Electrospray (ESI) mass spectra analysis of acetonitrile solutions of a series of neutral chloro dimers, pincer type, and monomeric palladacycles has enabled the detection of several of their derived ionic species. The monometallic cationic complexes Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2]+ (1a) and [Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)]+ (1b) and the bimetallic cationic complex [κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2]Pd-Cl-Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2]+ (1c) were detected from an acetonitrile solution of the pincer palladacycles Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2](Cl) 1. For the dimeric compounds {Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](μ-Cl)}2 (2, Y=H and 3, CF3), highly electronically unsaturated palladacycles [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2]+ (2d, 3d) and their mono and di-acetonitrile adducts, namely, [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)]+ (2e, 3e) and [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)2]+ (2f and 3f) were detected together with the bimetallic complex [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2]-Cl-Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N](CH3)2]+ (2a, 3a) and its acetonitrile adducts [κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)Pd-Cl-Pd[ κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2]+ (2b, 3b) and [κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)Pd-Cl-Pd[κ1-C, κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2(CH3CN)]+ (2c, 3c). The dimeric palladacycle {Pd[κ1-C,κ1-N-C(CH3O-2-C6H4)C(Cl)CH2N(CH3)2](μ-Cl)}2 (4) is unique as it behaves as a pincer type compound with the OCH3 substituent acting as an intramolecular coordinating group which prevents acetonitrile full coordination, thus forming the cationic complexes [(C6H4(o-CH3O)CC(Cl)CH2N(CH3)2-κO,κC,κN)Pd]+ (4b), [(C6H4(o-CH3O)CC(Cl)CH2N(CH3)2- κO,κC,κN)Pd(CH3CN)]+ (4c) and [(C6H4 (o-MeO)CC(Cl)CH2N(CH3)2-κO, κC,κN)Pd-Cl-Pd(C6H4(o-CH3O)CC(Cl)CH2N(CH3)2-κO,κC,κN)]+ (4a). ESI-MS spectra analysis of acetonitrile solutions of the monomeric palladacycles Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](Cl)(Py) (5, Y=H and 6, Y=CF3) allows the detection of some of the same species observed in the spectra of the dimeric palladacycles, i.e., monometallic cationic 2d-3d, 2e-3e and {Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](Py)}+ (5a, 6a) and {Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)(Py)}+ (5b, 6b) and the bimetallic 2a, 3a, 2b, 3b, 2c and 3c. In all cationic complexes detected by ESI-MS, the cyclometallated moiety was intact indicating the high stability of the four or six electron anionic chelate ligands. The anionic (chloride) or neutral (pyridine) ligands are, however, easily replaced by the acetonitrile solvent. 相似文献
The reaction of FcCOCl (Fc = (C5H5)Fe(C5H4)) with benzimidazole or imidazole in 1:1 ratio gives the ferrocenyl derivatives FcCO(benzim) (L1) or FcCO(im) (L2), respectively. Two molecules of L1 or L2 can replace two nitrile ligands in [Mo(η3-C3H5)(CO)2(CH3CN)2Br] or [Mo(η3- C5H5O)(CO)2(CH3CN)2Br] leading to the new trinuclear complexes [Mo(η3-C3H5)(CO)2(L)2Br] (C1 for L = L1; C3 for L = L2) and [Mo(η3-C5H5O)(CO)2(L)2Br] (C2 for L = L1; C4 for L = L2) with L1 and L2 acting as N-monodentade ligands. L1, L2 and C2 were characterized by X-ray diffraction studies. [Mo(η3-C5H5O)(CO)2(L1)2Br] was shown to be a trinuclear species, with the two L1 molecules occupying one equatorial and one axial position in the coordination sphere of Mo(II). Cyclic voltammetric studies were performed for the two ligands L1 and L2, as well as for their molybdenum complexes, and kinetic and thermodynamic data for the corresponding redox processes obtained. In agreement with the nature of the frontier orbitals obtained from DFT calculations, L1 and L2 exhibit one oxidation process at the Fe(II) center, while C1, C3, and C4 display another oxidation wave at lower potentials, associated with the oxidation of Mo(II). 相似文献
