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1.
A new compound containing a cubane tungsten chalcogenide cluster [W4(μ3-Te)4(CN)12]6− and Ca2+ complex units has been prepared by the reaction of aqueous solution of K6[W4(μ3-Te)4(CN)12] · 5H2O with the solution of a Ca(NO3)2 and phen(1,10-phenanthroline) (1:2 molar ratio) in a solvent mixture of H2O/EtOH. The structure of [{Ca(phen)2(H2O)}{Ca(phen)(H2O)4}{Ca(phen)2(H2O)3}][W4Te4(CN)12] · 5H2O 1 has been determined by X-ray crystallography. Compound 1 contains [{Ca(phen)(H2O)4}{Ca(phen)2(H2O)3}][W4(μ3- Te)4(CN)12] units bridged by {Ca(phen)2(H2O)}2+ units to form an one-dimensional zigzag chain structure. Interestingly, compound 1 showed a heterogeneous catalytic activity in the transesterification of a range of esters with methanol under the mild conditions. Moreover, it can be reused without any loss of activity through 10 runs with ester.  相似文献   

2.
The presence of tannins in the idioblasts of Elodea densa is conclusively disproved. Ten reagents for histochemical detection of tannin (K2Cr2O7, K3Fe(CN)6, FeCl3, (NH4)2MO4, Nessler's reagent, Fehling's reagent, methylene blue, gelatin, iodine-KI and lead acetate) gave negative tests in Elodea idioblasts. Two reagents (1% aqueous caffeine and a saturated solution of Ca(OH)2) gave apparently positive reactions that could be explained by the presence of lipids. Positive tests for lipids were obtained by direct microscopic examination of the removal of lipid materials from freeze-dried leaves, using a 1:1 ether-alcohol mixture. The lipid material was not removed when acetone was substituted for ether-alcohol. A lipoprotein complex was demonstrated by using Serra's method for masked lipids.  相似文献   

3.
The new inorganic 1D coordination polymer [Cu2(H3tea)2(μ4-pma)]n has been prepared, via self-assembly in aqueous medium, from copper(II) nitrate, triethanolamine (H3tea), pyromellitic acid (H4pma) and lithium hydroxide, and characterized by IR spectroscopy, elemental and single-crystal X-ray diffraction analyses. This compound and the related 2D polymer [Cu2(μ-H2tea)2{μ3-Na2(H2O)4}(μ6-pma)]n · 10nH2O are shown to mimic the alkane partial oxidation activity of the multicopper particulate methane monooxygenase, acting as catalysts precursors for the peroxidative oxidation of cyclohexane into cyclohexanol and cyclohexanone, by hydrogen peroxide (as green oxidant) and at room temperature in acidic MeCN/H2O medium. An overall yield (based on cyclohexane) of 29% has been achieved.  相似文献   

4.
Cis(or trans)-[RuCl2(CO)2(PPh3)2] react with two and one equivalents of AgBF4 to give the recently reported [Ru(CO)2(PPh3)2][BF4]2·CH2Cl2 (1) and novel [RuCl(CO)2(PPh3)2][BF4] · 1/2 CH2Cl2 (2), respectively. Cis-[RuCl2(CO)2(PPh3)2] also reacts with two equivalents of AgBF4 in the presence of CO to give [Ru(CO)3(PPh3)2][BF4]2 (3). Reactions of 1 and 2 with NaOMe and CO at 1 atm produce the carbomethoxy species [Ru(COOMe)2(CO)2(PPh3)2] (4) and [RuCl(COOMe)(CO)2(PPh3)2] (5), respectively. Complex 4 can also be formed from the reaction of 3 with NaOMe and CO. Alternatively, 4 is formed from cis-[RuCl2(CO)2(PPh3)2] with NaOMe and CO at elevated pressure (10 atm); if these reactants are refluxed under 1 atm of CO, [Ru(CO)3(PPh3)2] is the product. The reaction of [RuCl(CO)3(PPh3)2][AlCl4] with NaOMe provides an alternative route to the preparation of 5, but the product is contaminated with [RuCl2(CO)2(PPh3)2]. Compounds 1. 2, 4 and 5 have been characterised by IR, 1H NMR and analysis, whilst the formulation of 3 is proposed from spectroscopic data only. This account also examines the reactivity of [Ru(CO)2(PPh3)2][BF4]2 · CH2Cl2 with NaBH4, conc. HCl, KI and, finally, MeCOONa in the presence of CO. The products of these reactions, namely cis-[RuH2(CO)2(PPh3)2], cis-[RuCl2(CO)2(PPh3)2], cis-[RuI2(CO)2(PPh3)2] and [Ru(OOCMe)2(CO)2(PPh3)2], have been identified by comparison of their spectra with previous literature.  相似文献   

