Different topologies in three manganese-μ-azido 1D compounds: magnetic behavior and DFT-quantum Monte Carlo calculations

Coexistence of Spin Canting and Metamagnetism in a One-Dimensional Mn(II) Compound Bridged by Alternating Double End-to-End and Double End-On Azido Ligands and the Analog Co(II) Compound

Two new compounds of general formula [M(N3)2(dmbpy)] in which dmbpy = 5,5′-dimethyl-2,2′-bipyridine, and M = Mn(II) or Co(II), have been solvothermally synthesized and characterized structurally and magnetically. The structures consist of zig-zag polymeric chains with alternating bis-µ(azide-N1)2M and bis-µ(azide-N1,N3)2M units in which the cis-octahedrally based coordination geometry is completed by the N,N’-chelating ligand dmbpy. The molecular structures are basically the same for each metal. The Mn(II) compound has a slightly different packing mode compared to the Co(II) compound, resulting from their different space groups. Interestingly, relatively weak interchain interactions are present in both compounds and this originates from π–π stacking between the dmbpy rings. The magnetic properties of both compounds have been investigated down to 2 K. The measurements indicate that the manganese compound shows spin-canted antiferromagnetic ordering with a Néel temperature of TN = 3.4 K and further, a field-induced magnetic transition of metamagnetism at temperatures below the TN. This finding affords the first example of an 1D Mn(II) compound with alternating double end-on (EO) and double end-to-end (EE) azido-bridged ligands, showing the coexistence of spin canting and metamagnetism. The cobalt compound shows a weak ferromagnetism resulting from a spin-canted antiferromagnetism and long-range magnetic ordering with a critical temperature, TC = 16.2 K.

Crystal structure of bis-(aceto-nitrile-κN)bis-(4-benzoyl-pyridine-κN)bis-(thio-cyanato-κN)cobalt(II)

The crystal structure of the title compound, [Co(NCS)2(C2H3N)2(C12H9NO)2], consists of cobalt(II) cations that are octa-hedrally coordinated by the N atoms of two terminal thio-cyanate anions, two aceto-nitrile mol-ecules and two 4-benzoyl-pyridine ligands. The discrete complexes are located on centres of inversion. They are connected by weak inter-molecular C-H⋯O and C-H⋯S hydrogen-bonding inter-actions between one of the pyridine H atoms and the carbonyl O atom, and between one of the methyl H atoms of the aceto-nitrile mol-ecule and the thio-cyanate S atoms into layers parallel to (101). No pronounced inter-molecular inter-actions are observed between these layers.