Delicate Substituent Effect of Benzene-1,2,3-Tricarboxyl Tectons on Structural Assembly of Unusual Self-Penetrating Coordination Frameworks

Eight Zn-II and Cd-II coordination complexes, {[Zn-3(nbta)(2)(bpy)(2)(H2O)(2)](H2O)(2)}(n) (1), [Zn-4(nbta)(2)(bpe)(2)(OH)(2)](n) (2), {[Cd-3(nbta)(2)(bpy)(5)(H2O)(2)](H2O)(6)}(n) (3), {[Cd-3(nbta)(2)(bpe)(2)(H2O)(2)](H2O)(2)}(n) (4), [Zn-2(Hbta)(2)(bpy)(2)(H2O)](2)(H2O) (5), [Zn(bta)(Hbpe](n) (6), [Cd-5(Hbta)(2)(Hbta)(2)(bpy)(3)(H2O)(2)](n) (7), and {[Cd-4(bta)(2)(bpe)(2)(H2O)(4)(OH)(2)](H2O)(2))(n) (8), were prepared via hydrothermal reactions based on H(3)nbta or H(3)bta (H(3)nbta = 5-nitro-1,2,3-benzenctricarboxylic acid and H3bta = 1,2,3benzenetricarboxylic acid) and the dipyridyl-type coligand 4,4'-bipyridyl (bpy) or 1,2-di(4-pyridypethene (bpc), All complexes were characterized by elemental analysis, I R spectra, and X-ray powder diffraction techniques. Complexes 1-4 all display unusual three-dimensional (3-D) self-penetrating coordination networks. From the topology point of view, complexes 1 and 2 display the 4-connected frameworks with the Schlafli symbols of (4.10(4).12)(2)(4(3).6(2).8)(2)(4(4).6(2)) and (4.6(2).7(2).8)(2)(4(2).6(2).7.8), respectively. Complex 3 features an unprecedented 3-nodal network with (3,5,6)-connectivity and the Schlalli symbol of 6 10)(5(2).6(5).7(2).8)2(5(2).6)(2), also exhibiting an intriguing polyrotaxane entangled motif. Complex 4 shows a new 4-connected (42.63.8)4(64.8.10) topology. Different from 1-4, complexes 5-8 based on H3bta all present the non-selfpenetrating structural type. Complex 5 possesses binuclear units which are further extended to a two-dimensional (2-D) supramolecular network via extensive H-bondi ng interactions, showing alternate left- and right-handed helical chains. Complex 6 has a 2-D layered motif generated via 1-1-bonding interactions between the one-dimensional (1-D) coordination chains. Complex 7 shows a 3-D coordination framework, which is constructed from the 2-D metal-carboxylatc layers pillared by the rod-like bipy spacers. Complex 8 presents a 2-D net with the [Cd-4(mu(3)-OH)(2)](6+) clusters as the linking nodes. These results reveal that the existence of the electron-withdrawing -NO2 group in such a tricarboxyl building block plays a critical role in structural direction of the self-penetrating coordination frameworks.