Synthesis and structural evaluation of five coordination complexes of benzenepentacarboxylic acid with aza-donor ligands

Abstract

Synthesis and structural features of five new coordination assemblies, [Co(bpyH)(H2O)5](BPCH)�(bpyH2)0.5�(H2O) (1a), [{Cu(H2O)3}�{Cu0.5(bpy)0.5(H2O)0.5}2(?-BPCH)] (1b), [{Cd0.5(BPCH)}2�{Cd0.5(bpy)(H2O)2}2]�6(H2O) (1c), [Cu(BPCH2)(bpyeaH)]�2(H2O) (1d) and [Cd2 (bpyea)0.5(oxalate)0.5(?-BPC) (H2O)]�(bpyeaH2)�2(H2O) (1e), have been reported. All the assemblies were prepared by co-crystallization of benzenepentacarboxylic acid (BPCH5) either with 4,4?-bipyridine (bpy) or 1,2-bis(4-pyridyl)ethane (bpyea) in the presence of a transition metal ion (either Co(II), Cu(II) or Cd(II)) as the case may be. All the five compounds were synthesized by hydrothermal method and structures were determined by single crystal X-ray diffraction. All the obtained compounds, 1a�1e, exhibit distinct 3-D polymeric architectures either in the form of stacked layers or host-guest networks in which water molecules play a pivotal role providing additional stabilization by coordinate bonds as well as hydrogen bonds. Other non-covalent interactions such as C�H � ? and ? � ? stacking also participate in the formation of exotic 3-D structures of these complexes. � 2016 Elsevier B.V.