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1.
An amide-linked 2,6-bis{[(2-hydroxy-5-tert-butylbenzyl)(pyridyl-2-methyl)-amino]-methyl}-4-methylphenol-ruthenium(II) tris(bipyridine) 2PF6− complex, 1, was first used to recognize Co(II) in EtOH/H2O (1:1, v/v) solution, with the ruthenium(II) tris(bipyridine) moiety selected as a fluorophore and the multi-substituted phenol unit chosen as a receptor. The fluorescence quenching of 1 was attributed to the formation of an inclusion complex between multi-substituted phenol unit and Co(II) by 1:1 complex ratio (K = 2.5 × 105), which has been utilized as the basis of the fabrication of the Co(II)-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Co(II)-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Co(II) with a linear range covering from 1.0 × 10−7 to 5.0 × 10−5 M and a detection limit of 5 × 10−8 M. The experiment results show that the response behavior of 1 to Co(II) is pH-independent in medium condition (pH 4.5–9.5) and show excellent selectivity for Co(II) over transition metal cations except Cu(II). The chemosensor has been used for determination of Co(II) in water samples. 相似文献
2.
Ling-Ling Zhou Ling-Zhi Fu Qian-Nan Liang Chang Fang 《Journal of Coordination Chemistry》2016,69(4):628-637
A catalyst based on [LCo(H2O)] (1) is formed by the reaction of dimethylaminoethylamino-N,N-bis(2-methylene-4-tert-butyl-6-methyl)phenol (H2L) with CoBr2 for electrolytic proton or water reduction. 1 catalyzes hydrogen evolution, both from acetic acid with a turnover frequency (TOF) of 17.9 mol of hydrogen per mole of catalyst per hour at an overpotential of 792 mV (in DMF) and from water with a TOF of 260 mol of hydrogen per mole of catalyst per hour at an overpotential of 889 mV (in buffer, pH 7.0). 相似文献
3.
Xiao-Yong Zhang Xue-Lin Ma Jun-Fang Gao Mei-Rong Wang Yu-Heng Zhang Sheng-Li Yong 《印度化学会志》2022,99(4):100394
A novel complex [Co(NO3)2(APTY)2H2O] (1) is synthesized based on 1,5-dimethyl-2-phenyl-4-{[(1E)-pyridine-4-ylmethylene]amino}-1,2-dihydro-3H-pyrazol-3-one) antipyrine (APTY) and the structure of complex (1) is characterized via PXRD, SEM, FTIR and X-ray single crystal diffraction technique. It is found that the complex (1) has a good response to Fe3+ ion with colorimetric yellow change. In addition, we demonstrate that the sensing mechanism of complex (1) could is due to the disruption of complex (1) framework and the formation of complex Fe-APTY. The stability, rapid response and low detection limit enable this complex (1) to be a good Fe3+ ion chemical sensor for biological and environmental sensing applications. 相似文献
4.
A chiral Schiff base complex, bis(N-R-1-phenylethyl-3,5-dichlorosalicydenaminato) cobalt(II) was prepared newly and characterized to be a distorted tetrahedral trans-[CoN2O2] coordination geometry. Organic/inorganic hybrid materials containing the related cobalt(II), nickel(II), copper(II), and zinc(II) complexes and photochromic azobenzene in polymethylmethacrylate (PMMA) cast films were assembled for comparison of their flexibility and molecular arrangement in the photofunctional medium. Characterization of each component and hybrid materials was carried out by means of absorption and CD spectra and thermal analysis (TG–DTA and DSC). Moreover, we have attempted to observe changes of conformation and/or molecular arrangement of the complexes or azobenzene induced by cis–trans photoisomerization of azobenzene after alternate irradiation of polarized UV and visible light. Gradual increase of optical anisotropy was observed for all the hybrid materials regardless of flexibility of Schiff base complexes, and the degree of dichroism and weak intermolecular interactions were discussed based on polarized absorption electronic spectra. 相似文献
5.