5.
Chromium(III) acetate has been widely used in industry for decades. The commercial material is an ill-defined substance, which represents a large number of compounds having different compositions, physical properties and appearances. Several samples of Cr(III) acetate, from various commercial sources were examined by ion-exchange chromatography. All the samples were found to contain several species such as [Cr3O(O2CCH3)6(H2O)3]+ and other positively charged purple complexes. They also contain various amounts of the neutral violet complex [Cr8(OH)8(O2CCH3)16] (1) which crystallizes upon slow evaporation of its aqueous solution. 1 is a cyclic octanuclear complex with hydroxo and acetate ligands bridging the adjacent Cr(III) ions. The structure of a well-defined Cr(III) acetate, namely, [Cr(H2O)6](O2CCH3)3 (2) has been determined crystallographically and its decomposition products were examined by ion-exchange chromatography. Compound 2 decomposes under ambient conditions, releasing acetic acid and water producing neutral and charged polynuclear Cr(III) complexes.  相似文献   

6.
Two new multi-cobalt-containing polyoxotungstates K4Na6Co2(H2O)12{Co(H2O)4[Co2(H2O)10Co4(H2O)2(B--SiW9O34)2]2} · 40H2O (1) and K10Na2[Co4(H2O)2(GeW9O34)2] · 20H2O (2) have been obtained by the routine synthetic reactions in aqueous solution. The polyoxoanion framework of 1 consists of two sandwich-type polyoxoanions [Co4(H2O)2(B--SiW9O34)2]12− connected together by a [CoO2(H2O)4] cluster to constitute the sandwich dimer, and then, four isolated Co(H2O)5 cations coordinate to the dimer through four μ2-O atoms. The polyoxoanion 2 is isomorphic to the sandwich-type polyoxoanion [Co4(H2O)2(B--SiW9O34)2]12− in 1. The magnetic property of compound 1 has been studied by measuring its magnetic susceptibility in the temperature range 2.0–300.0 K, indicating the existence of intramolecular ferromagnetic Co–Co interactions, and, the electrochemical properties of 1 and 2 are detected in the pH 4 buffer solution.  相似文献   

7.
The complex [Ru(SB12H11)(NH3)5]·2H2O has been prepared by the reaction of Cs2B12H11SH with [RuCl(NH3)5]Cl2 in aqueous solution. The complex represents the first reported example of the borocaptate anion acting as a ligand. The structure of the complex has been determined by single crystal X-ray diffraction analysis. The crystal parameters are monoclinic, space group P21/c, A = 8.056(1), B = 14.240(2), C = 15.172(2) Å, β=98.48° and Z = 4. The ruthenium atom has a distorted octahedral coordination. The distortion is probably due to the high (3−) charge and the large bulk of the borocaptate ligand. These features can also be observed in the spectroscopic properties of the complex.  相似文献   

