Syntheses, structures and field-dependent slow magnetic relaxation of saddle-like Cu4 and reverse “U” shape Mn3 complexes

Three transition metal complexes [Cu4(ccsa)4(Py)8] (1) [Mn3(ccsa)4(Py)6(H2O)2]·2Py·H2O (2) and [MnFe2(ccsa)4(Py)6(H2O)2] (3) (H2ccsa = 3-carboxy-5-chloro-salicylald-ehyde) have been synthesized and structurally characterized. Complex 1 presents a 16-membered saddle-like ring with the [CuOCO] repeating unit. Magnetic measurements reveal 1 and 2 exhibited slow magnetic relaxation with complex 1 giving Ueff = 15.50 K and τ0 = 3.11 × 10− 8 s.325