Modulating Magnetic and Photoluminescence Properties in 2‐Aminonicotinate‐Based Bifunctional Coordination Polymers by Merging 3d Metal Ions

Herein, the synthesis and study of bifunctional coordination polymers (CPs) with both magnetic and photoluminescence properties, derived from a heterometallic environment, are reported. As a starting point, three isostructural monometallic CPs with the formula [M(μ‐2ani) 2 ] n (M II =Mn ( 1 Mn ), Co ( 3 Co ) and Ni ( 4 Ni ); 2ani=2‐aminonicotinate), crystallise as chiral 2D‐layered structures stacked by means of supramolecular interactions. These compounds show high thermal stability in the solid state (above 350 °C), despite which, in aqueous solution, compound 1 Mn is shown to partially transform into a novel 1D chain CP with the formula [Mn(2ani) 2 (μ‐H 2 O) 2 ] n ( 2 Mn ). A study of the direct current ( dc ) magnetic properties of 1 Mn , 3 Co and 4 Ni reveals a spin‐canted structure derived from antisymmetric antiferromagnetic weak exchanges along the chiral network (as confirmed by DFT calculations) and magnetic anisotropy of the ions, in such a way that long‐range ordering is observed with variable magnitude for the spin carriers. Moreover, compounds 3 Co and 4 Ni show no frequency‐dependent alternating current ( ac ) susceptibility curves under zero dc field; this is characteristic behaviour of a glassy state that may be partially supressed for 3 Co by applying an external dc field. To overcome long‐range magnetic ordering, Co II ions are diluted in a diamagnetic Zn II ‐based matrix, which enables single‐molecule magnet behaviour. Interestingly, this strategy allows a bifunctional Co x Zn 1− x 2ani material, which is imbued with a strong photoluminescent emitting capacity, as characterised by an intense blue light followed by a green afterglow, to be obtained.