工艺制备了Al替代的Ni0.5Zn0.5AlxFe2-xO4(x=0~0.10)铁氧体材料,用XRD、B-H分析仪和阻抗分析仪对其结构和磁性能进行了研究。实验发现,最佳烧结温度为1 250℃,过高和过低的烧结温度不利于降低磁芯损耗。当Al3+替代量x=0.06时,铁氧体能获得较好综合磁性能。     

Stereoselective Synthesis of Phosphoryl‐Substituted Phenols

Copper‐catalyzed C X activation‐phosphorylation of aryls bearing different groups has been achieved using P(O) H compounds as efficient phosphorylation reagents without the assistance of any ligand. Optically active H‐phosphinates can also act as good substrates in the reaction, giving the (Sp)‐phosphoryl substituted phenolic compounds stereospecifically with retention of configuration at the phosphorus center. Furthermore, it is shown that the migration of phosphorus on O‐aryl phosphonates from oxygen to carbon also proceeds stereospecifically to produce the corresponding optically active (Rp)‐phosphoryl‐substituted phenolic compounds with retention of configuration at phosphorus via treatment with lithium diisopropylamide (LDA). Plausible mechanisms have been proposed for these reactions.

     

Asymmetric Synthesis of Bioxindole‐Substituted Hexahydrofuro[2,3‐b]furans via Hydroquinine Anthraquinone‐1,4‐diyl Diether‐Catalyzed Domino Annulation of Acylidenoxindoles/Isatins,Acylidenoxindoles and Allenoates

Hydroquinine anthraquinone‐1,4‐diyl diether [(DHQ)₂AQN]‐catalyzed unprecedented asymmetric domino annulation reactions of acylidenoxindoles/isatins, acylidenoxindoles and allenoates are disclosed in this communication, providing a facile access to hexahydrofuro[2,3‐b]furans containing four contiguous chiral centers in good to excellent yields along with good to excellent ee values and moderate to good dr values. Based on theoretical investigations, a concerted [3+2] ring‐closure process was proposed, in which steric hindrance and π–π stacking interaction between catalyst and substrate subtly co‐control the diastereoselectivity of the reaction.

     

二烷氧基对苯乙炔聚合物发光材料的研究 Ⅰ.相转移催化合成中间体1,4-二丁氧基苯

以对苯二酚和溴代正丁烷为原料、乙醇和甲苯为溶剂,在碱性条件下,采用相转移催化剂合成二烷氧基对苯乙炔聚合物发光材料的中间体1,4-二丁氧基苯,考察了不同相转移催化剂和反应条件对产品收率的影响。实验结果表明,以双十八烷基甲基胺氯化苄季铵盐(C_(18)H_(37))2N~+MeCH_2PhCl~-为相转移催化剂,在原料配比n(对苯二酚):n(溴代正丁烷)=1:2.2、催化剂用量(基于对苯二酚的物质的量)2.0%、反应温度60℃、反应时间3.0 h的条件下,1,4-二丁氧基苯的收率达93.6%。通过IR和~1H NMR表征,对产品进行了分析和确认。     

苯酰胺类D_2受体新配体的合成,~(125)I标记及生物分布研究

合成了苯酰胺类D2受体配体（S）－N－[(1-羟乙基－2－四氢吡咯烷基）甲基]－50氨基－2，3－二甲氧基苯甲胺胺（HEABZM），用红外光谱，核磁共振和质谱法进行了表征。以HEABZM为标记前体，制备了（S）－N－[1－羟乙基－2－四氢吡咯烷基）甲基]－5－氨基－4－^125I，3－二甲苯甲酰胺。标记率为79％，经萃取分离后，放化纯度在90％以上。小鼠休丙初步生物分布研究表明，该配合物在小鼠脑中有一定的区域分布，纹状体与小脑的比值略大于1。     

