Anion-directed assemblies of Cu(II) mono, di, and poly-nuclear coordination compounds with a 32-membered azacrown ligand: Synthesis, characterisation and crystal structures

Abstract

A novel 32-membered azacrown ligand L was synthesized from the [2 + 2] condensation between 2-[3-(2-formylphenoxy)-2-hydroxy propoxy]benzaldehyde and 1,2-diaminopropane by following in situ reduction. Three metal-organic coordination compounds [CuL(NCS)]NO3·CH3OH (1), [Cu2L(CH3COO)4].0.5H2O (2), and [CuL(μ-Cl)(NO3)]n.2nCH3CN (3), were prepared from reaction of L with copper(II) salts containing different anions. Depending on the reaction controlling factor, i.e. NCS−, CH3COO−, NO3−, and Cl− anions, mono, di and polynuclear metal-organic coordination compounds were constructed. Complexes were characterized by spectroscopic methods and single crystal X-ray diffraction. Crystal structures indicate that L in presence of NCS− and Cu(NO3)2·3H2O forms mononuclear complex 1. Dinuclear complex 2 was formed by the reaction of L in presence of Cu(CH3COO)2·2H2O. Reaction of Cu(NO3)2·3H2O and CuCl2·3H2O with L give rise complex 3 which is a 1-dimensional coordination polymer. The coordination polymer constructed from distorted octahedron shaped copper nucleus that are exomacrocylic in which two Cl atoms serve as bridge. Potentially decadentate ligand, L, with four N- and six O-donor sites in presence of Cu(II) salts reacts only with its N-donors. Complexes 1 and 3, both, are crystalized in a centrosymmetric space group P21/c and dinuclear complex 2 is crystalized in a polar space group P21.