Scandium(III) coordination polymers containing capsules based on two p-sulfonatocalix[4]arenes

Reactions of sodium p-sulfonatocalix4]arene and scandium(III) tristriflate in the presence, and absence, of 18]crown-6 give the crystalline complexes Sc2(mu-OH)2(H2O)10]Na4(H2O)8-calix4]arene(SO3)4]2).13 H2O and Sc2(mu-OH)2(H2O)8]Sc(H2O)4]2calix4]-arene(SO3)4-H+]2(18]crown-6).16H2O. Both complexes involve novel coordination polymers with calixarene units linked through sodium or scandium centers and also feature capsule assemblies through to the head-to-head association of calixarenes. A linear array of capsules associated with an infinite chain of aquo-bridged sodium ions, and an aquated hydroxy-bridged scandium(III) dimer, Sc2(mu-OH)2(H2O)10]4+, are found in the absence of the crown ether. In the presence of 18]crown-6 both hydrated scandium monomers and dimers bridge between calixarenes in a two-dimensional coordination network. The crown ethers reside in cavities created by two calixarenes from adjacent polymeric sheets via a variety of supramolecular interactions(hydrogen-bonding, shape complementarity), and effectively add a third dimension to the network. The extended structure of both of these polymers is highly porous, and resembles a bilayer.