Syntheses, crystal structures and magnetic properties of two low-dimensional cyano-bridged CrIII–MnII/III assemblies

Abstract

Two low-dimensional cyano-bridged Cr^III–Mn^II/III assemblies {[Mn(salpn)][Cr(CN)₆]}_n·2n[Mn(salpn)(CH₃OH)₂]·2nH₂O (1) (salpn = N,N′-1,2-propylenebis(salicylideneiminato)dianion) and {[Mn(bipy)₂]₂(H₂O)Cl}[Cr(CN)₆]·2H₂O (2) (bipy = 2,2′-bipyridine) have been synthesized and characterized by thermal analyses, single crystal X-ray structural analyses and magnetic measurements. Complex 1 consists of [(CN)₅Cr^III–CN–Mn^III(salpn)]_n²ⁿ⁻ anionic chains, isolated [Mn^III(salpn)(CH₃OH)₂]⁺ cations, and crystallized water molecules. Each [Cr(CN)₆]³⁻ unit connects two adjacent [Mn^III(salpn)]⁺ moieties through trans-cyano groups, resulting in the formation of an anionic one-dimensional (1-D) wave-like chain. Complex 2 is composed of trinuclear clusters of {[Mn(bipy)₂]₂(H₂O)Cl}[Cr(CN)₆] and guest water molecules. In the trinuclear entity, the [Cr(CN)₆]³⁻ unit connects two neighboring [Mn^II(bipy)₂(H₂O)_0.5Cl_0.5]^1.5+ moieties in a trans fashion through two cyano ligands. Magnetic studies reveal that complexe 1 behaves as a ferrimagnet with critical temperature T_c of 4.5 K resulted from the interchain magnetic interactions, while complex 2 exhibits intramolecular antiferromagnetic coupling.