Crystal field study and magnetic properties of [TbCu6(μ3OH)3(HL)2(L)4](ClO4)2·25H2O (H2L=imino-diacetic acid)

A crystal field (CF) investigation of the magnetic properties of [TbCu6(μ3–OH)3(HL)2(L)4](ClO4)2·25H2O (H2L==imino-diacetic acid) has been carried out. An enhancement of the average magnetic susceptibility (defined by χ¯==(χ||+2χ⊥)/3, where χ|| and χ⊥ are the magnetic susceptibilities parallel and perpendicular to the symmetrical axis of the cluster) with respect to the Tb3+ free ion value has been noticed and is attributed to the Tb–Cu interaction. The CF parameters obtained for the system for the first time have been exploited to find the Stark splitting of the 7F manifold of Tb3+, paramagnetic resonance g-values, and the heat capacity. Two anomalies are obtained in the heat capacity at 40 and 5 K; the peak values are 3.1 and 5.98 J mol−1 K−1, respectively.