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Modulating Magnetic and Photoluminescence Properties in 2‐Aminonicotinate‐Based Bifunctional Coordination Polymers by Merging 3d Metal Ions
Author(s) -
PajueloCorral Oier,
ZabalaLekuona Andoni,
San Sebastian Eider,
RodríguezDiéguez Antonio,
García Jose Angel,
Lezama Luis,
Colacio Enrique,
Seco Jose M.,
Cepeda Javier
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002755
Subject(s) - isostructural , bifunctional , antiferromagnetism , diamagnetism , photoluminescence , chemistry , supramolecular chemistry , single molecule magnet , crystallography , materials science , magnetization , magnetic field , condensed matter physics , crystal structure , physics , organic chemistry , catalysis , optoelectronics , quantum mechanics
Abstract 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.