Temperature responsive fibers with anisotropic transitional behavior

Temperature sensitive polymer hydrogels are being extensively studied because of their potential applications in the biomedical, robotics, and chemical industries. However, major hurdles in their development have been their slow response, low efficiency (swelling/deswelling ratios), and poor mechanical properties due to difficulty in processing them into mechanically strong and fine structures. Fibers made from such polymers would be highly desirable. A temperature sensitive random linear copolymer of N‐tert‐butylacrylamide (NTBA) and acrylamide (Am) was synthesized by the solution polymerization method, using regulated dosing of comonomers. Using a novel approach, a high molecular weight poly(N‐tert‐butylacrylamide‐ran‐acrylamide::27 : 73) has been converted to insoluble strong fibers with fineness of 30–50 microns by solution spinning, drawing, and subsequent crosslinking. Fibers were solution spun in acetone using a 14% copolymer solution in acetic acid with polycarboxylic acid as a crosslinker and sodium hypophosphite as a catalyst. The crosslinks were formed, subsequent to drawing, between reactive amide side groups of the acrylamide moiety of the polymer and the carboxylic acid group of the crosslinker by thermal treatment at 160°C. The transition temperatures of the crosslinked fibers were found to shift towards the lower temperature from 37°C (in linear copolymer) to 22–25°C. These engineered fibers display sharp temperature sensitivity, extremely high reversible change in dimensions (1000% in diameter and ～ 70% in length), and extremely fast response time (< 20 s for expansion and < 2 s for contraction). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 681–688, 2005     

New Methods for the Preparation of Multiply Substituted Cyclopentadienes and Related Compounds

Substituents on cyclopentadienyl ligands significantly influence the reactivity and catalytic efficiency of their transition metal complexes. Therefore, development of synthetic methods for cyclopentadiene derivatives possessing different substituents has been in great demand. In this paper, we report new synthetic methods for multiply substituted cyclopentadienes recently developed in this group. In principle, three types of preparative methods are described. Firstly, zirconacyclopentadienes in the presence of Lewis acids react with aldehydes to afford multiply substituted cyclopentadienes, thus providing a one-pot procedure from two molecules of identical or different alkynes and one molecule of aldehyde; reaction of aluminacyclopentadienes with aldehydes also result in high-yield formation of multiply substituted cyclopentadienes. Secondly, 1,2,3,4-tetrasubstituted 1,4-dilithio- and 1,4-bis(magnesiobromo)-1,3-diene derivatives react with aldehydes or ketones via deoxygenation of the C=O moieties to afford cyclopentadiene derivatives. Thirdly, monolithio reagents, 1,2,3,4-tetrasubstituted 1-lithio-1,3-butadienes, and Grignard reagents, 1,2,3,4-tetrasubstituted 1-magnesiobromo-1,3-butadienes react with aldehydes or ketones to afford cyclopentadiene derivatives upon hydrolysis.     

铁磁性高分子——稳定自由基取代聚合物的研究EI

介绍了稳定自由基取代聚合物作为铁磁性高分子材料的发展概况、种类、结构特点以及制造方法。并对铁磁性高分子材料,尤其是稳定自由基取代的聚丁二炔类聚合物的研究前景进行了较详为细的分析,指出了该领域目前尚存在的问题和发展前景。     

Synthesis and spectral properties of axially substituted zirconium(IV) and hafnium(IV) water soluble phthalocyanines in solutions

Methods of synthesis of novel water soluble axially substituted Zr(IV) and Hf(IV) phthalocyanines with gallic, 5-sulfosalicyllic, oxalic acids, and methyl ester of gallic acid as axial ligands coordinated to the central atom metal of phthalocyanine are presented. The absorption spectra of complex solutions in various solvents were characterized. The dependence of the spectral red shift from Reichardt’s empirical polarity parameter is described. The deviation from the linearity of Beer–Bouguer–Lambert law was investigated for the range of concentration 5×10⁻⁶ to 10×10⁻⁵ M. Fluorescent properties of axially substituted phthalocyaninato metal complexes in DMSO solutions were investigated.