Synthesis and structural characterization of the dichloride complex formed by carb-oxy-functionalized Cu(di-aza-cyclam)2+ cation and its heterometallic coordination polymer with CdCl2.

The asymmetric unit of the complex [3,10-bis-(3-carb-oxy-prop-yl)-1,3,5,8,10,12-hexa-aza-cyclo-tetra-decane-κ4 N 1,N 5,N 8,N 12]di-chlorido-copper(II), [CuCl2(C16H34N6O4)] or [Cu(H2 L)Cl2] (I), consists of a centrosymmetric macrocyclic CuII dication and a chloride anion. The components of the heterometallic compound poly[[aqua-[μ3-3,10-bis-(3-carb-oxy-prop-yl)-1,3,5,8,10,12-hexa-aza-cyclo-tetra-dec-ane-κ4 N 1,N 5,N 8,N 12:κ2 O,O':κ2 O'',O''']-μ-chlorido--copper(II)cadmium(II] 1.25-hydrate], {[CuCd(C16H32N6O4)Cl2(H2O)]·1.25H2O} n or {[CuCd(L)(H2O)Cl2]·1.25H2O} n (II) are [Cu(L)(H2O)] moieties coordinated to CdCl2 units via the deprotonated carb-oxy-lic groups of the macrocycle, and four water mol-ecules of crystallization with partial occupancies. In each compound, the CuII ion coord-inates in the equatorial plane by the four secondary N atoms of the macrocyclic ligand, which adopts the most energetically stable trans-III conformation, and two mutually trans axial ligands in tetra-gonally elongated trans-CuN4Cl2 and trans-CuN4(H2O)Cl octa-hedral geometries in I and II, respectively. The coordination environment of the CdII ion in II is a CdO4Cl2 distorted octa-hedron formed by two bidentately coordinated deprotonated carb-oxy-lic groups of different macrocycles and two chloride anions, one of which displays a μ2-bridging function between the CuII and CdII ions. The extended structures of both complexes are distinctly lamellar. In particular, due to hydrogen-bonding inter-actions with participation of carb-oxy-lic groups, chloride atoms and secondary amino groups of the macrocycle, the electro-neutral mol-ecules in crystal of I are arranged in chains running in the [101] direction; hydrogen bonding between the chains leads to layers parallel to the (101) plane. In crystal of II, polymeric chains running along the [101] direction are joined into layers parallel to the (101) plane via formation of Cu-Cl bonds and inter-chain hydrogen bonds. There are no hydrogen-bonding inter-actions between the layers and the three-dimensional structure of II is based on the weak C-H⋯O and C-H⋯Cl contacts.