Spin canting and metamagnetism in 3D pillared-layer homospin cobalt(ii) molecular magnetic materials constructed via a mixed ligands approach

Abstract

Two new 3D pillared-layer cobalt(II) molecular magnetic materials, formulated as {[Co₂(TDA)(TZ)(H₂O)₂]·H₂O}_n (1) and {[Co₃(TDA)₂(bpy)₃]·6.75H₂O}_n (2) (H₃TDA = 1H-1,2,3-triazole-4,5-dicarboxylic acid, HTZ = 1H-1,2,4-triazole and bpy = 4,4′-bipyridine), have been successfully assembled with H₃TDA and auxiliary ligands, respectively. In 1, the neighboring Co(II) ions are connected via TDA³⁻ to generate 2D layers, which are further bridged by TZ⁻ to build a 3D 8-connected bcu net with a Schläfli symbol of (4²⁴·6⁴), whereas in 2, the nearest Co(II) ions are connected via TDA³⁻ to form a hexagonal [Co₆(TDA)₆]⁶⁻ macrocycle composed of 24-membered atoms, which can be further linked to each other to generate 2D Kagomé layers. The Kagomé layers are connected by bpy pillars to display a 3D (3,4,4,4)-connected KAVGAQ net with a Schläfli symbol of {6³}₂{6⁴·10²}{6⁴·8²}₂. Magnetic studies reveal that both of them show the spin canting and metamagnetic behaviors with critical temperatures of 3.5 K and 4 K, respectively.