Solvatochromic behaviour of new donor–acceptor oligothiophenes
Oligothiophene derivatives play a central role in the formulation of materials used in devices in the field of organic electronics. In this work, we report the results of the study of UV-vis absorption and fluorescence spectra, in several solvents, of a series of oligothiophenes recently synthesized in our laboratory. The studied oligothiophenes present different structures due to several factors: the donor– acceptor (D–A) or acceptor–donor–acceptor (A–D–A) architecture, the number of thiophene rings in the backbone (ranging from three to eight), the number and position of solubilizing octyl chains in the backbone, and the type of acceptor moieties (from Knoevenagel condensation either with…
Cathodic behaviour of dicationic imidazolium bromides: the role of the spacer
The cathodic reduction of dicationic imidazolium bromides, whose spacer is either an aliphatic chain or a xylyl group, leads to the formation of the corresponding N-heterocyclic carbenes (NHCs), which were isolated as the corresponding thiones, after reaction with elemental sulfur. The behaviour of the dications was compared with the corresponding monocations. The behaviour of dicarbenes depends on the nature of the spacer. This study evidenced that dicarbenes deriving from xylyl dications are less stable than the corresponding aliphatic ones (giving lower yields in thiones), due to a debenzylation reaction. On the other hand, the yields in thiones starting from aliphatic dications are high…