Cu(II) coordination polymers with 4,4′-bipyridine. Synthesis and crystal structures

Extensively research has been devoted to the isolation and characterization of Cu(II) coordination polymers. Since many aspects can influence the final crystal structure, the effect of the solvent molecules through intermolecular interactions has been proven to be a determining factor. Herein, we elucidated the structure of two Cu(II) concomitant 1D polymers containing piperonylic acid (HPip) and 4,4′-bipyridine (4,4′-bipy), which were simultaneously crystallized and subsequently isolated changing the synthetic conditions. Complex {[Cu(Pip) ₂(4,4′-bipy)]} _n (1) exhibits zig-zag polymeric chains while {[Cu(Pip) ₂(4,4′-bipy)(H ₂O)]•1/2(4,4′-bipy)•(DMF)} _n (2) displays linear polymeric chains stacked by water•••carboxylate intermolecular interactions, forming voids occupied by alternated guest 4,4′-bipy and DMF molecules.