Cation Exchange in Dynamic 3D Porous Magnets: Improvement of the Physical Properties.
We report two novel three-dimensional porous coordination polymers (PCPs) of formulas Li4{Mn4[Cu2(Me3mpba)2]3}·68H2O (2) and K4{Mn4[Cu2(Me3mpba)2]3}·69H2O (3) obtained-via alkali cation exchange in a single-crystal to single-crystal process-from the earlier reported anionic manganese(II)-copper(II) PCP of formula Na4{Mn4[Cu2(Me3mpba)2]3}·60H2O (1) [Me3mpba(4-) = N,N'-2,4,6-trimethyl-1,3-phenylenebis(oxamate)]. This postsynthetic process succeeds where the direct synthesis in solution from the corresponding building blocks fails and affords significantly more robust PCPs with enhanced magnetic properties [long-range 3D magnetic ordering temperatures for the dehydrated phases (1'-3') of 2.0 (1'), 12.0 (2'), and 20.0 K (3')]. Changes in the adsorptive properties upon postsynthetic exchange suggest that the nature, electrostatic properties, mobility, and location of the cations within the framework are crucial for the enhanced structural stability. Overall, these results further confirm the potential of postsynthetic methods (including cation exchange) to obtain PCPs with novel or enhanced physical properties while maintaining unaltered their open-framework structures.
Thais
T
Grancha
Alvaro
A
Acosta
Joan
J
Cano
Jesús
J
Ferrando-Soria
Catalysis Engineering-Chemical Engineering Department, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
Beatriz
B
Seoane
Catalysis Engineering-Chemical Engineering Department, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
Jorge
J
Gascon
Laboratorio de Rayos X y Materiales Moleculares, Departamento de Física Fundamental II, Universidad de La Laguna , E-38201 Tenerife, Spain.
Jorge
J
Pasán
Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria , Rende 87036, Cosenza, Italy.
Donatella
D
Armentano
Emilio
E
Pardo