Synthesis, Structure, and Magnetic Properties of Three 1D Chain Complexes Based on High-Spin Metal–Cyanide Clusters: [Mn<sup>III</sup><sub>6</sub>M<sup>III</sup>] (M = Cr, Fe, Co)

On the basis of high-spin metal–cyanide clusters of Mn<sup>III</sup><sub>6</sub>M<sup>III</sup> (M = Cr, Fe, Co), three one-dimensional (1D) chain complexes, [Mn(salen)]<sub>6</sub>[Cr(CN)<sub>6</sub>]<sub>2</sub>·6CH<sub>3</sub>OH·H<sub>2</sub>O (<b>1</b>), [Mn(5-CH<sub>3</sub>)salen)]<sub>6</sub>[Fe(CN)<sub>6</sub>]<sub>2</sub>·2CH<sub>3</sub>CN·10H<sub>2</sub>O (<b>2</b>), and [Mn(5-CH<sub>3</sub>)salen)]<sub>6</sub>[Co(CN)<sub>6</sub>]<sub>2</sub>·2CH<sub>3</sub>CN·10H<sub>2</sub>O (<b>3</b>) [salen = <i>N</i>,<i>N</i>′-ethylenebis(salicylideneiminato) dianion], have been synthesized and characterized structurally as well as magnetically. Complexes <b>2</b> and <b>3</b> are isomorphic but slightly different from complex <b>1</b>. All three complexes contain a 1D chain structure which is comprised of alternating high-spin metal–cyanide clusters of [Mn<sub>6</sub>M]<sup>3+</sup> and a bridging group [M(CN)<sub>6</sub>]<sup>3–</sup> in the trans mode. Furthermore, the three complexes all exhibit extended 3D supramolecular networks originating from short intermolecular contacts. Magnetic investigation indicates that the coupling mechanisms are intrachain antiferromagnetic interactions for <b>1</b> and ferromagnetic interactions for <b>2</b>, respectively. Complex <b>3</b> is a magnetic dilute system due to the diamagnetic nature of Co<sup>III</sup>. Further magnetic investigations show that complexes <b>1</b> and <b>2</b> are dominated by the 3D antiferromagnetic ordering with <i>T</i><sub>N</sub> = 7.2 K for <b>1</b> and 9.5 K for <b>2</b>. It is worth noting that the weak frequency-dependent phenomenon of AC susceptibilities was observed in the low-temperature region in both <b>1</b> and <b>2</b>, suggesting the presence of slow magnetic relaxations.