Synthesis of new polyporphines by replacing central ion in magnesium polyporphine

It is shown that the derivatives of the source electroactive polymer, magnesium polyporphine (pMgP), can be synthesized by successive treatment of electropolymerized pMgP film on the electrode surface with trifluoroacetic acid and zinc acetate solutions in the organic solvents. Based on the electrochemical and spectral characteristics of the modifying layers, it is concluded that the central magnesium ion in the porphine monomeric blocks is replaced with the formation of polyporphine in the form of free base (pH₂P) and zinc polyporphine, respectively. The oxidative transformation of thus obtained new polyporphines pH₂P and pZnP (which are the polymers of type I) is realized. It leads to a change in the molecular structure of polymer films (the transition to the type II); as a result, the potential range of their electroactivity is extended significantly.     

Electrochemical synthesis of cobalt polyporphine films

A method for modification of the inert electrode surface with an electroactive polymeric film containing the CoN₄ catalytic site has been suggested and approved. The described approach affords the maximal content of the metal porphine moiety per unit weight of the coating. The classical method of introduction of an ion into the porphine macrocycle has been replaced by electrochemical polarization of an electrode with a metallated film in a dilute solution. The metalation efficiency has been demonstrated by the presence of changes in the current–voltage and spectral characteristics of the resulting polymeric films of the unsubstituted porphine pH₂P and cobalt polyporphine pCoP.     

An electrochemical study of the incorporation of cobalt macrocyclic complexes into nafion films

Cobalt complexes of the macrocyclic ligand, 2,3,9,10-tetramethyl-1,4, 8,11-tetraazacyclotetradeca-1,3,8,10-tetraene (TIM) and its hydroxy derivatives, were incorporated in Nafion films by electrochemical cycling and by ion exchange in aqueous solution. Cyclic voltammetric studies show that the redox potentials of the Co(TIM) complexes undergo a significant anodic shift when incorporated in the films. Electrochemical studies also indicate that, while the Co(TIM) complexes reside in hydrophilic regions of the Nafion film, the metallated porphine complex, cobalt tetrakis(pentafluorophenyl)porphine, is probably immobilized in hydrophobic regions. The incorporation of the complexes was also followed by electronic absorption spectrophotometry.     

Electronic structure of porphyrin complexes of cobalt

The electronic structure of Co(I) and Co(II) porphine has been investigated by the MO-LCAO-SCF method in the CNDO/2 approximation. It has been shown that as a result of the one-electron reduction of the original Co(II) porphine, the extra electron is localized to a considerable degree on the central ion of the complex. Consequently, the spatial structure of cobalt porphine may be altered, and the cobalt ion can deviate from the plane of the macrocyclic ligand. The interaction of molecular oxygen with Co(I) porphine has been investigated, and it has been established that the formation of a complex of the bent type, in which the O₂ molecule is at a 135° angle to the plane of the ligand, is most favorable.Translated from Teoreticheskaya i Éksperimental'naya Khimii, Vol. 21, No. 1, pp. 1–10, January–February, 1985.     

Polymer-Complex Mediated Enzyme Electrodes for Amperometric Determination of Glucose

The immobilized enzyme chemically modified solid-state electrodes based on bilayer-film coating for amperometric determination of glucose have been fabricated and their sensor characteristics have been examined. The electrode substrate was coated with two kinds of polymeric films in a bilayer state, that is, System I: first with the cobalt tetrakis(o-aminophenyl)porphyrin polymer (poly-CoTAPP) film and then with an enzyme film consisting of bovine serum albumin and glucose oxidase (GOx), and System II: first with the Ru(NH₃)³⁺ ₆-containing montmorillonite clay film and then with the GOx enzyme film. The glucose concentration could be monitored by measuring the currents corresponding to the O₂ reduction and the H₂O₂ reduction which are electrocatalyzed by the poly-CoTAPP film (System I) and the clay film (System II), respectively. The reproducible relationship between glucose concentration and sensor output was obtained for both systems with a dynamic range of ～ 1-100 mM (for System I as an electrochemical detector for a flow injection analysis) and ～0.4-4 mM (for System II). In addition, the sensors showed long-term stability (more than 1 and 2 months in System I and System II, respectively) and relatively rapid response (response times of System I and System II are ? 5-10 and 40-60 s, respectively).     

