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1.
Summary The solution equilibria of 2-hydroxynicotinic acid (hyna) complexes with mercury(II) have been studied spectrophotometrically in 50% (v/v) ethanol at 20°C and an ionic strength of 0.1mol dm–3 (NaClO4). Three mercuric complexes are formed in solution in dependence on the acidity of the medium. The basic characteristics of the different complexes are determined and the analytical aspects of the complexation reaction are demonstrated. A critical investigation has also been presented of the solution equilibria and stability of the mixed complex of mercury(II) withhyna and thiosalicylic acid (tsa). The various complex transitions leading to the formation of the 1 : 1 : 1 Hg(tsa)(hyna) ternary complex in solution are investigated. The non-charged mono-ligand complex Hg(hyna) is used for UV-spectrophotometric determination of mercury atpH 4.5–5 (max=325nm, =0.8·104lmol–1cm–1). The system obeyed Beer's law up to 36.1 µg ml–1 of Hg(II). The optimum concentration range (Ringbom) is between 6 and 28.5µg ml–1. Interference caused by a number of ions was masked by the addition of fluoride ions.
Lösungsgleichgewichte und Stabilitätskonstanten von Komplexen der Pyridincarbonsäuren: Die Komplexierungsreaktion von Quecksilber(II) mit 2-Hydroxynikotinsäure
Zusammenfassung Die Lösungsgleichgewichte von 2-Hydroxynikotinsäure (hyna) mit Hg(II) wurde spektrophotometrisch in 50% (v/v) Ethanol bei 20°C und einer Ionenstärke von 0.1 mol dm–3 (NaClO4) untersucht. In Abhängigkeit von der Acidität des Mediums werden drei Quecksilberkomplexe gebildet. Die grundlegenden Charakteristika der Komplexe wurden bestimmt und die analytischen Aspekte aufgezeigt. Die gemischten Komplexe von Hg(II) mithyna und Thiosalicylsäure (tsa), insbesondere die verschiedenen Komplexübergänge zum ternären 1 : 1 : 1 Hg(tsa)(hyna)-Komplex, wurden ebenfalls untersucht. Der ungeladene Monoligandenkomplex Hg(hyna) kann beipH 4.5–5 zur UV-spektroskopischen Quecksilberbestimmung eingesetzt werden (max=325nm, =0.8·104lmol–1cm–1). Das System gehorcht bis zu einer Hg(II)-Konzentration von 36.1µgml–1 dem Beerschen Gesetz. Der optimale Konzentrationsbereich (Ringbom) liegt zwischen 6 und 28.5µgml–1. Interferenzen mit einer Reihe anderer Ionen konnten durch Maskierung mit Fluoridionen umgangen werden.
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2.
Within this study, coordination properties of the cyclic diphosphine 1,2,3,4-tetrahydro-1,4-diphenyl-1,4-benzodiphosphinine (bedip) are investigated, through the preparation of neutral and cationic Pt(II), Pt(IV) and Pd(II) complexes. The diphosphine acts as bridging ligand in the neutral Pt(II) and Pd(II) complexes, affording [MX(CH3)(μ-bedip)]2 (X = Cl, Br, I, CH3) species. Chelation is observed in all the remaining complexes. The molecular structures of [PtX(CH3)(μ-bedip)]2 (X = Br, I) and [PtI(CH3)3(bedip)] are also determined.  相似文献   

3.
The coordination preference of the ketoiminato ligand, RN(H)(C(Me))2C(Me)O, (R = 2,6-diisopropylphenyl, (Dipp)), L1, and RN(H)C(Me)CHC(Me)O, R = C2H4NEt2, L2, have been investigated with a range of d and p block metal halides, (or alkyls), to compare and contrast products obtained from the bulky ketoiminato ligand, L1, versus the less bulky, but multidentate ligand, L2. The products have been characterized by X-ray crystallography along with other spectroscopic techniques and show how the preferred metal geometry remains constant for products with either ligand, but the steric protection offered by the individual ligands governs the nuclearity of the products, affording monomers, dimers and tetramers.  相似文献   

