Effect of Organic Polycarboxylate Ligands on the Structures of a Series of Zinc(II) Coordination Polymers Based on a Conformational Bis-triazole Ligand

To explore the influence of six structurally different polycarboxylate ligands H2L1 to H4L6 in the system Zn(II)/btmx, six coordination polymers, formulated as [Zn(btmx)(L-1)](n) (1), {[Zn(btmx)(L-2)].2H(2)O}(n) (2), {[Zn-(btmx)(L-3)]center dot 1.5H(2)O) (3), [Zn(btmx)(L-4)] (4), {[Zn-4(btmx)(3)(L-5)(4)(H2O)(2)]center dot 4H(2)O}(n) (5), and [Zn(btmx)-(H2L6)](n) (6), have been obtained under similar conditions (btmx = 1,4-bis(1,2,4-triazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene, H2L1 = 1,3-benzenedicarboxylic acid, H2L2 = 1,4-benzenedicarboxylic acid, H2L4 = 1,3-adamantanedicarboxylic acid, H2L5 = 1,3-adamantanediacetic acid, H2L5 = 4,4'oxidibenzoic acid, and H4L6 = 3,3',4,4'-benzophenone tetracarboxylic acid). The structure determination reveals that complexes 1 and 4 are two-dimensional (2D) layered networks and exhibit typical (4,4) topological nets. Complex 2 shows an undulating 2D (4,4)-network with 2-fold interpenetration. Complex 3 possesses a three-dimensional (3D) 3-fold interpenetrating 4-connected framework of 6(6)-dia topology. Both 5 and 6 have different 3D interpenetrated motifs generated by 2D -> 3D interpenetration. Complex 5 belongs to a 3D framework built from the interpenetration of 2D bilayers in an inclined mode, while 6 involves a parallel interpenetration between the adjacent 2D (4,4) layers. This work markedly indicates that the effect of polycarboxylate ligands is significant in the construction of these networks.