Crystal structure of trans-di-aqua-(3,10-dimethyl-1,3,5,8,10,12-hexa-aza-cyclo-tetra-deca-ne)copper(II) pamoate.

The asymmetric unit of the title compound, trans-di-aqua-(3,10-dimethyl-1,3,5,8,10,12-hexa-aza-cyclo-tetra-decane-κ4 N 1,N 5,N 8,N 12)copper(II) 4,4'-methyl-ene-bis(3-hy-droxy-naphthalene-2-carboxyl-ate), [Cu(C10H26N6)(H2O)2](C23H14O6) {[Cu(L)(H2O)2](pam), where L = 3,10-dimethyl-1,3,5,8,10,12-hexa-aza-cyclo-tetra-decane and pam = dianion of pamoic acid} consists of two independent halves of the [Cu(L)(H2O)2]2+ cation and one di-carboxyl-ate anion. The CuII atoms, lying on inversion centres, are coordinated by the four secondary N atoms of the macrocyclic ligands and the mutually trans O atoms of the water mol-ecules in a tetra-gonally elongated octa-hedral geometry. The average equatorial Cu-N bond length is significantly shorter than the average axial Cu-O bond length [2.007 (10) and 2.486 (18) Å, respectively]. The macrocyclic ligand in the complex cations adopts the most energetically stable trans-III conformation. The complex cations and anions are connected via hydrogen-bonding inter-actions between the N-H groups of the macrocycles and the O-H groups of coordinated water mol-ecules as the proton donors and the O atoms of the carboxyl-ate as the proton acceptors into layers lying parallel to the (11) plane.