4.
Novel mercury(II) compounds of 3-hydroxypicolinic acid (HpicOH; IUPAC name: 3-hydroxy-2-pyridinecarboxylic acid) were synthesized and characterized. HgCl(picOH) (1) and HgBr2(HpicOH) (2) were obtained as reaction products from the reaction of the corresponding mercury(II) halide with HpicOH, irrespective of the molar ratio of the reactants. From the reaction of HpicOH and mercury(II) acetate, Hg(picOH)2 (3) was obtained, while mercury(II) nitrate monohydrate gave the 1/1 solvate with water Hg(picOH)2 · H2O (3a). Infrared, 1H and 13C NMR spectroscopic data were analyzed for complexes 1, 2 and 3. X-ray crystal structure analysis of 1 and 2 revealed their polymeric nature and different coordination modes of HpicOH. In 1 the deprotonated picolinic acid is N,O-chelating and bridging, while in 2 HpicOH is a O-monodentate weakly bound ligand. Compound 1 consists of HgCl(picOH) moieties with two linear covalent bonds, Hg–N 2.143(4) and Hg–Cl 2.298(1) Å, and four additional Hg?O contacts (2.460(3)–2.904(3) Å) in which both oxygen atoms from the carboxylic group are bridging and involved in coordination to three neighboring mercury atoms, thus forming infinite layers. The coordination of mercury is 2 + 4. 2 consists of {HgBr2(HpicOH)} moieties, which are linked into chains by means of mercury to bromine secondary long range interactions. The coordination sphere of mercury can be described as irregular 2 + 3 formed by two covalently bonded bromine atoms (Hg–Br 2.277(1) and 2.366(1) Å), two bridging bromine atoms (Hg?Br 3.309(1) and 3.247(1) Å) and by the HpicOH ligand attached to mercury in the zwitterionic form via the carboxylic oxygen atom (Hg?O 2.602(7) Å).  相似文献   

5.
Complexes of type {cis-[Pt](μ-σ,π-CCPh)2}AgX (3a, [Pt] = (bipy′)Pt, X = FBF3; 3b, [Pt] = (bipy′)Pt, X = FPF5; 3c, [Pt] = (bipy)Pt, X = OClO3; 3d, [Pt] = (bipy′)Pt, X = BPh4; bipy′ = 4,4′-dimethyl-2,2′-bipyridine; bipy = 2,2′-bipyridine) are accessible by combining cis-[Pt](CCPh)2 (1a, [Pt] = (bipy′)Pt; 1b, [Pt] = (bipy)Pt) with equimolar amounts of [AgX] (2a, X = BF4; 2b, X = PF6; 2c, X = ClO4; 2d, X = BPh4). In 3a-3d the platinum(II) and silver(I) ions are connected by σ- and π-bonded phenyl acetylide ligands. When the molar ratio of 1 and 2 is changed to 2:1 then trimetallic [{cis-[Pt](μ-CCPh)2}2Ag]X (8a, [Pt] = (bipy)Pt, X = BF4; 8b, [Pt] = (bipy′)Pt, X = PF6; 8c, [Pt] = (bipy)Pt, X = BF4) is produced. The solid state structure of 8a was determined by single X-ray crystal structure analysis. In 8a the silver(I) ion is embedded between two parallel oriented cis-[Pt](CCPh)2 units. Within this structural arrangement the phenyl acetylides of individual [Pt](CCPh)2 entities possess a μ-bridging position between Pt(II) and Ag(I). In addition, a very weak dative Pt → Ag interaction is found (Pt-Ag 2.8965(3) Å). The respective silver carbon distances Ag-Cα (2.548(7), 2.447(7) Å) and Ag-Cβ (3.042(7), 2.799(8) Å)(PtCαCβPh) confirm this structural motif.Complexes 8a-8c isomerize in solution to form trimetallic [{cis-[Pt](μ-σ,π-CCPh)2}2Ag]X (9a, [Pt] = (bipy)Pt, X = BF4; 9b, [Pt] = (bipy′)Pt, X = PF6; 9c, [Pt] = (bipy)Pt, X = ClO4). In the latter molecules the organometallic cation [{cis-[Pt](μ-σ,π- CCPh)2}2Ag]+ is set-up by two nearly orthogonal positioned [Pt](CCPh)2 entities which are hold in close proximity by the group-11 metal ion. Within this assembly all four PhCC units are η2-coordinated to silver(I). A possible mechanism for the formation of 9 is presented.  相似文献   

6.
Two new copper(II) and chromium(III) complexes of tridentate 2,6-pyridinedicarboxylic acid (H2pydc) with imidazole (im), (Him)[Cu(Hpydc)(pydc)]?H2pydc?5H2O (1) and (Him)[Cr(pydc)2]?H2pydc?5H2O (2), have been prepared and characterized by elemental analysis, TGA measurements, FT-IR, and UV–Vis spectroscopy, powder and single crystal X-ray crystallography. Crystal structure analyses reveal that both copper(II) and chromium(III) ions are in a distorted octahedral environment. The optimized geometrical parameters were calculated using methods based on the density functional theory (DFT). These calculations agree closely with the X-ray structure. The antimicrobial activities of the ligand and the complexes were evaluated in vitro and compared with drugs in use. The results show that the complexes had stronger antibacterial activity than the corresponding ligand and the effectiveness was confirmed against Bacillus subtilis (gram positive) and Klebsiella pneumoniae (gram negative) for 1, and Escherichia coli and K. pneumoniae (gram negative) for 2 by the well diffusion method.  相似文献   

