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1.
The simultaneous TG/DTG–DTA technique was used for three new cobalt(II) complexes with dipyridylamine (dpamH) and the anion of a 2-hydroxyphenone ligand (phenone), with the general formula [Co(dpamH)2(phenone)]Br, in order to determine their thermal degradation in static air and dynamic nitrogen atmospheres, which was found to be a multi-step decomposition related to the release of the ligand molecules. The complexes were characterized by elemental analyses, FT-IR and UV–Vis spectroscopy, magnetic and conductivity measurements. All structures were determined by X-ray crystallography revealing octahedral coordination of cobalt(II) and monomeric nature of the compounds, [Co(dpamH)2(2-OH-acetophenone)]Br (1), [Co(dpamH)2(2-OH-propiophenone)]Br (2) and [Co(dpamH)2(2-OH, 5-CH3-acetophenone)]Br·EtOH (3). The variable temperature (76–303 K) magnetic susceptibility measurements showed a paramagnetic nature of the complexes, in accordance with their molecular structure.  相似文献   

2.
The mononuclear pyrazolyl complexes [PdCl2(HIPz)2] (1), [PdBr2(HIPz)2] (2), [PdI2(HIPz)2] (3), [Pd(SCN)2(HIPz)2] (4), and [Pd(NHCOIPz)2] (5) have been prepared. Compound 1 was obtained from the displacement of acetonitrile from [PdCl2(CH3CN)2] precursor by the 4-iodopyrazole (HIPz) ligand, whereas 25 were synthesized by substitution of the chlorido in 1 by the respective anionic group. The compounds were characterized by elemental analysis, infrared spectroscopy, and 1H NMR spectroscopy. The thermal behavior of 15 has been studied by TG and DTA. The thermal stability of [PdX2(HIPz)2] compounds varies according to the trends X = Cl? < I? ? SCN?< Br?. No stable intermediates were isolated during the thermal decompositions due to the overlap of the degradation processes. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.  相似文献   

3.
Two cobalt(II) coordination polymers, [Co(L1)(tbi)(H2O)] n (1) and [Co(L2)(tbi)] n (2) (L1 = 1,4-bis(benzimidazole)butane, L2 = 1,4-bis(2-methylbenzimidazole)butane, H2tbi = 5-tert-butyl isophthalic acid) have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single-crystal X-ray diffraction analysis. Both complexes exhibit similar 2D (4,4) layer structures, constructed from tbi2? and bis(benzimidazole)-based bridging ligands. The cobalt centers display different coordination environments, with an octahedral geometry in 1 and a distorted square-pyramidal configuration in 2. The thermal stabilities, fluorescence and catalytic properties of both complexes have been investigated.  相似文献   

4.
Two new cobalt(III) complexes of the hexadentate ligand [1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane] (H2bpctb) with N4S2 donor set atoms have been synthesized. A reaction of Co(CH3COO)2·4H2O with (H2bpctb) leads to the formation of [CoIII(bpctb)]PF6 (1) having a CoN2(pyridine)N′2(amide)S2(thioether) coordination by symmetric bpctb2? ligand. A similar reaction under slightly different conditions, however, gives [CoIII(L a )(L b )] (2), resulting from a C–S bond cleavage reaction triggered by an acetate ion as a base, having CoN2(pyridine)N′2(amide)S(thioether)S′(thiolate) coordination. These two Co(III) complexes have been characterized by elemental analyses and spectroscopic methods, and the crystal and molecular structures of [CoIII(bpctb)]PF6 (1) in the form of the solvate (1·MeOH·H2O) and of [CoIII(L a )(L b )] (2) have been determined by X-ray crystallography. The Co atoms of both complexes exhibit distorted octahedral geometry. The electrochemical investigation of [Co(bpctb)]PF6·MeOH·H2O (1·MeOH·H2O) and [CoIII(L a )(L b )] (2) by cyclic voltammetry reveals a reversible CoIII–CoII redox process at E 1/2 = ?0.32 V (ΔE p = 80 mV); for 1, and E 1/2 = ?0. 87 V (ΔE p = 70 mV) for 2.  相似文献   

