Structural Diversity and Properties of Coordination Polymers Built from a Rigid Octadentenate Carboxylic Acid

Abstract

By using a rigid octadentenate carboxylate linker 5,5′,5″,5″′-silanetetrayltetraisophthalic acid (H8L), three new microporous coordination polymers, namely, [Cu4L(H2O)4]·2DMF·10H2O (1), [Zn5L2(H2O)4][NH2(CH3)2]6·2DMF·4H2O (2), and [Cd3(H2L)2][NH2(CH3)2]6·4DMF·14H2O (3), were solvothermally synthesized and structurally characterized. Compound 1 is a 3D framework built from a square paddlewheel [Cu2(O2CR)4] and a 8-connected cube L ligand to give a (4,8)-connected scu structure. Compound 2 is a 3D 4-nodal (4,4,4,8)-connected network with small 1D channels built on three tetrahedral Zn units and a 8-connecting ligand L. Compound 3 possesses a 3D structure with a (4,4,6)-connected net built on two tetrahedral Cd units and a 6-connecting ligand H2L6–. All the three compounds consist of large solvent accessible voids, but only compound 1 possesses permanent porosity as confirmed by N2, H2, O2, CO2 and CH4 gas adsorption measurements. Compounds 2 and 3 exhibited strong blue fluorescent emissions with a peak at 414 and 412 nm, respectively, at RT upon excitation owing to a ligand-centered excited state.

Tailoring porosity and rotational dynamics in a series of octacarboxylate metal-organic frameworks

“…In previously reported examples of octacarboxylate MOFs with tbo or scu nets (18)(19)(20)(21)(22)(23)(24)(25)(26), the linkers present a central 4-connected node with increasing distances between the central node and four isophthalate moieties. Although this strategy produced isoreticular MOF structures, no increase of porosity was observed, presumably because of flexibility issues and/or highly strained frameworks.…”

“…This strategy has been widely implemented for [Cu 2 (O 2 CR) 4 ] paddlewheel systems with hexacarboxylate linkers of C 3 symmetry to generate a family of rht-type MOFs with high and predictable porosity (15)(16)(17). In contrast, effective modulation of porosity for isoreticular MOFs based upon 8-connected linkers has not been achieved to date (18)(19)(20)(21)(22)(23)(24)(25)(26), thus representing a significant synthetic challenge. We report herein modulation of porosity in a series of isoreticular octacarboxylate MOFs.…”

Effect of Charge on the Structures of Zn(II) Coordination Polymers with Triazole-carboxylate Ligands: Syntheses, Structures, and Luminescent Properties

“…Through varying metal centers and organic linkers, CPs with specific characteristics can be obtained [8][9][10][11][12][13]. But in fact, the rational design and tuned synthesis of CPs still remains a major challenge since assembly is influenced by many factors such as the coordination requirements of the metal ions and the properties of the ligands, including shape, coordination mode, and flexibility, metal-to-ligand ratio, temperature, pH, solvent, and so on [14][15][16][17][18][19][20][21]. In addition, the assembly rule must concern the charges of metal ions and organic linkers since the final CPs are electrically neutral.…”

Hydrothermal Assembly of Two New 3D Zinc(II) pcu Nets: Coordination Chemistry, Crystal Structures, and Fluorescence Properties

“…[5][6][7][8][9] Moreover, the design of functional ligands with flexible binding modes and donor atoms has been confirmed to be the effective strategy to construct new coordination polymers. [10][11][12][13][14][15] Particularly, 2,5-dibenzoylterephthalic acid (H 2 L 1 ) and 4,6-dibenzoylisophthalic acid (H 2 L 2 ) (Scheme 1) with a variety of binding modes and excellent metal affinity have been proved to be the excellent candidate for the construction of CPs. [16][17][18][19][20][21][22] Actually, the multi-carboxylate ligands may provide much more coordination flexibility for constructing intriguing CPs.…”