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991.
Koji Takagi Hyunho Joo Yusuke Yamashita Eiki Kawagita Chikako Torii 《Journal of polymer science. Part A, Polymer chemistry》2011,49(18):4013-4020
2,5‐Dibromo‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene ( DBPyTh ) was synthesized by the Suzuki coupling reaction between two aromatic compounds followed by the bromination. The Grignard metathesis reaction of DBPyTh with isopropylmagnesium chloride proceeded in 85% conversion and the regioselective halogen–metal exchange at the 2‐position was confirmed. Namely, 5‐bromo‐2‐chloromagnesio‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene and 2‐bromo‐5‐chloromagnesio‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene were generated in 90:10 molar ratio. Subsequently, the Kumada coupling polymerization was carried out using 1,3‐bis(diphenylphosphinopropane)nickel(II) dichloride to obtain poly(3‐(6′‐hexylpyridine‐2′‐yl)thiophene) ( PolyPyTh ). The polymer molecular weight could be roughly controlled by the catalyst concentration and the molecular weight distribution ranged from 1.25 to 1.80. The gas chromatograph analysis indicated that 5‐bromo‐2‐chloromagnesio‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene was preferentially polymerized in 90% conversion and the percentage of the head‐to‐tail content (regioregularity) was calculated to be 96%. The matrix‐assisted laser desorption/ionization time‐of‐fright mass spectrum indicated that both polymer chain ends were substituted with the hydrogen atom. The absorption maxima of polymer in CHCl3 and thin film were observed at 447 and 457 nm, respectively, which were blue‐shifted compared with poly(3‐(4′‐octylphenyl)thiophene). From the CV measurement of the polymer thin film, highest occupied molecular orbital (HOMO) (?5.31 eV) and lowest unoccupied molecular orbital (LUMO) (?3.76 eV) energy levels were calculated from the oxidation and reduction onset potentials, respectively, and the electrochemical band gap energy was determined to be 1.62 eV. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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993.
Frontispiece: Control of the Spin Dynamics of Single‐Molecule Magnets by using a Quasi One‐Dimensional Arrangement 下载免费PDF全文
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995.
Successive structural transitions of KCdF3 and K0.5Rb0.5CdF3 have been studied by means of thermal diffusivity, polarized light scattering and X-ray diffraction. It is found that transitions occur at about 460 K and 475 K in KCdF3, and at 222 K, 232 K, 250 K, 258 K and 268 K in K0.5Rb0.5CdF3. The partial exchange between K+ and Rb+ ions gives rise to simultaneous condensation of the Mz 3 and Rx 25 soft phonons. 相似文献
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998.
Seiji Akiyama Kaito Yamada Makoto Yamashita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11932-11936
Lithium and magnesium salts of tetra(o‐tolyl)diborane(4) dianion, having B=B double bond character, were synthesized. It was clarified that the lithium salt of the dianion has a high‐lying HOMO and a narrow HOMO–LUMO gap, which were perturbed by dissociation of Li+ cation, as judged by UV/Vis spectroscopy and DFT calculations. The lithium salt of the dianion reacted as two equivalents of a diarylboryl anion with CH2Cl2 or S8 to give boryl‐substituted products. 相似文献
999.
Hitoshi Miyasaka Prof. Karin Takayama Ayumi Saitoh Sachie Furukawa Masahiro Yamashita Prof. Rodolphe Clérac Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(12):3656-3662
Two one‐dimensional compounds composed of a 1:1 ratio of MnIII salen‐type complex and NiII oximato moiety with different counter anions, PF6? and BPh4?, were synthesized: [Mn(3,5‐Cl2saltmen)Ni(pao)2(phen)]PF6 ( 1 ) and [Mn(5‐Clsaltmen)Ni(pao)2(phen)]BPh4 ( 2 ), where 3,5‐Cl2saltmen2?=N,N′‐(1,1,2,2‐tetramethylethylene)bis(3,5‐dichlorosalicylideneiminate); 5‐Clsaltmen2?=N,N′‐(1,1,2,2‐tetramethylethylene)bis(5‐chlorosalicylideneiminate); pao?=pyridine‐2‐aldoximate; and phen=1,10‐phenanthroline. Single‐crystal X‐ray diffraction study was carried out for both compounds. In 1 and 2 , the chain topology is very similar forming an alternating linear chain with a [‐MnIII‐ON‐NiII‐NO‐] repeating motif (where ‐ON‐ is the oximate bridge). The use of a bulky counteranion, such as BPh4?, located between the chains in 2 rather than PF6? in 1 , successfully led to the magnetic isolation of the chains in 2 . This minimization of the interchain interactions allows the study of the intrinsic magnetic properties of the chains present in 1 and 2 . While 1 and 2 possess, as expected, very similar paramagnetic properties above 15 K, their ground state is antiferromagnetic below 9.4 K and paramagnetic down to 1.8 K, respectively. Nevertheless, both compounds exhibit a magnet‐type behavior at temperatures below 6 K. While for 2 , the observed magnetism is well explained by a Single‐Chain Magnet (SCM) behavior, the magnet properties for 1 are induced by the presence in the material of SCM building units that order antiferromagnetically. By controlling both intra‐ and interchain magnetic interactions in this new [MnIIINiII] SCM system, a remarkable AF phase with a magnet‐type behavior has been stabilized in relation with the intrinsic SCM properties of the chains present in 1 . This result suggests that the simultaneous enhancement of both intrachain (J) and interchain (J′) magnetic interactions (with keeping J ? J′), independently of the presence of AF phase might be an efficient route to design high temperature SCM‐based magnets. 相似文献
1000.
Sakurai K Fukumoto T Noguchi K Sato N Asaka H Moriyama N Yohda M 《Organic letters》2010,12(24):5732-5735
The 3D structures of an antitumor glycosylsterol OSW-1 and its closely related congener were investigated by NMR studies and an X-ray crystallographic analysis. The disaccharide moiety was found as a structural scaffold for the formation of a hydrophobic cluster by the biologically required functionalities. 相似文献