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1.
The reaction of [CpCr(CO)3]2 (Cp = η5-C5H5) (1) with an equivalent of Bz2S3 at ambient temperature gave [CpCr(CO)2]2S (3) [L.Y. Goh, T.W. Hambley, G.B. Robertson, Organometallics 6 (1987) 1051], novel complexes of [CpCr(CO)2(SBz)]2 (4) and together with [CpCr(SBz)]2S (5) as main products. Thermolytic studies showed that 4 underwent complete decarbonylation to give [CpCr(SBz)]2S (5). Final thermal decomposition of 3 and 5 eventually yielded Cp4Cr4S4 (6) (Goh et al., 1987) after prolonged reaction at 100 °C. However, the reaction of [CpCr(CO)2]2 (CrCr) (2) with Bz2S3 was much slower at ambient temperature which required 72 h to complete eventually yielding 3 and 5. All the products have been characterized by elemental and spectral analyses. 4 has been structurally determined.  相似文献   

2.
The reduction of ethanolic solutions of niobium pentachloride with zinc, followed by treatment with aqueous acids serves as a versatile entry into the aqueous solution chemistry of niobium. From the zinc-reduced solution, the major intermediate, Nb42-O)22-OC2H5)4Cl4(OC2H5)4(HOC2H5)4, was isolated and the crystal structure determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pccn, with Z=4, a=21.0105(9), b=11.0387(5), c=19.1389(8), V=4438.9(3) Å3, Mr=1090.19,R1=0.0327 and wR2=0.0876. The structure revealed a centrosymmetric tetrameric Nb(IV) complex, consisting of a pair of edge-sharing bi-octahedral Nb22-OC2H5)4Cl2(OC2H5)2(HOC2H5)2 units that are joined by two axial oxo ligands. The Nb-Nb distance of 2.7458(3) Å is consistent with a single metal-metal bond.  相似文献   

3.
An oxalate-bridged binuclear iron(III) complex, [(acac)2Fe(μ-ox)Fe(acac)2], (acac=acetylacetonate anion and ox2−=oxalate anion) was prepared. The complex crystallized as two types of crystals under different conditions: one had 1,2-dichloroethane as a solvent molecule of crystallization 2, the other did not 1. Both compounds have been characterized by X-ray crystallography, infrared spectroscopy, and thermogravimetric analysis. Compound 1 has also been characterized by UV-Vis and 1H NMR spectroscopies, mass spectrometry, and electrochemistry. In both crystals, each iron(III) is coordinated in an octahedral arrangement by the oxygen atoms of an oxalate-bridging ligand and four oxygen atoms belonging to peripheral acac ligands in an octahedral arrangement. The intermetallic distance of Fe?Fe is 5.4368(9) Å in 1 and 5.438(2) Å in 2. Two iron(III) ions in each crystal are bridged by the oxalate and both lie in the oxalate-plane. The results of thermal analyses imply that the thermal stability of 2 is lower than that of 1. Cyclic voltammograms of 1 in acetonitrile and dichloromethane at low temperature showed two consecutive, quasi-Nernstian, one-electron reduction steps corresponding to the reduction of FeIII-FeIII to FeIII-FeII followed by the reduction of FeIII-FeII to FeII-FeII. The electrochemical comproportionation constants (Kc) of the equilibrium (FeIII-FeIII) + (FeII-FeII) ? 2(FeIII-FeII) are 108.9 in acetonitrile medium and 108.5 in dichloromethane, respectively. The considerably large Kc values indicate that the main factor contributing to the stabilization of the FeIII-FeII mixed-valence state is electronic delocalization through the oxalate-bridge.  相似文献   