The reaction of sodium cyclopentadienide (NaCp) with pentafluoropyridine gives Na[4-(C5F4N)C5H4] (PyFCpNa, 1) contaminated with starting NaCp from which pure 1 could be extracted with Et2O. Hydrolysis of 1 and subsequent crystallization gives pure Diels-Alder dimer 1,4-bis(tetrafluoro-4-pyridyl)tricyclo[5.2.1.02,6]deca-3,8-diene (2). The reactions of 1 with FeCl2, [MnBr(CO)5], CoBr2, [Ni(NH3)6]Cl2, [TiCl4(THF)2] and [CpTiCl3] cleanly affords the corresponding metallocenes [Fe(PyFCp)2] (3), [(PyFCp)Mn(CO)3] (5), [Co(PyFCp)2] (6), [Ni(PyFCp)2] (8), [(PyFCp)2TiCl2] (9) and [(PyFCp)(Cp)TiCl2] (10), respectively. Tetrafluoro-4-pyridyl-substituted ferrocene 3 and [Fe(PyFCp)(Cp)] (4) can be alternatively prepared by the reaction of the respective lithioferrocenes with C5F5N in THF. Air-oxidation of complex 6 affords the corresponding cobaltocenium salt [Co(PyFCp)2]PF6 (7). All prepared compounds were characterized spectroscopically and by elemental analysis. The crystal structures of 3-7 were determined, revealing extensive arene π?π stacking and C-H?F-C contacts. Electrochemical studies supported with the spectroscopic data of the prepared metallocene complexes evidenced strong electron-withdrawing nature of the tetrafluoro-4-pyridyl substituent. 相似文献
[M(P3C2tBu2)(CO)3I] (M = Mo, 1, W, 2) have been synthesised and reacted with PCl5 for oxidation study purposes. Compounds Ti(P3C2tBu2)(Ind)Cl2], 3, and [Zr(P3C2tBu2)(Cp)Cl2], 4, were detected spectroscopically, but showed to be too unstable to be isolated. A Ti(IV) complex, [Ti(P3C2tBu2)Cl3], 5, has been formed from the reaction of [TiCl4] with the base-free ligand K(P3C2tBu2), while the Ti(III) species, [Ti(P3C2tBu2) Cl2(THF)], 6, was prepared from [TiCl3(THF)3]. Compounds 5 and 6 were studied as ethylene catalyst precursors after activation with MAO. In the studied conditions, complex 5 is the most active one with an activity of 2.2 × 105 g(molTi [E] h)−1, one order of magnitude higher than compound 6. The produced polymer is linear polyethylene. 相似文献
The structure and composition of the cutin monomers from the flower petals of Vicia faba were determined by hydrogenolysis (LiAlH4) or deuterolysis (LiAlD4) followed by thin layer chromatography and combined gas-liquid chromatography and mass spectrometry. The major components were 10, 16-dihydroxyhexadecanoic acid (79.8%), 9, 16-dihydroxyhexadecanoic acid (4.2%), 16-hydroxyhexadecanoic acid (4.2%), 18-hydroxyoctadecanoic acid (1.6%), and hexadecanoic acid (2.4%). These results show that flower petal cutin is very similar to leaf cutin of V. faba. Developing petals readily incorporated exogenous [1-14C]palmitic acid into cutin. Direct conversion of the exogeneous acid into 16-hydroxyhexadecanoic acid, 10, 16-dihydroxy-, and 9, 16-dihydroxyhexadecanoic acid was demonstrated by radio gas-liquid chromatography of their chemical degradation products. About 1% of the exogenous [1-14C]palmitic acid was incorporated into C27, C29, and C31n-alkanes, which were identified by combined gas-liquid chromatography and mass spectrometry as the major components of the hydrocarbons of V. faba flowers. The radioactivity distribution among these three alkanes (C27, 15%; C29, 48%; C31, 38%) was similar to the per cent composition of the alkanes (C27, 12%; C29, 43%; C31, 44%). [1-14C]Stearic acid was also incorporated into C27, C29, and C31n-alkanes in good yield (3%). Trichloroacetate, which has been postulated to be an inhibitor of fatty acid elongation, inhibited the conversion of [1-14C]stearic acid to alkanes, and the inhibition was greatest for the longer