Magnetic susceptibility of Co2+ pairs in [Co-2(ox)tpmc](ClO4)(2)center dot3H(2)O cluster complex

Calculation of the magnetic susceptibility of Co2+ pairs in the recently sy nthesized cobaltous cluster complex [Co-2(ox)tpmc](ClO4)(2). 3H(2)O has bee n conducted by the use of two different theoretical models. The calculated results were compared to the experimental data collected in a wide temperat ure region. Conclusions on both the magnetic properties of Co2+ dimers and the validity of the proposed models have been drawn. In the temperature reg ion above chi(T) maximum, the best results are obtained with the Heisenberg model that includes spin-orbit coupling and excited single-ion levels. In the low-temperature region anisotropy of the magnetic properties dominates and Ising dimer ground-stare model gives a more appropriate description. Ob tained g-values (g(parallel to a) = 5.67, g(parallel to b) = 5.73, and g(pe rpendicular to) = 1.54) confirm strong Co2+ anisotropy. Each model gives th e same value of the intracluster exchange integral J/k(B) approximate to - 14.6 K, within the fitting error. (C) 2000 Elsevier Science B.V. All rights reserved.