Hierarchical tandem assembly of planar [33]building units into {3[33]} oligomers: mixedvalency, electrical conductivity and magnetism

摘要

A hierarchical tandem assembly coordination, oligomerisation and supramolecular organization isidentified using MALDI-TOF of the solid products of the solvothermal reaction of 5,50-pyridyl-3,30-bi-1Hpyrazole with CuSO4$5H2O in CH3OH–CH3CN. The initial coordination leads to a [3*3][CuI 4CuII 5(L)6] (SO4)·2CH3OH (Cu9) grid followed by oligomerisation to a 3*[3*3][CuI 6CuII 21(L)18(CN)6(SO4)](SO4)2$8CH3CN (Cu27) grid through bridging sulfate and in situ generatedcyanide with time and subsequent supramolecular organization. The isolated silvery lustrous crystals, Cu9and Cu27, are good electrical conductors, with conductivities of 3.2*10-2 and 5.4*10-3S cm-1,respectively, due to the mixed valency. Their magnetic properties are dominated by antiferromagneticinteractions. DFT and band structure calculations confirm their valence distribution and semiconductingbehavior. The planarity of the large 3*[3*3] Cu27 and its electro-activity renders it suitable for thedevelopment of large surface area molecular devices.