Crystal structure of the BaII-based CoII-containing one-dimensional coordination polymer poly[[aquaμ4-2,2'-[(4,10-dimethyl-1,4,7,10-tetra-aza-cyclo-dodecane-1,7-di-yl)bis(methylidene)]bis-(4-oxo-4H-pyran-3-olato)-perchloratocobaltbarium] perchlorate]

The title compound, [BaCo(H-2L1)(ClO4)(H2O)]ClO4 n ,L1 =4,10-bis-[(3-hy-droxy-4-pyron-2-yl)meth-yl]-1,7-dimethyl-1,4,7,10-tetra-aza-cyclo-dodeca-ne, is a one-dimensional coordination polymer. The asymmetric unit consists of a Ba[Co(H-2L1)](ClO4)(H2O)+cationic fragment and a non-coordinating ClO4-anion. In the neutral [Co(H-2L1)] moiety, the cobalt ion is hexa-coordinated in a trigonal-prismatic fashion by the surrounding N4O2donor set. The Ba2+ion is nine-coordinated and exhibits a distorted [BaO9] monocapped square-anti-prismatic geometry, the six oxygen atoms coming from three distinct [Co(H-2L1)] moieties, while the remaining three vertices are occupied by the oxygen atoms of a bidentate perchlorate anion and a water mol-ecule. A barium-μ2-oxygen motif develops along theaaxis, connecting symmetry-related dinuclear BaII-CoIIcationic fragments in a wave-like chain, forming a one-dimensional metal coordination polymer. Non-coordinating ClO4-anions are located in the space between the chains. Weak C-H⋯O hydrogen bonds involving both coordinating and non-coordinating perchlorate anions build the whole crystal architecture. To our knowledge, this is the first example of a macrocyclic ligand forming a BaII-based one-dimensional coordination polymer, containing CoIIions surrounded by a N4O2donor set.