Structures and chromotropic properties of 1,4-bis(4,5-diphenylimidazol-2-yl)benzene derivatives

Blue Emission of a Soluble Poly(p‐phenylene) with a Cross‐Conjugated Bisimidazole‐Based Chromophore

“…As already reported by several authors, [29][30][31] a marked change of the UV-vis absorption properties of 2,2 0 -( pphenylene)-bis(4,5-diphenylimidazole)s (5) can be achieved by an oxidation of the central bisimidazole unit to a quinoid-type structure. By a similar oxidation of 6 with potassium ferricyanide [30] in a two-phase water-chloroform mixture, polymer 7 was obtained (Scheme 3).…”

“…By a similar oxidation of 6 with potassium ferricyanide [30] in a two-phase water-chloroform mixture, polymer 7 was obtained (Scheme 3). In contrast to the deep yellow polymer 6, polymer 7 was showing a green color in the solid state, which can be attributed to the quinoid-type structure.…”

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

“…N-Unsubstituted diimidazoles can easily be oxidized to the corresponding quinoid structure (2 H -imidazole derivatives), as shown in Scheme 3 [ 19 , 59 – 61 ]. In 1999, Ye et al [ 61 ] reported the oxidation of D-π-A diimidazole 27a to quinoid 34 and a comparison of the linear and nonlinear optical properties.…”

Stress-induced colouration and crosslinking of polymeric materials by mechanochemical formation of triphenylimidazolyl radicals

“…Alkylation of commercial 4-hydroxybenzaldehyde with 6-chlorohexanol yielded ether 4 which, in turn, reacts with benzil followed up by saponification of the phenyl acetate side-product giving imidazole 3. 32 Relatively high molecular weights for PMA-2 were chosen as we discovered that increasing the molecular weight improved the coupling efficiency. 31 Oxidative coupling to PMA-1 was carried out with PbO 2 after the polymerization step instead of before because we found that the dynamic equilibrium of HABI with its TPI radicals is incompatible with the conditions of most living radical polymerizations.…”