Two Novel Cyanide-Bridged Bimetallic Magnetic Chains Derived from Manganese(III) Schiff Bases and Hexacyanochromate(III) Building Blocks

Two novel complexes, [{Mn(salen)}2{Mn(salen)(CH3OH)}{Cr(CN)6}]n·2nCH3CN·nCH3OH (1) and [Mn(5-Clsalmen)(CH3OH)(H2O)]2n[{Mn(5-Clsalmen)(μ-CN)}Cr(CN)5]n·5.5nH2O (2) (salen2− = N,N′-ethylene-bis(salicylideneiminato) dianion; 5-Clsalmen2− = N,N′-(1-methylethylene)-bis(5-chlorosalicylideneiminato) dianion), were synthesized and structurally characterized by X-ray single-crystal diffraction. The structural analyses show that complex 1 consists of one-dimensional (1D) alternating chains formed by the [{Cr(CN)6}{Mn(salen)}4{Mn(salen)(CH3OH)}2]3+ heptanuclear cations and [Cr(CN)6]3− anions. While in complex 2, the hexacyanochromate(III) anion acts as a bis-monodentate ligand through two trans-cyano groups to bridge two [Mn(5-Clsalmen)]+ cations to form a straight chain. The magnetic analysis indicates that complex 1 shows three-dimensional (3D) antiferromagnetic ordering with the Néel temperature of 5.0 K, and it is a metamagnet displaying antiferromagnetic to ferromagnetic transition at a critical field of about 2.6 kOe at 2 K. Complex 2 behaves as a molecular magnet with Tc = 3.0 K.