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1.
Mn(CO)5M′(CO)3DAB complexes (M′ = Mn, Re; DAB = R1N=C(R2)-C(R′2)=NR1) can be easily obtained from the reaction between Mn(CO)5? and M′(CO)3X(DAB) (M′ = Mn, Re; X = Cl, Br, I). The complexes are formed by a nucleophilic mechanism, while a redistribution is responsible for the formation of a small amount of Mn2(CO)10.A diastereotopic effect can be observed in the 1H and 13C NMR spectra of complexes having isopropyl groups attached to the DAB ligand skeleton. A comparison is made with mononuclear complexes of the same symmetry, and the chemical shift differences for the methyl groups strongly depend on the substituent on the central metal responsible for the asymmetry.The low temperature enhancement of the σ → σ★ transition localised on the metal—metal bond, which is normally observed for this type of compounds, was not observed for the Mn(CO)5M′(CO)3(DAB) complexes. The metal—metal bond can be activated by irradiating at the wave lengths associated with the CT transitions between the metal and the DAB ligand. Metal—metal bond cleavage occurs and Mn2(CO)10 is formed. 相似文献
2.
Lee R. Collins Gabriele Hierlmeier Dr. Mary F. Mahon Dr. Ian M. Riddlestone Prof. Michael K. Whittlesey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3215-3218
The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH3 and P4. Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6‐MesDAC‐R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6‐MesDAC)MR2], exhibiting barriers to migratory insertion which increase in the order MR2 = ZnEt2 < ZnMe2 < CdMe2. Compound [(6‐MesDAC‐Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β‐H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M‐R, M‐H). 相似文献
3.
The solid state reactions of MMoO4 (M = Mg2+, Fe2+, and Ni2+) and orthorhombic TeO2 were investigated. A new metal telluromolybdate MgTeMoO6 was obtained in the case of Mg; its structure belongs to the orthorhombic system with unit-cell dimensions a = 5.262Å, b = 5.028 Å, c = 8.880 Å. Fe2(MoO4)3 and a new compound were formed in the case of Fe. The new compound is made up with Fe3+ ions and its chemical formula cannot be recognized as FeTeMoO6. In the case of Ni a complex reaction mixture is obtained. An explanation is given of the ability of M2+ ions to form the metal telluromolybdates. The catalytic properties of MgTeMoO6 are discussed and compared to those of the other metal telluromolybdates. 相似文献
4.
New Alkaline‐Earth Metal Phosphides and Arsenides of Cobalt Five new compounds of cobalt were prepared by heating mixtures of the elements and investigated by means of single crystal X‐ray methods. Mg2Co12As7 (a = 12.096(6), b = 3.670(2), c = 24.93(1) Å) crystallizes in a new structure type (Pnma; Z = 4). Most of the Co atoms are coordinated tetrahedrally by arsenic, the other ones in the form of a square pyramid. Due to the linking of these polyhedra channels of hexagonal cross section are formed along [010], in which the Mg atoms are arranged. Mg2Co12P7 (a = 9.012(2), c = 3.504(1) Å), Ca2Co12P7 (a = 9.073(1), c = 3.585(1) Å) as well as Ca2Co12As7 (a = 9.428(5), c = 3.728(2) Å) crystallize in the Zr2Fe12P7 structure type (P6; Z = 1). Micro domains of the arsenide required refinements of the structure parameters in space group P63/m. MgCo6P4 (a = 6.609(1), c = 3.380(1) Å) is isotypic with LiCo6P4 (P6m2; Z = 1). The compounds belong to the large family of phosphides and arsenides with a metal : non‐metal ratio of about 2 : 1. Their structures can be described by the linkings of non‐metal centred trigonal prisms of metal atoms with additional metal atoms capping the rectangular faces of the prisms. 相似文献
5.
When the trimethyl derivatives of aluminium, gallium and indium react with glyoximato metallates, (R2C2N2(O)OH)2MetII (R = H, CH3; MetII = Ni, Pd, Pt, Cu), in a molar ratio, 2 mol of methane are evolved and monomeric bis(dimethylmetal(III)glyoximato)metallates(II) (metal(III) = Al, Ga, In) are formed in high yields. The vibrational and NMR spectra of the new complexes were measured and were partly resolved. The X-ray structure determinations of two of these compounds show non-planar structures of approximate C2h and C2 symmetry, respectively, with weak metal(III)?metal(II) π-interactions. 相似文献
6.
