Novel Copper(II)-Selective Potentiometric Sensor Based on a Folic Acid-Functionalized Carbon Nanotube Material

Abstract

A folic acid-functionalized carbon nanotube nanomaterial was prepared by immobilizing folic acid molecules on the carbon nanotubes through covalent bonds. The material was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy. Fourier transform infrared spectroscopy confirmed that folic acid molecules were grafted on the carbon nanotube surfaces through the amide bonds between the carboxylic acid functional groups of the oxidized carbon nanotubes and the amine groups of the folic acid molecules. The folic acid molecules bonded to carbon nanotube surfaces led to appreciable changes in the morphology. By using currently obtained folic acid-functionalized carbon nanotube nanomaterial as electroactive material in a polyvinyl chloride membrane, a potentiometric copper (II)-selective sensor was developed. Membrane optimization studies showed that the composition exhibiting the best potentiometric properties was 4.0% (w/w) folic acid–carbon nanotube, 64.0% (w/w) o-nitrophenyl octylether, and 32.0% (w/w) polyvinyl chloride. The developed sensor displayed a linear response in the copper (II) concentration ranging from 1.0?×?10^–6 to 1.0?×?10^–1 M with a correlation coefficient of 0.9993 and a slope of 29.8?±?0.6?mV/decade of activity. The response time, detection limit, and pH working range were determined to be 4?s, 3.8?×?10^–7 M and 4.0–8.0, respectively. The developed sensor showed highly selective and satisfactory potentiometric response for the determination of copper (II) in a Turkish coin.     

Synthesis,Characterization and Crystal Structures of Four Dinuclear Schiff Base Nickel(II) and Copper(II) Complexes with Versatile Bridging Groups

Four novel Schiff base nickel(II) and copper(II) complexes, derived from the end‐on (μ_1,1‐N₃) azide, end‐to‐end (μ_1,3‐NCS) thiocyanate, or phenolate oxygen bridges, have been synthesized and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Ni₂(L1)₂(MeCN)₂(μ_1,1‐N₃)₂]·MeOH ( 1 ), the dinuclear double end‐on azide‐bridged [Ni₂(L2)₂(MeOH)₂(μ_1,1‐N₃)₂][Ni₂(L2)₂(OH₂)₂(μ_1,1‐N₃)₂]·MeOH ( 2 ), the dinuclear double end‐to‐end thiocyanate‐bridged [Cu₂(L3)₂(μ_1,3‐NCS)₂] ( 3 ), and the dinuclear double phenolate O‐bridged [Cu₂(L4)₂(NCS)₂] ( 4 ), where HL1, HL2, HL3 and HL4 are four tridentate Schiff bases obtained by the condensation of 3,5‐dibromosalicylaldehyde with N‐ethylethane‐1,2‐diamine, of 3,5‐dichlorosalicylaldehyde with N‐methylpropane‐1,3‐diamine, of 3‐bromo‐5‐chlorosalicylaldehyde with 2‐aminomethylpyridine, and of 5‐nitrosalicylaldehyde with 2‐aminomethylpyridine, respectively. Each nickel(II) atom in 1 and 2 is in an octahedral coordination, while each copper(II) atom in 3 and 4 is in a square pyramidal coordination. There exists crystallographic inversion centre symmetry in each of the complexes.     

Copper(II) complexes of schiff bases derived of 2-hydroxy-3-naphthaldehyde. The crystal and molecular structures of bis-{(phenyl)[(2-oxo-3H-naphth-3-ylidene)methyl]aminato}copper(II) and bis-{(benzene-4-trifluoromethyl)[(2-oxo-3H-naphth-3-ylidene)-methyl]aminato}copper(II)

Summary The Schiff base ligands, 3-[(Phenyl)-2-hydroxy-3H-Naphth-3-ylidene)methyl]aldamine (1) and 3-[(benzene-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-ylidene)methyl]aldamine (2), and their corresponding Cu(II) complexes (I andII were synthesized. The crystal and molecular structures ofI andII were determined. CompoundI crystallizes in the triclinic crystal systema=10.804(5),b=12.589(5), andc=10.369(3) (Å), =107.72(3), =95.75(3), and =76.32(4)(°), in the space group P withZ=2. CompoundII crystallizes in the triclinic crystal systema=10.718(2),b=13.861(4), andc=10.110(9) (Å), =95.99(2), =90.16(2), and =93.90(2)(°), in the space group P withZ=2. The geometry around the metal atom in both complexesI andII is square planar.