7.
The complexes Cr(CO)5(R′SNR2) [R′ = CH3; NR2 = N(CH3)2, N(C4H8)O. R′ = C6H5; NR2 = N(CH3)2, N(C4H4)O, N(CH2? C6H5)2, N(C6H11)2] have been prepared by reaction of the sulfenamides with Cr(CO)5 · THF and characterized by analytical and spectroscopic methods. The IR, 1H-NMR, UV-VIS, and mass spectra of the complexes support the coordination of the sulfenamide via the sulfur atom. π-acceptor abilities of sulfenamides in the prepared coordination compounds, determined from IR and UV-VIS data, were compared with those of other divalent sulfur conpounds.  相似文献   

8.
Chelate complexes of antimony tetrachloride with dibenzoylmethane and (benzoylchloro-methyl)diphenylphosphine oxide were stndicd by X-ray diffraction, I R, and Raman spectroscopy. The antimony atom has a slightly distorted octahedral coordination in the complexes. The bond lengths in the chelate cycles are evidence for an appreciable electron delocalization in the O-C-C-C-0 and O-C-C-P-0 chains. Unlike the C3O2Sb chelate cycle, the chelate cycle with the phosphorus atom is nonplanar. The assignment of the stretching vibrations frequencies of the C-O, P-0, C-C, Sb-O, and Sb-CI bonds was presumably made on the basis of the IR and Raman spectral data.Deceased in 1995.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1474–1479, June, 1996.  相似文献   

9.
Compounds having general formula: [M(FO)(Cl)(x)(H(2)O)(y)].zH(2)O, where (M=Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II), FO=folate anion, x=2 or 4, y=2 or 4 and z=0, 1, 2, 3, 5 or 15) were prepared. The obtained compounds were characterized by elemental analysis, infrared as well as electronic spectra, thermogravimetric analysis and the conductivity measurements. The results suggested that all folate complexes were formed by 2:1 molar ratio (metal:folic acid) as a bidentate through both of the two carboxylic groups. The molar conductance measurements proved that the folate complexes are electrolytes. The kinetic thermodynamic parameters such as: E*, DeltaH*, DeltaS* and DeltaG* were estimated from the DTG curves. The antibacterial evaluation of the folic acid and their complexes was also done against some Gram positive/negative bacteria as well as fungi.  相似文献   

10.
New divalent transition metal 3,5-pyrazoledicarboxylate hydrates of empirical formula Mpz(COO)2(H2O)2, where M=Mn, Co, Ni, Cu, Zn and Cd (pz(COO)2=3,5-pyrazoledicarboxylate), metal hydrazine complexes of the type Mpz(COO)2N2H4 where M=Co, Zn or Cd and Mpz(COO)2nN2H4·H2O, where n=1 for M=Ni and n=0.5 for M=Cu have been prepared and characterized by physico-chemical methods. Electronic spectroscopic data suggest that Co and Ni complexes adopt an octahedral geometry. The IR spectra confirm the presence of unidentate carboxylate anion (Δν=νasy(COO)–νsym(COO)>215 cm–1) in all the complexes and bidentate bridging hydrazine (νN–N=985–950 cm–1) in the metal hydrazine complexes. Both metal carboxylate and metal hydrazine carboxylate complexes undergo endothermic dehydration and/or dehydrazination followed by exothermic decomposition of organic moiety to give the respective metal oxides as the end products except manganese pyrazoledicarboxylate hydrate, which leaves manganese carbonate. X-ray powder diffraction patterns reveal that the metal carboxylate hydrates are isomorphous as are those of metal hydrazine complexes of cobalt, zinc and cadmium.  相似文献   