Crystals of ordered Ba6EuF12Cl2 were found to form during high temperature flux growth. The structure was refined in the hexagonal space group P 6 to RF(R ) = 0.024(0.024) for 326 reflections and 46 parameters. Lattice parameters are a = b = 1059.27(8) pm and c = 416.36(2) pm; Z = 1. The structure is isotypic to Ba7F12Cl2. No solid solution of Ba/Eu was observed, the Eu2+ ions are located in the channels formed by 3 + 6 fluorine ions, occupying only one of the three metal sites of the Ba7F12Cl2 structure. 相似文献
7.
Preparation and Properties of Alkalimetal-Benzene-1,4-dicarbotetrathioates. The Crystal Structure of K2[S2C? C6H4? CS2] · 2 H2O By oxidation of α,α′-dichloro-p-xylene with elemental sulfur alkali metal salts of tetrathioterephthalic acid (H2TTTP) are formed. The complexing properties of the bischelating TTTP-dianion are investigated. Only one stable complex, the dimeric [(CO)5Mn]2TTTP, was obtained so far. K2TTTP crystallizes with a = 744.1(2), b = 1322.1(3), c = 691.5(2) pm, β = 106.11(2)°, Z = 2. The centrosymmetric dianion is nonplanar. 相似文献
8.
The nonhybrid OPBE/TZVP density functional theory (DFT) method and the Gaussian09 program package were used to calculate the thermodynamic and geometric parameters of asymmetric macrocyclic M(II) complexes with three six-membered metal rings and (NNNN)-coordination of the donor sites of the ligand. The complexes are formed upon self-assembly (template synthesis) of hexacyanoferrates(II) of the corresponding M(II), propanedithioamide H2N-C(=S)-CH2-C(=S)-NH2, and formaldehyde H2C(=O) in gelatin-immobilized matrix implants. Note that complexes of this type are formed only for M = Ni, Cu, and Zn, while for M = Mn, Co, and Fe, these compounds are unstable. Bond lengths and bond and torsion angles are presented. In each of these complexes, both the MN4 chelate units and the N4 units and all sixmembered metal rings were found to be non-coplanar. 相似文献
9.
Monomeric Dialkyl Metal Complexes of the R2M(NR′)2XR Type with M = Al, Ga, In, Tl; X = S, C and R, R′ = Alkyl and Silyl N,N′-Bis(trimethylsilyl)sulfurdiimide reacts with the trimethyl derivatives of aluminium, gallium, and indium within insertion. Hereby monomeric sulfinic acid imidamidates Me2M(NSiMe3)2SMe (Me = CH3) are formed. The lithium amidinates Li(NR′)2CMe (R′ = i-C3H7 and SiMe3) are formed likewise by insertion reactions with LiMe and the corresponding carbodiimides R′N?C?NR′ and were used in reactions with R2MCl (M = Al to Tl) to synthesize dialkyl metal amidinates R2M(NR′)2CMe. The NMR (1H and 13C) and the vibrational spectra (IR and Raman) are discussed and applied to describe the structure of these chelat complexes. 相似文献
10.
2‐Mercapto‐methyltetrazolate, Smetetraz–, acts as monoanionic, monodentate ligand in a number of technetium compounds. Anionic TcV complexes of the types [TcO(Smetetraz)4]– and [TcN(Smetetraz)4]2– are formed when (Bu4N)[TcVOCl4] or (Bu4N)[TcVINCl4], respectively, react with Na(Smetetraz). Reduction of the metal takes place in the latter case. (Bu4N)2[TcN(Smetetraz)4] crystallises in the monoclinic space group Pc (a = 9.701(5), b = 17.570(5), c = 16.821(10) Å, β = 96.50(3)°, Z = 2). The Tc atom is situated 0.580(3) Å above the basal plane of a square pyramid which is formed by the sulfur atoms and the nitrido ligand as its apex. The Tc–S bond lengths lie between 2.384(3) and 2.410(3) Å. [Tc(PPh3)(Smetetraz)3(CH3CN)] is formed during the reaction of [TcCl3(PPh3)2(CH3CN)] with NaSmetetraz as blue needles with co‐crystallised solvent toluene (space group C2/c, a = 24.188(4), b = 14.373(1), c = 25.617(5) Å, β = 109.48(1)°, Z = 8). The metal atom is coordinated by PPh3 and CH3CN in the axial position of a trigonal bipyramid. All three aryl rings are on the sterically less strained side of the plane defined by the sulfur atoms. The Tc–S bond lengths range between 2.233(2) and 2.247(2) Å. 相似文献
11.
