排序方式: 共有81条查询结果,搜索用时 15 毫秒
41.
Shuaishuai Hu Chenfan Xie Yu-Ping Xu Xuelu Chen Dr. Ming-Liang Gao He Wang Prof. Dr. Weijie Yang Prof. Dr. Zhong-Ning Xu Prof. Dr. Guo-Cong Guo Prof. Dr. Hai-Long Jiang 《Angewandte Chemie (International ed. in English)》2023,62(48):e202311625
The selectivity control of Pd nanoparticles (NPs) in the direct CO esterification with methyl nitrite toward dimethyl oxalate (DMO) or dimethyl carbonate (DMC) remains a grand challenge. Herein, Pd NPs are incorporated into isoreticular metal–organic frameworks (MOFs), namely UiO-66-X (X=-H, -NO2, -NH2), affording Pd@UiO-66-X, which unexpectedly exhibit high selectivity (up to 99 %) to DMC and regulated activity in the direct CO esterification. In sharp contrast, the Pd NPs supported on the MOF, yielding Pd/UiO-66, displays high selectivity (89 %) to DMO as always reported with Pd NPs. Both experimental and DFT calculation results prove that the Pd location relative to UiO-66 gives rise to discriminated microenvironment of different amounts of interface between Zr-oxo clusters and Pd NPs in Pd@UiO-66 and Pd/UiO-66, resulting in their distinctly different selectivity. This is an unprecedented finding on the production of DMC by Pd NPs, which was previously achieved by Pd(II) only, in the direct CO esterification. 相似文献
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[反]-β-法尼烯类似物的设计、合成与生物活性研究 总被引:7,自引:0,他引:7
对[反]-β-法尼烯(EBF)类似物的骨架结构原子进行改造,引入吡虫啉系列活性基团,设计合成了13个结构新颖的EBF类似物,并对其生物活性进行了研究.结果表明,这些化合物对蚜虫具有明显的抑制活性,尤其在低浓度时活性更明显,如质量浓度为25mg/L时,I10和I13对蚜虫的抑制率分别为93.1%和87.1%,远高于同浓度下吡虫啉的抑制率(66.7%). 相似文献
43.
The heterotrinuclear compound [PdCu2(tdt)((-dppm)2(MeCN)4](ClO4)2(2/3H2O 1 (tdt = 3,4-toluenedithiolate, dppm = bis(diphenylphosphino)methane) has been prepared and characterized by X-ray structural analysis. Compound 1 crystallizes in trigonal system, space group R3c with a = b = 34.4275(3), c = 32.6700(5) (A), V = 33534.4(7) (A)3, Mr = 1527.21, Z = 18, Dc = 1.361 g/cm3, F(000) = 13974, μ(MoKα) = 1.069 mm-1, the final R = 0.0703 and wR = 0.1389 for 8375 observed reflections with I>2σ(I). The dithiolate tdt displays a chelating and bridging coordination mode, which chelates a PdII and bridges two Cu Ⅰ atoms. The PdⅡ center is located in an approximate square-planar environment with S2P2 donors, and each CuⅠ center exhibits a tetrahedral geometry. 相似文献
44.
Xu HB Shi LX Ma E Zhang LY Wei QH Chen ZN 《Chemical communications (Cambridge, England)》2006,(15):1601-1603
Incorporation of diplatinum complex Pt2(micro-dppm)2(bpyC[triple bond]C)4 or Pt2(mu-dppm)2(phenC[triple bond]C)4 with Ln(hfac)3(H2O)2 (Ln = Nd, Eu, Yb) gave a series of Pt2Ln2 and Pt2Ln4 bimetallic arrays, in which the excitation of d(Pt) -->pi*(R-C[triple bond]C) MLCT absorption induces sensitisation of lanthanide luminescence through efficient d --> f energy transfer from Pt(II) alkynyl chromophores. 相似文献
45.
Two silver(I) complexes were prepared by the reaction of [Ag(C(CPh)]n with NP3 [NP3 = N(CH2CH2PPh2)3] or with NP3 and [Cu(CH3CN)4]ClO4. Complex 1 [(Ag2Cl(NP3)2)(Ag5(C(CPh)6)] contains both NP3 and PhC(C- ligands. The complex cation is (Ag2Cl(NP3)2)+, in which two Ag(NP3)+ cations were bridged by a Cl- donor. The anion is (Ag5(C(CPh)6)-, where five Ag+ ions are linked by six C(CPh- to form a pentanuclear cluster. Complex 2 only contains NP3 ligand, where the silver center adopts a trigonal-bipyramidal geometry. Crystal data for 1: C133H116Ag7Cl3N2P6, Mr = 2789.54, triclinic, space group P, a = 13.0780(2), b = 15.3678(2), c = 31.2041(3) (A), α = 91.3928(7), β = 90.9328(8), γ = 96.0244(4)o, V = 6233.8(1) (A)3, T = 293(2) K, Z = 2, Dc = 1.486 g/cm3, F(000) = 2796, μ = 1.266 mm-1, the final R = 0.0746 and wR = 0.1953 for 16475 observed reflections with I > 2σ(I). Crystal data for 2: C42H42AgClNO4P3, Mr = 861.00, trigonal, space group R3, a = 17.451(1), b = 17.451(1), c = 11.3985(7) (A), V = 3006.0(3) (A)3, T = 293(2) K, Z = 3, Dc = 1.427 g/cm3, F(000) = 1326, μ = 0.731 mm-1, the final R = 0.0251 and wR = 0.0663 for 1499 observed reflections with I > 2σ(I). 相似文献
46.