5.
A new ligand, (2-ethoxy-6-(1H imadazo[4,5-f][1,10]phenanthroline-2-yl)phenol) (HEPIP) and its three Co(III) complexes [Co(phen)2(HEPIP)](ClO4)3 (1), [Co(bpy)2(HEPIP)](ClO4)3 (2) and [Co(dmb)2(HEPIP)](ClO4)3 (3) have been synthesized and characterized. All three Co(III) complexes exhibited antitumor activity against four human tumor cell lines. The interaction of these complexes with calf thymus DNA was studied by absorption and emission spectroscopy, viscosity measurements and DNA cleavage assays. The DNA-binding constants of complexes 1, 2 and 3 were determined as 6.13 × 105, 4.46 × 105 and 3.72 × 105 M?1, respectively. The complexes appear to interact with DNA through intercalation. Studies on the mechanism of photocleavage indicated that both superoxide anion radical and singlet oxygen may play an important role.  相似文献   

6.
Two coordination polymers, namely {[Co2(L1)2(btec)]?4H2O}n (1) and [Co(L2)(btec)0.5(H2O)]n (2) [L1 = 1,3-bis(5,6-dimethylbenzimidazole)propane, btec = 1,2,4,5-benzenetetracarboxylate, L2 = 1,2-bis(5,6-dimethylbenzimidazole-1-ylmethyl)benzene], have been synthesized and characterized by physicochemical and spectroscopic methods as well as single-crystal diffraction. The cobalt(II) atoms display different environments with a tetrahedral geometry in 1 and trigonal–bipyramidal geometry in 2. Both complexes show 2D layer structures with a rare binodal (3,4)-connected topology structure, named 3,4L13. Their catalytic activities were tested for the degradation of congo red azo dye in a Fenton-like process.  相似文献   

7.
Four new mononuclear triazido-cobalt(III) complexes [Co(L 1/2/4 )(N3)3] and [Co(L 3 )(N3)3]·CH3CN where L 1  = [(2-pyridyl)-2-ethyl]-(2-pyridylmethyl)-N-methylamine, L 2  = [(2-pyridyl)-2-ethyl]-[6-methyl-(2-pyridylmethyl)]-N-methylamine, L 3  = [(2-pyridyl)-2-ethyl]-[3,5-dimethyl-4-methoxy-(2-pyridylmethyl)]-N-methylamine, and L 4  = [(2-pyridyl)-2-ethyl]-[3,4-dimethoxy-(2-pyridylmethyl)]-N-methylamine, respectively, were synthesized and structurally characterized. The four complexes were characterized by elemental microanalyses, IR and UV–VIS spectroscopy and X-ray single crystal crystallography. The complexes display two strong IR bands over the frequency region 2,020–2,050 cm?1 assigned for the asymmetric stretching frequency, νa(N3) of the coordinated azides indicating facial geometry. The molecular structure determinations of the complexes were in complete agreement with fac-[Co(L)(N3)3] conformation in distorted octahedral Co(III) environment.  相似文献   

8.
Two new Co(II) coordination polymers, [Co(L)(glu)] (1) and [Co(L)(npht)]·H2O (2) (H2glu = glutaric acid, H2npht = 3-nitrophthalic acid, L = 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene), have been hydrothermally synthesized by self-assembly of cobalt chloride with a semi-rigid bis(benzimidazole) derivative and different organic bicarboxylic acids. Single crystal X-ray diffraction analysis reveals that complex 1 is a one-dimensional tube-like coordination polymer containing one helical [Co-L] and two linear [Co-glu] chains. In complex 2, two npht ligands connect two Co(II) atoms to form a binuclear [Co(npht)]2 subunit, which is further linked by L ligands with two kinds of conformations to form a 3-D CdSO4-like framework. In addition, the electrochemical behaviors of the title complexes in bulk-modified carbon paste electrodes, and their thermal stabilities and fluorescent properties were investigated in this paper.  相似文献   

