Formation of supramolecular hydrogen-bonding chains and networks from copper (II) halogenobenzoates with N-methylnicotinamide: Supramolecular isomerism

Abstract The self-assembly of supramolecular structures from copper (II) halogenobenzoate complexes containing N-methylnicotinamide ligand have been explored. The following compound and polymorph structures were determined by single-crystal X-ray structural analysis- the compounds [Cu(4-Fbz)2(mna)2(H2O)], [Cu(4-Clbz)2(mna)2(H2O)], [Cu(4-Brbz)2(mna)2(H2O)], two polymorphs of [Cu(2,6-Cl2bz)2(mna)2(H2O)2]∙2H2O, [Cu(3,5-Cl2bz)2(mna)2(H2O)2]∙2H2O, [Cu(3-Fbz)2(mna)2(H2O)2]∙2H2O, and [Cu(3-Clbz)2(mna)2(H2O)2]∙2H2O, two polymorphs of [Cu(3-Brbz)2(mna)2(H2O)2]∙2H2O, [Cu(3-Ibz)2(mna)2(H2O)2]∙2H2O,[Cu(2,5-Cl2bz)2(mna)2(H2O)2]∙2H2O,[Cu(2,3-Cl2bz)2(mna)2(H2O)2]∙H2O,[Cu(2,6-Cl2bz)2(mna)2(H2O)]∙2H2O, [Cu(3,4-Cl2bz)2(mna)2(H2O)]∙2H2O, [Cu(3-Brbz)2(mna)2(H2O)] and [Cu(2-Fbz)2(mna)2(μ-H2O)]n, (mna = N-methylnicotinamide, 4-Fbz = 4-fluorobenzoate, 4-Clbz = 4-chlorobenzoate, 4-Brbz = 4-bromobenzoate, 3-Fbz = 3-fluorobenzoate, 3-Clbz = 3-chlorobenzoate, 3-Brbz = 3-bromobenzoate, 3-Ibz = 3-iodobenzoate, 2-Ibz = 2-iodobenzoate, 2,3-Cl2bz = 2,3-dichlorobenzoate, 2,5-Cl2bz = 2,5-dichlorobenzoate, 2,6-Cl2bz = 2,6-dichlorobenzoate, 3,4-Cl2bz = 3,4-dichlorobenzoate and 3,5-Cl2bz = 3,5-dichlorobenzoate) . The compounds are monomeric complexes with a distorted octahedral or square-pyramidal coordination sphere around Cu2+ ion. The two polymorph sets of [Cu(2,6-Cl2bz)2(mna)2(H2O)2]∙2H2O and [Cu(3-Brbz)2(mna)2(H2O)2]∙2H2O are two examples of coordination compounds which are conformation and supramolecular isomers. The crystal structure of complex [Cu(4-Fbz)2(mna)2(H2O)] shows the phase transition in two temperatures. The compound [Cu(2-Fbz)2(mna)2(μ-H2O)]n is a coordination polymer with bridging aqua ligand. The molecules of all compounds are connected by N—H…O and O—H…O hydrogen bonds from NHCH3 groups of N-methylnicotinamide and water molecules which create supramolecular hydrogen-bonding-coordination chains and networks. The intermolecular interactions were studied by Hirshfeld surface analysis.