Novel co-crystals with π-hole interactions between iodide anions and quinoid rings involving charge transfer

Six novel co-crystals of tetrabromoquinone with iodide salts of organic cations displaying short contact between iodide anion and the quinoid ring have been structurally characterised. Sandwich-like groups I−∙∙∙quinone∙∙∙I− are present...

Regioselective addition of DDQ on a quinoid ring: an entry into chiral zwitterionic bridging ligands

The Michael-type addition of DDQ on a zwitterionic ligand is described together with the chiral separation and full characterization of the two enantiomers of one derivative. These adducts offer a novel entry into chiral zwitterionic quinoidal ligands.

Amino-Functionalized Multiwalled Carbon Nanotubes for the Preparation of Electroactive Polyurea Composites with Improved Electrical Properties

Multiwalled carbon nanotube/electroactive polyurea (MWCNT/EPU) composites have been synthesized through oxidative coupling polymerization. The amino functional groups on AF-MWCNTs provided an opportunity to react with oligoaniline in oxidative coupling polymerization process. UV-visible spectra reveals that the quinoid ring on the EPU interact with MWCNTs. The results of the cyclic voltammetry studies indicate enhanced electrochemical properties for efficient electron/charge transfers behavior of MWCNT/EPU composites.

Synthesis of Polyaniline by Pulsed Plasma Polymerization Using Theta-Pinch Device

Polyaniline was synthesized by pulsed plasma polymerization using a theta-pinch device. The process was done using oxygen plasma at a voltage of 20 kV, a pressure of 2 Pa and a discharging current of 125 kA. The number of the plasma shots was varied from 10, 15, 20, 25, to 30 shots. This parameter significantly affected the chemical structures of the synthesized polyanilines as revealed by FTIR spectra. While all synthesized polyaniline exhibited the characteristic peaks of quinoid ring and benzenoid group, the peaks corresponding to the formation of oxygen containing groups was found when high numbers of plasma shots were employed. This also caused the difference in UV-VIS absorption of these polyanilines. The highest conductivity of polyaniline was obtained when 20 shots of oxygen plasma were used. At this condition, polyaniline had a semi-crystalline structure and the thermal decomposition temperature at 262oC.

Face-to-face stacking of quinoid rings of alkali salts of bromanilic acid

A series of alkali salts of hydrogen bromanilic acid trihydrates (K+, Rb+ and Cs+, potassium, rubidium and caesium 2,5-dibromo-4-hydroxy-3,6-dioxocyclohexa-1,4-dien-1-olate trihydrate), bromanilic acid tetrahydrate (Na+, disodium 2,5-dibromo-3,6-dioxocyclohexa-1,4-diene-1,4-diolate tetrahydrate) and bromanilic acid dihydrates (K+, Rb+ and Cs+, dipotasium, dirubidium and dicaesium 2,5-dibromo-3,6-dioxocyclohexa-1,4-diene-1,4-diolate dihydrate) were prepared and studied by single-crystal X-ray diffraction. Their crystal packings are dominated by quinoid ring stacking. The monoanionic quinoid rings pack face-to-face without offset and with short centroid separations (3.25–3.30 Å), while the dianionic rings form offset stacks (1.4–1.8 Å) with a larger centroid separation (3.8–4.1 Å).