Assembly of Discrete One-, Two-, and Three-Dimensional Zn(II) Complexes Containing Semirigid V-Shaped Tricarboxylate Ligands

Hydrothermal reaction of zinc nitrate, 4-(4-carboxyphenoxy)phthalate acid (H3cpop), and different N-donor coligands has afforded six novel supramolecular compounds, in which the nature of the neutral coligands plays a crucial structure-directing role. [Zn(Hcpop)(H2O)3]n (1) and [Zn(Hcpop)(phen)(H2O)]n (2, phen = 1,10-phenanthroline) form three-dimensional (3D) supramolecular frameworks linked by H-bonds and π–π interactions based on discrete molecules. Similarly, [Zn2(Hcpop)2(4,4′-bpy)3(H2O)2]n·4nH2O (3) possesses a 3D supramolecular structure, aggregated by interesting one-dimensional (1D) armed-polyrotaxane chains. [Zn6(cpop)4(4,4′-bpy)2(H2O)2]n (4, 4,4′-bpy = 4,4′-bipyridine) exhibits a complicated 3D framework, which can be rationalized as a (3,6,6)-connected trinodal net with a unique (4.62)2(42.69.83.10)(44.68.83) topology. [Zn3(cpop)2(bpdb)(H2O)2]n (5, bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) is a 3D structure containing two-dimensional (2D) metal–carboxylate layers motifs, which are further pillared by cpop3– and bpdb ligands to complete the structure. [Zn6(cpop)4(azpy)2(H2O)4]n (6, azpy = 4,4′-azopyridine) manifests a unique quadruple layer structure constructed from two types of bilayered architectures linked by Zn2+ ions and bridging azpy ligands. Meanwhile, solid-state properties such as thermal stability and the photoluminescence properties at room temperature for these complexes have also been systematically investigated.