Template- and pH-Directed Assembly of Diruthenium Diphosphonates with Different Topologies and Oxidation States

In the presence of organic templates, six diruthenium diphosphonates, namely, [H3N(CH2)3NH3]2[Ru2(hedp)2] (1),
[H3N(CH2)4NH3]2[Ru2(hedp)2]·4H2O (2), [H3N(CH2)5NH3]2[Ru2(hedp)2]·4H2O (3), [H3N(CH2)3NH3][Ru2(hedp)(hedpH)]·H2O (4), [H3N(CH2)4NH3][Ru2(hedpH0.5)2]·2H2O (5), and [H3N(CH2)5NH3]2{[Ru2(hedp)2][Ru2(hedpH)2]} (6) [hedp =
1-hydroxyethylidenediphosphonate, CH3C(OH)(PO3)2] have been synthesized under hydrothermal conditions.
Compounds 1−3 contain homovalent paddlewheel cores of Ru2II,II(hedp)24- that are connected through edge-sharing of the {RuO5Ru} octahedra, resulting in infinite linear chains. Compounds 4−6 contain mixed-valent
diruthenium(II,III) phosphonate paddlewheel cores of Ru2II,III(hedpHn)2(3-2n)- that are connected by phosphonate
oxygen atoms, forming distorted square-grid layers in 4 and 6 or a kagomé lattice in 5. Both the templates and the
pH values are found to play important roles in directing the final products with particular topologies and oxidation
states of the diruthenium unit. The magnetic studies show that weak antiferromagentic interactions are propagated
between the homovalent diruthenium units in compounds 1−3. For compounds 4−6, weak ferromagnetic interactions
are observed.