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Uwe Ruschewitz 《无机化学与普通化学杂志》2006,632(5):705-719
The first alkali metal transition metal acetylides of general composition A2M0C2 (A = Na ? Cs, M0 = Pd, Pt) were obtained by solid state reactions of alkali metal acetylides with palladium and platinum. They are characterized by chains, which are separated by alkali metal ions. Analogous chains also separated by alkali metal ions are the characteristic structural feature of acetylides of composition AMIC2, which are accessible by reacting AC2H with MII in liquid ammonia (A = Li ? Cs, MI = Cu, Ag, Au). Despite their structural similarities they possess different properties, as acetylides of composition A2M0C2 are semiconductors with very small indirect band gaps and slightly extended C–C distances compared to a C–C triple bond, whereas acetylides of composition AMIC2 show a typical salt‐like behavior with C–C distances close to the expected value for a C–C triple bond of 120 pm. But with the help of simple chemical models these differences can be made plausible. Furthermore, it is shown that only by a combination of different methods (powder diffraction with X‐rays and neutrons, solid state NMR spectroscopy, Raman spectroscopy) it was possible to characterize this new class of compounds structurally and chemically. 相似文献
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Dr. Fanping Huang Zhewei Yan Xuejuan Zheng Yapeng Cai Prof. Dr. Hong Zhang Prof. Dr. Haiping Xia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(54):e202201229
A novel one-pot reaction producing a metal vinylidene structure in a five-membered ring by cyclization of a multiyne has been achieved. The ring strain and the high stability of the cyclic metal vinylidene complexes have been analyzed experimentally and computationally. The metal vinylidene unit in a fused-ring complex is unreactive to both nucleophiles and electrophiles. It reacts however at the nearby carbonyl group achieving the unprecedented conversion of metal tributing factors for the aromaticity-driven process has been studied by DFT calculations. 相似文献
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Pedro MaroteBernard Durand Jean-Pierre Deloume 《Journal of solid state chemistry》2002,163(1):202-209
Zirconia powders are prepared by reaction of a zirconium precursor with an alkali metal nitrate. The major part of the reactions takes place before the melting points and then the reactions go slowly to completion at 450°C in the molten salts. The roles of the precursor and the alkali metal ion are discussed considering the reaction between two precursors, octahydrated zirconium oxychloride and zirconium tetrachloride, and two nitrates, LiNO3 and NaNO3, and some resulting physico-chemical differences. The obtained zirconia powders contain very small amounts of alkali metal ions which act as stabilizing agent. Their effect on the balance tetragonal-monoclinic ZrO2 depends upon the homogeneity of their distribution which is related to their ability to diffuse inside the bulk of particles and their polarizing power when located mainly on the surface. 相似文献
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HOU Peng HAN Dong-xue NIU Li LIN Hai-bo 《高等学校化学研究》2006,22(4):493-499
IntroductionPlatinumand gold surfaces can adsorb a wide vari-ety of ions, atoms and molecular functional groups,which is often accompanied by oxidation-reduction ordissociation of them. Numerous previous works havemade great progress in studying the surfa… 相似文献
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Stephan Ludwig Dr. Kai Helmdach Mareike Hüttenschmidt Elisabeth Oberem Dr. Jabor Rabeah Dr. Alexander Villinger Prof. Dr. Ralf Ludwig Prof. Dr. Wolfram W. Seidel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(70):16811-16817
A pair of diastereomeric dinuclear complexes, [Tp′(CO)BrW{μ-η2-C,C′-κ2-S,P-C2(PPh2)S}Ru(η5-C5H5)(PPh3)], in which W and Ru are bridged by a phosphinyl(thiolato)alkyne in a side-on carbon P,S-chelate coordination mode, were synthesized, separated and fully characterized. Even though the isomers are similar in their spectroscopic properties and redox potentials, the like-isomer is oxidized at W while the unlike-isomer is oxidized at Ru, which is proven by IR, NIR and EPR-spectroscopy supported by spectro-electrochemistry and computational methods. The second oxidation of the complexes was shown to take place at the metal left unaffected in the first redox step. Finally, the tipping point could be realized in the unlike isomer of the electronically tuned thiophenolate congener [Tp′(CO)(PhS)W{μ-η2-C,C′-κ2-S,P-C2(PPh2)S}Ru(η5-C5H5)-(PPh3)], in which valence trapped WIII/RuII and WII/RuIII cationic species are at equilibrium. 相似文献