High, electrochemically controlled electrical conductivity (0.2–0.3 S cm?1) was measured for the first time for the metal–metal bonded polymeric compound [Ru(bpy)(CO)2]n (bpy = 2,2′-bipyridine). The conductivity depended on the degree of partial oxidation of the initially zero-valent Ru to RuI in the chains and was found to increase by four orders of magnitude after 5% oxidative doping. Linear conductance vs. doping level dependence was found for low levels and the conductivity of films could repeatedly be switched on and off. The conduction process is ascribed to charge delocalisation on the Ru chains in analogy to that of other similar chains formed by stacking of planar transition metal d8 complexes. 相似文献
12.
Dr. Svetlana A. Katkova Alexander S. Mikherdov Dr. Mikhail A. Kinzhalov Dr. Alexander S. Novikov Dr. Andrey A. Zolotarev Prof. Dr. Vadim P. Boyarskiy Prof. Dr. Vadim Yu. Kukushkin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8590-8598
Inspection of the X-ray structures of the newly prepared trans-[MII(CNXyl)2(DAPT)2]Cl(BF4) (M=Pd, Pt; Xyl=2,6-Me2C6H3; DAPT=4,6-diaminopyrimidine-2(1H)-thione) complexes and the appropriate Hirshfeld molecular surface analysis allowed the recognition of the previously unknown π-hole⋅⋅⋅metal interactions between a ligated isocyano group (acting as a π-hole donor) and the positively charged d8-PtII and d8-PdII metal centers (acting as nucleophiles); this is the first identification of π-hole⋅⋅⋅metal interactions with triple-bond species. Results of DFT calculations followed by the topological analysis of the electron density distribution within the framework of Bader's theory (quantum theory of atoms in molecules, QTAIM) confirmed the presence of these contacts. The electrostatic surface potential calculations indicated that π-hole⋅⋅⋅metal contacts are formed upon interaction between the electrophilic isocyano C atom (π-hole donor) and the nucleophilic d orbital of the metal centers, which act as π-hole acceptors. Available CCDC data were processed from the perspective of the π-hole⋅⋅⋅metal interactions with isocyanide ligands, and their analysis disclosed the role of metal nucleophilicity in the corresponding π-hole acceptor ability. 相似文献
13.
《Journal of organometallic chemistry》1986,315(1):119-133
A detailed study has been made of the halogenation of toluene in the presence of a range of transition metal complexes. Both side-chain and ring chlorination are observed, the favoured route depending on the metal complex. Side-chain halogenation, in the presence of [M(PPh3)4] and MCl2(PPh3)2] (M = Pd, Pt), has been shown to proceed by a free radical chain reaction in which the metal complex acts solely as an initiator. In the presence of, [M2(CO)10] (M = Mn, Re), [Re2(CO)8-(PPh3)2], [Fe2(CO)4(η-cp)2] and [Mo2(CO)6(η-cp)2], ring chlorinated products are formed by a Friedel-Crafts mechanism. 相似文献
14.
