Synthesis and structural characterization of the dichloride complex formed by carboxy-functionalized Cu(diazacyclam)2+ cation and its heterometallic coordination polymer with CdCl2

The asymmetric unit of the complex [3,10-bis(3-carboxypropyl)-1,3,5,8,10,12-hexaazacyclotetradecane-κ 4 N 1 , N 5 , N 8 , N 12 ]dichloridocopper(II), [CuCl 2 (C 16 H 34 N 6 O 4 )] or [Cu(H 2 L )Cl 2 ] ( I ), consists of a centrosymmetric macrocyclic Cu II dication and a chloride anion. The components of the heterometallic compound poly[[aqua[μ 3 -3,10-bis(3-carboxypropyl)-1,3,5,8,10,12-hexaazacyclotetradecane-κ 4 N 1 , N 5 , N 8 , N 12 :κ 2 O , O ′:κ 2 O ′′, O ′′′]-μ-chlorido-copper(II)cadmium(II] 1.25-hydrate], {[CuCd(C 16 H 32 N 6 O 4 )Cl 2 (H 2 O)]·1.25H 2 O} n or {[CuCd( L )(H 2 O)Cl 2 ]·1.25H 2 O} n ( II ) are [Cu( L )(H 2 O)] moieties coordinated to CdCl 2 units via the deprotonated carboxylic groups of the macrocycle, and four water molecules of crystallization with partial occupancies. In each compound, the Cu II ion coordinates 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 tetragonally elongated trans -CuN 4 Cl 2 and trans -CuN 4 (H 2 O)Cl octahedral geometries in I and II , respectively. The coordination environment of the Cd II ion in II is a CdO 4 Cl 2 distorted octahedron formed by two bidentately coordinated deprotonated carboxylic groups of different macrocycles and two chloride anions, one of which displays a μ 2 -bridging function between the Cu II and Cd II ions. The extended structures of both complexes are distinctly lamellar. In particular, due to hydrogen–bonding interactions with participation of carboxylic groups, chloride atoms and secondary amino groups of the macrocycle, the electro-neutral molecules 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 (10 1 ) plane via formation of Cu—Cl bonds and interchain hydrogen bonds. There are no hydrogen-bonding interactions between the layers and the three-dimensional structure of II is based on the weak C—H...O and C—H...Cl contacts.