Crystal structures of two Cu compounds: -poly[[chlorido-copper(II)]-μ--[eth-oxy(pyridin-2-yl)methyl-idene]-'-[oxido(pyridin-3-yl)methyl-idene]hydrazine-κ ,',:''] and di-μ-chlorido-1:4κ :-2:3κ :-di-chlorido-2κ,4κ-bis[μ-eth-oxy(pyridin-2-yl)methano-lato-1:2:3κ :,:;1:3:4κ ::,]bis-[μ-eth-oxy(pyridin-2-yl)methano-lato-1:2κ ,:;3:4κ ,:]tetracopper(II).

Two Cu complexes [Cu(CHNO)Cl] , , and [Cu(CHNO)Cl] , , have been synthesized. In the structure of the mononuclear complex , each ligand is coordinated to two metal centers. The basal plane around the Cu cation is formed by one chloride anion, one oxygen atom, one imino and one pyridine nitro-gen atom. The apical position of the distorted square-pyramidal geometry is occupied by a pyridine nitro-gen atom from a neighbouring unit, leading to infinite one-dimensional polymeric chains along the axis direction. Each chain is connected to adjacent chains by inter-molecular C-H⋯O and C-H⋯Cl inter-actions, leading to a three-dimensional network structure. The tetra-nuclear complex lies about a crystallographic inversion centre and has one core in which two Cu metal centers are mutually inter-connected two enolato oxygen atoms while the other two Cu cations are linked by a chloride anion and an enolato oxygen. An open-cube structure is generated in which the two open-cube units, with seven vertices each, share a side composed of two Cu ions bridged by two enolato oxygen atoms acting in a μ-mode. The Cu atoms in each of the two CuONCl units are connected by one μ-O and two μ-O atoms from deprotonated hydroxyl groups and one chloride anion to the three other Cu centres. Each of the penta-coordinated Cu cations has a distorted NOCl square-pyramidal environment. The Cu atoms in each of the two CuONCl units are connected by μ-O and μ-O atoms from deprotonated alcohol hy-droxy groups and one chloride anion to two other Cu ions. Each of the penta-coordinated Cu cations has a distorted NOCl square-pyramidal environment. In the crystal, a series of intra-molecular C-H⋯O and C-H⋯Cl hydrogen bonds are observed in each tetra-nuclear monomeric unit, which is connected to four tetra-nuclear monomeric units by inter-molecular C-H⋯O hydrogen bonds, thus forming a planar two-dimensional structure in the (01) plane.