Heterometallic tetranuclear 3d-4f complexes: Syntheses, structures and magnetic properties

Four novel heterometallic tetranuclear 3d-4f complexes M2Dy2L10(Phen)(2) (M = Co (1), Ni (2), Cu (3) and Zn (4); HL = 4-trifluoromethylbenzoic acid, phen = phenanthroline) have been synthesized hydrothermally and characterized by single crystal X-ray diffraction study, IR, elemental analysis and thermal gravimetric analyses. The structures of 1 and 4 are isostructural and the completely deprotonated L ligands adopt mu(2): eta(1), eta(1) coordination mode to bridge adjacent metal ions which further connect into 1D chains by hydrogen bonds. The tetranuclears in complex 2 were linked by L ligands with mu(2): eta(1), eta(2) and mu(2): eta(1), eta(1) coordinated patterns and spread into 2D layers through hydrogen bonds. In complex 3 L ligands possess the same coordinated styles with 2 and a 3D supramolecular network was fabricated via hydrogen-bonding interactions. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for 1 and 3, suggesting SMM type behavior for these compounds. (C) 2015 Elsevier B.V. All rights reserved.