Three-Dimensional FeII-[MoIII(CN)7]4- Magnets with Ordering below 65 K and Distinct Topologies Induced by Cation Identity.

Abstract

Two cyanide-bridged compounds based on the FeII cation and the anisotropic [MoIII(CN)7]4- anion, namely, {Fe2(H2O)5[Mo(CN)7]·5H2O}n (1) and {[NH2(CH3)2]2Fe5(H2O)10[Mo(CN)7]3·8H2O}n (2), have been prepared. Single crystal X-ray analyses revealed that their structures exhibit different three-dimensional topologies as a result of the addition of [NH2(CH3)2]+ during the synthesis of 2. For both 1 and 2, the geometry of the [Mo(CN)7]4- unit is a slightly distorted capped trigonal prism; all FeII centers are hexacoordinate and adopt a distorted octahedral configuration. Compound 1 is a three-nodal 3,4,7-connected net with the point symbol of {4.62}{45.6}{46.612.83}, while compound 2 is a five-nodal 4,4,4,6,7-connected net with the point symbol of {44.62}{45.6}4{46.67.82}{49.611.8}2. Magnetic studies revealed that both compounds exhibit magnetic ordering below 65 K. Apart from the plethora of MnII-[Mo(CN)7]4- compounds documented in the literature, these two FeII-[Mo(CN)7]4- compounds are the only other [Mo(CN)7]4- extended structures to be characterized by single crystal structures to date.