11.
The reactions of PhCboSeNa (Cbo = o-C2B10H10), prepared by reductive cleavage of Se-Se bond in (PhCboSe)2 by NaBH4 in methanol, with Na2PdCl4, MCl2(PR3)2 and [M2Cl2(μ-Cl)2(PR3)2] afforded a variety of complexes, viz., [Pd(SeCboPh)Cl] (1), [M(SeCboPh)2(PR3)2], [M2Cl2(μ-SeCboPh)(μ-Cl)(PR3)2] (M = Pd, Pt) and [Pd2Cl(SeCb0Ph)(μ-Cl)(μ-SeCboPh)(PEt3)2] (7) have been isolated. These complexes were characterized by elemental analyses and NMR (1H, 31P, 77Se, 195Pt) spectroscopy. The structures of [Pd(SeCboPh)2(PEt3)2] (2), [Pt(SeCboPh)2(PMe2Ph)2] (3), [Pd2Cl2(μ-SeCboPh)(μ-Cl)(PMe2Ph)2] (5) and [Pd2Cl(SeCboPh)(μ-Cl)(μ-SeCboPh)(PEt3)2] (7) were established by X-ray crystallography. The latter represents the first example of asymmetric coordination of selenolate ligands in binuclear bis chalcogenolate complexes of palladium and platinum. Thermolysis of [Pd(SeCboPh)2(PEt3)2] (2) in HDA (hexadecylamine) at 330 °C gave nano-crystals of Pd17Se15.  相似文献   

12.
A diselenide, (MeOOCCH2CH2Se)2 (1) has been prepared by esterification of (HOOCCH2CH2Se)2 in methanol. The reductive cleavage of Se-Se bond in 1 by NaBH4 in methanol generates MeOOCCH2CH2SeNa. The latter in different stoichiometries reacts with [M2Cl2(μ-Cl)2(PR3)2] to give a variety of products of compositions [M2Cl2(μ-SeCH2CH2COOMe)2(PR3)2] (2); [M2Cl2(μ-Cl)(μ-SeCH2CH2COOMe)(PR3)2] (3); [Pd2(SeCH2CH2COOMe)2(μ-SeCH2CH2COOMe)2(PR3)2] (4);[Pd3Cl2(μ-SeCH2CH2COOMe)4(PR3)2] (5). Treatment of complexes 2 with [M2Cl2(μ-Cl)2(PR3)2] affords complexes 3 in nearly quantitative yield. The formation of various products in these reactions is sensitive to stoichiometric ratio of reactants employed. This enables interconversion of various complexes by manipulating mole ratios of appropriate starting materials. A homoleptic palladium complex, [Pd(SeCH2CH2COOMe)2]6 (6) was isolated from a reaction between Na2PdCl4 and MeOOCCH2CH2SeNa. All these complexes have been characterized by elemental analysis, IR, UV-Vis and NMR (1H, 13C, 31P, 77Se, 195Pt) spectroscopy. Structures of trans-[Pd2Cl2(μ-SeCH2CH2COOMe)2(PPh3)2] (2d), [Pt2Cl2(μ-Cl)(μ-SeCH2CH2COOMe)(PnPr3)2] (3e), [Pd3Cl2(μ-SeCH2CH2COOMe)4(PnPr3)2] (5) and [Pd(SeCH2CH2COOMe)2]6 (6) have been established unambiguously by X-ray crystallography. In these complexes, there are bridging selenolate ligands with their uncoordinated ester groups. Compound 6 has a centrosymmetric Pd6Se12 hexagon in which every two palladium atoms are bridged by selenolate ligands. Thermal behaviour of some complexes has been investigated. Pyrolysis of compound 2b in tributylphosphate at 195 °C gave Pd17Se15 nanoparticles which were characterized by XRD and EDAX.  相似文献   

13.
A convenient synthetic method for the preparation of organothiomethylpyridine ligands 2-(RSCH2)C5H4N (R = Ph (L1), Me (L2)), 2-MeS–6-Me-C5H3N (L3), and 2-MeS–4-Me-C5H3N (L4) via the initial lithiation of substituted 2-picolines followed by the nucleophilic reaction with a diorganyldisulfide is described. The complexes [PtBr2L] (L = L1L4) have been prepared in good to high yields as yellow solids with low solubility in organic solvents. The solid state structures of the complexes have been determined, showing the spatial arrangement of the complexes to depend significantly upon varying substituents within the ligand. The complexes undergo oxidation by bromine to form the tetravalent complexes [PtBr4(L)] (L = L1L4). The solid state structures of [PtBr4(L2)] and [PtBr4(L4)] have been determined, and shown to be monomeric with the ligand chelating the platinum centre.  相似文献   

