Topological Diversity of Coordination Polymers Containing the Rigid Terephthalate and a Flexible N,N′-Type Ligand: Interpenetration, Polyrotaxane, and Polythreading

Abstract

Reactions of zinc(II) or cadmium(II) salts with terephthalic acid (H 2 tp) and 1,3-bis(4-pyridyl)propane (bpp) have afforded four coordination polymers at room temperature, [Zn(µ-tp), and [Cd 2 (µ-tp)(µ-bpp) 2 (bpp) 2 Br 2 ] n (4). Single-crystal X-ray diffraction has revealed interesting topological features for these compounds. In 1, the Zn atoms act as 4-connected nodes bridged by the tp and bpp ligands to give a 3-fold interpenetrated 3D network with a unique 6 6 topology, which is evidently distinct from 4-connected diamondoid networks. 2 represents the first example of a 2-fold interpenetrated coordination polymer, which possesses a 5-connected 3D framework with a unique 6 10 topology constructed from Cd nodes and tp and bpp spacers. 3 manifests a polyrotaxane motif comprised of two interlocked sets of identical sheets, which result in a 2D f 2D polythreaded layer. Parallel mutual polythreading of 2D layers with dangling bpp ligands is observed in 4, involving five polymeric layers at a time and thus affording a 3D architecture. All compounds were characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, and their fluorescence properties were also investigated.

Network analysis of barium oxalates Ba(C2O4)m(HC2O4)n(H2C2O4)p(H2O)q, including the new, uniform, five-connected loh net

“…Another difference is that it contains no four-membered rings, and that all rings are, in fact, six-membered rings. Together with the recently reported 6 10 -rld-z [34] and 6 10 -ghw [35] nets, and the 6 10 -fnu [13,9], of which no examples seem to exist, it forms a subclass of five-connected 6 10 -nets based on the distorted trigonal bipyramidal coordination. These four are also the only known five-connected nets containing no rings with fewer than six members (of the 236 nets listed in the RCSR).…”

Diversified architectures of one-dimensional zinc(II) and cadmium(II) coordination polymers incorporating bipyridyl ligands: Syntheses, structures, theoretical studies, fluorescent and nonlinear optical properties

“…Nevertheless, the formation of CPs only at the 1-D level is still a long-term challenge, as transition metal centers have many coordination sites available, which tend to be connected to the various bridging ligands to further construct two-dimensional (2-D) or three-dimensional (3-D) structures [23,24]. To obtain the desirable 1-D architectures, one effective strategy is to introduce ancillary ligands, such as chelating anions or ligands, at the metal centers to block some of their coordination sites [25,26] conformational freedom in the assembly process, rigid or semirigid ligands are more attractive than flexible ligands [27][28][29].…”

Diaquabis(2,2’-dipyridylamine)M(II) Terephthalate Dihydrates, M(II) = Ni, Co: Synthesis, Crystal Structures, Thermal and Magnetic Properties

“…The anion of 1,4-benzenedicarboxylic (terephthalic, H 2 tpht) acid, as one out of three positional isomers of benzenedicarboxylic (BDC) acids, is widely used as bridging ligand for designing new metal-organic compounds, 2,3 especially due to its diversity of the coordination modes, high structural stability, rigidity and planarity. Earlier studies 4,5 have vigorously stated that the usage of tpht ligand in combination with aromatic diamines as secondary ligands could afford a wide range of intriguing multi-dimensional structures with transition metal (TM) ions. The interest in tpht complexes is related to the molecular magnetism, and most published articles were focused on Cu(II) complexes and their magnetic properties together with an orbital interpretation of the magnetic exchange mechanism.…”

“…[5][6][7][8][9] 2,2'-Dipyridylamine (dipya) as aromatic diamine ligand was not frequently used in combination with tpht. The survey of CSD showed 10 that only seven dipya-tpht complexes with different TM ions as nodes are structurally 4 ](tpht), tpht was a counter anion. The role of tpht as counter anion as well as the hydrogen bond acceptor is not uncommon and it was described earlier for some TM-tpht complexes.…”