Reactions between macrocyclic nickel(II) complexes and ferricyanide. Metamagnetic properties of a two-dimensional honeycomb assembly [NiL3]3[Fe(CN)6]2·8H2O (L3 = 3,10-dihydroxyethyl-1,3,6,8,10,12-hexaazacyclotetradecane) †

Abstract

The synthesis, structural and magnetic properties of the 2-D bimetallic complex [NiL3]3[Fe(CN)6]2·8H2O (L3 = 3,10-dihydroxyethyl-1,3,6,8,10,12-hexaazacyclotetradecane) are presented. The structure consists of cyano-bridged neutral honeycomb-like layers. Each hexacyanoferrate(III) ion connects three nickel(II) ions using three cis CN− groups and the remaining CN− groups are terminal. The bridging cyanide ligands coordinate to the nickel ion in a trans fashion. Magnetic studies showed that the complex displays a metamagnetic behaviour arising from intralayer ferromagnetic coupling and interlayer antiferromagnetic interactions. A long-range magnetic ordering at Tc = 6.0 K was observed. In addition, the ionic complex [NiL4]3[Fe(CN)6]2·6H2O (L4 = 8-methyl-1,3,6,8,10,13,15-heptaazatricyclo[13.1.1.113,15]octadecane) showing the absence of cyano bridging, is reported.