Abstract
Two analogous tetranuclear lanthanide complexes have been synthesized with the general formula [Ln(4)(vht)(4)(MeOH)(8)](NO3)(4)center dot aMeOH center dot bH(2)O, where H(2)vht = (3,6-bis(vanillidenehydrazinyl)-1,2,4,5-tetrazine) and Ln = Dy-III (1), Gd-III (2). These complexes are characterized by several techniques; including singlecrystal X-ray diffraction, SQUID magnetometry and single-crystal micro-SQUID hysteresis loop measurements. Elucidation of the crystal structure of the complexes shows that the lanthanide ions are bridged by a tetrazine ring, a rare bridging moiety for lanthanide ions. Magnetic studies reveal that both 1 and 2 exhibit weak ferromagnetic exchange interactions between Ln ions, and 1 displaying Single-Molecule Magnet (SMM) behaviour with a magnetisation reversal barrier of U-eff = 158 K (tau(0) = 1.06 x 10(-7) s).