Electrochemistry and spectroelectrochemistry of polymers based on D-A-D and D-D-D bis( N -carbazolyl) monomers, effect of the donor/acceptor core on their properties

In this work we present electropolymerization of monomers of an unusual type using N-linked carbazole units to limit their conjugation. The polymers thus obtained have limited conjugation through the backbone. Using donor-acceptor-donor (D-A-D) and donor-donor-donor (D-D-D) monomers we evaluate the effects of the presence (or absence) of charge transfer states on synthesized electropolymers. The use of a D-A-D monomer resulted in obtaining an ambipolar polymer with quasi-reversible reduction

Microbial Transformation of Isoprenoid Systems By Means of Zoophthora (erynia) Ovispora (nowakowski) Batko

Epoxidation of double bond was the main reaction performed by Zoophthora (Erynia) ovispora on methyl and ethyl alpha-campholenyl ketones 1 and 6. Apart from epoxides 2, 3, 7, and 8, some other products were isolated, with additional oxygen function in alpha-position to the double bond (9 and 10). The presence of the BAEYER-VILLIGER reaction product (4) and diketone 11 is also postulated

Evidence for Solid State Electrochemical Degradation Within a Small Molecule OLED

Acridone derivative have been synthesised and used as OLED (Organic Light Emitting Diode) emitters which were found to be electroactive. Electrochemical investigations showed a side reaction takes place inside an active layer which diminished the overall device efficiency. By using a dopant and host active layer architecture, the formation of the by product was removed. The by-product was identified as a sigma-dimer formed inside an oligomer. The active layers were investigated by electrochemical techniques (cyclic voltammetry, UV-Vis-NIR spectroelectrochemistry, Electron Paramagnetic Resonance (EPR) spectroelectrochemistry and Dynamic Electrochemical Impedance Spectroscopy (DEIS)) to characterize the layers, charge carriers, and electronic energy levels. It is clear from these observations that electrochemical reactions of emitter molecules in a working devices is a route to device degradation. (C) 2015 Elsevier Ltd. All rights reserved

Synthesis and characterization of chalcogenophene-based monomers with pyridine acceptor unit.

2,4,6-Trisubstituted pyridine derivatives with different electropolymerizable groups were investigated. It was shown that steric hindrance caused by bichalcogenophene substituents in the 2,6-positions of pyridine enables successful electropolymerization whereas previous studies on 3,5-substituted pyridines shown difficulties caused by the presence of the pyridine nitrogen lone electron pair. Cyclic voltammetry and differential pulse voltammetry techniques were used to determine the electronic properties of the studied compounds and obtained polymers. UV-Vis-NIR and EPR spectroelectrochemistry were used to determinate the behavior of the polymers in the doping-dedoping cycles. The polymers were found to have coloration efficiency up to 245 cm(2) C-1 and exhibit sufficient stability for application and highlighting their possible use as electroactive layers in electrochromic devices. (C) 2016 Elsevier Ltd. All rights reserved

Unusual properties of electropolymerized 2,7-and 3,6-carbazole derivatives

Differently linked carbazole derivatives possessing pyrene and selenophene moieties were electrochemically investigated. Cyclic voltammetric as well as differential pulse voltammetric studies demonstrated that they display comparatively low oxidation potentials. One-step cyclic voltammetric process was used for the preparation of their highly dimensional, stable and electroactive polymers. The electrodeposited polymers displayed unusual properties upon electrochemical doping that may help tailoring the dimensional features of these polymers. The electrodeposited polymers were investigated by electrochemical and optical tools and correlation between different parameters such as oxidation characteristics or absorption behavior and the effective conjugation length was established. Spectroelectrochemical investigations showed the polaronic and bipoloronic features of the electropolymers. Multielectrochromic properties of electrodeposited polymers on successive doping suggested their application as electroactive layers in electrochromic devices

Herbicidally active derivatives of aminomethylene-bisphosphonic acid - Mode of action and structure-activity relationship.

(N-pyridylamino)methylenebisphosphonates exhibit strong herbicidal activity which may be reversed by supplementation of the growth media with aromatic amino acids. They appeare to be the inhibitors of aromatic amino acids biosynthesis acting as inhibitors of DAHP synthase the first enzyme of shikimate pathway. Over 40 analogues of these acids were synthesized in order to determine the structure-activity relationship

Inkjet printing, pyrolysis and crystallization of YBa₂Cu₃O₇-δ precursor layers for fully chemical solution deposited coated conductors

AbstractA complete reaction path for the pyrolysis of trifluoroacetate-derived YBa2Cu3O7-! precursor solution is reported based on the authors’ investigations of the separate trifluoroacetate salt decompositions using thermal analysis and infrared spectroscopy of evolved gases. Optimal conditions for the pyrolysis of inkjet printed films are proposed, and the influence of pyrolysis on the YBa2Cu3O7-! crystal growth on a fully buffered Ni-5%W substrate is revealed. Optimisation of the annealing step revealed a strong dependence of the superconducting properties on the heat treatment temperature and duration. The critical temperature (Tc) and critical current density (Jc) of fully chemical solution deposited coated conductor samples were examined by means of inductive and Hall probe measurements