Oliver Waldmann, Hans U. Güdel, Timothy L. Kelly and Laurence K. Thompson
The Mixed-Valent Manganese [3×3] Grid [Mn(III)₄Mn(II)₅(2poap-2H)₆](ClO₄)₁₀·10H₂O, a Mesoscopic Spin-¹/₂ Cluster
Inorg. Chem. 45, 3295-3300 (2006)                       

Abstract: The magnetic susceptibility and low-temperature magnetization curve of the [3×3] grid [Mn(III)₄Mn(II)₅(2poap-2H)₆](ClO₄)₁₀·10H₂O (1) are analyzed within a spin Hamiltonian approach. The Hilbert space is huge (4 860 000 states), but the consequent use of all symmetries and a two-step fitting procedure nevertheless allows the best-fit determination of the magnetic exchange parameters in this system from complete quantum mechanical calculations. The cluster exhibits a total spin S = ¹/₂ ground state; the implications are discussed.