Halogen-Bonded, Eight-fold PtS-Type Interpenetrated Supramolecular Network. A Study toward Redundant and Cross-Bar Supramolecular Nanowire Crystal

Abstract

Making crystalline organic conducting nanowires will allow three-dimensional nanoscale wiring, owing to their periodic arrangement in the solid state. In order to find new motifs for insulation sheaths in a crystal, new large and rigid spacer molecules containing iodine atoms have been successfully synthesized. One novel nonplanar aromatic tecton with an extended skeleton, 2,2′,4,4′,6,6′-hexafluoro-3,3′,5,5′-tetrakis((4-(iodoethynyl)phenyl)ethynyl)biphenyl (1) has formed halogen-bonded supramolecular self-assemblies in the presence of halide anions. Bis(propylenedithio)tetrathiafulvalene (PT), a precursor of organic conductors, was electrochemically oxidized to the cation radical state as Cl– or Br– salt and cocrystallized with this neutral iodinated tecton 1 to form multicomponent supramolecular self-assembled isostructural crystalline salts PT(1)X (X = Cl, Br). X-ray structure analysis, conductivity, and magnetic susceptibility measurements were performed on these ternary salts. Owing to the pseudotetrahedral symmetry of the tecton, an eight-fold interpenetrated PtS-type network of class Ia has been identified and some clues for future developments of cross-bar nanowire monocrystals have been obtained. In these layer-by-layer type crystals, the fully oxidized PT molecules adopt a rare purely two-dimensional S = 1/2 Heisenberg square lattice type organization with weak antiferromagnetic interactions.