4.
Reactions of [Pt2(μ-S)2(PPh3)4] with the diarylthallium(III) bromides Ar2TlBr [Ar = Ph and p-ClC6H4] in methanol gave good yields of the thallium(III) adducts [Pt2(μ-S)2(PPh3)4TlAr2]+, isolated as their salts. The corresponding selenide complex [Pt2(μ-Se)2(PPh3)4TlPh2]BPh4 was similarly synthesised from [Pt2(μ-Se)2(PPh3)4], Ph2TlBr and NaBPh4. The reaction of [Pt2(μ-S)2(PPh3)4] with PhTlBr2 gave [Pt2(μ-S)2(PPh3)4TlBrPh]+, while reaction with TlBr3 gave the dibromothallium(III) adduct [Pt2(μ-S)2(PPh3)4TlBr2]+[TlBr4]. The latter complex is a rare example of a thallium(III) dihalide complex stabilised solely by sulfur donor ligands. X-ray crystal structure determinations on the complexes [Pt2(μ-S)2(PPh3)4TlPh2]BPh4, [Pt2(μ-S)2(PPh3)4TlBrPh]BPh4 and [Pt2(μ-S)2(PPh3)4TlBr2][TlBr4] reveal a greater interaction between the thallium(III) centre and the two sulfide ligands on stepwise replacement of Ph by Br, as indicated by shorter Tl-S and Pt?Tl distances, and an increasing S-Tl-S bond angle. Investigations of the ESI MS fragmentation behaviour of the thallium(III) complexes are reported.  相似文献   

5.
Routes to the synthesis of the mixed sulfide-phenylthiolate complex [Pt2(μ-S)(μ-SPh)(PPh3)4]+ have been explored; reaction of [Pt2(μ-S)2(PPh3)4] with excess Ph2IBr proceeds readily to selectively produce this complex, which was structurally characterised as its PF6 salt. Reactions of [Pt2(μ-S)2(PPh3)4] with other potent arylating reagents (1-chloro-2,4-dinitrobenzene and 1,5-difluoro-2,4-dinitrobenzene) also produce the corresponding nitroaryl-thiolate complexes [Pt2(μ-S){μ-SC6H2(NO2)2X}(PPh3)4]+ (X = H, F). The complex [Pt2(μ-S)(μ-SPh)(PPh3)4]+ reacts with Me2SO4 to produce the mixed alkyl/aryl bis-thiolate complex [Pt2(μ-SMe)(μ-SPh)(PPh3)4]2+, but corresponding reactions with the nitroaryl-thiolate complexes are plagued by elimination of the nitroaryl group and formation of [Pt2(μ-SMe)2(PPh3)4]2+. [Pt2(μ-S)(μ-SPh)(PPh3)4]+ also reacts with Ph3PAuCl to give [Pt2(μ-SAuPPh3)(μ-SPh)(PPh3)4]2+.  相似文献   

6.
Two trinuclear NiFe2 complexes Fe2(CO)63-S)2[Ni(Ph2PCH2)2NR] (R = n-Bu, 1; Ph, 2) containing an internal base were prepared as biomimetic models for the active sites of FeFe and NiFe hydrogenases. Treatment of complex Fe2(CO)63-S)2[Ni(Ph2PCH2)2N(n-Bu)] (1) with HOTf gave an N-protonated complex [Fe2(CO)63-S)2{Ni(Ph2PCH2)2NH(n-Bu)}][OTf] ([1H][OTf]). The structures of complexes 1, 2 and [1H][OTf] were determined by X-ray crystallography, which shows that the proton held by the N atom of [1H][OTf] lies in an equatorial position. Cyclic voltammograms of complexes 1 and [1H][OTf] were studied and compared with that of Fe2(CO)63-S)2[Ni(dppe)].  相似文献   

7.
8.
The reaction of [Cp(CO)2Fe{μ-CH2CH(CH2)3}W(CO)3Cp]PF6 with NaBPh4 in dry acetone gave [Cp(CO)2Fe{μ-CH2CH(CH2)3}W(CO)3Cp]BPh4. The bond Fe-Cβ is shorter than that reported for the shorter chain carbocationic complexes. The data suggest that metallacyclopropane character is on the iron side of the molecule both in the solid state and in solution.  相似文献   

9.
The room temperature reactions of RSH (R = Et, Ph) with (CO)3Mo(μ-dppm)2Ru(CO)3 (1) in toluene yield (CO)2Mo(μ-SR)(μ-CO)(μ-dppm)2Ru(H)(CO) [R = Et (3); Ph (4)], which are characterized by elemental analysis, 1H NMR and IR spectroscopies and, in the case of 3, by X-ray crystallography. The complexes contain a trans,trans-Mo(μ-dppm)2Ru unit with a bridging thiolate, a terminal hydride at the Ru, three terminal CO ligands (two at the Mo, and one at the Ru), and one semi-bridged CO closer to the Mo.  相似文献   

