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1.
Fenske-Hall molecular orbital calculations have been applied to a new, structurally isolable analog of the intermediate involved in catalytic rhodium carboxylate carbenoid transformations. Results from the structural characterization of axially ligated rhodium acetate phenylisonitrile complexes have been utilized in approximate molecular orbital calculations. The results from the calculations suggest that a significant degree of π back-bonding exists between the metal and isonitrile fragments which, by analogy, implies that π back-bonding should also exist in the rhodium carbenoid intermediate. Sensitivity of the Fenske-Hall method to the magnitude of π back-donation in these complexes was gauged through calculations involving different phenylisonitrile groups in which the π back-bonding ability was modulated through derivativization. The reliability of the Fenske-Hall method was evaluated through a comparison to a high-level calculation. Received: 13 December 1996 / Accepted: 18 March 1997  相似文献   
2.
Biocidal and spectroscopic aspects of organotin(IV) complexes with (E)-3-[(2′,6′-dichlorophenylamido)]propenoic acid are described with support of elemental analysis. IR, 1H, 13C, 119Sn NMR and mass spectral data suggest that the ligand is bidentate, coordinating through oxygen atoms and that diorganotin(IV) complexes are six-coordinate. Triorganotin(IV) carboxylates exist as pentacoordinated trigonal bipyramidal complexes in the solid state and tetrahedral ones in solution. The complexes have been screened against bacteria, fungi and brine-shrimp larvae to assess their biological activity.  相似文献   
3.
Bis-paddlewheel heterobimetallic complexes in which palladium(II) is connected to the rare-earth metals(III) [Pd(μ-OOCMe)4Ln(OH2)(μ,η2-OOCMe)]2 × 2HOOCMe (Ln = Nd, Sm, Eu, Yb and Tm) by four acetate bridges were synthesised by the reaction of Pd3(μ-OOCMe)6 with the LnIII acetates. The tetraacetate-bridged complexes were unexpectedly found to be readily transformed by the stoichiometric amount of pivalic acid into the mono-paddlewheel tetrapivalate-bridged analogues in which the paddlewheel structure [Pd(μ-OOCR)4Ln] maintains as established by X-ray crystallography. The role of the intra- and intermolecular H-bonding in these complexes is discussed.  相似文献   
4.
The preparation and characterization of the 1:1 inclusion compound of rhodium(II) -methyl cinnamate in -cyclodextrin is reported. Evidence of inclusion was obtained from X-ray powder diffraction results, Raman, IR and UV-Vis spectroscopic studies and thermal analysis. Given the potential antitumor activity of the rhodium(II) carboxylate and its virtual insolubility in water, its inclusion in -cyclodextrin opens the possibility for its transference to the aqueous phase.  相似文献   
5.
A one-dimensional chain chlorodibenzyltin 2-quininate has been synthesized and characterized by IR, NMR spectra and elemental analysis. The crystal structure has been determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group I4(—) with a = 19.1171(10), b = 19.1171(10), c = 12.5158(6) , Z = 8, V = 4574.1(4) 3, Dc = 1.477 g·cm-3, μ(MoKα) = 1.252 mm-1, F(000) = 2032, R = 0.0259 and wR = 0.0723. In the complex, the tin atom is six-coordinated to adopt a distorted octahedral configuration with bridging carboxyl of quinoline-2-carboxylic acid. The result of fluorescence spectrum analysis shows that the title complex at room temperature exhibits an intense photoluminescence with maximum emission at 364.2 nm (λex = 303.0 nm).  相似文献   
6.
Organotincompoundsareextensivelystudiedfortheirbiologicalactivity'.Organogermaniumisanotherkindofelementthathasawiderangeofbiologicalactivity=.Tolinkbiologicalactivepropertiesoforganotinandorganogermaniumcompounds.wehavepreviouslyreportedthebiologicalactivityoftrialkyltingermylpropionates'andanticanceractivityofdibutyltindigermylpropionates'.ItiswellknownthatTorque(his[tri(2-methyl-2-phenylpropyl)tin]oxide)iswidelyusedinagricultureasanacaricide.Inthispaper,asthecontinuationofourpreviouswork"'…  相似文献   
7.
8.
2-Trifluoromethyl-substituted 1,2,3,6-tetrahydro-2-pyridyl carboxylates were synthesized in one step by the aza Diels—Alder reactions of methyl trifluoropyruvate sulfonyl- and phosphorylimines with 1,3-dienes.  相似文献   
9.
Summary A simple and general method for the determination of both C1−C10 alkyl sulfonates and alkyl carboxylates using the same basic methodology, based on High Performance ion Chromatography, using relatively simple eluent systems allowing fast analysis with both high sensitivity and accuracy is presented.  相似文献   
10.
    
The anodic oxidation of tetrabutylammonium carboxylates bearing aromatic or unsaturated terminal groups is a reaction that allows the covalent grafting of organic moieties on carbon electrodes in acetonitrile as solvent. The electron transfer step is followed by a fast decarboxylation reaction, which releases the respective unsaturated free radicals, whose transient formation at the interface explain the surface grafting phenomenon, however; the lack of grafting during the oxidation of saturated aliphatic carboxylates is unexpected. Therefore, this work shows that the covalent grafting by oxidation of unsaturated carboxylates is favored for a parallel orientation of the radicals on the electrode surface, which is originated by the positive polarization of the electrode and the partially negative electronic density on the terminal unsaturated groups in the radical structure. This orientation is furthermore the result of a previous similar orientation of the unsaturated carboxylates, which is transitorily retained because of the very high rate of the decarboxylation step. Cyclic voltammetry experiments performed using different saturated and unsaturated alkyl-carboxylates, their respective carboxylic acids, as well as the use of ferrocene derivatives as redox probes were used to indirectly support the main conclusions given here.  相似文献   
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