A method to determine water content in organic solvents was developed based on the color change of cobalt(Ⅱ) nitrate in different solvents.The color-change mechanism and optimal conditions for determining the water content were investigated.The results showed that there was a good linear relationships between the absorbance of cobalt(Ⅱ) complexes in organic solvents and water contents withγin 0.9989~0.9994.This method has the advantages of low cost,good reproducibility,good sensitivity,simple in operation,fast in detection,friendly to the environment and no limitation on linear range for determining water content.It was used to determine water in samples with a satisfactory recovery in 97.81%~101.24%. 相似文献
6.
The reaction of 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP) with Cd(II), Pb(II), Hg(II) and Zn(II) was studied spectrophotometrically and kinetics, equilibrium constants as well as photodecomposition of complexes were determined. It was verified that these metal ions with large radius accelerate the incorporation reaction of zinc into TCPP. On the basis of the mechanism and kinetics of this reaction, a sensitive method for the spectrophotometric determination of trace amounts of Zn(II) has been developed. The molar absorptivity of examined Zn-TCPP complex and Sandell's sensitivity at 423 nm were 3.5×105 M−1 cm−1 and 18.3 ng cm−2. The detection limit for the recommended procedure was 1.4×10−9 M (0.9 ng ml−1) and precision in range 20-100 ng ml−1 not exceeds 2.7% RSD. The proposed method applied for zinc determination in natural waters and nutritional supplement was compared with AAS results and declared value. 相似文献
7.
A fluorescent chemical sensor for Hg(II) using 5,10,15-tris(pentafluorophenyl)corrole (H3(tpfc)) as fluorophore is described in this paper. The response of the sensor is based on the fluorescence quenching of H3(tpfc) by coordination with Hg(II). H3(tpfc) based sensor shows a linear response towards Hg(II) in the concentration range from 1.2 × 10−7 to 1.0 × 10−4 M, with a working pH range from 5.0 to 8.0. The response time for Hg(II) concentration ≤1.0 × 10−5 M is less than 5 min. The sensor shows good selectivity for Hg(II) over alkali, and alkaline earth, and most of transition metal cations. The effect of the composition of the sensor membrane has been studied and the experimental conditions optimized. The corrole based sensor membrane can be easily regenerated just by washing with blank buffer solution after each measurement. The sensor has been used for determination of Hg(II) in water samples with satisfactory results. 相似文献
8.
Jesús Morales-Juárez Jesús Pastor-Medrano Raymundo Cea-Olivares Verónica García-Montalvo R. Alfredo Toscano 《Polyhedron》2007
Nickel(II) and cobalt(II) bis-chelates of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe) were synthesized and characterized by spectroscopic methods and in the case of the nickel complex, X-ray single-crystal diffraction. The ligand exhibits the (N, S) coordination mode on interacting with the metal centers. The X-ray structure of the nickel(II) complex reveals a NiN2S2 distorted square planar coordination geometry with the ligands showing a cis configuration. There is no interaction between the –CH2COOMe moieties of the ligand and the metal center, however intermolecular hydrogen bonds through the carbonyl group leads to the building of dimeric associations. 相似文献
9.
The influence of small additives of cobalt(II) porphyrin (CoIIPn) on cross-linking radical polymerization of butane-1,4-diol dimethacrylate and its structural analog butane-1,4-diol diacrylate
was studied. The kinetics of cross-linking radical polymerization of di(meth)acrylates in the absence and presence of CoIIPn and the diffusional sorption and physical mechanical properties of the resulting polymers were studied. Cobalt(II) porphyrin
decreases substantially the polymerization rate and partially suppresses the gel effect. Diacrylate polymerization in the
presence of CoIIPn proceeds with an induction period, whose value is determined by the content of CoIIPn. Cobalt(II) porphyrin modifies the structure and properties of the formed cross-linked polymers. In the case of dimethacrylate,
this is caused by the catalytic chain transfer reaction, whereas for diacrylate the reason is the reversible inhibition reaction.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 807–816, May, 2006. 相似文献
10.