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金属离子在细菌浸取金属硫化矿中的催化作用 总被引:13,自引:1,他引:13
用氧化亚铁硫杆菌浸取某低品位原生硫化矿中Cu、Ni时,金属离子对细菌浸矿有明显的催化作用.金属离子(Ag+,Hg2+,Co2+,Bi3+)能显著提高细菌浸出Cu、Ni的浸出率.对细菌浸Cu而言,金属离子催化能力排序为:Ag+Co2+>Bi3+>Hg2+;对浸Ni,其排序则为:Bi3+>Ag+>Co2+>Hg2+.金属离子的浓度、性质及矿石粒度等影响金属离子的催化能力.金属离子的催化作用机理与其性质、矿物结构及细菌氧化作用等因素有关 相似文献
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Hyeonbin Ha Youngik Kim Dopil Kim Jihyun Lee Yoodae Song Suyeon Kim Prof. Dr. Myung Hwan Park Prof. Dr. Youngjo Kim Hyungjun Kim Prof. Minyoung Yoon Prof. Dr. Min Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(63):14414-14420
The effect of metal on the degree of flexibility upon evacuation of metal–organic frameworks (MOFs) has been revealed with positional control of the organic functionalities. Although Co-, Cu-, and Zn-based DMOFs (DMOF = DABCO MOF, DABCO = 1,4-diazabicyclo[2.2.2]octane) with ortho-ligands (2,3-NH2Cl) have frameworks that are inflexible upon evacuation, MOFs with para-ligands (2,5-NH2Cl) showed different N2 uptake amounts after evacuation by metal exchange. Considering that the structural analyses were not fully sufficiently different to explain the drastic changes in N2 adsorption after evacuation, quantum chemical simulation was explored. A new index (η) was defined to quantify the regularity around the metal based on differences in the oxygen-metal-oxygen angles. Within 2,5-NH2Cl, the η value becomes larger as the metal are varied from Co to Zn. A large η value means that the structures around the metal center are less ordered. These results can be used to explain flexibility changes upon evacuation by altering the metal cation in this regioisomeric system. 相似文献
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Alec Kirkeminde Stan Spurlin Laura Draxler‐Sixta Jamie Cooper Prof. Shenqiang Ren 《Angewandte Chemie (International ed. in English)》2015,54(14):4203-4207
Nanocrystalline metals have received widespread interest and found various applications owing to their magnetic and catalytic properties and in energy‐related fields. A flexible approach for the growth of nanoalloys with controlled properties and well‐defined structures on the atomic scale is thus greatly desired. A new synthetic method that avoids incompatible reduction potentials and rates would be critical to grow metal nanostructures with high purities and the desired stoichiometries. A metal‐redox strategy that employs spontaneous oxidation/reduction reactions to grow nanocrystalline alloys using molecular‐scale zerovalent metal precursors is now described. The selection of suitable zerovalent metal species allows for thermodynamic control of the compositional stoichiometry during the temperature‐dependent formation of the metal alloy nanoparticles. A practical and scalable strategy for nanoalloy growth that can potentially produce key metal components of superior metallurgical quality for catalytic and magnetic systems has thus been developed. 相似文献
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Summary A convenient synthesis of the ligand ethylenediaminetetraacetamide (L) is described, and a number of metal complexes of the general formula MLCln · xH2O (Mn+=CaII, MnII, FeII, CoII, NII, CuII, ZnII, MgII, BaII, CdII, HgII and LaIII) prepared. The deprotonated Cu(L-H)2 · 2 H2O complex has been characterised and the associated pK values determined. I.r., conductivity, magnetic susceptibility and electronic spectral data are discussed. 相似文献
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Summary A number of metal complexes of the ligand tetramethylethylenediaminetetraacetate [Edta(OMe)4 = L] have been characterised. The complexes may be formulated MLCl2 · xH2O where M2+ = MnII, FeII, CoII, NiII, CuII, CdII, HgII and SnII. I.r., conductivity, magnetic susceptibility and electronic spectral data are discussed. 相似文献
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Metal–metal bonded dinuclear compounds of Group 6 and 7 transition metals with several primary structural motifs and their reactivity toward halides and organic molecules are reviewed. The reactivities of dinuclear compounds of Cr, Mo, W, Mn, Tc, and Re are discussed in context with reaction types (ligand metathesis, oxidative addition), the types of ligands (carbon, sulfur or nitrogen containing), or the ligand substituted in the original starting material (carbonyl). Since the depth and breadth of the chemistry is extensive, the categories are fairly general and some overlap between ligand types and reaction types occurs. A brief history followed by recent studies of each of these transition metal centers provides a general overview of the reactivity of these metal–metal bonded systems. 相似文献
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报道了有关金属和金属氧化物之间热反应的实验,经研究发现,一种金属都能在高温下夺取另一种金属性比它弱的金属氧化物中的氧,能够将另一种金属从氧化物中还原出来。 相似文献