A series of redox active, tetrathiafulvalene-based amidopyridines and bipyridines ligands: Syntheses, crystal structures, a radical cation salt and group 10 transition-metal complexes

Amidopyridine and -2,2'-bipyridine derivatives of EDT-TTF and BTM-TTF (EDT = ethylenedithio, BTM = bis(thiomethyl), TTF = tetrathiafulvalene) have been synthesized and crystallographically characterized. In the solid state, the different supramolecular organization of all these donors results from the competition between the intermolecular interactions, that is, van der Waals, hydrogen-bonding, pi-pi stacking, and donor-acceptor interactions. The electron-donating properties of the new donors have been investigated by cyclic voltammetry measurements. A radical cation salt, formulated [EDT-TTF-CONH-m-Py](.+)[PF6](-), has been prepared by electrocrystallization and its crystal structure determined by X-ray analysis. Square planar dicationic complexes with the same donor and (ML2)-L-II fragments (M = Pd, Pt, L-2 = bis(diphenylphosphino)propane (dppp) or bis(diphenylphosphino)ethane (dppe)) have been synthesized and one of them, containing the Pd(dppp) unit, has been structurally characterized. The conformation of the complex in the crystalline state is anti, with the coexistence of the dl racemic pair of enantiomers.