Electroactive tetrathiafulvalenyl-1,2,3-triazoles by click chemistry: Cu- versus Ru-catalyzed azide-alkyne cycloaddition isomers.

Two series of 4- and 5-tetrathiafulvalenyl-1,2,3-triazoles, as multifunctional ligands and precursors for molecular materials, have been synthesized by copper- or ruthenium-based "click" chemistry. The solid-state structures of three ligands and two Cu(II) complexes were determined. Large differences in the electron-donating properties between the 1,4- and 1,5-isomers were evidenced by cyclic voltammetry. Theoretical calculations support this observation and allow the assignment of the electronic transitions observed in UV/Vis spectra of the ligands.