10.
Synthesis and characterization of two new cobalt(II) complexes, namely monomeric [Co(2-MeSnic)2(H2O)4] · 4H2O (2-MeSnic is 2-methylthionicotinate) and polymeric {[{2,6-(MeO)2nic}2(H2O)2Co(μ-H2O)Co(H2O)4(μ-H2O)]{2,6-(MeO)2nic}2 · 6H2O}n (2,6-(MeO)2nic is 2,6-dimethoxynicotinate), are reported. The characterizations were based on elemental analysis, infrared and electronic spectra as well as magnetic measurements. Crystal structures of both complexes have been determined. In both of them - ([Co(2-MeSnic)2(H2O)4] · 4H2O and {[{2,6-(MeO)2nic}2(H2O)2Co(μ-H2O)Co(H2O)4(μ-H2O)]{2,6-(MeO)2nic}2 · 6H2O}n) - the CoII atom is six-coordinated. In the 2nd complex, there are two nonequivalent CoII central atoms, involved in forming a linear polymeric chain with alternating cationic and neutral part. One of them is octahedrally coordinated by a carboxyl oxygen atom of 2,6-(MeO)2nic, two water molecules and the corresponding centrosymmetrically located atoms. The second CoII atom is also octahedrally coordinated by six water molecules. Both coordination polyhedra are bridged by a water molecule. The charge of the cationic part is compensated for by two independent anionic 2,6-(MeO)2nic units. The structure is held together by a complicated system of hydrogen bonds.  相似文献   

11.
A new polynuclear copper (II) complex, derived from the azido-bridging ligand and 2-aminopyrimidine, has been synthesized and its 3-D structure has been determined by X-ray diffraction methods at two different temperatures. The compound crystallizes in the triclinic system space group, with the central copper atom lying on an inversion centre. The crystal structure is built up by trinuclear units (each of them contains two double end-on azido bridges) linked through two azide ions in an end-to-end (EE) fashion, to yield the polymer chain [Cu3(ampym)21,1-N3)41,3-N3)2(dmf)2]n. Magnetic susceptibility measurement shows a ferromagnetic interaction above 30 K, whereas a weak anti-ferromagnetic interaction prevails in the range of 30-2 K.  相似文献   

12.
By employing the common precursor Na3[Fe(CN)5(NH3)]·3H2O in a new synthetic approach, the azidopentacyanoferrate(III) ion has been isolated and structurally characterized as (Ph4As)2[Na(H2O)4][Fe(CN)5(N3)] 1. In order to confirm its building block ability, compound 1 has been reacted with the mononuclear complex [Mn(valphen)(H2O)2]ClO4 (H2valphen represents the Schiff base resulting from the condensation of o-vanillin with 1,2-phenylenediamine in a 2:1 M ratio) to afford the new MnIII-FeIII heterometallic system [Mn(valphen)(H2O)2]2[(H2O)(valphen)Mn(μ-CN)Fe(CN)4(N3)]·8H2O 2. The crystal structure of compound 2 reveals a supramolecular assembly generated by [(H2O)(valphen)Mn(μ-CN)Fe(CN)4(N3)]2− dianions and discrete [Mn(valphen)(H2O)2]+ counterions. The dynamic magnetic measurements of compound 2 point to a slow relaxation of the magnetization.  相似文献   

13.
The thermal reaction of Ru3(CO)12 with the biologically active acids acetyl salicylic acid (Aspirin), α-methyl-4-(isobutyl)phenylacetic acid (Ibuprofen) and 3α,7α,12α-trihydroxy-5β-cholanic acid (cholic acid) in refluxing tetrahydrofuran, followed by addition of triphenylphosphine, gives the dinuclear complexes Ru2(CO)4(OOCR)2(PPh3)2 (1: R = C6H4-2-OCOMe, 2: R = CHMe-C6H4-4-Bui, 3: C23H39O3). The single-crystal structural analysis of 1 and 2 reveals a dinuclear Ru2(CO)4 sawhorse structure, the diruthenium backbone being bridged by the carboxylato ligands, while the two phosphine ligands occupy the axial positions at the ruthenium atoms. However, chiral carbon atoms in the carboxylic acid undergo racemisation during the thermal reaction.  相似文献   