Five new coordination polymers, namely, [Ni2(L)2(4, 4′‐bipy)3)] · H2O]n ( 1 ), [Ni2(L)2(O) (bpp)2]n ( 2 ), [Zn(L)(bib)0.5]n ( 3 ), [Zn(L)(PyBIm)]n ( 4 ), and [Zn3(L)2(OH)(im)]n ( 5 ) [H2L = benzophenone‐2, 4′‐dicarboxylic acid, 4, 4′‐bipy = 4, 4′‐bipyridine, bpp = 1, 3‐bis(4‐pyridyl)propane, PyBIm = 2‐(4‐pyridyl)benzimidazole, and im = imidazole] were synthesized under hydrothermal conditions. Structure determination revealed that compound 1 is a 3D network and exhibits a 4‐connected metal‐organic framework with (42.63.8) topology, whereas compounds 2 , 3 , 4 , and 5 are two‐dimensional layer structures. In compounds 2 – 4 , dinuclear metal clusters are formed through carboxylic groups. In compound 5 , trinuclear metal clusters are formed through μ3‐OH and carboxylic groups. The carboxylic groups exhibit three coordination modes in compounds 1 – 5 : monodentately, bidentate‐chelating, and bis‐monodentately. Furthermore, the luminescent properties for compounds 3 , 4 , and 5 were investigated. 相似文献
15.
Shigeo Tazuke Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1967,5(5):1083-1099
Radical polymerization of 4-vinylpyridine (4-VP), 2-vinylpyridine (2-VP), and 2-methyl-5-vinylpyridine (MVP) was studied in concentrated DMF solutions of ZnCl2, ZnBr2, ZnI2, Zn(CH3COO)2, and Cd(CH2COO)2 at 50°C. Polymerization of 4-VP and MVP was accelerated by the addition of the metal salts, while the polymerization of 2-VP was greatly retarded. The sequence of the accelerating effect of metal salts for 4-VP was in the following order: Cd(CH3COO)2 > ZnCl2 > Zn(CH3COO)2 > ZnBr2 > ZnI2. This sequence is almost the same as that reported in a previous report for MVP. However, the order was reversed for the retarding effect on the polymerization of 2-VP. At the intermediate concentration of metal salts, polymerization of 4-VP proceeded heterogeneously, which was explained by considering crosslinking of poly-4-VP by the metal ion. Since a linear correlation between the rate Rp and the degree of polymerization was observed for the 4-VP–Zn(CH3COO)2 system, the accelerating effect was postulated to be due to the enhancement in kp. Results of copolymerization of VP with styrene as M2 in a concentrated solution of Zn(CH3COO)2 indicated the strong activation of 4-VP by complex formation (r1 = 2.7 ± 0.5, r2 = 0.08 ± 0.03), whereas the change in the monomer reactivity of MVP is smaller (r1 = 2.0 ± 0.2, r2 = 0.35 ± 0.05). The behavior of 2-VP was abnormal (r1 = 3.35 ± 0.3, r2 = 0.55 ± 0.15, then r1r2 > 1), which was attributed to the steric effect by complex formation. Solid complexes formed between pyridine, 4-VP, 2-VP, or MVP and zinc salts were prepared as samples for infrared spectroscopy. The shifts in infrared absorption bands of these amines were studied by comparing the infrared spectra of the amines before and after the complex formation, and the results were interpreted in terms of electronic as well as steric interactions of metal salts with ligands. Conjugation of the metal salt with the ligand π-orbitals was necessary to explain both infrared spectra and polymerization results. 相似文献
16.
Marie-Louise Wind Santina Hoof Dr. Christian Herwig Dr. Beatrice Braun-Cula Prof. Christian Limberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(22):5743-5750
In recent years, it has become clear that the presence of redox-inactive Lewis acidic metal ions can decisively influence the reactivity of metal–dioxygen moieties that are formed in the course of O2 activation, in molecular complexes, and metalloenzymes. Superoxide species are often formed as the primary intermediates but they are mostly too unstable for a thorough investigation. We report here a series of chromium(III) superoxide complexes [L2Cr]M2O2(THF)y (L=−OSiPh2OSiPh2O−, M+=Li+, Na+, K+ and y=4, 5), which could be accessed, studied spectroscopically and partly crystallized at low temperatures. They only differ in the two incorporated Lewis acidic alkali metal counterions (M+) and it could thus be shown that the nature of M+ determines considerably its interaction with the superoxide ligand. This interaction, in turn, has a significant influence on the stability and reactivity of these complexes towards substrates with OH groups. Furthermore, we show that stability and reactivity are also highly solvent dependent (THF versus nitriles), as donor solvents coordinate to the alkali metal ions and thus also influence their interaction with the superoxide moiety. Altogether, these results provide a comprehensive and detailed picture concerning the correlation between spectroscopic properties, structure, and behavior of such superoxides, that may be exemplary for other systems. 相似文献
17.
