Interligand π,π-stacking interactions giving a bi-layered 2D framework in the crystal of poly-{(N4′-2,4′-bipyridine)-μ-(N,O,O′,O"-iminodiacetato)copper(II) hydrate}, {[Cu(IDA)(2,4′-bipy)]•H2O}n

The stoichiometric reaction Of Cu2CO3(OH)2, iminodiacetic acid [H(2)IDA = HN(CH2CO2H)(2))] and 2,4'-bipyridine (2,4'-bipy) in water yields crystalline samples of {[Cu(IDA)(2,4'-bipy)] . H2O}(n). The compound was studied by thermal, spectral (FT-IR and reflectance), magnetic (ESR and susceptibility) and X-ray diffraction methods. The structure was solved and refined to a final R, = 0.035. The Cu(II) atom exhibits a type 4 + 1 coordination and 2,4'-bipy ligand links the metal by its N4-donor. IDA exhibits a mer-tridentate chelating role and uses a syn-anti-bridging carboxylato group to give polymeric chains extending parallel to the c axis, leaving all 2,4'-bipy ligands towards the same side. Water molecule reinforces the chain stability forming H-bonds with two 0(carboxyl) acceptors from adjacent complex units. Both pyridyl rings of 2,4-bipy are nearly coplanar (1.0(2)degrees). Adjacent 2,4'-bipy ligands of the same complex chain define an open dihedral angle (69degrees). 2,4'-bipy ligands belonging to symmetry related chains stack both pyridyl rings at 3.40 Angstrom, thus forming a 2D framework with IDA ligands lying towards both external faces and N-heterocyclic ligands inside. In the crystal N(IDA)-H (. . .) O(IDA) hydrogen bonds connect up and down adjacent 2D frameworks in a 3D network. (C) 2002 Elsevier Science B.V. All rights reserved.