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Kupfer(II)-Komplexe von Schiffbasen von 2-Hydroxy-3-naphthaldehyd. Die Kristall-und Molekülstrukturen von Bis{(phenyl)[(2-oxo-3H-naphth-3-yliden)methyl]aminato}kupfer(II) und Bis{(benzen-4-trifluoromethyl)[(2-oxo-3H-naphth-3-yliden)methyl]aminato}kupfer(II)

Zusammenfassung Es wurden die Schiffbasen-Liganden 3-[(Phenyl)-2-hydroxy-3H-naphth-3-yliden)-methyl]aldamin (1) und 3-[(Benzen-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-yliden)-methyl]aldamin (2) inklusive der entsprechenden Kupfer(II)-KomplexeI undII dargestellt. VonI undII wurden die Kristallstrukturen ermittelt. KomplexI kristallisiert im triklinen System mita=10.804(5),b=12.589(5),c=10.369(3) Å, =107.72(3), =95.75(3) und =76.32(4)° in der Raumgruppe P mitZ=2. VerbindungII kristallisiert ebenfalls im triklinen System mita=10.718(2),b=13.861(4),c=10.110(9) Å, =95.99(2), =90.16(2) und =93.90(2)° in der Raumgruppe P mitZ=2. Die Geometrie rund um Cu ist in beiden Komplexen quadratisch-planar.

     

Solvent-controlled synthesis and crystal structures of a pair of azido-bridged copper(II) complexes constructed from 1-[(3-dimethylaminopropylimino)methyl]naphthalen-2-ol

A pair of azido-bridged copper(II) complexes, [Cu₂L₂(μ _1,1-N₃)₂] (1) and [Cu₂L₂(μ _1,3-N₃)₂] · H₂O (2) (HL = 1-[(3-dimethylaminopropylimino)methyl]naphthalen-2-ol), have been obtained from an identical synthetic procedure and starting materials with solvents as the only independent variable. Complex 1 was synthesized and crystallized using the anhydrous methanol, while 2 was synthesized and crystallized using 95% ethanol. Both complexes show interesting self-assembled structures in their crystals as elucidated by X-ray analysis. The end-on azido-bridged dinuclear 1 crystallizes in the P 1 space group. The end-to-end azido–bridged polymeric 2 crystallizes in the P2₁/c space group.     

Synthesis and Crystal Structure of a Copper(II) Complex with 2,4-Dihydroxybenzylidene Benzoylhydrazone Ligand

1 INTRODUCTION The chemical properties of acylhydrazones Schiff bases and their complexes with some transition metal ions have been intensively investigated in several re- search areas because of their chelating capability and pharmacological applications[1～10]. Intriguingly, the copper(II) complexes are shown to be signifycantly more potent than the metal free chelate, suggesting that the metal complex is the biologically active species. Owing to the biological interest in these types …     

Ni(II) and Cu(II) complexes of new unsymmetrical N2O2 Schiff bases derived from 3-(2-aminobenzylimino)-1-phenylbutan-1-ol: synthesis,structure, antibacterial properties,and electrochemistry

Two new N₂O₂ unsymmetrical Schiff bases, H₂L¹ = 3-[({o-[(E)-(o-hydroxyphenyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol and H₂L² = 3-[({o-[(E)-(2-hydroxy-1-naphthyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol, and their copper(II) and nickel(II) complexes, [CuL¹] (1), [CuL²] (2), [NiL¹] (3), and [NiL²] (4), have been synthesized and characterized by elemental analyses and spectroscopic methods. The crystal structures of these complexes have been determined by X-ray diffraction. The coordination geometry around Cu(II) and Ni(II) centers is described as distorted square planar in all complexes with the CuN₂O₂ coordination more distorted than the Ni ones. The electrochemical studies of these complexes indicate a good correlation between the structural distortion and the redox potentials of the metal centers. The ligand and metal complexes were also screened for their in vitro antibacterial activity.     