Zhang LY Zhang HX Ye S Wen HM Chen ZN Osawa M Uosaki K Sasaki Y 《Chemical communications (Cambridge, England)》2011,47(3):923-925
A 1,3-butadiyne-linked diruthenium complex 4 is successfully brought onto the gold surface in a lying flat mode to form self-assembled monolayers (SAMs) showing reversible multiple redox behaviors on the electrode surface. The diruthenium species with different oxidation states, particularly the Ru(2)(III,III) state which is unstable and impossible to isolate from the solution, can be detected by in situ IR spectroscopy. 相似文献
47.
Luo Shu-Qiang Wang Qian Quan Jian Yang Ming Wang Yue Zhang Xu Chen Zhong-Ning 《Transition Metal Chemistry》2021,46(5):415-421
Transition Metal Chemistry - In this work, the synthesis, characterization, and phosphorescent properties of the coordination polymer, {Ag3(dppy)2[μ-SCN]3}n (1), are described. X-ray... 相似文献
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Preparation and characterization of a series of rodlike binuclear ruthenium polyynediyl complexes capped with redox-active organometallic fragments [(bph)(PPh3)2Ru]+ (bph=N-(benzoyl)-N'-(picolinylidene)-hydrazine) or [(Phtpy)(PPh3)2Ru]2+ (Phtpy=4'-phenyl-2,2':6',2' '-terpyridine) have been carried out. The length of the molecular rods is extended by successive insertion of 2,5-thiophene or 1,4-phenylene spacers in the bridging ligands. Oxidation of thiophene-containing Ru2II,II complexes induces isolation of stable Ru2II,III or Ru2III,III species. Electrochemical and UV-vis-NIR spectral studies demonstrate that the polyynediyl bridges with 2,5-thiophene units are more favorable for metal-metal charge transfer compared with those containing the same number of 1,4-phenylene units. Successive increase of thiophene spacers in mixed-valence complexes {RuII}-CC(C4H2S)mCC-{RuIII} (m=1, 2, 3) induced a smooth transition from almost electronic delocalization (m=1) to localization (m=3). For binuclear ruthenium complexes with intramolecular electron transfer transmitted across nine Ru-C and C-C bonds, electronic conveying capability follows {Ru}-CC(CC)2CC-{Ru}>{Ru}-CC(C4H2S)CC-{Ru}>{Ru}-CC(C6H4)CC-{Ru}>{Ru}-CC(CH=CH)2CC-{Ru}. It is revealed that molecular wires capped with electron-rich (bph)(PPh3)2Ru endgroups are much more favorable for electronic communication than the corresponding electron-deficient (Phtpy)(PPh3)2Ru-containing counterparts. The intermetallic electronic communication is fine-tuned by modification of both the bridging spacers and the ancillary ligands. 相似文献
50.
Duan Ping Liu Junyang Wang Jin-Yun Qu Kai Cai Shuning Wang Fei Chen Lichuan Huang Xiaoyan Li Ruihao Shi Jia Zhang Qian-Chong Hong Wenjing Chen Zhong-Ning 《中国科学:化学(英文版)》2020,63(4):467-474
Seeking the strategies of designing highly conductive molecular structures is one of the core researches in molecular electronics.As asymmetric structure has manifested feasible properties in comprehensive fields, we introduce the structures of asymmetric platinum(Ⅱ) complexes into the charge transport study at single-molecule scale for the first time. The single-molecule conductance measurement results reveal that, in platinum(Ⅱ)-aryloligoynyl structures, the conductance of asymmetrically coordinated complexes is obviously higher than that of the symmetric isomers with the same molecular length, while the conductance is almost identical in symmetric and asymmetric platinum(Ⅱ)-oligoynyl complexes. Theoretical study uncovers that, upon connecting to the oligoynyl structure, the aromatic group effectively extends the π-system of the whole conductive backbone and gathers the HOMO population mainly on the longer oligoynyl ligand, which reduces the energy barrier in electron transport and enhances the conductance through HOMO energy lifting. This result provides feasible strategy for achieving high conductive molecular devices. 相似文献