Extension of the voltammetric theory to inert,permeable thin-film coated rotating disc electrodes: Part II. Behaviour of ferrocene-ferricinium ion and quinone-hydroquinone systems on polymer-coated electrodes

The voltammetric behaviour of ferrocene-ferricinium ion and quinone-hydroquinone systems is investigated on electrochemically thin film polymer coated electrodes. Ferrocene oxidation is studied in 0.1 M NBu₄ ClO₄-nitromethane on rotating disc platinum electrodes coated with poly(2-hydroxymethyl-1,4-phenylene) oxide (I), poly-(2,6-dimethyl-1,4-phenylene) oxide (II), and poly[4-(2-aminoethyl)-1,2-phenylene] oxide (III) films. The quinone-hydroquinone system is investigated in aqueous medium (1 M HClO₄) with (I), (II) and poly-(2-cyano-1,4-phenylene) oxide films. Experimental results are in good agreement with the previously calculated voltammetric curves in steady-state mass transfer conditions. The charge transfer and diffusion parameters on these polymer-coated electrodes are calculated The quinone-hydroquinone system is rendered reversible by coating a platinum electrode with I.     

catena‐Poly[[[N,N′‐bis­(salicyl­idene)propane‐1,3‐diaminato]cobalt(III)]‐μ‐azido] and catena‐poly[[[N,N′‐bis(salicyl­idene)propane‐1,3‐diaminato]cobalt(III)]‐μ‐thio­cyanato]

The two title complexes, catena‐poly[[{2,2′‐[1,3‐propane­diylbis(nitrilo­methyl­idyne)]diphenolato}cobalt(III)]‐μ‐azido], [Co(C₁₇H₁₆N₂O₂)(N₃)]_n, (I), and catena‐poly[[{2,2′‐[1,3‐propane­diylbis(nitrilo­methyl­idyne)]diphenolato}cobalt(III)]‐μ‐thio­cyanato], [Co(C₁₇H₁₆N₂O₂)(NCS)]_n, (II), are isomorphous polynuclear cobalt(III) compounds. In both structures, the Co^III atom is six‐coordinated in an octa­hedral configuration by two N atoms and two O atoms of one Schiff base, and two terminal N or S atoms from two bridging ligands. The [N,N′‐bis­(salicyl­idene)propane‐1,3‐diaminato]cobalt(III) moieties are linked by the bridging ligands, viz. azide in (I) and thio­cyanate in (II), giving zigzag polymeric chains with backbones of the type [–Co—N—N—N—Co]_n in (I) or [–Co—N—C—S—Co]_n in (II) running along the c axis.     

Electrodeposition of cobalt oxide films from carbonate solutions containing Co(II)–tartrate complexes

An electrochemical procedure of anodic deposition of cobalt oxyhydroxide film on a glassy carbon substrate in an alkaline medium (i.e. pH 11.6) is described. The electrodeposited film was obtained either by voltage cycling or by potentiostatic conditions using non-deaerated 0.1 M Na₂CO₃ solutions containing 40 mM tartrate ions and 4 mM CoCl₂. The effects on the film formation and growth, such as tartrate–cobalt ratio, pH, applied potential, etc. were widely evaluated. The electrodeposition process, under anodic conditions and moderately alkaline solutions, most likely involves a redox transition Co(II)→Co(III)/Co(IV) with destruction of the tartrate complex and formation of insoluble oxide/hydroxide cobalt species on the glassy carbon surface. The resulting cobalt oxyhydroxide films were characterised by cyclic voltammetry (CV) in 0.1 M NaOH solutions and by scanning electron microscopy (SEM) analysis after different strategies of preparation and various electrochemical treatments. The electrochemical activity of the deposited films was checked using various organic molecules as model compounds.     

