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(N-3)(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-mu(azide-N1)(2)M and bis-mu(azide-N1,N3)(2)M 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 pi-pi 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 Neel temperature of T-N = 3.4 K and further, a field-induced magnetic transition of metamagnetism at temperatures below the T-N. 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, T-C = 16.2 K.

Automated summary

Two new compounds with general formula [M(N-3)(2)(dmbpy)], where dmbpy = 5,5'-dimethyl-2,2'-bipyridine and M = Mn(II) or Co(II), have been synthesized and characterized structurally and magnetically. Both compounds exhibit weak interchain interactions due to pi-pi stacking between the dmbpy rings. The manganese compound shows spin-canted antiferromagnetic ordering with metamagnetism, while the cobalt compound displays weak ferromagnetism and long-range magnetic ordering.