STRUCTURAL CHARACTERIZATION OF THIOCYCLOPHANES THAT PROMOTE EDGE-TO-FACE AROMATIC-AROMATIC GEOMETRIES

Several [4.4]thiocyclophanes have been examined in solution and the so lid state. These molecules contain two aromatic units, phenyl and/or n aphthyl, with linking chains attached meta or para on the phenyl group s, and 1,3 or 1,4 on the naphthyl groups. Most previous studies of cyc lophanes containing two aromatic rings have focused on enforcing paral lel alignment of those rings. The molecules discussed here, in contras t, were chosen to promote edge-to-face juxtapositions. Crystallographi c data confirm that edge-to-face orientations between the linked aroma tic groups are available for these cyclophanes, and H-1 NMR data indic ate that conformations containing these orientations are populated in solution. These cyclophanes provide spectroscopic references for NMR-b ased studies of folding in more flexible diphenyl and dinaphthyl compo unds.