Syntheses and structural characterizations of the first coordination polymers assembled from the Ni(cyclam)2+ cation and the benzene-1,3,5-tri-carboxyl-ate linker.

Abstract

The asymmetric unit of catena-poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ2-5-carb-oxy-benzene-1,3-di-carboxyl-ato-κ2 O 1:O 3] octa-hydrate], {[Ni(C9H4O6)(C10H24N4)]·8H2O} n (I), consists of a macrocyclic Ni2+ cation, a carboxyl-ate dianion and eight highly disordered water mol-ecules of crystallization. The components of the compound catena-poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ2-5-carb-oxy-benzene-1,3-di-carboxyl-ato-κ2 O 1:O 3] monohydrate], {[Ni(C9H4O6)(C10H24N4)]·H2O} n (II), are two crystallographically unique centrosymmetric macrocyclic dications, a carboxyl-ate dianion and one water mol-ecule of crystallization. In each compound, the metal ion is coordinated 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 O atoms of the carboxyl-ate anions in a slightly tetra-gonally distorted trans-NiN4O2 octa-hedral geometry. The crystals of both compounds are composed of parallel coordination polymeric chains running along the [010] direction in I and the [110] and [10] directions in II. The bridging carboxyl-ate anions display different modes of coordination connected with the relative orientation of coordinated O atoms, i.e., remote in I and inter-mediate in II, thus resulting in essentially different distances between the Ni atoms in the chains [11.0657 (4) and 8.9089 (2) Å in I and II, respectively]. As a result of hydrogen-bonding inter-actions, the chains are joined together in sheets oriented parallel to the (10) and (001) planes in I and II, respectively.