8.
The complex [Et4N][W(CO)5OMe] (1) has been prepared from the reaction of the photochemically generated W(CO)5THF adduct and [Et4N][OH] in methanol. Complex 1 was shown to undergo rapid CO dissociation in THF to quantitatively provide the dimeric dianion, [W(CO)4OMe]22−. The resulting THF insoluble salt [Et4N]2[W(CO)4OMe]2 (2) has been structurally characterized by X-ray crystallography, with the doubly bridging methoxide ligands being in an anti configuration. Complex 2 was found to subsequently react with excess methoxide ligand in a THF slurry to afford the face-sharing octahedron complex [Et4N]3[W2(CO)6(OMe)3] (3) which contains three doubly bridging methoxide groups. In the absence of excess methoxide ligand complex 2 cleanly yields the tetrameric complex [Et4N]4[W(CO)3OMe]4 (4) which has been structurally characterized as a cubane-like arrangement with triply bridging μ3-methoxide groups and W(CO)3 units. Although complex 3 was not characterized in the solid state, the closely related glycolate derivative [Et4N]3[W2(CO)6(OCH2CH2OH)3] (5) was synthesized and its structure determined by X-ray crystallography. The trianions of complex 5 are linked in the crystal lattice by strong intermolecular hydrogen bonds. Crystal data for 2: space group P21/n, a = 7.696(2), b = 22.019(4), c = 9.714(2) Å, β = 92.22(3)°, Z = 4, R = 6.43%. Crystal data for 4: space group Fddd, a = 12.433(9), b = 24.01(2), c = 39.29(3) Å, Z = 8, R = 8.13%. Crystal data for 5: space group P212121, a = 11.43(2), b = 12.91(1), c = 29.85(6) Å, Z = 8, R = 8.29%. Finally, the rate of CO ligand dissociation in the closely related aryloxide derivatives [Et4N][W(CO)5OR] (R = C6H5 and 3,5-F2C6H3) were measured to be 2.15 × 10−2 and 1.31 × 10−3 s−1, respectively, in THF solution at 5°C. Hence, the value of the rate constant of 2.15 × 10−2 s−1 establishes a lower limit for the first-order rate constant for CO loss in the W(CO)5OMe− anion, since the methoxide ligand is a better π-donating group than phenoxide.  相似文献   

9.
The reaction of [N(PPh3)2]2[Ni6(CO)12] with Cu(PPh3)xCl (x=1, 2), as well as the degradation of [N(PPh3)2]2[H2Ni12(CO)21] with PPh3, affords the new and unstable dark orange–brown [N(PPh3)2]2[Ni9(CO)16].THF salt in low yields. This salt has been characterized by a CCD X-ray diffraction determination, along with IR spectroscopy and elemental analysis. The close-packed two-layer metal core geometry of the [Ni9(CO)16]2− dianion is directly related to that of the bimetallic [Ni6Rh3(CO)17]3− trianion and may be envisioned to be formally derived from the hcp three-layer geometry of [Ni12(CO)21]4− by the substitution of one of the two outer [Ni3(CO)3(μ−CO)3]2− layers with a face-bridging carbonyl group.  相似文献   

10.
Lewis acid adducts of the hydrides cis- and trans-Re(CO)(PMe3)4H (1) and (2), mer-Re(CO)2(PMe3)3H (3), fac-Re(CO)2(PMe3)3H (4) and trans-Re(CO)3(PMe3)2H (5) were studied with BH3 and 9-borabicyclo[3,3,1] norbonane (BBNH). Using BH3·THF and (BBNH)2 1 and 2 afforded Re(CO)(PMe3)3(η2-BH4) (6) and Re(CO)(PMe3)3(η2-BBNH2) (7) as stable and isolable products. VT IR studies established for the reaction to 7 that BBNH first attaches in a pre-equilibrium to the OCO atom of 1 or 2. At higher temperatures ReH adduct formation occurs with instantaneous transformation to 7 and elimination of PMe3·BBNH. In a similar way, the hydrides 3 and 4 were converted with BH3·THF and (BBNH)2 to yield the stable complexes Re(CO)2(PMe3)2(η2-BH4) (8) and Re(CO)2(PMe3)2(η2-BBNH2) (9). The intermediacy of the η1-BH4 adducts mer-/fac-Re(CO)2(PMe3)3(η1-BH4) was confirmed by VT 1H, 31P NMR and VT IR experiments. The conversion of 5 with BH3·THF led to equilibria with adducts at the OCO terminus in trans position to H and with HRe as revealed by VT IR studies. Temperature dependent 31P equilibrium studies allowed to calculate ΔH=−4.9 kcal mol−1 and ΔS=+0.034 e.u. for this reaction. These adducts could not be isolated. Compound 5 does not react with (BBNH)2 even at elevated temperatures. DFT calculations were carried out to support the structures of the BH3 adducts of 5. In addition a vibrational analysis helped to unravel the IR band assignments of the involved compounds. DFT calculations on 8 confirmed its C2v structure. X-ray diffraction studies were carried out on single crystals of 6 and 7.  相似文献   