Synthesis,Characterization, and Electrocatalytic Behavior for Hydrogen Evolution of a Dinuclear Copper(II) Complex of 1-[(2-Carboxymethyl) benzene]-3-[2-carboxybenzene] triazene

A dinuclear copper(II) complex, [Cu^II₂(L)₂] is afforded by the reaction of CuCl₂ · 2H₂O with a triazenido ligand, 1-[(2-carboxymethyl) benzene]-3-[2-carboxybenzene] triazene (H₂L). Structural investigation shows that the copper-copper distance [2.3985(7) Å] is significantly shorter than the sum of the van der Waals radii of Cu (1.40 Å), suggesting that there are metal-metal bonds in [Cu^II₂(L)₂]. In solid, there is a strong antiferromagnetic interaction between copper(II) ions (J = –135.6 cm^–1). In homogeneous environment, [Cu^II₂(L)₂] shows electrocatalytic activities for hydrogen generation both from acetic acid with a turnover frequency (TOF) of 32 mol of hydrogen per mole of catalyst per hour [mol(H₂) · mol^–1(catalyst) · h^–1] at an overpotential (OP) of 941.6 mV, and neutral buffer with a TOF of 512 mol(H₂) · mol^–1(catalyst) · h^–1 at an OP of 836.7 mV.     

Copper(II), palladium(II) and platinum(II) chloride complexes with 5-amino-2-tert-butyltetrazole: Synthesis, characterization and cytotoxicity

Complexes CuL₃Cl₂, PdL₂Cl₂ and PtL₂Cl₂, where L is a novel ligand from the series of 2-substituted 5-aminotetrazoles, namely 5-amino-2-tert-butyltetrazole (1), have been synthesized by the reaction of metal(II) chlorides with 1 and characterized by IR spectroscopy, thermal and X-ray analyses. The crystallographic structural analysis of these complexes revealed that 1 acts as a monodentate ligand coordinated to the metal via endocyclic N4 atom. Platinum complex demonstrates promising cytotoxicity against human cervical carcinoma cells with IC₅₀ value average between those of cisplatin and carboplatin.     

Analytical Use of Copper (II)-Neocuproine in The Spectrophotometric Determination of Hydrazines

Abstract

This work characterizes a newly developed, sensitive and convenient spectrophotometric procedure for determination of sub-ppm concentrations of hydrazine and its organic derivatives. The method is based on formation of the cuprous neocuproine chelate after reaction of hydrazines with a prepared aqueous solution of the copper (II)-neocuproine complex. The cuprous chelate is then directly measured in aqueous solution at 458 nm. The effect of several experimental conditions influencing the reaction are presented and the method was employed for the analyis of 5 different hydrazine compounds. The standard deviation did not exceed ± 0.47%.     

Synthesis,crystal structure and electronic properties of bis(N-2-bromophenyl-salicydenaminato)copper(II) complex

A new series of complexes of the type bis(N-substituted-salicydenaminato)copper(II) (1–9), have been synthesized and characterized by IR, UV–Vis and elemental analysis methods. The molecular structure of bis(N-2-bromophenyl-salicydenaminato)copper(II) (6), was determined using X-ray crystallography. There are two independent molecules in the structure. Each shows a neutral, mononuclear, four-coordinate, square-planar trans-Cu[N₂O₂] geometry and, in each, the Cu atom and the ligating atoms are coplanar. The chelating N–Cu–O angle is 91.39(11)° for molecule one and 91.20(11)° for molecule two, whereas the non-chelating N–Cu–O angles are 88.61(11) and 88.80(11)°, respectively. The trans-N–Cu–N and trans-O–Cu–O bond angles are 180°. The electronic absorption spectra of copper(II) complexes (1–9), indicate that the d–d band energy is dependent on the nature and position of substituent on phenyl ring of the salicyldenimine ligand. The UV–Vis spectra in various solvents were measured and a relationship between absorption spectra and dielectric constant of the solvents is reported.     