alkanes. Developing flower petals also incorporated exogenous C28, C30, and C32 acids into alkanes in 0.5% to 5% yields. [G-3H]n-octacosanoic acid (C28) was incorporated into C27, C29, and C31n-alkanes. [G-3H]n-triacontanoic acid (C30) was incorporated mainly into C29 and C31 alkanes, whereas [9, 10, 11-3H]n-dotriacontanoic acid (C32) was converted mainly to C31 alkane. Trichloroacetate inhibited the conversion of the exogenous acids into alkanes with carbon chains longer than the exogenous acid, and at the same time increased the amount of the direct decarboxylation product formed. These results clearly demonstrate direct decarboxylation as well as elongation and decarboxylation of exogenous fatty acids, and thus constitute the most direct evidence thus far obtained for an elongation-decarboxylation mechanism for the biosynthesis of alkanes. 相似文献
Biosynthesis of the aliphatic components of suberin was studied in suberizing potato (Solanum tuberosum) slices with [1-14C]oleic acid and [1-14C]acetate as precursors. In 4-day aged tissue, [1-14C]oleic acid was incorporated into an insoluble residue, which, upon hydrogenolysis (LiA1H4), released the label into chloroform-soluble products. Radio thin layer and gas chromatographic analyses of these products showed that 14C was contained exclusively in octadecenol and octadecene-1, 18-diol. OsO4 treatment and periodate cleavage of the resulting tetraol showed that the labeled diol was octadec-9-ene-1, 18-diol, the product expected from the two major components of suberin, namely 18-hydroxyoleic acid and the corresponding dicarboxylic acid. Aged potato slices also incorporated [1-14C]acetate into an insoluble material. Hydrogenolysis followed by radio chromatographic analyses of the products showed that 14C was contained in alkanols and alkane-α,ω-diols. In the former fraction, a substantial proportion of the label was contained in aliphatic chains longer than C20, which are known to be common constituents of suberin. In the labeled diol fraction, the major component was octadec-9-ene-1,18-diol, with smaller quantities of saturated C16, C18, C20, C22, and C24-α,ω-diols. Soluble lipids derived from [1-14C]acetate in the aged tissue also contained labeled very long acids from C20 to C28, as well as C22 and C24 alcohols, but no labeled ω-hydroxy acids or dicarboxylic acids were detected. Label was also found in n-alkanes isolated from the soluble lipids, and the distribution of label among them was consistent with the composition of n-alkanes found in the wound periderm of this tissue; C21 and C23 were the major components with lesser amounts of C19 and C25. The amount of 14C incorporated into these bifunctional monomers in 0-, 2-, 4-, 6-, and 8-day aged tissue were 0, 1.5, 2.5, 0.8, and 0.3% of the applied [1-14C]oleic acid, respectively. Incorporation of [1-14C]acetate into the insoluble residue was low up to the 3rd day of aging, rapid during the next 4 days of aging, and subsequently the rate decreased. These changes in the rates of incorporation of exogenous oleic acid and acetate reflected the development of diffusion resistance of the tissue surface to water vapor. As the tissue aged, increasing amounts of the [1-14C]acetate were incorporated into longer aliphatic chains of the residue and the soluble lipids, but no changes in the distribution of radioactivity among the α-ω-diols were obvious. The above results demonstrated that aging potato slices constitute a convenient system with which to study the biochemistry of suberization. 相似文献