11.
Many natural and synthetic organic amphiphiles have been discovered, prepared, and/or characterized. Aggregation behavior has been studied for many of these monomers. Very few of these many amphiphiles are organometallic compounds and almost nothing is known about this novel group of amphiphiles. Under appropriate circumstances, aggregation of certain organometallic amphiphile monomers can be controlled by use of redox switching. Compounds which are not amphiphilic can be made so and amphiphilic compounds can be deprived of this property by appropriate alterations in the metal ion's oxidation state. Redox-switched aggregation-deaggregation behavior is described for bis(hexadecycloxy)-1,10-phenanthrolinium perchlorate (2), its nickel complex (3), [CH3(CH2)15NH2]2Ag+AcO− (4) and bis(hexadecylamine)copper dichloride (5), chloride acetate (6) and diacetate (7), all of the general formula: [CH3(CH2)15NH2]2Cu2+X22. Two completely new switching mechanisms are disclosed for the first time which involve electron transfer from dilute aqueous sugar solutions or from solid zinc metal which are effective in collapsing [CH3(CH2)15NH2]2Cu2+X22− vesicles.  相似文献   

12.
A series of diplatinum(III) complexes derived from cis-(NH3)2PtII and the model nucleobase 1-methylcytosine (1-MeC) has been prepared and X-ray structurally characterized, all of which contain two anionic base ligands (1-MeC−) in a head–tail (ht) arrangement: ht-cis-[(ONO2)(NH3)2Pt(1-MeC−-N3,N4)2Pt(NH3)2(ONO2)](NO3)2·HNO3·3H2O (2b), ht-cis-[(NO2) (NH3)2 Pt(1-MeC−-N3,N4)2Pt(NH3)2(OH2)](ClO4)3·3.5H2O (3), ht-cis-[(OH2)(NH3)2Pt(1-MeC−-N3,N4)2Pt(NH3)2(OH2)](ClO4)4·H2O (4b), and ht-cis-[(9-EtGH-N7)(NH3)2Pt(1-MeC−-N3,N4)2Pt (NH3)2(9-EtGH-N7)](NO3)4·9H2O (7b) (9-EtGH=9-ethylguanine). Several other compounds, differing in the nature of the axial ligands, have been isolated and or observed in solution by 1H and 195Pt NMR spectroscopy. The chemistry of these diplatinum(III) compounds is dominated by facile substitution reactions of the axial ligands. Of particular interest in this context is the ready reaction of 2b or 3 with guanine nucleobases. Since similar compounds are not obtained with any of the other common nucleobases, 2b and 3 can be considered guanine-specific chemical probes.  相似文献   