14.
New platinum(II) and palladium(II) complexes of glyoxilic acid oxime (gao) have been prepared and characterised by infrared (4000–150 cm−1) and Raman (4000–200 cm−1) spectra. The gao acts as bidentate ligand bonding through the oxime nitrogen and carboxyl oxygen atoms to form neutral bis-chelate square-planar complexes. The lowest energy conformer of the gao ligand (ectt) was selected among 16 theoretically possible conformers on the basis of ab initio calculations at HF/3-21G*, HF/6-31G* and HF/6-311** levels of the theory from which structural parameters and conformational stabilities have been obtained. A complete vibrational assignment of the gao was performed for the lowest energy ectt conformer on the basis of ab initio optimised parameters and normal coordinate analysis calculations (PED). NCA calculations of the complexes studied were also performed.  相似文献   

15.
Phosphine ligands determine the excited state properties of a variety of coordination compounds. Phosphines not only influence metal-centered excited states, but participate directly in charge transfer transitions owing to their electron donating and accepting ability. Moreover, intraligand excited states are accessible if the phosphine carries suitable substituents. This diversity is illustrated by selected examples. The excited state behavior is discussed on the basis of spectral (absorption and emission) and photochemical properties of appropriate phosphine complexes.  相似文献   

16.
Nickel(II) and cobalt(II) complexes with the commercial herbicides 2,4-dichlorophenoxyacetic acid (2,4D; C8H6O3Cl2) and 2-(2,4-dichlorophenoxy)-propionic acid (2,4DP; C9H8O3Cl2) were prepared and characterized. On the basis of the results of elemental analysis and Ni and Co determination, the following molecular formulae were proposed for the obtained compounds: Ni(C8H5O3Cl2)2·6H2O, Co(C8H5O3Cl2)2·6H2O, Ni(C9H7O3Cl2)2·2H2O and Co(C9H7O3Cl2)2·2H2O. X-ray powder analysis was carried out. The IR, electronic (VIS) spectra and conductivity data were discussed. Water solubility of the synthesized complexes at room temperature was examined. Thermal decomposition of the compounds was studied. Dehydration processes occur during heating in air. The anhydrous compounds decompose via different intermediate products to oxides. TG/MS studies indicate formation of gaseous mass fragments of decomposition including H2O+, OH+, CO2 +, HCl+, Cl2 +, CH3Cl+, CH2O+, C6H6 + and other. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

17.
Two new transition metal complexes, [Zn(Hdiba)2(H2O)]?·?H2O (1) and [Cu(Hdiba)2] (2) (H2diba?=?2-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid), were synthesized and characterized by IR, elemental analysis, and single-crystal X-ray diffraction. Complex 1 exhibits a monomeric structure, while 2 displays a dimeric structure. Both structures extend to 2-D supramolecular networks via hydrogen bonds. Thermal stabilities of 1 and 2 and photophysical properties of 1 are also discussed.  相似文献   

18.
Reactions of dinuclear tetrakis(pyridine-2-thiolato)dipalladium(II) or platinum(II), M2(C5H4NS)4, with divalent metal halides in organic solvents formed compounds of stoichiometry: [M2(C5H4NS)4·(M′X2)2] {M = Pd, M′X2 = HgCl2 (1), PtCl2 (2), CdCl2 (3); M = Pt, M′X2 = HgCl2 (4)}. Similarly, bis(1-oxopyridine-2-thione)-palladium(II)/platinum(II) formed compounds: [M(C5H4NOS)2·M′X2] {M = Pd, M′X2 = HgCl2 (5), HgBr2 (6), HgI2 (7), CdCl2 (8), PtCl2 (9); M = Pt, M′X2 = HgBr2 (10), HgI2, (11)}. Compounds 111 have been characterized using elemental analysis, IR, far-IR, and NMR (1H, 13C) spectroscopy. Coordination to metal centers of M′X2 occurs via coordinated sulfur. Possible structures are suggested. The crystallization of (5) in dimethyl sulfoxide formed crystals of Pd(C5H4NOS)2 as revealed by X-ray crystallography.  相似文献   

19.
合成了2-苯基-4-硒唑甲酸配体(HL)和相应的6个过渡金属配合物[ML2(H2O)2](M=Co,Ni,Cu,Cd)1~4,[ZnL2](5),[CuL2(py)2](6).用元素分析、红外光谱、热重分析等表征手段确定了配合物的组成;用单晶X射线衍射测定了配合物3和6的结构;用溴化乙锭荧光探针初步研究了它们与DNA作用的强度和模式;考察了配体和配合物对大肠埃氏杆菌(E.coliJM109)、大肠杆菌(E.coli,DH5α)、表皮葡萄球菌(S.epidermidis)、金黄色葡萄球菌(S.aureus)、鲍曼不动杆菌(baumanii)、草绿色链球菌(S.viridans)6种细菌的抗菌活性及对正常细胞293T和肿瘤细胞RAW264.72的体外增殖抑制作用.  相似文献   

20.
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