Magnetic exchange, anisotropy and excitonic fluctuations in a [NiII7] Anderson wheel

The solvothermal reaction of Ni(ClO4)(2)center dot 6H(2)O with hmpH and picH in a basic MeOH solution affords [Ni-7(hmp)(7.55)(pic)(4.45)](ClO4)(2)center dot 6MeOH (1 center dot 6MeOH) directly upon cooling the mother liquor. The metallic skeleton of 1 describes a [Ni-7(II)] centred hexagon, commonly referred to as an Anderson wheel. Magnetic measurements reveal ferromagnetic exchange between the central Ni ion and the ring Ni ions, and anti-ferromagnetic exchange between neighbouring ring Ni ions. They also confirm the presence of easy-plane anisotropy for the central Ni ion, and easy-axis anisotropy for the ring Ni ions, in agreement with DFT calculations and neutron scattering. For the analysis of the latter we apply an excitonic formalism using a Green's function response theory.

Automated summary

In a basic MeOH solution, the solvothermal reaction of Ni(ClO4)(2)center dot 6H(2)O with hmpH and picH leads to the formation of [Ni-7(hmp)(7.55)(pic)(4.45)](ClO4)(2)center dot 6MeOH (1 center dot 6MeOH) directly upon cooling the mother liquor. Magnetic measurements and DFT calculations reveal the characteristics of the metallic skeleton of compound 1.