Tuning of High Spin Ground State and Slow Magnetic Relaxation within Trimetallic Cyanide‐Bridged {Ni^II_<i>x</i>Co^II_9−<i>x</i>[W^V(CN)₈]₆} and {Mn^II_<i>x</i>Co^II_9−<i>x</i>[W^V(CN)₈]₆} Clusters

Abstract

Abstract Two series of trimetallic {Ni II x Co II 9− x [W V (CN) 8 ] 6 } ( NiCoW ) and {Mn II x Co II 9− x [W V (CN) 8 ] 6 } ( MnCoW ) ( x= 1–8) crystalline solid‐solutions were constructed and systematically studied by SEM EDX, single‐crystal X‐ray diffraction (SC XRD), and magnetic measurements. The atomic Ni:Co:W and Mn:Co:W ratios in the solid state follow the stoichiometric concentration in the mother MeOH solutions fairly well. The structural studies revealed a definite strong tendency of smaller 3d ions to locate in the central [M(μ‐NC) 6 ] moiety of the skeleton: Ni II over the Co II and Co II over Mn II . In contrast, the external fac ‐[M(μ‐NC) 3 (MeOH) 3 ] are consecutively occupied by the mixture of 3d metal ions, accessible according to the stoichiometry of the mother solutions. The DC magnetic χT ( T ) and M ( H ) curves illustrate the continuous tendency of change with x along both series, nicely reproducing the changes of the theoretical high spin in the ground state S gr , assuming the ferromagnetic HS Co II ‐NC‐W V and antiferromagnetic Mn II ‐NC‐W V interactions established by numerous literature reports. The AC magnetic measurements indicate the occurrence of slow magnetic relaxation, with the highest energy barrier Δ E/k B of 26 K for the Ni 6 Co 3 W 6 congener and of 17 K for the Mn 6 Co 3 W 6 congener, and relatively large values of distribution parameter α . The values of Δ E are correlated with possible anisotropy of distribution of fac ‐[Co II (μ‐NC) 3 (MeOH) 3 ] moieties at the external corners of the cube substructure.