Hydrogen bonding induced lowering of the intra-chain metal-metal distance in single end-on azide bridged one-dimensional copper(II) complexes with tridentate Schiff bases as blocking ligands

Three copper(II) complexes, [Cu(L-1)(N-3)]n (1), [Cu(L-2)(N-3)](n)center dot H2O (2) and [Cu(L-3)(N-3)](n) (3) {where HL1 = 2-[(2-dimethylamino-ethylimino)-methyl]-4-nitro-phenol, HL2 = 2-[(2-methylamino-ethylimino)-methyl]-4-nitro-phenol and HL3 = 2-[(2-ethylamino-ethylimino)-methyl]-4-nitro-phenol are tridentate Schiff-base ligands}, were prepared and characterized. Single crystal X-ray diffraction studies confirm that each complex is an end-on azide bridged one-dimensional polymer. All the complexes exhibit a square pyramidal geometry around the copper(II) centre. Weak forces like hydrogen bonding interactions lead to various supramolecular architectures. The copper(II)center dot center dot center dot copper(II) distance is minimized by intra chain hydrogen bonding in complex 3. (C) 2013 Elsevier Ltd. All rights reserved.