Syntheses and crystal structures of iron co-ordination polymers with 4,4′-bipyridine (4,4′-bpy) and 4,4′-azopyridine (azpy).: Two-dimensional networks supported by hydrogen bonding, {[Fe(azpy)(NCS)2(MeOH)2]•azpy}n and {[Fe(4,4′-bpy)(NCS)2-(H2O)2]•4,4′-pby}n

New iron(Ir) co-ordination polymers, {[Fe(azpy)(NCS)(2)(MeOH)(2)]. azpy}(n) 1 (azpy = 4,4'-azopyridine), {[Fe(4,4'-bpy)(NCs)(2)(H2O)(2)]. 4,4'-bpy}(n) 2 (4,4'-bpy = 4,4'-bipyridine) and {[Fe(azpy)(2)(NCS)(2)]. 3H(2)O}(n) 3 have been synthesized and characterized. The crystal structures of both compounds 1 and 2 contain two types of bridging ligands; one is of the co-ordination bond type, directly bridging iron centers to form a one-dimensional chain of [Fe(L)] (L = azpy or 4,4'-bpy), while the other links these chains by hydrogen bonds between the pyridine nitrogen atoms and coordinated methanol or water molecules, resulting in a grid sheet. Each sheet shows non-interpenetration because of incorporation of NCS anion in the grid. Cyclic voltammograms of 1 and 3 demonstrate that the directly bridging azpy ligands show no apparent redox activity, whereas a reversible redox wave observed for 1 is attributed to the hydrogen-bonding supported azpy. Magnetic susceptibilities measured from 1.9 to 300 K are indicative of no appreciable magnetic exchange interaction between the adjacent metal ions.