New 3-D supramolecular networks formed via hydrogen bonding and π-π stacking interactions: Synthesis, characterization and crystal structures

Two new 3-D supramolecular networks, {[Cd2(dap)2(tp)2(H2O)2] · 2H2O}n (1) and {[Cu3(tp)2(dpq)2(OH)2]}n (2) (tp, terephthalate; dap, 5,6-diamino-1,10-phenanthroline; dpq, dipyrido[3,2-d:2′,3′-f]quinoxaline), have been synthesized and structurally characterized by X-ray diffraction. Single-crystal X-ray analyses show that complex 1 is constructed by CdII and mixed ligands of daps and tps to form a 1-D polymer chain. In complex 2, a tetra-coordinated CuII and two penta-coordinated CuII are linked by two bridging hydroxyl oxygen atoms to form a Cu3(OH)2(dpq)2 unit, which is a noteworthy feature in the framework, and such units are connected through tp to form a 2-D lamellar polymer. Moreover, complexes 1 and 2 are further extended into 3-D supramolecular networks by H-bonding and π-π stacking interactions, respectively.