Crystal Structures and Magnetic Properties of Two Low-Dimensional Materials Constructed from [Mn<sup>III</sup>(salen)H<sub>2</sub>O]<sup>+</sup> and [M(CN)<sub>8</sub>]<sup>3-/4-</sup> (M = Mo or W) Precursors

The syntheses, X-ray structures, and magnetic behaviors of two new cyano-bridged assemblies, the molecular [Mn<sup>III</sup>(salen)H<sub>2</sub>O]<sub>3</sub>[W<sup>V</sup>(CN)<sub>8</sub>]·H<sub>2</sub>O (<b>1</b>) and one-dimensional [Mn(salen)(H<sub>2</sub>O)<sub>2</sub>]<sub>2</sub>{[Mn(salen)(H<sub>2</sub>O)][Mn(salen)]<sub>2</sub>[Mo(CN)<sub>8</sub>]}·0.5ClO<sub>4</sub>·0.5OH·4.5H<sub>2</sub>O (<b>2</b>), are presented. Compound <b>1</b> crystallizes in the monoclinic system, has space group <i>P</i>2<sub>1</sub>/<i>c</i>, and has unit cell constants <i>a</i> = 13.7210(2) Å, <i>b</i> = 20.6840(4) Å, <i>c</i> = 20.6370(2) Å, and <i>Z</i> = 4. Compound <b>2</b> crystallizes in the triclinic system, has space group <i>P</i>1̄, and has unit cell dimensions <i>a</i> = 18.428(4) Å, <i>b</i> = 18.521(3) Å, <i>c</i> = 18.567(4) Å, and <i>Z</i> = 2. The structure of <b>1</b> consists of the asymmetric V-shaped Mn−NC−W−NC−Mn−O<sub>phenolate</sub>−Mn molecules, where W(V) coordinates with [Mn(salen)H<sub>2</sub>O] and singly phenolate-bridged [Mn(salen)H<sub>2</sub>O]<sub>2</sub> moieties through the neighboring cyano bridges. The [W<sup>V</sup>(CN)<sub>8</sub>]<sup>3-</sup> ion displays distorted square-antiprism geometry. The structure of <b>2</b> consists of the cyano-bridged {Mn<sub>3</sub><sup>III</sup>Mo<sup>IV</sup>}<i><sub>n</sub></i><sup>-</sup> repeating units linked by double phenolate bridges into one-dimensional zigzag chains. The Mn(III) centers are bound to Mo(IV) of square-antiprism geometry through the neighboring cyano bridges. The magnetic studies of <b>1</b> reveal the antiferromagnetic intramolecular interactions through the CN and phenolate bridges and the relatively weak intermolecular interactions. Compound <b>1</b> becomes antiferromagnetically ordered below <i>T</i><sub>N</sub> = 4.6 K. The presence of the magnetic anisotropy is documented with the <i>M</i>(<i>H</i>) measurements carried out for both polycrystalline and single-crystal samples. At <i>T</i> = 1.9 K, the <i>spin</i><i>−</i><i>flop</i> transition is observed in the field of 18 kOe applied parallel to the <i>bc</i> plane, which is the easy plane of magnetization. Field dependence of magnetization of <b>1</b> shows field-induced metamagnetic behavior from the antiferromagnetic ground state of <i>S</i><sub>T</sub> = <sup>3</sup>/<sub>2</sub> to the state of <i>S</i><sub>T</sub> = <sup>5</sup>/<sub>2</sub>. The magnetic properties of <b>2</b> indicate a weak antiferromagnetic interaction between Mn(III) centers in double-phenolate-bridged [Mn<sup>III</sup>(salen)]<sub>2</sub> dinuclear subunits and a very weak ferromagnetic interaction between them through the diamagnetic [Mo<sup>IV</sup>(CN)<sub>8</sub>]<sup>4-</sup> spacer.