Praseodymium(III)-based bis-metallacalix[4]arene with host-guest behaviour.

The reaction of Pr(NO(3))(3).6H(2)O with the ligand 2-hydroxy-N-(2'-hydroxyethyl)-3-methoxybenzamide (H(3)L) in MeOH-MeCN generates the nonanuclear compound [Pr(9)(H(2)L)(8)(OH)(10)(NO(3))(8)](NO(3))(H(2)O)(2)(CH(3)CN) (), whose single-crystal X-ray structure reveals the presence of metallacalix[4]arene cavities that host guest molecules. The crystal packing of the antiferromagnetic Pr(9) cluster shows an intricate network of hydrogen bonds producing a one-dimensional supramolecular chain.