Properties of polyimide films doped with copper complexes

Polyimide films based on either 3, 3′, 4, 4′-benzophenone tetracarboxylic acid dianhydride or pyromellitic dianhydride with 4,4′-oxydianiline have been doped with copper(I) and copper(II) complexes. High-quality, flexible, glass-cast films have been obtained which exhibit increased softening temperatures and lower polymer decomposition temperatures. The atmosphere and glass sides of the films are quite different. The copper(I) dopant is oxidized on the air side of the film, while the glass side contains predominantly copper (I). In the copper(II) case most of the copper appears on the air side as a silvery substance in the Cu(II) state. Chemical as well as ion etching can remove this material. Electrical resistivity of the copper(II)-doped films is decreased by three to five orders of magnitude relative to the polymer alone.     

Resistive‐type humidity sensors based on PVP–Co and PVP–I2 complexes

Poly(vinylpyrrolidone) films containing cobalt chloride or iodine were investigated to obtain information on their possible use as a humidity sensor element. FTIR and UV‐VIS spectroscopies were used to characterize the PVP–I₂ and PVP–Co complexes. Infrared spectroscopy revealed a structural change of both shape and intensity of the carbonyl and lactam bands, indicating the formation of an ion‐coordination polymer. The J–E curves for pure PVP, PVP–I₂, and PVP–Co films obey ohm's law at low voltages, deviate from the linear response at higher voltages, and finally display breakdown behavior. An increase in current density of the PVP matrix with iodine or cobalt doping is attributed to the formation of charge transfer complexes. The observed hysteresis of the I–V characteristics implies that there was some standing voltage in the film, which could be attributed to a disorientation of polar side groups of PVP. The electrical conductivities of the polymeric complexes were very sensitive to environmental humidity. An explanation of the humidity‐sensing behavior of the PVP–I₂ and PVP–Co complexes is presented. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 459–469, 2001     

Structure of iodide ion arrays in iodinated nylon 6 and the chain orientation induced by iodine in nylon 6 films

Two species of iodide ions (I₃^? and I₅^?) are found in iodine—nylon 6 complexes. Orientation of I₅^? arrays (most likely I₂/I₃^? complex) along the polymer chain and I₃^? ions perpendicular to the chain axis in uniaxially drawn films and in films with planar orientation suggests that there is and intrinsic relation between the direction of iodide ion arrays and nylon 6 chains. When an unoriented film of nylon 6 in the amorphous or the α crystalline form is treated with an aqueous solution of iodine—potassium iodide, the I₃^? species in the resulting iodine—nylon complex lie in planes parallel to the surface of the film, and I₂/I₃^? units are oriented normal to the surface of the film. The γ form obtained by desorbing the iodine from this complex shows considerable uniaxial rientation with the nylon chains oriented perpendicular to the plane of the film; this orientation is maintained during the γ to α transition. It is proposed that the iodine-induced orientation of the nylon 6 chains is due to the nucleating effects of the iodide ion species as the iodine diffuses unidirectionally into the film.     

Development of Functional Composite Cu(II)-Polyoxometalate/PLA with Antimicrobial Properties