The novel non-chelated monodentate benzimidazole (BI) complexes CoCl2(BI)2 (1)-(3), where BI = 1-(2-methoxybenzyl)- 2-(2-methoxyphenyl)-1H-benzimidazole (1), BI = 2-(2,6-difluorophenyl)-1H-benzimidazole (2) and 2-methyl-1H-benzimidazole (3) were synthesized and characterized by single X-ray crystallography. Unexpectedly, in solid state these complexes show similar coordination behavior to their analogue nickel(II) benzimidazole complexes such as inter-molecular H-bonding pattern and presence of acetonitrile solvent molecules per unit of complex molecule. Moreover, among these cobalt catalysts 1-3, similar trend to that of nickel catalysts is observed for metal-to-nitrogen (M-X) coordination bond length and halogen-metal-halogen (X-M-X) bond angle. But unlike nickel(II) benzimidazole complexes, these catalysts show very low activity for vinyl polymerization of norbornene (NB) upon activation with methylaluminoxane (MAO); however, the activity abruptly increased in modified methylaluminoxane (MMAO). The presence of a small amount of toluene strongly hampered the activity, and the use of dry methylaluminoxane (dMAO) as a cocatalyst did not result in a high activity. The use of toluene-free solid modified methylaluminoxane (sMMAO) is found to be the best cocatalyst, where the highest activity of value 3.9 × 107 g of PNB molCo−1 h−1 was achieved for 3/sMMAO at 30 °C. 相似文献
11.
Saugata KonarAtanu Jana Kinsuk DasSangita Ray Sudipta ChatterjeeJames A. Golen Arnold L. RheingoldSusanta Kumar Kar 《Polyhedron》2011,30(17):2801-2808
Varying coordination modes of the Schiff base ligand H2L [5-methyl-1-H-pyrazole-3-carboxylic acid (1-pyridin-2-yl-ethylidene)-hydrazide] towards different metal centers are reported with the syntheses and characterization of four mononuclear Mn(II), Co(II), Cd(II) and Zn(II) complexes, [Mn(H2L)(H2O)2](ClO4)2(MeOH) (1), [Co(H2L)(NCS)2] (2), [Cd(H2L)(H2O)2](ClO4)2 (3) and [Zn(H2L)(H2O)2](ClO4)2 (4), and a binuclear Cu(II) complex, [Cu2(L)2](ClO4)2 (5). In the complexes 1-4 the neutral ligand serves as a 3N,2O donor where the pyridine ring N, two azomethine N and two carbohydrazine oxygen atoms are coordinatively active, leaving the pyrazole-N atoms inactive. In the case of complex 5, each ligand molecule behaves as a 4N,O donor utilizing the pyridine N, one azomethine N, the nitrogen atom proximal to the azomethine of the remaining pendant arm and one pyrazole-N atom to one metal center and the carbohydrazide oxygen atom to the second metal center. The complexes 1-4 are pentagonal bipyramidal in geometry. In each case, the ligand molecule spans the equatorial plane while the apical positions are occupied by water molecules in 1, 3 and 4 and two N bonded thiocyanate ions in 2. In complex 5, the two Cu(II) centers have almost square pyramidal geometry (τ = 0.05 for Cu1 and 0.013 for Cu2). Four N atoms from a ligand molecule form the basal plane and the carbohydrazide oxygen atom of a second ligand molecule sits in the apex of the square pyramid. All the complexes have been X-ray crystallographically characterized. The Zn(II) and Cd(II) complexes show considerable fluorescence emission while the remaining complexes and the ligand molecule are fluorescent silent. 相似文献
12.
《Journal of Coordination Chemistry》2012,65(8):1212-1220
An asymmetric bidentate Schiff-base ligand (2-hydroxybenzyl-2-furylmethyl)imine (L–OH) was prepared. Three complexes derived from L–OH were synthesized by treating an ethanolic solution of the appropriate ligand with an equimolar amount of metallic salt. Three complexes, Cu2(L–O?)2Cl2 (1), Ni(L–O?)2 (2) and Co(L–O?)3 (3), have been structurally characterized through elemental analysis, IR, UV spectra and thermogravimetric analysis. Single crystal X-ray diffraction shows metal ions and ligands reacted with different proportions 1?:?1, 1?:?2 and 1?:?3, respectively, so copper(II), nickel(II), and cobalt(III) have different geometries. 相似文献
13.