Novel Isatin-Schiff Base Cu (II) and Ni(II) Complexes. X-ray Crystal Structure of Bis[3-(4-hexylphenylimino)-1H-indol-2(3H)-one]-dichlorocopper(II) Complex

Schiff bases of isatin were reported to possess antibacterial, antifungal, antiviral, anti-HIV, antiprotozoal, and anthelmintic activities1. They also exhibit significantanticonvulsant activity, apart from other pharmacological properties2. Conductingsubs…     

Synthesis,spectroscopic characterization,and antimicrobial activities of Ni(II) and Fe(II) complexes with N-(2-hydroxyethyl)-5-nitrosalicylaldimine

Metal complexes [Ni(HL1)₂H₂O] (1) and [Fe(HL1)₂] (2), where HL1 is the tridentate Schiff base N-(2-hydroxyethyl)-5-nitrosalicylaldimine, were synthesized and characterized by spectroscopic methods. The crystal structures of 1 and 2 have been determined by single crystal diffraction at 100?K. Complexes 1 and 2 have a distorted octahedral geometry. The ligand and metal complexes were screened for antibacterial and antifungal activities by the disk diffusion, microdilution broth, and single spore culture techniques. Antimicrobial activities of the ligand and its complexes have been tested against 10 bacteria, two yeast, and five filamentous fungi. The ligand and metal complexes were found to be active against all tested micro-organisms.     

Synthesis and Characterization of Nickel(II) and Copper(II) Complexes with Schiff Base (1R,2R)-(-)-Diaminocyclohexane-N,N'-bis(3-tert-butyl-5-(4'-benzoic acid)-salicylidene)

Two homochiral metallosalen complexes, Ni(salen) (salen = (1R,2R)-(-)-diaminocyclohexane-N,N'-bis(3-tert-butyl-5-(4'-benzoic acid)-salicylidene) 1 and Cu(salen) 2, have been synthesized and characterized by IR, microanalysis, TGA, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 4. For 1, a = 12.082(2), b = 15.447(3), c = 18.784(4) , V = 3505.7(12) 3, Mr = 731.50, Dc = 1.386 g/cm3, μ = 0.606 mm–1, F(000) = 1544, the final GOOF = 1.043, R = 0.0496 and wR = 0.1248 for 4791 observed reflections with I > 2σ(I). For 2, a = 12.181(2), b = 15.501(3), c = 18.877(4) , V = 3564.3(12) 3, Mr = 736.33, Dc = 1.372 g/cm3, μ = 0.665 mm–1, F(000) = 1548, the final GOOF = 1.062, R = 0.0575 and wR = 0.1508 for 4562 observed reflections with I > 2σ(I). The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. An infinite two-dimensional network is generated by hydrogen bonding interactions and intermolecular π···π interactions.     

Trisannelated Benzene Synthesis by Copper(II) Chloride

Different ketones such as cyclohexanone, cyclopentanone, acetophenone, 2‐acetonaphthalene, 4‐methylcyclohexanone in the presence of an hydrous CuCl₂ (catalytic amounts) at reflux condition for 2–4 hours, without using a solvent led to dimers 2‐(1‐cyclohexane‐1‐yl)‐cyclohexanone 6 , 2‐cyclopentylidene cyclopentanone 10 , trimer dodecahydrotriphenylene (DTP) 4 , trindan (tricyclopentabenzene) 9 , 1,3,5‐ triphenylbenzene (TBP) 12a , 1,3,5‐tri β‐naphthylbenzene 12b and dodecahydro‐2,6,10‐trimethyltriphenylenes 17 and 18 .     

