Binary and Ternary Core-Shell Crystals of Polynuclear Coordination Clusters via Epitaxial Growth

For thefirst time, an abundant series of 12 colorfulbinary and ternary millimeter-sized core-shell composite crystals,representative of hierarchical crystalline species, were designed andprepared from functional magnetic polynuclear clusters phasesusing the epitaxial growth method. The synthesis is based onisomorphous (space groupC2/c) crystalline phases composed of15 nuclear clusters {M9[WV(CN)8]6(MeOH)24}(M9W6) (M,color = MnII, pale brown; FeII, green; CoII, red; NiIIyellow; and anFe/Co 2:1 mixture, dark brown, respectively) of six-capped body-centered-cubic topology, revealing appealing magnetic propertiessuch as a high spin in the ground state, slow magnetic relaxation,and structural spin-phase transitions. A series of 11 binary core-shell composites and 1 ternary composite have been reproduciblysynthetized and carefully characterized from a structural and composition point of view. Phase composition agreement and the sizeof the interface ofca.10 mu m were assessed using microscopic observations, single-crystal X-ray diffration, and scanning electronmicroscopy???energy-dispersive spectroscopy. SQUID measurements reveal an active spin transitionFe6Co3W6seed compoundenveloped within the paramagneticMn9W6crystalline shell, providing a rare example of a millimeter-sized hierarchical crystallinearchitecture,Fe6Co3W6@Mn9W6, with a switchable function