Synthesis of a new polymorph in [Cu(pyridine-2-carboxylate)(2)]system

Single crystal X-ray studies on a doubly carboxylate bridged {[Cu(pic)(2)].2H(2)O}(n) (1) (pic = pyridine-2-carboxylate) polymeric chains extending along the crystallographic a axis reveal that adjacent polymeric chains are joined by the lattice water chains running parallel to the polymeric chain leading to a 2D sheet in the (101) plane. The successive sheets are interdigitated and glued to each other by a novel C=O...pi interaction into a 3D supramolecular motif. The complex (1) can be regarded as a pseudo-polymorph of [Cu(pic)(2)](n) which has been realized in two forms, violet (2) and blue-violet (3) from methanol.