A nickel(ii)–manganese(ii)-azido layered coordination polymer showing a three-dimensional ferrimagnetic order at 35 K

Abstract

The work in this report describes the synthesis, characterization, crystal structure and magnetic properties of a two-dimensional azido-bridged Ni^IIMn^II heterometallic coordination polymer, [{(Ni^IILMn^II)₂(μ_1,1,3-N₃)₂}(μ_1,3-N₃)₂]_n (1), in which the H₂L Schiff base is the [2 + 1] condensation product of 3-methoxysalicylaldehyde and 1,3-diaminopropane. In 1, two bis(μ-phenoxo)-μ_1,1,3-azido-Ni^IIMn^II dinuclear units are interlinked to form a dimer-of-dinuclear moiety {Ni^IIMn^II}₂; the {Ni^IIMn^II}₂ structural units are further interlinked with each other by μ_1,3-azido ligands to form a layered coordination polymer. Upon cooling, the χ_MT product slowly decreases from 300 K to about 100 K, then increases abruptly from 3.74 cm³ K mol⁻¹ at 100 K to 113.2 cm³ K mol⁻¹ at 30 K, indicating a ferrimagnetic behaviour; a three-dimensional magnetic order below 37 K was determined by the divergence in the ZFC-FC measurements and ac measurements, in which the peak temperature 35 K in the in-phase at different frequencies suggests that the Curie temperature is 35 K, whereas the out-of-phase is somewhat frequency dependent, due to the glassy magnet behaviour. The title compound is among the rare examples of metallo-organic systems having a magnetic ordering Curie temperature above 30 K. Other interesting aspects in 1 regarding magnetic properties and structural features are discussed.