9.
The aim of this study was to explore the influence of the position and angles of carboxyl groups of polycarboxylates on constructing coordination polymers. Three Co(II) metal–organic coordination polymers based on a tri-pyridyl-bis-amide ligand, namely [Co(L)(1,2-BDC)(H2O)2]·2H2O (1), [Co(L)(1,4-BDC)(H2O)2]·2H2O (2) and [Co(L)2(BTEC)0.5]·H2O (3) (L = N,N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,4-H2BDC = 1,4-benzenedicarboxylic acid, H4BTEC = 1,2,4,5-benzenetetracarboxylic acid), have been obtained by tuning the auxiliary polycarboxylate ligands. Structural analyses reveal that complexes 13 display diverse structures. Complex 1 displays a meso-helical chain linked by L ligands, which is further extended into a three-dimensional supramolecular framework through hydrogen-bonding interactions. The 1,2-BDC with a chelating coordination mode only acts as the hydrogen bond acceptor. In complex 2, the 1,4-BDC anions connect adjacent Co(II) atoms to form a linear chain, which is connected by hydrogen-bonding interactions to construct a 3D supramolecular network. Complex 3 exhibits a chain, which is composed of left-/right-handed Co-L helical chains and Co-BTEC linear chain. The 1D chains are ultimately extended into a two-dimensional supramolecular network by hydrogen-bonding interactions. Moreover, the thermal stability and the fluorescent properties of the title complexes and the electrochemical behaviors of a bulk-modified carbon paste electrode with complex 2 have been investigated at room temperature.  相似文献   

10.
Two coordination polymers, [Co(L1)(IPA] n (1) and {[Ag(L2)(HMIPA)]·H2O} n (2) (H2IPA = isophthalic acid, L1 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H2MIPA = 5-methylisophthalic acid, L2 = 1,6-bis(5,6-dimethylbenzimidazol-1-yl)hexane, have been synthesized and characterized by physicochemical and spectroscopic methods, as well as single-crystal X-ray diffraction. In 1, six-coordinated cobalt centers are bridged by L1 and IPA2? ligands to generate a (4,4) two-dimensional layer. However, complex 2 features a 1D chain structure, which is further extended by O–H···O hydrogen bonding interactions into a 2D supramolecular layer with (63) topology. The fluorescence and thermal gravimetric analysis of both complexes were also explored. Furthermore, the complexes 1 and 2 exhibit remarkable catalytic properties for the degradation of methyl orange dyes in a Fenton-like process.  相似文献   

11.
Two new bis(5,6-dimethybenzimidazole)-based CoII complexes, Co(pydca)(L)2·2H2O (1) and [Co(bdc)(L)] n (2) (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)-2-propanol, H2pydca = pyridine-2,6-dicarboxylic acid, H2bdc = 1,4-benzenedicarboxylic acid) were synthesized and characterized by physicochemical, spectroscopic methods and single-crystal diffraction. The cobalt(II) centers display different environments with distorted square-pyramidal geometry in 1 and a perfect tetrahedral geometry in 2. Complex 1 is a mononuclear structure, which is further assembled into a 3D supramolecular network via strong hydrogen bonding as well as ππ interactions; while complex 2 possesses a 2D corrugated (4,4) network that is further formed into a (3,4,4)-connected network with (62.84)(63)2(64.82)2-3,4,4T25 topology due to classical hydrogen bonds. The fluorescence and catalytic performances of the two complexes for the degradation of methyl orange by sodium persulfate have been investigated.  相似文献   

12.
Three new Schiff base complexes, namely [Mn(L)Cl] · H2O (1), [Co(L)Cl]2 · 2CH3COCH3 (2) and [Co(L)NCS]2 (3), where H2L = 2,2′-[propane-1,2-diylbis(nitriloeth-1-yl-1-ylidene)]diphenol, have been prepared and characterized. The syntheses of 1 and 2 have been achieved by reacting equimolar amounts of the respective metal chloride and the tetradentate Schiff base ligand (H2L). While the mononuclear Mn(III) complex 1 was obtained with MnCl2 in acetone medium, the same synthetic system yielded the binuclear Co(III) complex 2 in the presence of CoCl2. Dissolution of 1 and 2 followed by crystallization with ammonium thiocyanate in methanol yielded two isostructural phenoxo-bridged binuclear complexes, namely [Mn(L)NCS]2 (previously reported by us) and a new complex [Co(L)NCS]2 (3), respectively. All the complexes 13 have been characterized by microanalytical, spectroscopic, single crystal X-ray diffraction and other physicochemical studies. Structural studies reveal that 1 adopts a distorted tetragonal pyramidal geometry while 2 and 3 comprise dimeric Co(III) units with bridging phenolate oxygen atoms. All the complex units in 1–3 and the respective solvent molecules are held together by weak intermolecular H-bonding to constitute a supramolecular network in the solid state. The antibacterial activity of the complexes has been tested against some Gram(+) and Gram(?) bacteria.  相似文献   

