Crystal structure of the BaII-based CoII-containing one-dimensional coordination polymer poly[[aqua- {μ4-2,2'-[(4,10-dimethyl-1,4,7,10-tetraazacyclododecane- 1,7-diyl)bis(methylidene)]bis(4-oxo-4H-pyran- 3-olato)}perchloratocobaltbarium] perchlorate].

The title compound, {[Ba{Co(H_-2L1)}(ClO₄)(H₂O)]ClO₄}_n, L1 = 4,10-bis­[(3-hy­droxy-4-pyron-2-yl)meth­yl]-1,7-dimethyl-1,4,7,10-tetra­aza­cyclo­dodeca­ne, 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 hexa­coordinated in a trigonal–prismatic fashion by the surrounding N₄O₂ donor set. The Ba²⁺ ion is nine-coordinated and exhibits a distorted [BaO₉] monocapped square-anti­prismatic 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 mol­ecule. A barium–μ₂-oxygen motif develops along the a axis, connecting symmetry-related dinuclear Ba^II–Co^II cationic 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—HO 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 Ba^II-based one-dimensional coordination polymer, containing Co^II ions surrounded by a N₄O₂ donor set. [ABSTRACT FROM AUTHOR]