Mg²⁺ intercalation/deintercalation is achieved by using aqueous electrolytes and Prussian blue analog electrodes. Ex situ X-ray diffraction evidenced the solid solution process of Mg²⁺ intercalation/deintercalation, while the ⁵⁷Fe Mössbauer spectroscopy and X-ray absorption near edge structure revealed redox of both Cu and Fe.

Heterometallic coordination compounds [Cu^II(L)(C₃H₆O)Ln^III(NO₃)₃] and [V^IVO(L)(C₃H₆O)Ln^III(NO₃)₃] (abbreviated as LnCu and LnV, respectively; H₂L = N,N′-bis(3-methoxysalicylidene)-1,3-diamino-2,2-dimethylpropane; Ln = Gd, Tb, Dy, Ho, and Er) were synthesized, and the X-ray crystallographic analysis shows that their structures are isomorphous for each series. The single-molecule magnet behavior was observed for TbCu and DyCu, and the activation energies of magnetization reversal were 42.3(4) and 11.5(10) K, respectively. The magnetic exchange couplings in LnCu and LnV were precisely evaluated by means of combined high-frequency EPR and pulsed-field magnetization studies, to give J_Tb–Cu/k_B ≥ 3.3 K, J_Dy–Cu/k_B = 1.63(1) K, J_Ho–Cu/k_B = 1.09(2) K, and J_Er–Cu/k_B = 0.24(1) K. A monotonic decrease of ferromagnetic J_Ln–Cu was found in the order of the atomic number, ₆₄Gd to ₆₈Er. The corresponding exchange parameters in LnV are smaller than those of the Cu derivatives, and J_Gd–V was antiferromagnetic (−3.0 K determined from the magnetization jump). A possible mechanism for the exchange coupling and chemical trend is discussed.

Heteroleptic assemblies composed of several kinds of building blocks have been seen in nature. It is still unclear how natural systems design and create such complicated assemblies selectively. Past efforts on multicomponent self-assembly of artificial metal-organic cages have mainly focused on finding a suitable combination of building blocks to lead to a single multicomponent self-assembly as the thermodynamically most stable product. Here, we present another approach to selectively produce multicomponent Pd(II)-based self-assemblies under kinetic control based on the selective ligand exchanges of weak Pd-L coordination bonds retaining the original orientation of the metal centers in a kinetically stabilized cyclic structure and on local reversibility given in certain areas of the energy landscape in the presence of the assist molecule that facilitates error correction of coordination bonds. The kinetic approach enabled us to build all six types of Pd₂L₄ cages and heteroleptic tetranuclear cages composed of three kinds of ditopic ligands. Although the cage complexes thus obtained are metastable, they are stable for 1 month or more at room temperature.