13.
New water soluble Co(II) 1, Ni(II) 2 and Cu(II) 3 complexes of 4,15-bis(2-hydroxyethyl)-2,4,6,13,15,17-hexaazatricyclodocosane Co(II) were synthesized and characterized by various techniques, viz. elemental analysis, conductivity measurements, infrared, electronic, ESI-MS, 1H and 13C NMR spectroscopy. Molar conductance measurements in aqueous solution showed that complexes 1, 2 and 3 are ionic in nature. On the basis of spectroscopic data, a square planar geometry was assigned to the complexes involving four N-atoms of the two cyclohexane moieties. Interaction studies of 1 and 3 with CT-DNA were carried using UV/Visible absorption spectroscopy, fluorescence spectrophotometry, cyclic voltammetry and viscosity measurements. Absorption spectral traces reveal 27.7 and 23.3% hyperchromism for complexes 1 and 3, respectively indicative of strong binding to CT-DNA. These results were authenticated by fluorescence quenching experiments and viscosity measurements. The intrinsic binding constants K b of 1 and 3 are 2.94 × 104 and 2.71 × 104 M?1, respectively. Early transition metals show preference for O6 position while later ones copper and cobalt prefer N7 position of DNA base guanine. To validate this hypothesis, interaction studies of copper (II) and cobalt (II) complexes were carried out with 5′GMP, which revealed electrostatic interactions are more favored along with hydrogen bonding than coordinate covalent interaction to N7 position of guanine.  相似文献   

14.
Four coordination compounds of copper(II) were synthesised and characterised in solid state by elemental analysis, infrared, electronic and EPR spectroscopy, as well as by thermal analysis (TG/DTA). The complexes were formulated on the basis of experimental data as: [Cu(BzIm)2(H2O)]·H2O (1), [Cu2(Acr)4(HBzIm)2] (2), [Cu(Acr)2(HBzIm)2] (3) and [Cu(Acr)2(HBzIm)2(H2O)]·H2O (4). IR data are in accordance with the unidentate nature of benzimidazole, in complexes (2), (3) and (4), and bridge bidentate nature of benzimidazole, in complex (1), while acrylato acts as uni- or bridge/chelate ligand. The electronic spectra display the characteristic pattern of square planar, square pyramidal, or octahedral stereochemistry, also confirmed by EPR spectra. Thermal decomposition evidenced several well-defined steps as dehydration of complexes (1) and (4), benzimidazole molecule releases for all complexes and acrylate decomposition in carbonate for complexes (3) and (4). In all four cases, the final residue after thermal treatment in air flow is copper(II) oxide, formed during the decomposition steps for complexes (3) and (4), and, respectively, after the oxidation of the metallic copper for complexes (1) and (2). Antimicrobial activities of the complexes have been determined by in vitro assays, against various Gram-negative and Gram-positive bacterial and fungal strains. Copper(II) complexes were also evaluated for their cytotoxicity on eukaryotic cells.  相似文献   

15.
The Schiff base bis(4-ethylbenzyl) p-phenylenediimine, 4-eb-p-phen (1), and six new dimeric Pd(II) complexes of the type [Pd(μ-X)(4-eb-p-phen)]2 {X = Cl (2), Br (3), I (4), N3 (5), NCO (6), SCN (7)} have been synthesized and characterized by elemental analysis, IR spectroscopy, and 1H and 13C{1H}-NMR experiments. The thermal behavior of the complexes 27 has been investigated by means of thermogravimetry and differential thermal analysis. From the final decomposition temperatures, the thermal stability of the complexes can be ordered in the following sequence: 3 > 4 > 7 > 2 ≈ 5 > 6. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction (XRD).  相似文献   

16.
Four new cobalt(II)-based metal–organic coordination polymers, namely {[Co(L)(ox)]·3H2O}n (1), [Co2(L)(chda)2]n (2), {[Co(L)(mip)(H2O)]·H2O}n (3) and [Co(L)(oba)]n (4), [L = N,N′-bis(pyridine-3-yl)pyridine-3,5-dicarboxamide, H2ox = oxalic acid, H2chda = trans-1,4-cyclohexanedicarboxylic acid, H2mip = 5-methylisophthalic acid, H2oba = 4,4′-oxybis(benzoic acid)] were hydrothermally synthesized and structurally characterized by IR, TG, PXRD and single-crystal X-ray diffraction. In 1, the oxalate anions display μ 2-bridging mode connecting the adjacent 1D [Co–L]n zigzag chains to afford a 2D layer. In 2, the chda anions take the μ 4-bridging mode connecting the neighboring four CoII ions to construct a [Co–chda]2n 1D double chain, which contains the Co2(CO2)4 paddle-wheel subunit. These double chains are further linked by L ligands to furnish a 2D layer. In 34, Co(II) ions are linked by L ligands to give rise to a 1D left-, right-helical chain [Co–L]n, respectively. These helical chains are further linked by μ 2-bridging mip and oba anions to furnish a 2D network, respectively. The Co(II) ions, L ligands and dicarboxylates exhibit different coordination modes and conformations. The effect of organic dicarboxylates with different rigidity and length on the structures of the Co(II) complexes is discussed. The fluorescence, electrochemical behaviors and photocatalytic activities of the title complexes are reported.  相似文献   

