An Efficient, Redox-Enhanced Pair of Hydrogen-Bond Tweezers for Chloride Anion Recognition, a Key Synthon in the Construction of a Novel Type of Organic Metal based on the Secondary Amide-Functionalized Ethylenedithiotetrathiafulvalene, β‘ ‘-(EDT-TTF-CONHMe)₂[Cl·H₂O]

Electrocrystallization of 1,1,2-trichloroethane solutions of the redox-active secondary amide, 3-methylamido-3‘,4‘-ethylenedithiotetrathiafulvalene (EDT-TTF-CONHMe 1 ) in the presence of n -Bu 4 NF supported on silica gel afforded a mixed-valence chloride salt, formulated ( 1 ) 2 [Cl·H 2 O] from elemental analysis and X-ray crystal structure resolution. The chloride anion and water molecule are disordered on the same site, and coordinated to the π-donor molecule by two strong hydrogen bonds involving the amidic N−H and the aromatic C−H group ortho to the amide, thereby qualifying a robust pair of tweezers-like cyclic motif. This efficient anion recognition effect is also observed in solution, as demonstrated by 1 H NMR downfield shifts of both the N−H and C−H hydrogen atom resonances, as well as by a cathodic shift of the oxidation potential of 1 upon Cl - complexation, establishing that the actual electrocrystallized species is a solvated anionic chloride complex [( 1 ·Cl - )(H 2 O) n ] rather than the free amide. ( 1 ) 2 [Cl·H 2 O] adopts a layered β‘ ‘-type structure with segregation of the hydrophobic (EDT-TTF) and hydrophilic (amide, Cl -, H 2 O) fragments. The HOMO−HOMO intermolecular interaction energies for the donor layers are large and the Fermi surface exhibits a pronounced two-dimensional character. The EPR Dysonian line observed below 120 K indicates an highly conducting system, confirmed by high room-temperature conductivity of 120 S cm - 1 and metallic behavior down to 0.47 K, with a 167-fold increase of the conductivity, but no indication however of a transition to a superconducting state, a likely consequence of the Cl - /H 2 O disorder.