14.
2-Hydroxypyridine (Hhp), 2-hydroxynicotinic acid (HnicOH) and 6-hydroxypicolinic acid (HpicOH) react with Re2Cl4(μ-dppm)2 (dppm=Ph2PCH2PPh2) to afford the complexes Re22-hp)Cl3(μ-dppm)2 (1), Re22-HnicO)Cl3(μ-dppm)2 (2) and Re2(μ-picO)2(μ-dppm)2 (3). The identities of 1 and 2 have been established by single-crystal X-ray structure determinations (Re-Re distances of 2.2602(3) and 2.2539(3) Å, respectively) and they are shown to have unsymmetrical structures with staggered rotational geometries and trans, cis coordination of the pair of μ-dppm ligands. The crystal of 2 that was used in the structure determination was found to be of composition 2Re22-HnicO)Cl3(μ-dppm)2 · Re2Cl6(μ-dppm)2 · 2.906CH2Cl2. The structure of Re2Cl6(μ-dppm)2 in this crystal is compared with structures reported in the literature for other crystals that contain this edge-sharing bioctahedral dirhenium(III) complex.  相似文献   

15.
Pt(II) complexes of the types cis- and trans-Pt(amine)2I2 with amines containing a phenyl group were synthesized and studied mainly by IR and multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopies. The compounds are not very soluble. In 195Pt NMR spectroscopy, the cis isomers were observed at slightly lower fields than the trans analogues (average Δδ = 11 ppm) in acetone. In 1H NMR, the NH groups were also found at slightly lower fields in the cis isomers. The coupling constants 2J(195Pt-1HN) varied from 53 to 85 Hz and seem slightly smaller in the trans configuration. The 13C NMR spectra of most of the complexes were measured. No coupling constants J(195Pt-13C) were detected due to the low solubility of the compounds. The cis isomers containing a phenyl group on the N atom could not be isolated except for Ph-NH2 which was shown to be a mixture of isomers in acetone. The tetrasubstituted ionic compounds [Pt(amine)4]I2 for the less crowded ligands were also studied mainly by NMR spectroscopy in aqueous solution. The 195Pt chemical shifts vary between −2855 and −2909 ppm. The coupling constants 3J(195Pt-1H) are about 40 Hz. The iodo-bridged dinuclear species I(amine)Pt(μ-I)2Pt(amine)I were also synthesized and characterized. Two isomers are present in acetone solution for most of the compounds. Their δ(Pt) signals were observed at about −4000 ppm and their coupling constants 2J(195Pt-1HN) are around 69 Hz.  相似文献   

16.
《Inorganica chimica acta》2004,357(9):2561-2569
Ni(II), Cu(II), Zn(II) and Cd(II) complexes of an N4-donor Schiff base, containing (CH2)2 as spacer, have been prepared. The X-ray crystal structures of monohelical Ni(ETs) · H2O and the homochirally crystallised Δ-Cu(ETs), as well as the meso-helicate Zn2(ETs)2 · MeCN [H2ETs: N,N-bis(2-tosylaminobenzylidene)-1,2-diaminoethane] have been solved. In the latter, the ligand behaves as bis-bidentate, displaying a “C”-type arrangement, instead of the typical “S”-type fashion present in bis-helical dinuclear complexes.  相似文献   

17.
The reaction between [Fe2Ir2(CO)12]2− and diphenylacetylene in refluxing CH3CN yields the substituted cluster [Fe2Ir2(CO)10(PhC2Ph)]2− (1). In the crystals, the four metal atoms define a butterfly arrangement whose Ir-Ir hinge is parallel to the acetylenic C2 unit. The neutral triangular cluster [FeIr2(CO)9(PhC2Ph)] (2) is obtained by the treatment of 1 with acids at room temperature; in this 48 valence electrons species, the C-C and the Ir-Ir bonds are also parallel, in the coordination mode.The cluster [Fe2Rh(CO)10] reacts with diphenylacetylene in refluxing THF yielding [Fe2Rh(CO)8(PhC2Ph)] (3). In this 46 C.V.E.’s cluster, the C2 unit is perpendicular to the Fe-Fe edge, exemplifying the bonding mode. According to 13C NMR spectra, the structure of the three clusters is maintained in solution. Electrochemical investigations show that the one-electron oxidation of [Fe2Ir2(CO)10(L)]2− (L = 2CO, PhC2Ph) as well as the one-electron reduction of [Fe2Rh(CO)8(PhC2Ph)] only generates the respective short lived products.  相似文献   

