Unprecedented family of heterometallic LnIII[18-metallacrown-6] complexes: syntheses, structures, and magnetic properties†
Abstract
Herein, a new family of LnIII[18-metallacrown-6] compounds with the formula [Fe6O2Ln(tBu-sao)6(OH)(MeO)4(MeOH)(H2O)]·6MeOH [Ln = DyIII (1), TbIII (2), GdIII (3), and YIII (4), tBu-saoH2 = 3,5-di-tert-butylsalicylaldoxime] was synthesized through one-pot reactions using tBu-saoH2, Fe(ClO4)3·6H2O, and Ln(NO3)3·6H2O. The four compounds are isostructural, and the encapsulation of a Ln ion in the ring cavity of 18-metallacrown-6 (18-MC-6) was exhibited for the first time. The structural analysis shows a ship-like 18-MC-6 core with a beset lanthanide ion connecting six ring oxygen atoms (OMC). Magnetic measurements reveal domain antiferromagnetic coupling interactions between metal ions and field-dependent slow magnetic relaxation in 1–3.