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排序方式: 共有490条查询结果,搜索用时 375 毫秒
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The reaction of methylphosphine sulfide, MeP(S)(3,5-Me2Pz)2, 1, with anhydrous CuCl2 affords a tetranuclear copper cluster[Cu2Cl2(3,5-Me2Pz)3(MePO3)]2, 2, and a dinuclear compound Cu2Cl4(3,5-Me2Pz)4, 3. This reaction involves a metal-assisted desulfurization along with concomitant hydrolysis of P-N bonds. The X-ray structures of 1-3 have been determined, and the crystal parameters for these are the following. 1: space group = C2/c, a = 15.2552(1) A, b = 8.7364(2) A, c = 21.4490(3) A, beta = 93.349(1) degrees, V = 2853.74(8) A3, and Z = 8. 2: space group = P2(1)/n, a = 12.5964(4) A, b = 15.7773(4) A, c = 13.9781(4) A, beta = 116.6280(10) degrees, V = 2483.32(12) A3, and Z = 2. 3: space group = P2(1)/c, a = 8.7137(8) A, b = 13.5493(14) A, c = 11.8847(12) A, beta = 106.179(2) degrees, V = 1347.6(2) A3, and Z = 2. The structure of 2 shows that it comprises two dinuclear copper cores bridged together by two tripodal methylphosphinate, MePO3, ligands. 2 is weakly antiferromagnetically coupled, as revealed by variable temperature magnetic susceptibility measurements. 相似文献
4.
[reaction: see text] A new Pd(0) complex of a pendant cyclophosphazene-containing cross-linked polymer is found to be an effective heterogeneous catalyst for the Heck arylation reaction. The catalyst is robust and can be recycled without significant loss of activity. 相似文献
5.
The near-diffusion-controlled reactions of hydroxyl radical, hydrated electron, and hydrogen atom with platinum macrocyclic complex ions in aqueous media have been studied using pulse radiolysis in conjunction with UV-visible absorption and conductivity detection. The hydrated electron and hydrogen atom react with trans-[Pt(cyclam)(Cl)(2)](2+) where cyclam is 1,4,8,11-tetraazacyclotetradecane to yield platinum(III) transients that exhibit intense absorption peaks in the 280-300 nm region; however in the case of the H-atom, the reaction involves a competition between chloride abstraction and a minor process, suggested to be attack on the organic ligand. The platinum(III) products are kinetically labile toward loss of chloro ligands, but these reactions are reversible in the presence of added KCl. The reactions of hydroxyl radical with [Pt(cyclam)](2+) and with [Pt(tmc)](2+), where tmc is 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, lead to platinum(III) intermediates absorbing in the 250-300 nm region. Depending on the presence or absence of added KCl and on the pH, the platinum(III) cyclam systems can react to form a product(s) exhibiting absorption peaks near 330 and 455 nm, and this species is proposed to be a long-lived amidoplatinum(III) complex. In support of this proposal is the observation that the tmc system does not give rise to a similar visible-absorbing product. The interrelations of the cyclam-based transients through acid-base, chloro-substitution and water-elimination processes are discussed. 相似文献
6.
Zhu H Chai J Chandrasekhar V Roesky HW Magull J Vidovic D Schmidt HG Noltemeyer M Power PP Merrill WA 《Journal of the American Chemical Society》2004,126(31):9472-9473
The reaction of beta-diketiminated aluminum(I) monomer LAl with a large bulky azide N3Ar' (L = HC(CMeNAr)2, Ar' = 2,6-Ar2C6H3, Ar = 2,6-iPr2C6H3) in the temperature range from -78 degrees C to room temperature affords two different isomers 2 and 3, which have been characterized by spectroscopic and X-ray structural analyses, as well as elemental analysis. The variable-temperature 1H NMR kinetic studies of this reaction indicate the existence of the monomer LAlNAr' (1) at low temperature and the thermal stability of the compounds increases in the order of 1 < 2 < 3. 相似文献
7.
Chandrasekhar S Jagadeshwar V Saritha B Narsihmulu C 《The Journal of organic chemistry》2005,70(16):6506-6507
A combination of Pd(OAc)2 (5 mol %), PPh3 (10 mol %), and Et3B (200 mol %) promotes the formation of allyl phenyl sulfones from the allylic alcohols directly with excellent yields under mild conditions. The activation of an alcohol group is not necessary which is achieved in situ. The conjugated dienols also were equally effective for the said transformation. 相似文献
8.
Total synthesis of (-)-lentiginosine was achieved from D-mannitol using highly stereoselective reactions. Similarly, (+)-lentiginosine was synthesized from L-tartaric acid. 相似文献
9.
Chandrasekhar S Narsihmulu Ch Reddy NR Sultana SS 《Chemical communications (Cambridge, England)》2004,(21):2450-2451
We demonstrate for the first time, L-proline as a chiral catalyst for transfer aldol reaction between aldehydes and diacetone alcohol. 相似文献
10.
Utilization of one waste material to control pollution caused by another is of high significance in the remediation of environmental
problems. Rice husk, an abundantly available agricultural waste, can be used as a low cost adsorbent for dyes and heavy metals
in effluent streams. The possible utilization of rice husk ash as an adsorbent for methylene blue dye from aqueous solutions
has been investigated. Ash samples from husks of two origins were prepared at different temperatures and their physical, chemical
spectroscopic and morphological properties were determined. XRD, FTIR and SEM were some of the techniques adopted for the
characterization. The samples were also analyzed for bulk density, pH, nitrogen adsorption properties and lime reactivity.
Experiments of methylene blue adsorption on the ash samples were conducted using batch technique and a comparative study was
made. Results were analyzed using linear, Langmuir and Freundlich isotherms. The values of separation factor indicate that
most of the ash samples do adsorb the dye molecules, but in varying quantities. Calcination at 900∘C reduces the adsorption capacity of the ash to a great extent. Regression analysis shows that the experimental data fits
both Langmuir and Freundlich isotherms for certain concentration limits. The adsorbate species are most probably transported
from the bulk of the solution into the solid phase through intra-particle diffusion process. Kinetics of adsorption was found
to follow pseudo second order rate equation with R
2∼ 0.99. The highest adsorption capacity (Q
0) achieved is found to be ∼690 mg/g, which is even higher than the values reported for activated carbon from rice husk. The
adsorption capacity of the ash samples are in good agreement with their surface area and pore volume. 相似文献