Several palladium complexes of the type [Pd(im)2Cl2], [Pd(im)3Cl]Cl, and [Pd(im)4]Cl2 (im = imidazole 1, 1-methylimidazole 2, 1,2-dimethylimidazole 3, 1-butylimidazole 4, 4a, 1-phenylimidazole 6, 1-phenylimidazoline 7, and 1-methylimidazoline 8) were prepared and structurally characterized. The square planar structure of two new complexes with the composition [Pd(im)4]Cl2 (2b, 4b) was confirmed by X-ray analysis. In solution, exchange of imidazole ligands leading to heteroleptic products was evidenced by ESI-MS studies. Two bis-ligated complexes, bearing 1-methylimidazole (2a) and 1-propoxymethylimidazole (5) ligands, were obtained in the reaction of palladium with imidazoles formed by deprotection of one nitrogen atom in the respective imidazolium halides. Catalytic Suzuki-Miyaura reactions were carried out using the obtained palladium complexes in isopropanol-water solution. High yields of the cross-coupling products were obtained at 40 and 60 °C when 2-bromotoluene, 4-bromotoluene, and 4-bromoanizole were used as substrates. 相似文献
Trityl borate salts [4-RPyCPh3][B(C6F5)4] (R = H 1, tBu 2, Et 3, NMe24) and [R3PCPh3][B(C6F5)4] (R = Me 5, nBu 6, Ph[1] 7, p-MeC6H48) are readily prepared via equimolar reaction of the appropriate pyridine or phosphine and trityl borate [CPh3][B(C6F5)4]. The analogous reactions of PiPr3 affords the product [(p-iPr3P-C6H4)Ph2CH][B(C6F5)4] (9) while the corresponding reactions of Cy3P and tBu3P gave the cyclohexadienyl derivatives [(p-R3PC6H5)CPh2][B(C6F5)4] (R = Cy 10, tBu 11). X-ray structures of 5 and 9 are reported. 相似文献
Titration curves were measured for three molybdocene dimers, [Cp2Mo(μ-OH)]2[OTs]2 (4), [Mo(μ-OH)]2[OTs]2 (4′; Cp′ = C5H4CH3), and ansa-[C2Me4Cp2Mo(μ-OH)]2[OTs]2 (4a), and for two monomeric molybdocene complexes, Cp2MoO (6) and Cp2MoCl2 (1). The titration curves for 4, 6, and 1 were identical and showed three equivalence points each. The titration curve for 4′ was also similar in appearance but the equivalence points were shifted higher by ∼0.3, as expected for the more electron-rich Mo center in this molecule. The titration curve for the ansa-[C2Me4Cp2Mo(μ-OH)]2[OTs]2 complex showed only two equivalence points. Two of the equivalence points observed in the titration of 4, 6, and 1 were previously reported in potentiometric measurements of aqueous solutions of Cp2MoCl2 and were attributed to the Cp2Mo(OH2)2+ species (pKa = 5.5 ± 0.1 and 8.3 ± 0.2). The third equivalence point (pKa = 2.2 ± 0.2) is assigned to protonation/deprotonation of the [Cp2Mo(μ-OH)]2[OTs]2/[Cp2Mo(μ-OH2)(μ-OH)MoCp2]3+ dimer. A new equilibrium scheme is proposed for the aquated molybdocenes to provide a more complete picture of the aqueous speciation of the non-ansa molybdocene complexes, specifically by accounting for the third acidic proton in the titration curves and by describing the hydrolysis of Cp2MoO. Although the titration curve of the ansa-[C2Me4Cp2Mo(μ-OH)]2[OTs]2 complex is different from that of [Cp2Mo(μ-OH)]2[OTs]2, 1H NMR data suggest that the aqueous speciation of the ansa-[C2Me4Cp2Mo(μ-OH)]2[OTs]2 complex is analogous to that of the non-ansa molybdocenes. 相似文献
A comparative study of metallophilic interactions of [Pt(tpy)X]+ cations (tpy = 2,2′:6′,2″-terpyridine) in the presence of two different types of anions, (i) []− anions that form double salts and (ii) simple p-block anions, is reported. Single-crystal X-ray diffraction data, solution-state 195Pt NMR spectra, and variable temperature solid-state luminescence spectra are reported. Three [Pt(tpy)Cl]Y derivatives (Y = SbF6, 1, SbF6·CH3CN, 4, PF6, 2) and the [Pt(tpy)Br]PF6 analog, 3, as well as two new double salts [Pt(tpy)CN][Au(CN)2], 5, and [Pt(tpy)CN]2[Au(C6F5)2](PF6), 6, have been synthesized and characterized. Structural analysis shows consistent patterns in Pt···Pt interactions that vary slightly depending on the coordinating halogen or pseudo-halogen X, counter anion Y, and lattice solvent. Metallophilic interactions are seen between [Pt(tpy)X]+ cations with all types of X ligands, but only with π-accepting X′ ligands from []− anions are Pt?Au metallophilic interactions seen to be favored over Pt?Pt interactions. The [Au(CN)2]− anion consistently forms Pt···Au metallophilic contacts, unlike [Au(C6F5)2]−. The 195Pt NMR chemical shifts are ∼−2750 ppm for π-donor ligands and near −3120 ppm for π-acceptor ligands in [Pt(tpy)X]PF6 compounds. Luminescence data show an unusual blue shift in [Pt(tpy)CCPh][Au(C6F5)2] versus [Pt(tpy)CCPh]PF6 ascribed to an intermolecular charge transfer. 相似文献
