Crystal structures and magnetic properties of two low-dimensional materials constructed from [MnIII(salen)H2O]+ and [M(CN)8]3-/4-(M = Mo or W) precursors

The syntheses, X-ray structures, and magnetic behaviours of two new cyano-bridged assemblies, the molecular [Mn-III(salen)H2O](3)[W-V(CN)(8)].H2O (1) and one-dimensional [Mn(salen) (H2O)(2)](2) {[Mn(salen)(H2O)][Mn(salen)](2)[Mo(CN)(8)]}. 0.5CIO(4).0.5OH..4.5H(2)O (2), are presented. Compound 1 crystallizes in the monoclinic system, has space group P2(1)/c, and has unit cell constants a = 13.7210(2) Angstrom, b = 20.6840(4) Angstrom, c = 20.6370(2) Angstrom, and Z = 4. Compound 2 crystallizes in the triclinic system, has space group P1, and has unit cell dimensions a = 18.428(4) Angstrom, b = 18.521(3) Angstrom, c = 18.567(4) Angstrom, and Z = 2. The structure of 1 consists of the asymmetric V-shaped Mn-NC-W-NC-Mn-O-phenolate-Mn molecules, where W(V) coordinates with [Mn(salen)H2O] and singly phenolate-bridged [Mn-(salen)H2O](2) moieties through the neighboring cyano bridges. The [W-V(CN)(8)](3-) ion displays distorted square-antiprism geometry. The structure of 2 consists of the cyano-bridged {(Mn3MoIV)-Mo-lll}(n)(-) 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 1 reveal the antiferromagnetic intramolecular interactions through the CN and phenolate bridges and the relatively weak intermolecular interactions. Compound 1 becomes antiferromagnetically ordered below T-N = 4.6 K. The presence of the magnetic anisotropy is documented with the M(M measurements carried out for both polycrystalline and single-crystal samples. At T = 1.9 K, the spin-flop transition is observed in the field of 18 kOe applied parallel to the bc plane, which is the easy plane of magnetization. Field dependence of magnetization of 1 shows field-induced metamagnetic behaviour from the antiferromagnetic ground state of S-T = (3)/(2) to the state of S-T = (5)/(2). The magnetic properties of 2 indicate a weak antiferromagnetic interaction between Mn(III) centers in double-phenolate-bridged [Mn-III(salen)](2) dinuclear subunits and a very weak ferromagnetic interaction between them through the diamagnetic [Mo-IV(CN)(8)](4-) spacer.