The reagent 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) was used for the spectrophotometric determination of copper(II) and cobalt(II) in the presence of pyridine and imidazole catalysts. Optimum conditions were investigated and the methods were applied to the determination of parts per billion levels of copper(II) and cobalt(II). The Sandell sensitivities of the recommended procedures were 0.568 μm cm−2 and 0.464 μg cm−2 (for A = 0.001) for copper and cobalt, respectively. The relative standard deviations were 2.0% for copper and 1.0% for cobalt. The kinetics of the reaction of CPI with copper(II) and cobalt(II) in the presence of the catalysts and the influence of the temperature were studied, and their kinetic constants determined.The influence of light on the photodecomposition of CPI was also studied. 相似文献
14.
《Journal of Coordination Chemistry》2012,65(23):2621-2627
Schiff-base complexes of cobalt(II), nickel(II), copper(II) and, zinc(II) with 3-ethoxysalicyliden-p-aminoacetophenoneoxime (HL) were prepared and characterized on the basis of elemental analyses, IR, 1H- and 13C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses (TGA). A tetrahedral geometry has been assigned to the complexes. 相似文献
15.
《Journal of Coordination Chemistry》2012,65(21):3375-3389
The ligand 1,1,3,3-tetramethylbutylisocyanide, CNCMe2CH2CMe3, i.e. t-octylisocyanide, with Co(ClO4)2 · 6H2O or Co(BF4)2 · 6H2O in ethanol, produces pentakis(alkylisocyanide)cobalt(II) complexes, [Co(CNC8H17-t)5](ClO4)2 (1) and [Co(CNC8H17-t)5](BF4)2 · 2.0H2O (2). These Co(II) complexes undergo reduction/substitution upon reaction with trialkylphosphine ligands to produce [Co(CNC8H17-t)3{P(C4H9-n)3}2]ClO4 (3), [Co(CNC8H17-t)3{P(C4H9-n)3}2]BF4 (4), and [Co(CNC8H17-t)3{P(C3H7-n)3}2]ClO4 (5). Complex 3 is oxidized with AgClO4 to produce [Co(CNC8H17-t)3{P(C4H9-n)3}2](ClO4)2 (6). Complex 1 yields [Co(CNC8H17-t)4py2](ClO4)2 (7) upon dissolving in pyridine. Reactions with triarylphosphine and triphenylarsine ligands were unsatisfactory. The chemistry of 1 and 2 is therefore more similar to that of Co(II) complexes with CNCMe3 than with CNCHMe2, other alkylisocyanides, or arylisocyanides, but shows some behavior dissimilar to any known Co(II) complexes of alkylisocyanides or arylisocyanides. Infrared and electronic spectra, magnetic susceptibility, molar conductivities, and cyclic voltammetry are reported and compared with known complexes. 1H, 13C, and 31P NMR data were also measured for the diamagnetic complexes 3, 4, and 5. 相似文献
16.
N. T. Madhu P. K. Radhakrishnan Matthias Grunert Peter Weinberger Wolfgang Linert 《Thermochimica Acta》2003,400(1-2):29-36
The phenomenological, kinetic and mechanistic aspects of thermal decomposition of perchlorate, nitrate, chloride, bromide and iodide complexes of cobalt(II) with the Schiff base 1,2-di(imino-4′-antipyrinyl)ethane (GA) have been studied by TG and DTG analyses. The kinetic parameters like the activation energy, pre-exponential factor and entropy of activation were calculated. The decomposition reactions follow “random nucleation with one nucleus on each particle—Mampel model”. 相似文献
17.
