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

Calix[4]thiacrowns with hetero-(1) and a homodonor set (L-2) were synthesized and characterized by X-ray analysis. From the reaction of L-2 with AgPF6, disilver complex [Ag-2(L-2)](PF6)(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.