Unprecedented family of heterometallic Ln III [18-metallacrown-6] complexes: syntheses, structures, and magnetic properties.

Herein, a new family of LnIII [18-metallacrown-6] compounds with the formula [Fe6 O2 Ln(tBu-sao)6 (OH)(MeO)4 (MeOH)(H2 O)]·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 ·6H2 O, and Ln(NO3 )3 ·6H2 O. 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.