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排序方式: 共有2047条查询结果,搜索用时 15 毫秒
1.
Mitsuki Yamashita Yuna Kawasumi Yuki Tachibana Dr. Shinnosuke Horiuchi Dr. Koji Yamamoto Prof. Tetsuro Murahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(5):1212-1216
Although small cyclic- and open-chain unsaturated hydrocarbon anions such as cyclopentadienide and open-chain pentadienide are used as the strongly electron-donating auxiliary ligands for metal complexes, more extended π-conjugated unsaturated hydrocarbon anions have rarely been used in coordination chemistry, despite their potential ability to serve as the multiply bridging π-ligands for metal clusters. This work reports isolation of metal chain clusters bearing the multi-dentate, open-chain extended unsaturated hydrocarbon anion ligands. The extended open-chain π-conjugated polyenyl ligands could effectively stabilize oxidized palladium chains, including an unprecedented [Pd4]4+ chain. 相似文献
2.
Hideaki Murasugi Dr. Shohei Kumagai Dr. Hiroaki Iguchi Prof. Dr. Masahiro Yamashita Dr. Shinya Takaishi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9885-9891
Crystal structures of a series of organic–inorganic hybrid gold iodide perovskites, formulated as A2[AuII2][AuIIII4] [A=methylammonium (MA) ( 1 ) and formamidinium (FA) ( 2 )], A′2[I3]1−x[AuII2]x[AuIIII4] [A′=imidazolium (IMD) ( 3 ), guanidinium (GUA) ( 4 ), dimethylammonium (DMA) ( 5 ), pyridinium (PY) ( 6 ), and piperizinium (PIP) ( 7 )], systematically changed depending on the cation size. In addition, triiodide (I3−) ions were partly incorporated into the AuI2− sites of 3 – 7 , whereas they were not incorporated into those of 1 and 2 . Such a difference comes from the size of the organic cation. Optical absorption spectra showed characteristic intervalence charge-transfer bands from AuI to AuIII species, and the optical band gap increased as the size of the cation became larger. 相似文献
3.
Tsutomu KumagaiMasaaki Tomura Jun-ichi NishidaYoshiro Yamashita 《Tetrahedron letters》2003,44(36):6845-6848
1,3-Dithiol-2-ylidene derivatives containing bis(ethynylpyridine) units were synthesized using a Pd-catalyzed reaction of the corresponding dibromide. X-Ray crystal analysis revealed unique crystal structures depending on the aromatic groups. The absorption spectra and redox properties indicated intramolecular charge-transfer interactions between the 1,3-dithiole unit and the pyridyl parts. 相似文献
4.
Yamashita Hiromi Ariyuki Masao Yoshizawa Katsuhiro Kida Keiko Ohshiro Satoshi Anpo Masakazu 《Research on Chemical Intermediates》2004,30(2):235-245
The photocatalytic reactivities of chromium-containing mesoporous silica molecular sieves (Cr-HMS) under visible light irradiation have been investigated. Cr-HMS involves tetrahedral chromium oxide (Cr-oxide) moieties which are highly dispersed and incorporated in the framework of molecular sieve with two terminal Cr=O groups. In the presence of propane with molecular oxygen, a partial oxidation proceeded under visible light irradiation to produce acetone and acrolein, with high selectivity, while a complete oxidation proceeded under UV light irradiation mainly to produce CO2. The charge-transfer excited state of the tetrahedral Cr-oxide moieties plays a significant role in the photocatalytic reactions. 相似文献
5.
In this paper we focus on the problem of identifying the index sets P(x):=i|xi>0, N(x):={i|Fi(x)>0 and C(x):=i|xi=Fi(x)=0} for a solution x of the monotone nonlinear complementarity problem NCP(F). The correct identification of these sets is important from both theoretical and practical points of view. Such an identification enables us to remove complementarity conditions from the NCP and locally reduce the NCP to a system which can be dealt with more easily. We present a new technique that utilizes a sequence generated by the proximal point algorithm (PPA). Using the superlinear convergence property of PPA, we show that the proposed technique can identify the correct index sets without assuming the nondegeneracy and the local uniqueness of the solution.This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan.Mathematics Subject Classification (2000): 90C33, 65K10 相似文献
6.
7.
A spinel-type structure was found in cadmium stannate CdSnO3 prepared by thermal decomposition of the hydroxostannate CdSn(OH)6 at 550–800°C. Its occurrence depends strongly on the precipitation conditions of CdSn(OH)6 from CdCl2 and Na2Sn(OH)6 aqueous solutions. In the (Cd1–xCax)SnO3 system, the spinel phase appears in the composition range of 0.0 ≤ x ≤ 0.35. The experimental results suggest the presence of cation vacancies in the spinel octahedral sites. 相似文献
8.
Hoon Kim Toshihiko Koseki Tomohiro Ohta Hiroshi Sato Yukihiro Shimogaki 《Applied Surface Science》2006,252(11):3938-3942
The adhesion of Cu on Ru substrates with different crystal orientations was evaluated. The crystal orientation of sputter deposited Ru could be changed from (1 0 0) to (0 0 1) by annealing at 650 °C for 20 min. The adhesion of Cu was evaluated by the degree of Cu agglomeration on Ru. Cu films on annealed Ru films with the (0 0 1) crystal orientation showed 28% lower RMS values and 50% lower Ru surface coverage than Cu as-deposited on Ru having the (1 0 0) crystal orientation after annealing at 550 °C for 30 min, which suggest that Cu wettability on the Ru(0 0 1) was better than that on the Ru(1 0 0) plane. The low lattice misfit of 4% between Cu(1 1 1) and Ru(0 0 1) may be the reason for this good adhesion property. 相似文献
9.
10.
S. Takahashi T. Yamashita H. Imamura S. Maekawa 《Journal of magnetism and magnetic materials》2002,240(1-3):100-102
The effect of spin relaxation on tunnel magnetoresistance (TMR) in a ferromagnet/superconductor/ferromagnet (FM/SC/FM) double tunnel junction is theoretically studied. The spin accumulation in SC is determined by balancing of the spin-injection rate and the spin-relaxation rate. In the superconducting state, the spin-relaxation time τs becomes longer with decreasing temperature, resulting in a rapid increase of TMR. The TMR of FM/SC/FM junctions provides a useful probe to extract information about spin-relaxation in superconductors. 相似文献