Novel composite self-disinfecting films of polylactic acid (PLA) filled with nanosized particles of double sodium–copper(II) paratungstate B Na₂Cu₃(CuOH)₂[W₁₂O₄₀(OH)₂]·32H₂O (POM) were developed. The solvent casting (POM/PLA film) and solvent-free melt extrusion methods (Extr. POM/PLA film) were applied for film preparation. The copper (II) ion release to water from both types of the films after 10 days at different temperatures demonstrated that the PLA matrix acts as a diffusion barrier, and the resulting concentration of released copper in water at room temperature remained low, at 0.79% for POM/PLA film and 0.51% for Extr. POM/PLA film. The POM-containing films reveals a significant inhibitory effect against E. coli ATCC 25922 in the agar diffusion test. The numbers of CFUs in washes of the films after incubation for 24 h were found to be 3.6 log CFU mL^–1 (POM/PLA film) and 4.1 log CFU mL^–1 (Extr. POM/PLA film). The films combine the antibacterial properties of POM and a bio-based polymer matrix, which makes them a prospective coating material for applications in hospital indoor environments. Excellent thermal stability of POM gives a technological advantage for industrial manufacturing to allow the processing of novel composite material in the solvent free (molten) state.     

Effect of sol temperature on the structure,morphology, optical and photoluminescence properties of nanocrystalline zirconia thin films

Transparent nanocrystalline zirconia thin films were prepared by sol–gel dip coating technique using Zirconium oxychloride octahydrate as source material on quartz substrates, keeping the sol at room temperature (SET I) and 60 °C (SET II). X-ray diffraction (XRD) pattern shows the formation of mixed phase [tetragonal (T) + monoclinic (M)] in SET I and a pure tetragonal phase in SET II ZrO₂ thin films annealed at 400 °C. Phase transformation from tetragonal to monoclinic was achieved in SET II film annealed at 500 °C. Atomic force microscopy analysis reveals lower rms roughness and skewness in SET II film annealed at 500 °C indicating better optical quality. The transmittance spectra gives a higher average transmittance >85% (UV–VIS region) in SET II films. Optical spectra indicate that the ZrO₂ films contain direct—band transitions. The sub- band in the monoclinic ZrO₂ films introduced interstitial O⁻defect states above the top of the valance band. The energy bandgap increased (5.57–5.74 eV) in SET I films and decreased (5.74–5.62 eV) in SET II films, with annealing temperature. This is associated with the variations in grain sizes. Photoluminescence (PL) spectra give intense band at 384 and 396 nm in SET I and SET II films, respectively. A twofold increase in the PL intensity is observed in SET II film. The “Red” shift of SET I films and “Blue” shift of SET II films with annealing temperature, originates from the change of stress of the film due to lattice distortions.     

Metal ion incorporation into n-methyl-5,10,15,20-tetrakis (4-sulfonatophenyl) porphine and its differential rates as applied to the kinetic determination of copper(II) and zinc(II) in serum

Metal ion incorporation intoN-methyl-5,10,15,20-tetrakis(4-sulfonatophenyl)porphine (N-CH₃TSPP) has been shown to be much faster than that for non-methylated porphyrins such as 5,10,15,20-tetrakis(4-sulfonatophenyl)porphine (TSPP). We have proposed a kinetic method, utilizing differential rate of metal ion incorporation into N-CH₃TSPP, for the determination of submicrogram amounts of copper(II) and zinc(II) in serum.     

A one‐dimensional zigzag coordination polymer of di­aqua­(pyridine‐2,3‐di­carboxyl­ato)­cobalt(II)

The asymmetric unit of the title one‐dimensional coordination polymer, catena‐poly­[[μ‐pyridine‐2,3‐di­carb­oxyl­ato‐1κO:2κ²N,O′‐bis­[di­aqua­cobalt(II)]]‐μ‐pyridine‐2,3‐di­carboxyl­ato‐1κ²N,O:2κO′:1′κO′], [Co(C₇H₃NO₄)(H₂O)₂]_n, is composed of a cobalt(II) ion, a pyridine‐2,3‐di­carboxyl­ate dianion and two water mol­ecules. The polymer has a zigzag structure consisting of a chain of edge‐fused rings, and the polymer chains are linked by O—H⃛O hydrogen bonds into a three‐dimensional framework.     

Thermal behaviourof complexes of antipyrine derivatives Part III.

