Electroinitiated polymerization of bis(tribromophenoxo)‐N,N,N′,N′‐tetramethylethylenediamine copper(II) complex

Abstract

Tribromophenol copper(II) complexes with ligands such as pyridine and ethylenediamine are known to polymerize thermally. Generally, high temperature is required for thermal polymerization of such complexes. Thermal polymerization of trihalophenol copper(II) complexes in toluene has an induction period of c. 30 min. Electroinitiated polymerization of trihalophenol copper(II) complexes has also been accomplished recently using pyridine or ethylenediamine as ligands. However, the above mentioned copper(II) complexes cannot be polymerized electro‐chemically in acetonitrile. When pyridine and ethylenediamine are used as ligands, such complexes rapidly polymerize in acetonitrile without the passage of any current even at room temperature. Therefore, the electrochemical polymerization of trihalophenol copper(II) complexes with pyridine and ethylenediamine ligands must be carried out in dimethylformamide. In the present work, electroinitiated polymerization of bis(2,4,6‐tribromo‐phenoxo)‐N,N,N′,N′‐tetramethylethylenediamine copper(II) complex (TBPTD) was accomplished for the first time in acetonitrile. When N,N,N′,N′‐tetramethylethylene diamine is used as the ligand in the preparation of tribromophenol copper(II) complex it is found that acetonitrile can be used as solvent. This complex does not polymerize in acetonitrile without the application of potential. Electroinitiated polymerization of TBPTD was carried out by constant potential electrolysis, at each anodic peak potential of the complex. These potentials of TBPTD were measured, in advance, by cyclic voltammetry in acetonitrile. Electrolysis of TBPTD yielded polymers in the anode compartment only. Electroinitated polymerization of this monomer exhibited no induction period in contrast to the case of thermal polymerization. The reacted monomer concentration was simultaneously followed by cyclic voltammetry, in the same electrolysis cell. This process was accomplished by a specially designed H‐type cell equipped with six electrodes. Use of cyclic voltammetry for simultaneous in‐situ monitoring of reacted monomer concentrations was found to be more accurate, quicker and more reproducible than gas chromatography or spectroscopy. Polymers were characterized by FTIR, 1HNMR, and 13CNMR spectral analyses as well as measurement of molecular weight by the isopiestic method.

Investigation of phenol electrooxidation in aprotic non-aqueous solvents by using cyclic and normal pulse voltammetry

“…Film porosity determines the diffusion transport barrier properties, and redox species can be selected to estimate the permeability. There are some works about the electropolymerization of halogenated phenols from their transition metal complexes and electroinitiated polymerization of phenols having unsaturated side chain mainly in acetonitrile and dimethyl formamide [17][18][19][20][21][22][23][24][25][26]. Application of a strong pyridinetype base determines the product of electrooxidation of phenols; for example, in case of 4-tercbutylphenol the corresponding dimer forms [27].…”

Polymerization and characterization of various di(pyridine)bis(trihalophenolato)cobalt(II) complexes in solid and melt states

“…The polymerization of halogenated phenols from copper(II) complexes with various amine ligands has been studied since 1959. A series of copper complexes with different types of phenols with various amine ligands were decomposed thermally in solution4–13 or in the solid state14–18 or by electro initiation in solution19–34 in order to examine the effect of the method of decomposition, ligand type and position of substituted halogen on the phenol ring on the structure, molecular weight and percentage conversion of the polymeric products. In addition to copper complexes, halogenated phenol complexes with nickel(II)35, 36 and cobalt(II)37 with pyridine as ligand were synthesized and their thermal decomposition in the solid state was investigated.…”