13.
The chloro complexes trans-[Pt(Me)(Cl)(PPh3)2], after treatment with AgBF4, react with 1-alkynes HC---C---R in the presence of NEt3 to afford the corresponding acetylide derivatives trans-[Pt(Me) (C---C---R) (PPh3)2] (R = p-tolyl (1), Ph (2), C(CH3)3 (3)). These complexes, with the exception of the t-butylacetylide complex, react with the chloroalcohols HO(CH2)nCl (n = 2, 3) in the presence of 1 equiv. of HBF4 to afford the alkyl(chloroalkoxy)carbene complexes trans-[Pt(Me) {C[O(CH2)nCl](CH2R) } (PPh3)2][BF4] (R = p-tolyl, N = 2 (4), N = 3 (5); R=Ph, N = 2 (6)). A similar reaction of the bis(acetylide) complex trans-[Pt(C---C---Ph)2(PMe2Ph)2] with 2 equiv. HBF4 and 3-chloro-1-propanol affords trans-[Pt(C---CPh) {C(OCH2CH2CH2Cl)(CH2Ph) } (PMe2Ph)2][BF4] (7). T alkyl(chloroalkoxy)-carbene complex trans-[Pt(Me) {C(OCH2CH2Cl)(CH2Ph) } (PPh3)2][BF4] (8) is formed by reaction of trans-[Pt(Me)(Cl)(PPh3)2], after treatment with AgBF4 in HOCH2CH2Cl, with phenylacetylene in the presence of 1 equiv. of n-BuLi. The reaction of the dimer [Pt(Cl)(μ-Cl)(PMe2Ph)]2 with p-tolylacetylene and 3-chloro-1-propanol yields cis-[PtCl2{C(OCH2CH2CH2Cl)(CH2C6H4-p-Me}(PMe2Ph)] (9). The X-ray molecular structure of (8) has been determined. It crystallizes in the orthorhombic system, space group Pna21, with a = 11.785(2), B = 29.418(4), C = 15.409(3) Å, V = 4889(1) Å3 and Z = 4. The carbene ligand is perpendicular to the Pt(II) coordination plane; the PtC(carbene) bond distance is 2.01(1) Å and the short C(carbene)-O bond distance of 1.30(1) Å suggests extensive electronic delocalization within the Pt---C(carbene)---O moietry.  相似文献   

14.
The dimetal μ-vinylidene complexes Cp(CO)2MnPt(μ-C = CHPh)L2 (L = tert.-phosphine or -phosphite), which have been obtained by coupling of the mononuclear complex Cp(CO)2Mn=C=CHPh and unsaturated PtL2 unit, add smoothly the Fe(CO)4 moiety to produce trimetal MnFePt compounds. The μ3-vinylidene cluster CpMnFePt(μ3-C=CHPh)(CO)6(PPh3) was prepared in quantitative yields from the reactions of Cp(CO)2MnPt(μ-C=CHPh)(PPh3)L (L = PPh3 or CO) with Fe2(CO)9 in benzene at 20 °C. The phosphite-substituted complexes Cp(CO)2Mnpt(μ-C=CHPh)L2 (L = P(OEt)3 or P(OPri)3) react under analogous conditions with Fe2(CO)9 to give mixtures (2:3) of the penta- and hexacarbonyl clusters, CpMnFePt(μ3-C = CHPh)(CO)5L2 and CpMnFePt(μ3-C = CHPh)(CO)6L, respectively. The similar reaction of the dimetal complex Cp(CO)2MnPt(μ-C = CHPh)(dppm), in which the Pt atom is chelated by dppm = Ph2PCH2PPhPin2 ligand, gives only a 15% yield of the analogous trimetal μ3-vinylidene hexacarbonyl product CpMnFePt(μ3-C = CHPh)(CO)(dppm), but the major product (40%) is the tetranuclear μ4-vinylidene cluster (dppm)PtFe3(μ4-C = CHPh)(CO)9. The IR and 1H, 13C and 31P NMR data for the new complexes are reported and discussed.  相似文献   

15.
Reactions of cct-RuH(SR)(CO)2(PPh3)2 (1) (cct = cis, cis, trans) with R′SH provide cct-RuH(SR′)(CO)2(PPh3)2 (R = alkyl, aryl): based on described kinetic data, the proposed mechanism involves PPh3 loss, coordination of R′SH, intramolecular protonation of RS− by R′SH, and RSH elimination. The intramolecular protonation step circumvents a potentially slow RSH reductive elimination step. A similar mechanism is proposed for the thiol exchange reactions of cct-Ru(SR)2(CO)2(PPh3)2 (2). A corresponding dissociative mechanism is also proposed for the reaction of 1 with P(p-tolyl)3, which gives cct-RuH(SR)(CO)2(PPh3)(P(p-tolyl)3) and cct-RuH(SR)(CO)2− (P(p-tolyl)3)2. Other reactions described include the reactions of 1 with H2, CO, HCl and PPh3, and the reactions of 2 with P(p-tolyl)3 and H2. Exposure to light causes 2 to dimerize in solution.  相似文献   