The mixed-metal trinuclear cluster cations [H3Ru2(C6Me6)2Os(C6H6)(O)]+ (1), [H3Ru2(1,2,4,5-C6H2Me4)2Os(p-MeC6H4iPr)(O)]+ (2) and [H3Ru2(1,2,4,5-C6H2Me4)2Os(C6H6)(O)]+ (3) have been synthesised from the corresponding dinuclear precursors [H3Ru2(arene)2]+ and the corresponding mononuclear complexes [Os(arene)(H2O)3]2+, isolated and characterised as the tetrafluoroborate and hexafluorophosphate salts. The cations 1, 2 and 3 are heteronuclear analogues of the cluster cation [H3Ru3(C6H6)(C6Me6)2(O)]+ that possesses a homonuclear metallic core. The single-crystal X-ray structure analyses of [1][BF4], [2][PF6] and [3][PF6] reveal an equiangular metal triangle despite the presence of an osmium atom in the metallic core. 相似文献
The insertion reaction of maleic anhydride into the Cu-O bond in [CuOtBu] produced the complexes [Cu2(CO2C2H2CO2tBu)4 · dme] (1), [Cu(CO2C2H2CO2tBu)2 · tmeda] (2) and [Cu2(CO2C2H2CO2tBu)2 · dppm]2 (3) (dme = 1,2-dimethoxyethane; tmeda = N1,N1,N2,N2-tetramethylethane-1,2-diamine; dppm = bis(diphenylphosphino)methane). This reaction represents a useful synthetic strategy for a range of functionalised Cu(I) and Cu(II) carboxylates. 相似文献
Cut seedlings of Mercurialis annua L. were supplied with solutions containing [1-13C1]glucose or [U-13C4,15N1]aspartate. After 5–7 days, the pyridinone-type chromogen, hermidin, was isolated and analyzed by NMR spectroscopy. In the experiment with [1-13C1]glucose, five single-labelled isotopomers of hermidin were detected at high abundances (2.7–1.8 mol%). In the experiment with [U-13C4,15N1]aspartate, contiguous labelling was observed for carbon atoms 2 and 3 and the nitrogen atom in hermidin. The labelling patterns of hermidin and of amino acids from the same experiments rule out predominant formation of the pyridinone by pathways resembling the biosyntheses of vitamin-B6, anabasine, or polyketides, but suggest a pathway by condensation of aspartate and dihydroxyacetone phosphate affording nicotinate as a precursor of hermidin. 相似文献
This study investigates the effects of ethanol on neuronal and astroglial metabolism using 1H‐[13C]‐NMR spectroscopy in conjunction with infusion of [1,6‐13C2]/[1‐13C]glucose or [2‐13C]acetate, respectively. A three‐compartment metabolic model was fitted to the 13C turnover of GluC3, GluC4, GABAC2, GABAC3, AspC3, and GlnC4 from [1,6‐13C2]glucose to determine the rates of tricarboxylic acid (TCA) and neurotransmitter cycle associated with glutamatergic and GABAergic neurons. The ratio of neurotransmitter cycle to TCA cycle fluxes for glutamatergic and GABAegic neurons was obtained from the steady‐state [2‐13C]acetate experiment and used as constraints during the metabolic model fitting. 1H MRS measurement suggests that depletion of ethanol from cerebral cortex follows zero order kinetics with rate 0.18 ± 0.04 μmol/g/min. Acute exposure of ethanol reduces the level of glutamate and aspartate in cortical region. GlnC4 labeling was found to be unchanged from a 15 min infusion of [2‐13C]acetate suggesting that acute ethanol exposure does not affect astroglial metabolism in naive mice. Rates of TCA and neurotransmitter cycle associated with glutamatergic and GABAergic neurons were found to be significantly reduced in cortical and subcortical regions. Acute exposure of ethanol perturbs the level of neurometabolites and decreases the excitatory and inhibitory activity differentially across the regions of brain.
