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

摘要

Herein, a new family of Ln(III)[18-metallacrown-6] compounds with the formula [Fe(6)O(2)Ln(tBu-sao)(6)(OH)(MeO)4(MeOH)(H2O)]center dot 6MeOH [Ln = Dy-III (1), Tb-III (2), Gd-III (3), and Y-III (4), tBu-saoH(2) = 3,5-di-tert-butyl-salicylaldoxime] was synthesized through one-pot reactions using tBu-saoH2, Fe(ClO4)(3)center dot 6H(2)O, and Ln(NO3)(3)center dot 6H(2)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 (O-MC). Magnetic measurements reveal domain antiferromagnetic coupling interactions between metal ions and field-dependent slow magnetic relaxation in 1-3.