《Journal of Coordination Chemistry》2012,65(12):1407-1411
The complexes [Co(CNCMe3)3{P(C6H4NMe2-p)3}2](ClO4)2 and [Co(CNCMe3)3{P(C6H4NMe2 -p)3}2]ClO4 are reported. The Co(II) complex, formed by reaction of excess triarylphos-phine with the alkylisocyanide Co(II) complex, is stable and the favoured product. The Co(I) complex, formed by hydrazine reduction of the Co(II) complex, has limited stability in solution, readily oxidizing to the Co(II) species. Upon prolonged irradiation of the Co(II) complex in acetone, [Co{OP(C6H4NMe2-p)3}4](ClO4)2 is produced. 相似文献
18.
As a new detection model, the reversible fluorescence “turn-off-on” sensor based on quantum dots (QDs) has already been successfully employed in the detections of many biochemical materials, especially in the researches on the interactions between anticancer drugs. The previous studies, however, mainly focused on simple-structured oligonucleotides and Calf thymus DNA. G-quadruplex, an important target for anti-cancer drug with special secondary structure, has been stimulating increasing research interests. In this paper, we report a new detection method based on the fluorescence “turn-off-on” model with water-soluble ZnCdSe QDs as the fluorescent probe, to analyze the interactions between anticancer drug (N-methyl-4-pyridyl) porphyrin (TMPyP) and nucleic acid, especially the G-quadruplex. The fluorescence of QDs can be quenched by TMPyP via photo-induced electron transfer and fluorescence resonance energy transfer, while on the other hand, the combination between TMPyP and G-quadruplex releases QDs from their quenchers and thus recovers the fluorescence. Most importantly, the fluorescence “turn-off-on” model has been employed, for the first time, to analyze the impacts of special factors on the interaction between TMPyP and G-quadruplex. The excellent selectivity of the system has been verified in the studies of the interactions between TMPyP and different DNAs (double-stranded DNA, single-stranded G-quadruplex, and different types of G-quadruplexes) in Na+ or K+-containing buffer. 相似文献
19.
A mixed-valence cluster of cobalt(II)hexacyanoferrate possesses an electron transfer property and is suitable for the development of an effective hydrogen peroxide detection scheme. The characteristics of cobalt(II)hexacyanoferrate have been studied using both elemental analysis and infrared spectra, confirming the structure is Co[FeII(CN)6]. The cobalt(II)hexacyanoferrate-modified electrode exhibits a rapid response (t95% - 6.5 s) to the injection of 5.0 × 10−5 M hydrogen peroxide. The linearity of the response is up to 1.1 × 10−3 M (correlation coefficients is 0.999). The sensitivity of this modified electrode is 11.8 μA/mM-mm2. The detection limit of cobalt(II)hexacyanoferrate-modified electrode to hydrogen peroxide is 6.25 × 10−8 M. The current chemical sensor modified with Co[FeII(CN)6] has better sensitivity than previous ones. The modified glassy carbon electrode shows no interference from ascorbic acid, uric acid, acetaminophen, 1,4-dihydroxyquinone, dopamine at the 2.0 × 10−4 M level and polyamines at 5.0 × 10−5 M level. 相似文献
20.
Animesh Patra Sandipan Sarkar Michael G.B. Drew Ennio Zangrando Pabitra Chattopadhyay 《Polyhedron》2009
Three new mononuclear complexes of nitrogen–sulfur donor sets, formulated as [FeII(L)Cl2] (1), [CoII(L)Cl2] (2) and [NiII(L)Cl2] (3) where L = 1,3-bis(2-pyridylmethylthio)propane, were synthesized and isolated in their pure form. All the complexes were characterized by physicochemical and spectroscopic methods. The solid state structures of complexes 1 and 3 have been established by single crystal X-ray crystallography. The structural analysis evidences isomorphous crystals with the metal ion in a distorted octahedral geometry that comprises NSSN ligand donors with trans located pyridine rings and chlorides in cis positions. In dimethylformamide solution, the complexes were found to exhibit FeII/FeIII, CoII/CoIII and NiII/NiIII quasi-reversible redox couples in cyclic voltammograms with E1/2 values (versus Ag/AgCl at 298 K) of +0.295, +0.795 and +0.745 V for 1, 2 and 3, respectively. 相似文献