Two novel Dy-8 and Dy-11 clusters with cubane [Dy-4(mu(3)-OH)(4)](8+) units exhibiting slow magnetic relaxation behaviour

Two unique octa-and hendeca-nuclear dysprosium(III) clusters incorporating [Dy-4(m(3)-OH)(4)](8+) cubane units have been synthesized with the 1,10-phenanthroline-2,9-dicarbaldehyde dioxime (H(2)phendox) ligand and DyCl3 center dot 6H(2)O or Dy(OAc)(3)center dot 4H(2)O. They are [Dy-8(OH)(8)(phendox)(6)(H2O)(8)]Cl-2(OH)(2)center dot 18H(2)O center dot 18MeOH (1) and [Dy-11(OH)(11)(phendox)(6)(phenda)(3)(OAc)(3)](OH)center dot 40H(2)O center dot 7MeOH (2). Adjacent Dy-8 in 1 or Dy-11 in 2 motifs are packed by off-set pi-pi interactions of the aromatic rings on phendox(2-) to generate a 3D supramolecular architecture in the honeycomb topology and with 1D or 3D channels along the c-axis. Adsorption research shows that complex 1 has selective adsorption ability for H2O over small gas molecules (H-2, N-2, CO2). Complex 2 is stable upon the removal of guest molecules and the desolvated compound absorbed a considerable amount of CO2. Furthermore, the oximes underwent hydrolysis to carboxylic acid and the resulting 1,10-phenanthroline-2,9-dicarboxylate link the dysprosium atoms to form a hendecanuclear cluster of 2. Magnetic studies reveal that both clusters exhibit slow magnetic relaxation behavior, expanding upon the recent reports of the pure 4f type single-molecule magnets (SMMs).