Types Of Coordination Polymers Research Articles

Two series of luminescent phosphonate coordination polymers of lanthanides for sensing ketones and Fe3+ in water

Two series of phosphonate coordination polymers (CPs) were designed and synthesized as probes for sensing certain pollutants in water. Six Ln phosphonate CPs, namely, Sm-HL1 (1), Pr-HL1(2), Nd-HL1(3), Sm-HL2(4), Pr-HL2(5), Nd-HL2(6) based on ((2′-cyano-[1,1′-biphenyl]-4-yl)methyl)phosphonic acid (HEtL1) 4′-((hydroxy(methoxy) phosphoryl)methyl)-[1,1′-biphenyl]-2-carboxylic acid (H2EtL2) were obtained by hydrothermal method. Their structures were confirmed and described through Single-crystal X-ray diffraction analysis, infrared spectra and thermogravimetric analysis. Their luminescence properties and sensing behaviors toward certain organic solvents and metal ions were detected and discussed. It was found that two types of CPs with different structures exhibited similar sensing ability toward iron ions and some ketone molecules, suggesting that the sensing activity might be mainly relative to the available uncoordinated oxygen atoms in the CPs rather than specific structures. The investigated CPs also showed good recyclability, guaranteeing its application as detecting probes.

Multifunctional Aromatic Carboxylic Acids as Versatile Building Blocks for Hydrothermal Design of Coordination Polymers

Selected recent examples of coordination polymers (CPs) or metal-organic frameworks (MOFs) constructed from different multifunctional carboxylic acids with phenyl-pyridine or biphenyl cores have been discussed. Despite being still little explored in crystal engineering research, such types of semi-rigid, thermally stable, multifunctional and versatile carboxylic acid building blocks have become very promising toward the hydrothermal synthesis of metal-organic architectures possessing distinct structural features, topologies, and functional properties. Thus, the main aim of this mini-review has been to motivate further research toward the synthesis and application of coordination polymers assembled from polycarboxylic acids with phenyl-pyridine or biphenyl cores. The importance of different reaction parameters and hydrothermal conditions on the generation and structural types of CPs or MOFs has also been highlighted. The influence of the type of main di- or tricarboxylate ligand, nature of metal node, stoichiometry and molar ratio of reagents, temperature, and presence of auxiliary ligands or templates has been showcased. Selected examples of highly porous or luminescent CPs, compounds with unusual magnetic properties, and frameworks for selective sensing applications have been described.

Ultralong Persistent Room Temperature Phosphorescence of Metal Coordination Polymers Exhibiting Reversible pH-Responsive Emission.

Ultra-long-persistent room temperature phosphorescence (RTP) materials have attracted much attention and present various applications in illumination, displays, and the bioimaging field; however, the persistent RTP is generally from the inorganic phosphor materials to date. Herein, we show that the metal coordination polymers (CPs) could be new types of emerging long-lived RTP materials for potential sensor applications. First, two kinds of Cd-based CPs, Cd(m-BDC)(H2O) (1) and Cd(m-BDC)(BIM) (2) (m-BDC = 1,3-benzenedicarboxylic acid; BIM = benzimidazole), were obtained through a hydrothermal process, and the samples were found to exhibit two-dimensional layered structures, which are stabilized by interlayer C-H···π interaction and π···π interaction, respectively. The CPs show unexpected second-time-scale ultra-long-persistent RTP after the removal of UV excitation, and this persistent emission can be detected easily on a time scale of 0-10 s. The CPs also feature a tunable luminescence decay lifetime by adjusting their coordination situation and packing fashion of ligands. Theoretical calculation further indicates that the introduction of the second ligand could highly influence the electronic structure and intermolecular electron transfer toward tailoring the RTP of the CP materials. Moreover, CP 2 exhibits well-defined pH- and temperature-dependent phosphorescence responses. Therefore, this work provides a facile way to develop new type of CPs with steady-state and dynamic tuning of the RTP properties from both experimental and theoretical perspectives, which have potential applications in the areas of displays, pH/temperature sensors, and phosphorescence logic gates. On account of suitable incorporation of inorganic and organic building blocks, it can be expected that the ultra-long-persistent RTP CPs can be extended to other similar systems due to the highly tunable structures and facile synthesis routes.

Two Types of Cu-Ln Heterometallic Coordination Polymers with 2-Hydroxyisophthalate: Syntheses, Structures, and Magnetic Properties

Two types of Cu-Ln heterometallic coordination polymers (CPs), [Ln4Cu8(ipO)8(ox)2(H2O)12] (Ln = Sm (1); Eu (2); ipO = 2-hydroxyisophthalate; ox = oxalate) (type I) and [Ln2Cu6(ipO)6(H2O)12] [Ln = Gd (3); Tb (4); Dy (5)] (type II), were synthesized under the same hydrothermal conditions and structurally characterized. The first type of CPs displays a three-dimensional framework with a rare case of MoGe2 topology based on {Cu8} and {Ln2} secondary building units (SBUs), while the second type of CPs exhibits a chain structure built up from {Cu6} SBUs and Ln ions. Both of the {Cu8} and {Cu6} SBUs consist of planar [Cu2(ipO)2]2– units linked together by weak Cu–O bonds and π–π interactions. The structural variation from type I to type II can be ascribed to different reactions of H3ipO ligands induced by lanthanide ions. The magnetic investigations revealed that 3 displays a magnetocaloric effect (MCE) with a maximum −ΔSm value of 13.97 J kg–1 K–1 for ΔH = 50 kOe at 4.0 K. It was also found that 5 displays fiel...

Tailored Design of Multiple Nanoarchitectures in Metal-Cyanide Hybrid Coordination Polymers

Recently, coordination polymers (CPs) with nanoscale porosity and unique property have demonstrated great potential in many applications. Encouraged by significant progress in the controlled synthesis of nanomaterials, such as metals and semiconductors, the morphologically controlled synthesis of CPs has been considered a potential way to further enhance the inherent properties and develop new functions. In particular, hollow-based CPs are promising nanoarchitectures that can bring several properties derived from crystalline thin shells and interior cavities. Here we demonstrate an exquisite construction method to synthesize CPs with multiple hollow-based nanoarchitectures. Through step-by-step CP crystal growth and subsequent etching processes, various types of CPs with shell-in-shell, yolk-shell, and yolk-double-shell hollow structures can be synthesized for the first time. This type of nanoarchitecture is powerful for the exploration of alternative properties of CPs. The resultant hollow-based nanoarchitectures significantly increase gas adsorption and bring out interesting magnetic properties.