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, beta ''-(EDT-TTF-CONHMe)(2)[Cl center dot H2O]

Electrocrystallization of 1,1,2-trichloroethane solutions of the redox-acti ve secondary amide, 3-methylamido-3',4'-ethylenedithiotetrathiafulvalene (E DT-TTF-CONHMe 1) in the presence of n-Bu4NF supported on silica gel afforde d a mixed-valence chloride salt, formulated (1)(2)[Cl . H2O] from elemental analysis and X-ray crystal structure resolution. The chloride anion and wa ter molecule are disordered on the same site, and coordinated to the pi-don or molecule by two strong hydrogen bonds involving the amidic N-H and the a romatic C-H group ortho to the amide, thereby qualifying a robust pair of t weezers-like cyclic motif. This efficient anion recognition effect is also observed in solution, as demonstrated by H-1 NMR downfield shifts of both t he 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 a ctual electrocrystallized species is a solvated anionic chloride complex [( 1 . Cl-)(H2O),1 rather than the free amide. (1)(2)[Cl . H2O] adopts a layer ed beta "-type structure with segregation of the hydrophobic (EDT-TTF) and hydrophilic (amide, Cl-, H2O) fragments. The HOMO-HOMO intermolecular inter action energies for the donor layers are large and the Fermi surface exhibi ts a pronounced two-dimensional character. The EPR Dysonian line observed b elow 120 K indicates an highly conducting system, confirmed by high room-te mperature 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 o f a transition to a superconducting state, a likely consequence of the Cl-/ H2O disorder.