2-Ethynyl-6-methylthieno[3,2- b ]thiophene as an efficient π spacer for porphyrin-based dyes

Ethyne Functionalized Meso-Phenothiazinyl-Phenyl-Porphyrins: Synthesis and Optical Properties of Free Base Versus Protonated Species

“…Ethynyl groups were attached to the porphyrin core as a linker capable for inducing an extensive conjugation through π−π orbital interactions favourable to charge delocalization between the macrocycle and (hetero)aromatic units with the goal of achieving subsequent tailored electronic properties of porphyrin-based materials. The ethynyl bridges were grafted in the β [ 18 ] but mainly in the meso positions of the porphyrine core [ 19 , 20 , 21 , 22 ]. Substituents attached at the level of the peripheral porphyrin ring often caused minor structural changes without modifying the planar geometry of the porphyrin core, which instead could be affected by bulky aromatic substituents on meso or β positions and also by introducing substituents at the inner pyrrole nitrogen atom.…”

Metal-Free Organic Chromophores Featuring an Ethynyl-Thienothiophene Linker with an n-Hexyl Chain for Translucent Dye-Sensitized Solar Cells

“…Recently, we also reported the facile synthesis of two organic dyes featuring ethynyl-thiophene from commercially available starting materials [11,12]. Zhao et al introduced ethynyl-thiophene or 2-ethynyl-6-methylthieno[3,4-b]thiophene to zinc-porphyrin dyes to enhance the light-harvesting capability and prevent the intermolecular aggregation [13]. Fernandes et al synthesized three push-pull organic dyes featuring 2,2’-bithiophene, ethynyl-2,2’-bithiophene or ethynyl-thieno[3,2-b]thiophene spacers [14].…”