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

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 $[CuL(NCS)]NO_3·CH_3OH (1), [Cu_2L(CH_3COO)_4].0.5_H2O (2)$, and $[CuL(μ-Cl)(NO_3)]_n.2nCH_3CN (3)$, were prepared from reaction of L with copper(II) salts containing different anions. Depending on the reaction controlling factor, i.e. $NCS^−, CH_3COO^−$, , 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 $Cu(NO_3)_2·3H_2O$ forms mononuclear complex 1. Dinuclear complex 2 was formed by the reaction of L in presence of $Cu(CH_3COO)_2·2H_2O$. Reaction of $Cu(NO_3)_2·3H_2O$ and $CuCl_2·3H_2O$ 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 $P2_{1/c}$ and dinuclear complex 2 is crystalized in a polar space group $P2_1$