The metabolism of 14C-labeled fatty acids and triacylglycerols was followed in intact germinating oil palm seedlings as well as in tissue slices. In the germinating seedling, the shoot contained a normal pattern of membrane fatty acids (mainly C16, C18:1, C18:2) but the kernel contained about 68% C12 and C14 fatty acids. Haustorium fatty acids were intermediate between the two. [14C]Acetate was actively metabolized by shoot and haustorium slices but not so actively by the kernel. Approximately 9% to 17% was converted to water-soluble substances, 4% to 6% to CO2, and 0.5% to 5.9% to lipids. The fatty acids synthesized in the shoot and haustorium were mainly C16, C18, and C18:1 fatty acids but in the kernel about 18% to 32% of the 14C-fatty acids were C12 fatty acids.
[14C]Lauric acid was absorbed and metabolized by haustorium slices and by the haustorium in intact seedlings; it was partly esterified to triacylglycerols and also converted to water-soluble substances and insoluble tissue material. In contrast, tri-[14C]laurin was absorbed but not metabolized. The haustorium also absorbed other fatty acids but the longer chain (C16 and C18) fatty acids were not esterified or metabolized further. Preincubation of the haustorium with plant hormones or in the presence of kernel tissue did not alter its inactivity towards tri-[14C]laurin.
When tri-[14C]laurin or [14C]lauric acid were injected into the seed or the shoot, there was no movement or radioactivity to other parts of the seedling. When injected into the shoot, but not into the seed, tri-[14C] laurin was hydrolyzed and partly metabolized to water-soluble substances.
The synthesis of palladacyclic derivatives with the hybrid pyridylphosphine ligands Py(CH2)OPPh2 (a) and PyNHPPh2 (b) in a neutral P,N-chelating coordination mode has been achieved. Treatment of selected chloride-bridged cyclometallated precursors [Pd(C∧N)(μ-Cl)]2 [C∧N = 2-pyridinin-phenyl Phpy, I-compounds; 7,8-benzoquinolyl Bzq, II-compounds; phenylazophenyl Azb, III-compounds or 2-(2-oxazolinyl)phenyl Phox, IV-compounds] with a or b in the presence of stoichiometric KPF6 gave the mononuclear derivatives Ia-IVa and Ib-IVb. The crystal structures of compounds [Pd(Azb)(Ph2POCH2Py-P,N)][PF6] (IIIa) and [Pd(Phpy)(Ph2PNHPy-P,N)][PF6] (Ib) have been determined. The new palladacyclopentadiene precursor [Pd{C4COOMe4}(CH3CN)2] (V) has been prepared starting from the polymeric complex [Pd{C4COOMe4}]n. Its usefulness in the preparation of new derivatives has been tested by means of the straightforward reaction with ligands (a) or (b) to give mononuclear compounds [Pd{C4(COOMe)4}(Ph2POCH2Py-P,N)] (Va) and [Pd{C4(COOMe)4}(Ph2PNHPy-P,N)] (Vb). The reactions of hydroxo-bridged precursors [Pd(C∧N)(μ-OH)]2 or [Pd2{C4(COOMe)4}2 (μ-OH)2][NBu4]2 with PyNHPPh2 afforded mononuclear complexes Ic-Vc in which a less common anionic P,N-binding mode is forced as a result of ligand deprotonation. The new complexes were characterised by partial elemental analyses and spectroscopic methods (IR, FAB, 1H and 31P{1H} NMR). 相似文献
