Bis-calix[4]arenes Bridged by an Electroactive Tetrathiafulvalene Unit

Syntheses of the first bis-calixarenes systems bridged by a tetrathiafulvalene (TTF) framework
5a,b have been carried out in good yields through triethyl phosphite-mediated dechalcogenation−dimerizations of the corresponding 1,3-dithiole-2-(thi)ones 3 or 4. X-ray structures of the calix[4]arene−TTF−calix[4]arene assembly 5b and of the calix[4]arene−thione intermediate 3b are
analyzed and confirm the cone conformations adopted by the calix[4]arene parts, as it is also
observed by 1H NMR analysis of these systems. The solid-state organization in 5b leads to alternate
layers of calixarene and TTF units. The cyclic voltammograms of 5a,b show as expected a two-step
redox behavior but display a CV deformation for the second redox process.