18.
Two novel tetranuclear compounds with an unprecedented mode of a hydrogenphosphato bridge, [Cu4(dpyam)443-HPO4)2(μ-X)2]2+ (in which dpyam = di-2-pyridylamine and X = Cl (1), Br (2)) have been synthesised and characterised structurally and magnetically. The Cu(II) ions in the structures each display a square-pyramidal geometry, with two tridentate hydrogenphosphato groups bridging four copper atoms in a μ43 coordination mode which is rarely found in hydrogenphosphate metal compounds. Each (different) pair of Cu(II) ions is additionally bridged by halide ions, with relatively long Cu-X distances (2.551(3)-2.604(3) Å for 1 and 2.707(1)-2.766(2) Å for 2) and subsequently also a small Cu-X-Cu angle (65.7(1)° and 65.1(1)° for 1 and 61.6(1)° and 62.4(1) for 2) and a large Cu-X-Cu angle (95.5(1)° and 96.5(1)° for 1 and 91.1(1)° and 92.6(1)° for 2). Cu?Cu distances in the tetranuclear units varies from 2.802(3) to 5.232(3) Å for 1 and from 2.834(1) to5.233(1) Å in 2. The lattice structures are stabilised by extensive intermolecular hydrogen bonds. The magnetic susceptibility measurements down to 5 K revealed a weak ferromagnetic interaction between the outer pairs of Cu(II) ions which vary from 22 to 46 cm−1 in 1 and 12 to 33 cm−1 in 2 and a moderately strong antiferromagnetic interaction between the inner Cu(II) ions of −79 cm−1 in 1 and −83 cm−1 in 2, via the Cu-O-P-O-Cu pathway.  相似文献   

19.
The (β/α)8-barrel is one of the most common folds functioning as enzymes. The emergence of two (β/α)8-barrel enzymes involved in histidine biosynthesis, each of which has a twofold symmetric structure, has been proposed to be a consequence of tandem duplication and fusion of a (β/α)4-half-barrel. However, little evidence has been found for the existence of an ancestral half-barrel in the evolution of other (β/α)8-barrel proteins. In order to detect remnants of an ancestral half-barrel in the (β/α)8-barrel structure of Escherichia coli N-(5′-phosphoribosyl)anthranilate isomerase, we engineered three potential half-barrel units, (β/α)1-4, (β/α)3-6, and (β/α)5-8. Among these three arrangements, only (β/α)3-6 is stable; it exists in equilibrium between monomeric and dimeric forms. Thus, the central segment of N-(5′-phosphoribosyl)anthranilate isomerase from E. coli can serve as a half-barrel precursor. A tandem duplication of (β/α)3-6 yielded predominantly monomeric structures that were quite stable. This result exemplified that the structural characteristics of noncovalently assembled half-barrels could be improved by duplication and fusion. Moreover, our results may provide information regarding the local structural units that encompass interactions important for the early folding events of this ubiquitous protein conformation.  相似文献   

20.
New one-dimensional copper(I) coordination polymer [Cu2(μ-I)2(μ-(thio)2dapte)]n (1) {(thio)2dapte = N,N′-di-(thiophenecarbaldehyde)-1,2-di(o-aminophenylthio)ethane} involving a novel (NS)2 Schiff-base with a flexible spacer has been synthesized and structurally characterized by X-ray diffraction analysis. Each Cu(I) center adopts a distorted [CuN2S2] tetrahedron environment arising from two crystallographically equivalent (thio)2dapte Schiff-base ligands. Each ligand acts as N2S2-bis-chelating ligand with the nitrogen atoms of the two imine functions and from the two thioether atoms in anti-form leading to the dinuclear [Cu2(μ-(thio)2dapte)] groups. Such [Cu2] entities are bridged by two iodine anions [(μ-I)2] to form a neutral one-dimensional copper(I) coordination polymer (1).  相似文献   

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