Bis(pyrrolo)tetrathiafulvalene - An efficient pi-donor in supramolecular chemistry

The synthesis of three novel macrocycles 3-5 based on the two electron dono rs bis(2,5-dimethylpyrrolo)[3,4-d]tetrathiafulvalene (1) and 1,4-hydroquino ne is presented. Their abilities to include the electron acceptor paraquat (6) have been investigated by UV/Vis and H-1 NMR spectroscopy and an X-ray crystallographic analysis. Also, the complex formation between the cyclic a cceptor cyclobis(paraquat-p-phenylene) (7) and different tetrathiafulvalene derivatives has been studied. A strong association between 1 and 7 facilit ates the self-assembly of catenanes from the macrocycles 3-5. However, the preferred position of the cyclic acceptor 7 in the catenanes around either the pyrrolo-annelated TTF or around the hydroquinone donor relies on a fine balance between all the individual noncovalent forces acting in cooperatio n.