An aqua-bridged helical-chain copper(II)-saccharinato polymer linked into a two-dimensional supramolecular framework

A new assembly [Cu-2(sac)(2)(mu-dmea)(2)(mu-H2O)](n) (sac = saccharinate and Hdmea = 2-dimethylaminoethanol) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space group C2/c and consists of di-nuclear modules of [Cu-2(sac)(2)(dmea)(2)]. The sac ligand is N-coordinated, while the dmea ligand is in the deprotanated form by losing the ethanol hydrogen atom and acts as a bidentate donor through the alkoxo group and N atom. The alkoxo group also serves as a bridge between two copper(II) ions, leading to an intra-dimer (CuCu)-Cu-... separation of 3.0229(7) angstrom. The dimeric units are bridged by aqua ligands to generate a one-dimensional water-bridged helical chain, in which the copper(II) ions exhibit a distorted square-pyramidal CuN2O3 coordination. The Cu-Cu distance in the chain separated by the bridging aqua ligands is 5.297 angstrom. The polymeric chains are further linked by pi(sac)(...)pi(sac) and C-H-...mu(sac) interactions into a two-dimensional supramolecular network.