New coordination polymer based on salpn Schiff base and azide bridging ligands: Synthesis and structural characterization of {Na[CoIII(μ-salpn)(μ1,1-N3)2]}n (H2salpn=N,N′-bis(salicylidene)-1,3-diaminopropane)

Abstract : One-pot reaction of cobalt(II) nitrate hexahydrate Co(NO3)2 · 6H2O with H2salpn (N,N′-bis(salicylidene)-1,3-diaminopropane) in presence of a large excess of sodium azide (NaN3) gives the new Co(III) compound {Na[CoIII(μ-salpn)(μ1,1-N3)2]}n (1), which was characterized by single crystal X-ray diffraction analysis. The crystal structure shows polymeric 1D complex generated by the hexadentate Schiff base salpn2− and two crystallographically different azide ligands. The two nitrogen atoms of the salpn ligand are bonded to the cobalt(III) ion while each phenoxo oxygen atom is bonded to the same Co(III) ion and to two equivalent sodium ions. Each azide ligand acts with the end-on bridging coordination mode between Co(III) and Na(I) ions. The Co(III) ion adopts a distorted octahedral geometry arising from two oxygen and two nitrogen atoms of the salpn ligand and from two nitrogen atoms of the two crystallographically different azide ligands in trans positions. Such [Co(salpn)(N3)2] entities are connected each other by sodium ions through four oxygen atoms of two equivalent Schiff base ligands and two nitrogen atom of the two different azide ligands to generate the 1D structure of 1.