17.
Three Ru(II) polypyridyl complexes [Ru(dmb)2(HMSPIP)](ClO4)2 (1), [Ru(phen)2(HMSPIP)](ClO4)2 (2) and [Ru(dmp)2(HMSPIP)](ClO4)2 (3) were synthesized and characterized. The cytotoxicity in vitro, apoptosis, cell cycle arrest, reactive oxygen species and mitochondrial membrane potential were assayed. The IC50 values of complexes 1, 2 and 3 toward BEL-7402, A549, MG-63 and SK-BR-3 cell lines ranged from 10.9 ± 1.6 to 42.0 ± 3.4 μM. Complexes 1, 2 and 3 can effectively induce apoptosis and inhibit the growth of BEL-7402 cells at the G2/M phase. These complexes can enhance the level of reactive oxygen species and induce decrease in the mitochondrial membrane potential. Additionally, complex 2 can down-regulate the expression of antiapoptotic protein of Bcl-2 protein and up-regulate the levels of proapoptotic protein Bim in BEL-7402 cells.  相似文献   

18.
New cobalt(II), nickel(II), and copper(II) complexes based on 5-methoxycarbonyl-3-me-thylpyrazole (MePzCOOMe), [Co(MePzCOOMe)2(H2O)2](NO3)2 (I), [Ni(MePzCOOMe)2(H2O)2] (NO3)2 (II), and [Cu(MePzCOO)2(H2O)] · 3H2O (III), were synthesized. The compounds were studied by X-ray diffraction analysis, IR spectroscopy, and static magnetic susceptibility. The molecular and crystal structures of complexes I and III were determined by X-ray structure analysis.  相似文献   

19.
Three novel metal-organic complexes [Co(BDC)(TBZ)2] (I), [Cd2(BDC)2(TBZ)2(H2O)2] · 2(H2O) (II), [Mn2(BDC)(TBZ)4(SO4)] (III) (BDC = 1,4-benzenedicarboxylate, TBZ = thiabendazole) have been prepared and characterized by IR spectrum, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. X-ray structure analysis reveals that both three complexes are one-dimensional chain polymers. The 1D chain architecture of I is constructed from terephthalic acid and cobalt atoms. A simultaneous presence of chelating and monodentate coordination modes of BDC ligands is observed in complex II. In complex III, the coordinated BDC ligands adopt monodentate mode and with SO 4 2? anions alternately bridge the Mn2+ ions into 1D chains. The 3D structures of the three complexes are stabilized by π-π stacking interactions and hydrogen-bonds.  相似文献   

20.
Three new coordination complexes of Zn(II) and Mn(II) have been synthesised using two different tridentate N,N,O donor hydrazone ligands, Hpbh and Hacpbh respectively. The complexes [Zn(pbh)2] (1) and [Zn(acpbh)2] (2) have been synthesized by the treatment of ZnSO· 7H2O with Hpbh and Hacpbh hydrazone ligands, respectively. The Mn(II) complex [Mn(acpbh)2] (3) was obtained on reacting Mn(NO3)· 4H2O with the ligand Hacpbh. The ligands Hpbh and Hacpbh were prepared by condensing pyridine-2-carboxaldehyde and 2-acetylpyridine with benzhydrazide respectively. Inspite of varying the carbonyl functionality attached to the pyridine moiety present in the hydrazone ligands in both the Schiff bases, we obtained three mononuclear complexes 1, 2, and 3 which were clearly characterized from single crystal X-ray diffraction studies. Spectroscopic investigations like IR and UV/Vis have been carried out for 1, 2, and 3. Fluorescence studies have been performed for 1 and 2. For 3 cyclic voltammetry, room temperature magnetic study and EPR measurements have been recorded.  相似文献   

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