Donald S. Bethune Costantino S. Yannoni Mark Hoinkis Mattanjah de Vries Jesse R. Salem Mark S. Crowder Robert D. Johnson 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(1):153-158
Fullerenes containing metal atoms and clusters can be formed by the arc-vaporization method. The electronic structure of these metallofullerenes can be probed using magnetic resonance techniques. Electron paramagnetic resonance (EPR) spectra of LaC82, YC82, ScC82 and Sc3C82 have been obtained. Metallofullerenes containing a single metal atom (MC82 with M = La, Y, or Sc), have small hyperfine couplings and g-values close to 2, implying that they can be described as + 3 metal cations within — 3 fullerene radical anion cages. In the La and Y cases, additional EPR active MC82 species have been found. The EPR spectrum of Sc3C82 shows that the metal atoms are equivalent, suggesting that they may form a triangular molecule. No EPR spectrum is found for Y2C82 or for Sc2C2n species (with 2n = 82,84,86), suggesting that they are diamagnetic. Sc NMR spectra of a solution containing Sc2C2n species have been obtained which confirm the diamagnetism of the discandium metallofullerenes. 相似文献
18.
Dieter Fenske Johannes Ohmer Johannes Hachgenei Kurt Merzweiler 《Angewandte Chemie (International ed. in English)》1988,27(10):1277-1296
In both physics and chemistry, increased attention is being paid to metal clusters. One reason for this attitude is furnished by the surprising results that have been obtained from studies of the preparation, structural characterization and physical and chemical properties of the clusters. Whereas investigations of cluster reactivity are at present generally limited to three- or four-membered clusters, successful syntheses of clusters with many more metal atoms have recently been designed. These substances occupy an intermediate position between solid state chemistry and the chemistry of metal complexes. This review presents a versatile method for synthesizing metal clusters: the reaction of complexes of transition metal halides with silylated compounds such as E(SiMe3)2 (E = S, Se, Te) and E′R(SiMe3)2 (R = Ph, Me, Et; E′ = P, As, Sb). Although some of the compounds thus formed have already been prepared by other routes, the method affords ready access to both small and large transition metal clusters with unusual structures and valence electron concentrations; a variety of reactions in the ligand sphere are also possible. 相似文献
19.
Francisco López-Linares Alberto Fuentes Rita Tenia Maria Martinez Arquímedes Karam 《Reaction Kinetics and Catalysis Letters》2007,92(2):285-292
This work describes the homogeneous hydrogenation of different α,β-unsaturated substrates by using as catalyst systems the
complex [Ir(COE)2Cl]2 stabilized by tris(2-pyridyl)amine (tpN) or tris(2-pyridyl)phosphine (tpP) formed in situ under the following reaction conditions:
pH2 = 34 atm; T=373 K; substrate/catalyst ratio = 100, [ligand]/[metal]: 2,1; toluene (50 mL); R.P.M.: 430; t = 6 h. The activities
varies from low to moderate range, where both ligands proved to be catalyst systems able to hydrogenate C=C and C=O bonds. 相似文献
20.
M. I. Kabachnik L. S. Zakharov E. I. Goryunov P. V. Petrovskii T. M. Schcherbina A. P. Laretina 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The phosphorylation of tertiary alcohols can be performed only in some exceptional cases. We established, that phosphorylation of tertiary fluoroalkanols H(CF2) nCMe2OH (I, n = 2,4) with aryl- and polyfluoroalkyl-phosphorodicnlor-idates or aryl- and alkylphosphonic dichlorides in the presence of metal of metal salt catalysts yields chloroan-hydrides (II) and (III). When benzyl phosphorochloridates (IV) are used as phosphorylating agents, either products of phosphorylation or products of alkylation are formed depending on the nature of the substituent in the aromatic ring. 相似文献