A 2D coordination polymer based on Co3-SBU showing spin-canting ferromagnetic behaviour

Abstract

A 2D MOF with the secondary building unit [Co₃(CTC)₆(Py)₂(OH)₂] is synthesized using the sodium salt of a flexible ligand, cis,cis-cyclohexane-1,3,5-tricarboxylate (Na-CTC), and a cobalt trimer ([Co₃O(CH₃COO)₆(Py)₃]·ClO₄). Structural analysis shows that the complex crystallizes in the monoclinic space group P21/n and forms a 2D framework with channel sizes of 9.0 × 4.2 Ų. Magnetic characterization shows spin-canting ferromagnetic behaviour at low temperatures. Frequency dependency for in-phase (χ^′_M) and out-of-phase (χ^′′_M) signals at low temperatures is observed from the AC measurements. The gas adsorption behaviour suggests selectivity towards CO₂ over N₂, and demonstrates enhancement of CO₂ uptake (19–33 cm³ g⁻¹) on lowering the temperature (273–195 K).