Crystal structures of trans-di-aqua-(3-R-1,3,5,8,12-penta-aza-cyclo-tetra-deca-ne)copper(II) isophthalate hydrates (R = benzyl or pyridin-3-ylmethyl)

Synthesis and crystal structure of trans-diaqua(1,4,8,11-tetraazaundecane)copper(II) isophthalate monohydrate

The complex cation of the title compound contains a tetra­gonally distorted trans-CuN₄O₂ octa­hedron. In the crystal, the components are linked by numerous N—H⋯O and O—H⋯O hydrogen bonds, forming electroneutral sheets oriented parallel to the ac plane, which are further consolidated into bilayers due to hydrogen-bonding with the participation of the water mol­ecule of crystallization.

In the title hydrated mol­ecular salt, [Cu(C₇H₂₀N₄)(H₂O)₂](C₈H₄O₄)·H₂O, the metal ion is coordinated by the two primary and two secondary N atoms of the amine ligand and the mutually trans O atoms of the water mol­ecules in a tetra­gonally distorted octa­hedral geometry. The average equatorial Cu—N bond lengths (2.013 and 2.026 Å for Cu—N_prim and Cu—N_sec, respectively) are substanti­ally shorter than the average axial Cu—O bond length (2.518 Å). The tetra­amine ligand adopts its energetically favored conformation with its five- and six-membered chelate rings in gauche and chair conformations, respectively. In the crystal, the N—H donor groups of the tetra­amine, the acceptor carboxyl­ate groups of the isophthalate dianion and both the coordinated water mol­ecules and the water mol­ecule of crystallization are involved in numerous N—H⋯O and O—H⋯O hydrogen bonds, resulting in the formation of electroneutral layers oriented parallel to the ac plane.

The first structural characterization of the proton-ated aza-cyclam ligand in catena-poly[[[(perchlorato)copper(II)]-μ-3-(3-carb-oxy-prop-yl)-1,5,8,12-tetra-aza-3-azonia-cyclo-tetra-deca-ne] bis-(per-chlorate)]

The asymmetric unit of the title com-pound, catena-poly[[[(perchlorato-κO)copper(II)]-μ-3-(3-carb-oxy-prop-yl)-1,5,8,12-tetra-aza-3-azonia-cyclo-tetra-decane-κ4 N 1,N 5,N 8,N 12] bis-(per-chlorate)], {[Cu(C13H30N5O2)(ClO4)](ClO4)2} n , (I), consists of a macrocyclic cation, one coordinated per-chlorate anion and two per-chlorate ions as counter-anions. The metal ion is coordinated in a tetra-gonally distorted octa-hedral geometry by the four secondary N atoms of the macrocyclic ligand, the mutually trans O atoms of the per-chlorate anion and the carbonyl O atom of the protonated carb-oxy-lic acid group of a neighbouring cation. The average equatorial Cu-N bond lengths [2.01 (6) Å] are significantly shorter than the axial Cu-O bond lengths [2.379 (8) Å for carboxyl-ate and average 2.62 (7) Å for disordered per-chlorate]. The coordinated macrocyclic ligand in (I) adopts the most energetically favourable trans-III conformation with an equatorial orientation of the substituent at the protonated distal 3-position N atom in a six-membered chelate ring. The coordination of the carb-oxy-lic acid group of the cation to a neighbouring com-plex unit results in the formation of infinite chains running along the b-axis direction, which are cross-linked by N-H⋯O hydrogen bonds between the secondary amine groups of the macrocycle and O atoms of the per-chlorate counter-anions to form sheets lying parallel to the (001) plane. Additionally, the extended structure of (I) is consolidated by numerous intra- and interchain C-H⋯O contacts.