Complexation of M+=Li+, Na+, Ag+ and TI+ by the cryptands 4, 7, 13, 18-tetraoxa-l, 10-diazabicyclo[8.5.5]eicosane (C211) and 4,7,13-trioxa-1,10-diazabicyclo[8.5.5]eicosane (C21C5) to form the cryptates [M.C211]+ and [M.C21C5]+ has been studied in trimethyl phosphate by potentiometric titration and 7Li and 23Na NMR spectroscopy. For [M.C211]+ the logarithm of the apparent stability constants, log K (dm3 mol-1)=6.98±0.05, 5.38±0.05, 9.82±0.02 and 3.95±0.02 for M+ =Li+, Na+, Ag+ and TI+, respectively; and for [M.C21C5]+ log K (dm3 mol-1)=2.40±0.10, 1.90±0.05, 6.04±0.02 and 2.42±0.10 for M+=Li+, Na+, Ag+ and Tl+, respectively. The decomplexation kinetic parameters for [Na.C211]+ are: kd (298.2 K)=6.924±0.50 s-l, ΔHd≠=62.2±0.9 kJ mol-1, and ΔSd≠= -20.3±2.7 J K-1 mol-1; and those for [Li.C21C5]+ are: kd (298.2 K)=23.3±0.4 s-1, ΔHd≠ =61.2±1.1 kJ mol-1, and ΔSd≠= -13.6±3.6 J K-1 mol-1. Metal ion exchange on [Li.C211]+ is in the very slow extreme of the NMR timescale up to 390 K and kd « 4 s-1 at 298.2 K, while in contrast exchange on [Na.C21C5]+ is in the fast extreme of the NMR timescale at 298.2 K (kd≈ 104 s-1). These data are compared with those obtained in other solvents. 相似文献
The crystalline compounds (Hbipy)2[Ge(C2O4)3] (1) and (Hphen)2[Ge(C2O4)3] · 2(H2O) (2) [Hbipy+ is the 2,2′-bipyridinium cation (C10H9N2), and Hphen+ is the 1,10′-phenathrolinium cation (C12H9N2)] were isolated from mild hydrothermal syntheses and their structures were elucidated from single-crystal X-ray diffraction. The two compounds were further characterised by vibrational spectroscopy (FT-IR and FT-Raman), thermogravimetric analysis (TGA) and CHN elemental composition. Compounds 1 and 2 comprise the tris(oxalato-O,O′)germanate dianion complex, [Ge(C2O4)3]2−, which co-crystallises with Hbipy+ (in 1), or Hphen+ and water molecules (in 2). In 1, the germanium oxalate anionic complex, [Ge(C2O4)3]2−, and the Hbipy+ organic residues interact mutually via N-H?O hydrogen bonding interactions, leading to supramolecular discrete hydrogen-bonded units which are further interconnected via π-π stacking. Compound 2, on the other hand, exhibits a more complex hydrogen bonding network due to the presence of the water molecules of crystallisation which, along with π-π stacking between neighbouring Hphen+ residues, mediate the crystal packing. 相似文献
Copper(I) and silver(I) complexes of formulae [Cu(NCCH3)4]+[A]− ([A]− = [B(C6F5)4]− (1), {B[C6H3(CF3)2]4}− (2), [(C6F5)3B–C3H3N2–B(C6F5)3]− (3), and [Ag(NCCH3)4]+[B(C6F5)4]− (4) are examined with particular emphasis on the strength of their M–N bond and its influence on the catalytic performance of these complexes in cyclopropanation and aziridination. To examine the strength of the M–N interactions, vibrational spectra of the related hydrogenated and deuterated species [Cu(NCCH3)4]+, [Cu(NCCD3)4]+, [Ag(NCCH3)4]+, and [Ag(NCCD3)4]+ are also determined. It is found that the metal–nitrile bond strength is an important factor for the catalytic activity of the respective complexes. 相似文献
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