16.
Cobalt(III) complexes with a thiolate or thioether ligand, t-[Co(mp)(tren)]+ (2), t-[Co(mtp)(tren)]2+ (1Me) and t-[Co(mta)(tren)]2+ (2Me), (mp = 3-mercaptopropionate, MA = 3-(methylthio)propionate and MTA = 2-(methylthio)acetate) have been prepared in aqueous solutions. The crystal structures of 1, 2, 1Me and 2Me were determined by X-ray diffraction methods. The crystal data are as follows, t-[Co(mp)(tren)]ClO4 (1CIO4): monoclinic, P21/n, A = 10.877(8), B = 11.570(4), c = 12.173(7) Å, β = 92.20(5)°, V = 1531(1) Å3, Z = 4 and R = 0.060; t-[Co(ma)(tren)]Cl·3H2O (2Cl·3H2O): monoclinic, P21/n, a = 7.7688(8), B = 27.128(2), C = 7.858(1) Å, β = 100.63(1)°, V = 1627.7(3) Å3, Z = 4 and R = 0.066; (+)465CD-t-[Co(mtp)(tren)](ClO4)2 ((+)465CD-1Me(ClO4)2): orthorhombic, P212121, A = 10.6610(7), B = 11.746(1), C = 15.555(1) Å, V = 1947.9(3) Å3, Z = 4 and R = 0.068; (+)465CD-t-[Co(mta)(tren)](ClO4)2 ((+)465CD-2Me(ClO4)2): orthorhombic, P212121, a = 10.564(1), B = 11.375(1), C = 15.434(2) Å, V = 1854.7(4) Å3, Z = 4 and R = 0.047. All central Co(III) atoms have approximately octahedral geometry, coordinated by four N, one O, and one S atoms. All of the complexes are only isomer, of which the sulfur atom in the didentate-O,S ligands are located at the trans position to the tertiary amine nitrogen atom of tren. 1 and 1Me contain six-membered chelate ring, and 2 and 2Me do five-membered chelate ring in the didentate ligand. The chirality of the asymmetric sulfur donor atom in (+)465CD-1Me is the S configuration and that in (+)465CD-2Me is the R one. The 1H NMR, 13C NMR and electronic absorption spectral behaviors and electrochemical properties of the present complexes are discussed in relation to their stereochemistries.  相似文献   

17.
The reactions of the alkylsulfonated phosphines LM=Ph2P(CH2)nSO3Na/K (n=2, 3, 4) with K2PtCl4 and K2PdCl4 have been studied in homogeneous aqueous solution as a function of pH. In homogeneous acidic solution the protonated phosphines react to give cis- and trans-PtCl2(LH)2. The biphasic reaction between 1,5-cyclooctadiene platinum(II) chloride in dichloromethane and acidified aqueous LNa/K gives a higher proportion of the cis isomer. In neutral solution the initial reaction to give [PtCl(LNa/K)3]+Cl− is followed by slow formation of cis-PtCl2(LNa/K)2. K2PdCl4 reacts more rapidly to give PdCl2(LNa/K)2. In homogeneous alkaline solution rapid oxidation of the phosphine occurs with only small amounts of platinum complex being observable. The biphasic reaction yields phosphine oxide in the aqueous layer and a small amount of the chelate complexes PtL2 in the organic. Representative complexes have been isolated and characterised and the mechanisms for the reactions discussed. The electrospray mass spectra of solutions of the isolated complexes have been recorded in both positive and negative ionisation modes. The positive ionisation spectra are complicated, but platinum and palladium containing ions derived from loss of chloride, H+ and HCl are observed in the negative ionisation spectra.  相似文献   

18.
The kinetics and equilibria of complex formation by Ga(III) with NCS− in aqueous solution have been measured over a range of acidities and temperatures, the contributing paths to the reaction resolved, and their rate constants and activation parameters determined. The hydrolysis equilibria required to carry out this resolution of kinetic behaviour have also been measured.

