The Role of Weak Intermolecular Interactions in the Assembly of a Series of d10 Metal Coordination Polymers Based on N,Nʹ-Bis-Pyridin-3-Ylmethylene-Naphtalene-1,5-Diamine Ligand; Ultrasonic Synthesis, Spectroscopic and Structural Characterization

Boosting Ammonia Uptake within Metal-Organic Frameworks by Anion Modulating Strategy

Ammonia with toxic and corrosive features needs advanced protective materials and removal tools, although it is a vital component in human food supply processes. So, to satisfy these requirements, materials with high adsorption capacity and affinity for ammonia should be developed. The present research has been focused on a series zinc-based metal-organic frameworks (MOF) containing mixed ligands, biphenyl dicarboxylic acid (BPDA) and tris(4-(4H-1,2,4-triazol-4-yl)phenyl)amine (TTPA), which are modulated by different anions including CH₃COO^-, CF₃COO^-, and CF₃SO₃^-. Ammonia uptake capacity was measured via static and dynamic conditions under 50% relative humidity. Among all compounds, CF₃SO₃^- anion could enhance the ammonia uptake capacity of MOFs up to 177.85 and 349 mg/g during static and breakthrough measurements, respectively, so that 83.30% of the total uptake capacity (at P/P_o = 1.0 and 298 K) was achieved at low relative pressure range (up to 0.1). The isosteric heats of ammonia adsorption on PFC-27 and derivatives were calculated in the range of 7.03-10.16 kJ mol^-1 so that they increased upon CF₃SO₃^-, CF₃COO^-, and CH₃COO^- ion incorporation. This is potentially beneficial for enhanced ammonia adsorption. Interestingly, adsorption capacities were retained with only slight changes after five cycles and three regeneration temperatures, 25 °C, 60 °C, and 120 °C, under vacuum. The special affinity for NH₃ adsorption and MOF phase stability after desorption is clearly proved by FTIR spectra and PXRD analysis, respectively. Generally, the results suggest that ion insertion modification is an efficient strategy for enhancement of MOF adsorption performance.

Two coordination polymers constructed by 5-[(4-carboxyphenoxy)methyl]benzene-1,3-dicarboxylic acid and 2,2'-bipyridine: syntheses, structures and luminescence properties

Coordination polymers (CPs) have attracted increasing interest in recent years. In this work, two new CPs, namely poly[[aquabis(2,2'-bipyridine-κ²N,N'){μ₃-5-[(4-carboxylatophenoxy)methyl]benzene-1,3-dicarboxylato-κ⁴O¹,O^1':O³:O⁵}(μ-formato-κ³O:O,O')dicadmium(II)] monohydrate], {[Cd₂(C₁₆H₉O₇)(HCO₂)(C₁₀H₈N₂)₂(H₂O)]·H₂O}_n (1), and poly[[(2,2'-bipyridine-κ²N,N'){μ₃-5-[(4-carboxylphenoxy)methyl]benzene-1,3-dicarboxylato-κ⁴O¹,O^1':O³:O⁵}manganese(II)] sesquihydrate], {[Mn(C₁₆H₁₀O₇)(C₁₀H₈N₂)]·1.5H₂O}_n (2), have been prepared using the tricarboxylic acid 5-[(4-carboxyphenoxy)methyl]benzene-1,3-dicarboxylic acid and 2,2'-bipyridine under hydrothermal conditions. CP 1 displays a two-dimensional layer structure which is further extended into a three-dimensional (3D) supramolecular structure via intermolecular π-π interactions, while CP 2 shows a different 3D supramolecular structure extended from one-dimensional ladder chains by intermolecular π-π interactions. In addition, the solid-state luminescence spectra of 1 and 2 were studied at room temperature.