The thermal behaviour of the mixed-ligand complexes of cobalt(II) and copper(I) ions with antipyrine derivatives of 1,2-ethanediamine or piperazine (BAMP and TAMEN), with water and with 2-mercapto-benzothiazole (Hmbt) was investigated. The complexes contain 2-mercaptobenzothiazole (Hmbt, in the case of cobalt(II) ion) or dimercaptobenzothiazine (mbt–mbt, in the case of copper(I) ion) molecules as ligands and perchlorate (ClO₄^–) or thiocyanate (SCN – ) ion as counterion. By heating, water and ligands release the solid phase at lower temperature. At higher temperatures process of different organic reactions of ligands (e.g. polymerization, polycondensation) could be suggested to interpret the relative high final mass values.     

Electrochemical formation of cation-exchanging polypyrrole films within various hydrophilic–hydrophobic domains

The electrochemical polymerization technique has been successfully applied to produce conducting polymer film of controlled ion exchange properties. Polypyrrole films were prepared by electro-oxidative polymerization with doping some alkylsulfonates or Nafion. The ion exchange characteristics across polypyrrole films were examined by means of a novel electrochemical technique, namely, the in situ electrochemical quartz crystal microbalance (EQCM) method. According to EQCM measurements, exchanging ion species was found to be successfully controlled by changing the hydrophilic–hydrophobic balance of the incorporated sulfonated-based dopants. The film's characteristics became anion- to cation-exchanging as the dopants became more hydrophobic in nature. The polypyrrole–Nafion(poly(perfluoroethylene sulfonate)) composite film became to be a complete cation exchanger.     

A new selective and high affinity polymeric complexing agent for transition metal ions

Summary The synthesis and characteristics of a new chelating glycinohydroxamate-containing polymer resin is described. The functionality of the polymer is 1.76 mmolg^–1. The hydrogen capacity, water regain and adsorption capacities for iron(III), cadmium(II), cobalt(II), copper(II), nickel(II) and zinc(II) were measured at various pH values; uptake of the metal ions increased with pH and was quantitative above pH 3 for most of the metal ions. All cations studied showed high exchange rates towards the resin. The half saturation times for iron(III), cadmium(II), copper(II) and zinc(II) were all less than 1 min. The coordination behaviour of the resin was studied with the help of e.p.r., i.r., u.v. and potentiometry. The pK _a of the resin is 10.70 and the log value of the stability constants for iron(III), copper(II), lead(II), zinc(II), cobalt(II), manganese(II), cadmium(II) and nickel(II) were measured as 21.81, 19.50, 19.20, 18.59, 18.51, 18.46, 18.37 and 18.36, respectively, at 25 ° C and I = 0.2M KCl.     

PREPARATION, CHARACTERIZATION AND ELECTROCHEMICAL PROPERTIES OF POLYPYRROLE-POLYSTYRENE SULFONIC ACID COMPOSITE FILM

Polypyrrole-polystyrene sulfonic acid (PPy-PSSA) composite films have been electrosynthesized in an aqueous solution of PSSA. The electro-active films exhibit cation exchange during the redox process. Infrared, Raman and energy-dispersive spectroscopic results demonstrated that the polyanion of PSS^- is co-deposited into the PPy matrix and couldn‘t be stripped from the film extensively by dedoping. The doping level together with dipolaron content of the PPy-PSSA composite film increases during electrochemical polymerization process. SEM images revealed that the composite film has smooth and compact morphology and AFM pictures suggested that PPy chains are possibly grown perpendicular to the electrode surface. TGA tests indicated that the composite films has much better thermal stability than that of pure PPy.Furthermore, electrochemical studies showed that the relaxation process at certain holding potential has great effect on the shape of the cyclic voltammetric curves of PPy-PSSA composite film. The composite film exhibits cation and anion exchange during the redox process after undergoing the relaxation step. It is more difficult for divalent anion to enter the polymer matrix than a univalent ion, and a large cation such as (CH3CH2CH2CH2)4N^ cannot be involved in the ion exchange process.