Unlike the other reported complexation reactions of Ga(III) in aqueous solution, the separate reaction pathways can be assigned with no ambiguity. At 25 °C and ionic strength 0.5 M, the observed forward rate constant for the complex formation is described by {k1 + k2K1h/[H+] + k3K1hK2h/[H+]2} M−1 s−1. For these conditions, the first and second successive hydrolysis constants of Ga(H2O)63+ are given by pK1h = 3.69 ± 0.01 and pK2h = 3.74 ± 0.04. The rate constants corresponding to the reactions of the species Ga(H2O)63+, Ga(H2O)5(OH)2+ and Ga(H2O)4(OH)2+ with NCS− are k1 = 57 ± 4 M−1 −1, k2 = (1.08 ± 0.01) × 105 M−1 s−1 and k3 = 3 × 106 M−1 s−1 respectively. The complexation equilibrium quotient [GaNCS2+]/([Ga3+][NCS−]) has been independently determined by spectrophotometric titration to be 20.8 ± 0.3 M−1 at 25 °C and ionic strength 0.5 M.

These kinetic results lead to an interpretation of the data, and a reinterpretation of other data for aquo-Ga(III) complex formation kinetics from the literature which support the assignment of a dissociative interchange mechanism for these reactions rather than the associative activation mode sometimes proposed.  相似文献   


19.
The trinuclear complexes [Ag(PR3)2]2[Ni(mnt)2] and [AgL]2[Ni(mnt)2] have been prepared by reactions of (NEt4)2[Ni(mnt)2] and Ag2SO4 with alkyl phosphines (PR3=P(CH3)3 (PMe3) for 1, P(C2H5)3 (PEt3) for 2 and P(C6H11)3 (PCy3) for 3), or with chelating diphosphines (L=1,1′-bis(diphenylphosphino)ferrocene (dppf) for 4 and bis(diphenylphosphino)methane (dppm) for 5). The structures of all the complexes have been determined by X-ray crystallography. Interactions between the [Ag(PR3)2]+ and [Ni(mnt)2]2− groups occur in compounds 1 and 2 with Ni---Ag distances of 3.063(4) and 2.9311(6) Å, respectively. Only one sulfur atom of each mnt ligand bridged [Ag(PR3)2]+ cations and [Ni(mnt)2]2− anions in compound 1 through 3 with Ag---S distances of about 2.7 Å. There is no interaction between Ag and Ni in compound 3 due to the flexibility of the cyclohexyl groups. Interactions between [AgL]+ and [Ni(mnt)2]2− groups also occur in compound 4 with a much shorter Ag---Ni distance of 2.7213(7) Å, while silver atoms and the NiS4 plane in compound 4 make a chair conformation with Ag---S distances of about 2.8 Å. In compound 5, dppm bridges two silver atoms, and interaction between silver atoms occurs at a distance of 2.9859(11) Å, and only one sulfur atom of mnt is used to bridge Ni and Ag atoms with Ag---S distances of 2.582(3) and 2.663(3) Å.  相似文献   

20.
Kinetic and activation parameter data for the reactions of cct-Ru(H)2(CO)2(PPh3)2 (1) (cct = cis, cis, trans) in THF with thiols, CO and PPh3 to give cct-RuH(SR)(CO)2(PPh3)2, Ru(CO)3(PPh3)2 and Ru(CO)2(PPh3)2, respectively, reveal a common, rate-determining step, the initial dissociation of H2 from 1; the activated complex probably resembles the corresponding Ru(η2-H2) species. Reaction of Ru(H)2(dppm)2 (2) (as a cis/trans mixture, DPPM = bis(diphenylphosphino)methane) with thiols initially generated cis- and trans- RuH(SR) (dppm)2 with a rate that depends on both the type and concentration of thiol. The higher basicity of the hydride ligands in 2 (versus 1), which is demonstrated by deuterium exchange with CD3OD, gives rise in the thiol reaction to an initial protonation step prior to loss of H2. A species detected in the thiol reaction is possibly [RuH(η2-H2 (dppm)2]2, the anticipated intermediate for this reaction and for the hydrogen exchange with alcohol. A longer reaction of 2 with PhCH2SH gives solely cis-Ru(SCH2Ph)2(dppm)2.  相似文献   

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