Calix[4]thiacrowns as ditopic hosts for homo- and heterobinuclear accommodation: first report of a chopsticks-type pi-coordination

reaction: see text] Calix4]thiacrowns with hetero-L(1) and a homodonor set (L(2)) were synthesized and characterized by X-ray analysis. From the reaction of L(2) with AgPF(6), disilver complex Ag(2)(L(2))](PF(6))(2) (1) was isolated. By comparing 1,3-alternate conformations of L(2) and 1, we found a considerable decrease of dihedral angles of two opposite aromatic rings upon complexation. This finding can be explained in terms of the "chopsticks process", which illustrates how Ag(+)-arene pi-coordination occurs. Heterobinuclear complexation of L(1) in solution was also observed.