Ring-forming transformation associated with hydrazone changes of hexadecanuclear dysprosium phosphonates

{Dy-16(mu(6)-C10H7PO3)(2)(mu(5)-C10H7PO3)(8)(spch)(8)(mu(3)-OH)(2)(mu(2)-OH)(2)(mu(2)-AcO)(6)(mu(3)-COO)(2)(DMF)(2)(H2O)(6)}center dot 0.5CH(3)OH center dot 4.5H(2)O (1) and {Dy-16(mu(5)-C10H7PO3)(4)(mu(3)-C10H7PO3)(12)(mu(2)-C10H7PO3H)(8)(opch)(4)(DMF)(8)(MeOH)(4)}center dot 2.5CH(3)OH center dot 3H(2)O (2), where H(2)spch is ((E)-N '-(2-hydroxybenzylidene)pyrazine-2-carbohydrazide, C10H7PO3H2 is 1-naphthylphosphonic acid and H(2)opch is (E)-N '-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide, were successfully synthesized by varying the hydrazone ligands in the Dy-phosphonate system. It is important that the ellipsoidal core experiences a ring forming structural transformation to the supramolecular square motif upon the incorporation of an ortho-methoxy substituent into the hydrazone. Alternating-current (ac) magnetic susceptibility studies of 1 and 2 suggest that similar single molecule magnet behaviors occur for these two complexes. The result represents an effective molecular assembly tactic to develop highly complicated lanthanide coordination clusters through the multicomponent self-assembly of the coalescence of phosphonate- and hydrazone-based ligands and metal salts.

Automated summary

Two complexes were successfully synthesized by varying the hydrazone ligands in the Dy-phosphonate system, resulting in significant structural transformations. Magnetic studies indicated similar single molecule magnet behaviors for both complexes, demonstrating an effective molecular assembly tactic for developing highly complicated lanthanide coordination clusters.