Syntheses and structures of 2,4-dichloro-6-(cyclopropyliminomethyl)phenol and its copper(II) complex

A new Schiff base ligand, 2,4-dichloro-6-(cyclopropyliminomethyl)phenol, and a copper(II) complex containing it have been synthesized and characterised. The ligand and complex crystallise in space groups Cmca and C2/c, respectively. In the complex, the Cu atom is four-coordinate (distorted tetrahedral), bonded to two imine N and two phenolate O atoms from two Schiff base ligands. Bond lengths associated with the donor atoms in the complex are different to those in the ligand. The structure is compatible with spectra of the bulk sample.     

The synthesis,electrochemical properties and structural characterization of bis ( N -(4-dimethylaminophenyl)-3,5-di- tert -butylsalicylaldiminato)copper(II)

A Cu(II) complex of a Schiff base obtained by the condensation of N,N-dimethyl-1,4-phenylenediamine with 3,5-di-tert-butyl-2-hydroxybenzaldehyde has been synthesized and characterized. The structure of the complex was determined by single-crystal X-ray methods. The four-coordinate Cu(II) ion possesses a compressed tetrahedral coordination environment.     

Development of an Amperometric Sensor Highly Selective For Dopamine and Analogous Compounds Determination Using Bis(2,2′‐Bipyridil) Copper(II) Chloride Complex

The use of [Cu(bipy)₂]Cl₂?6H₂O as a biomimetic catalyst in the construction of an amperometric sensor for dopamine determination is reported. The sensor was prepared modifying a glassy carbon electrode with a Nafion membrane doped with [Cu(bipy)₂]Cl₂?6H₂O complex. The sensor presented a higher response in 0.25 mol L^?1 phosphate buffer solution (pH 7.0), with an applied potential of ?50 mV (vs. SCE). In the optimized operational conditions, a linear response range between 35 and 240 μmol L^?1, with a sensitivity of 2.02±0.07 nA l μmoL^?1 cm^?2 and detection limit of 8.0 μmol L^?1 were typically observed for the sensor. The response time presented for this sensor was 0.5 s, presenting the same response for at least 40 successive measurements, with good repeatability (3.0%) expressed as relative standard deviation for n=6. The difference of the response between four sensor preparations was 4%. A detailed investigation about the sensor response for other sixteen phenolic compounds and interfering species were carried out. The sensor was applied in the determination of dopamine in pharmaceutical preparation with success.     

Synthesis and Characterization of New Macrocyclic Cu（Ⅱ） Complexes from Various Diamines, Copper（Ⅱ） Nitrate and 1,4-Bis（2-formylphenoxy）butane

Six new macrocyclic complexes were synthesized by a template reaction of 1,4-bis（2-formylphenoxy）butane with diamines and Cu（NO3）2·3H2O and their structures were proposed on the basis of elemental analysis, FT-IR, UV-Vis, magnetic susceptibility measurements, molar conductivity measurements and mass spectra. The metal to ligand molar ratios of the Cu（Ⅱ） complexes were found to be 1 ： 1. The Cu（Ⅱ） complexes are 1 ： 2 electrolytes as shown by their molar conductivities （∧m） in DMF at 10^-3 mol·L^-1. Due to the existence of free ions the Cu（Ⅱ） complexes are electrically conductive. Their configurations were proposed to be probably distorted octahedral.     

Synthesis and spectroscopic studies of copper(II) and nickel(II) complexes containing hydrazonic ligands and heterocyclic coligand

Two types of copper(II) and nickel(II) complexes derived from benzophenone anthranoylhydrazone (L1), 2-acetonaftanone anthranoylhydrazone (L2), 4-phenylacetonaftonone anthranoylhydrazone (L3), benzophenone salicyoylhydrazone (L4), 2-acetonaftanon salicyoylhydrazone (L5), 4-phenylacetonaftanon salicyoylhydrazone (L6) and bidentate heterocyclic base [1,10-phenanthroline (phen)] with general stoichiometry [ML2] and [ML(phen)]Cl have been synthesized and characterized by elemental analysis, infrared spectra, UV-vis electronic absorption spectra and magnetic susceptibility measurements. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes have been investigated. According to the IR spectra, the ligands act as monobasic bidentate and coordination takes place in the enol tautomeric form.