An unique stair-like infinite chain polymer containing dimeric N2S3 square-pyramidal iron(III) complex

A one-dimensional stair-like coordination polymer, [Fe2L2Na2(CH3CN)2(Et2O)2]n {1, where L4− = N,N’-bis-(2-mercaptophenyl)-2-methyl-2-[(2-methylthio)phenylmethyl] malonyl diamide}, was produced from the one-pot reaction of iron(III) chloride with 2-methyl-2-[(2-methylthio)phenylmethyl] malonyl chloride, 2-aminobenzenethiol and sodium hydride in DMF solution, and was structurally characterized. The dimeric pentacoordinate Fe(III) anionic units are linked by two bridging four-coordinate Na+ cations. Each trivalent iron atom is equatorially coordinated by two deprotonated carboxamido N and S atoms of the ligand. The bridging S atom, occupying the axial position, accomplishes the square-pyramidal geometry of iron center. The coordination environment is very similar to the unmodified active site of Fe-containing nitrile hydratase. In addition, the electronic and magnetic properties of this dimeric complex are included in this report.