Construction of Fe6, Fe8 and Mn8 metallamacrocyclic complexes and magnetic properties

Abstract

By treating FeSO₄ or Mn(OAc)₂ with 5′-(pyridin-2-yl)-2H,4′H-3,3′-bi(1,2,4-triazole) (H₂pbt), three novel metallamacrocycle-based complexes [Fe(Hpbt)(C₂O₄)_0.5]_n (1), {[Fe(pbt)(H₂O)]·2H₂O}_n (2), {[Mn(pbt)(H₂O)]·2EtOH·0.5H₂O}_n (3) have been synthesized and characterized. In 1, the hexanuclear metallamacrocycle units are connected with each other resulting in the formation of two-dimensional frameworks. Octanuclear metallamacrocycle-based complexes 2 and 3 display three-dimensional porous frameworks. Interestingly, left- and right-handed helical chains present alternately along the crystallographic c axis in 2 and 3. Magnetic susceptibility measurements show that the three complexes display different antiferromagnetic coupling intensities.