Two novel lead-based coordination polymers for luminescence sensing of anions, cations and small organic molecules

A novel lead-based compound is reported as a multi-responsive luminescent sensor for detecting anions, cations and small organic molecules, especially Cr₂O₇²⁻, CrO₄²⁻, Fe³⁺ and nitrobenzene.

Synthesis, Structural Features, and Catalytic Activity of an Iron(II) 3D Coordination Polymer Driven by an Ether-Bridged Pyridine-Dicarboxylate

New iron(II) three-dimensional coordination polymer (3D CP), [Fe(µ3-Hcpna)2]n (1), was assembled under hydrothermal conditions from 5-(4’-carboxyphenoxy)nicotinic acid (H2cpna) as a trifunctional organic N,O-building block. This stable microcrystalline CP was characterized by standard methods for coordination compounds in the solid state (infrared spectroscopy, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffraction). Structure and topology of 1 were examined and permitted an identification of a 3,6-connected framework of the rtl topological type. In addition, compound 1 acts as effective catalyst precursor for oxidative functionalization of alkanes (propane and cyclic C5−C8 alkanes) under homogeneous catalysis conditions, namely for the oxidation of saturated hydrocarbons with H2O2/H+ system to produce ketones and alcohols, and for alkane carboxylation with CO/H2O/S2O82− system to obtain carboxylic acids. The influence of an acid promoter and substrate scope (propane and cyclic C5−C8 alkanes) were investigated.

Hydrothermal generation, structural versatility and properties of metal(ii)-organic architectures driven by a pyridine-tricarboxylic acid

A new series of metal(ii) coordination compounds driven by a pyridine-tricarboxylate block was generated, their structural features, magnetic, luminescent or photocatalytic properties were explored.

New Topologically Unique Metal-Organic Architectures Driven by a Pyridine-Tricarboxylate Building Block

Two new three-dimensional (3D) coordination compounds, namely a lead(II) coordination polymer (CP) {[Pb3(µ5-cpta)(µ6-cpta)(phen)2]·2H2O}n (1) and a zinc(II) metal-organic framework (MOF) {[Zn2(µ4-cpta)(µ-OH)(µ-4,4′-bipy)]·6H2O}n (2), were hydrothermally assembled from 2-(5-carboxypyridin-2-yl)terephthalic acid (H3cpta) as an unexplored principal building block and aromatic N,N-donors as crystallization mediators. Both products were isolated as air-stable microcrystalline solids and were fully characterized by IR spectroscopy, elemental and thermogravimetric analysis, and powder and single-crystal X-ray diffraction. Structural and topological features of CP 1 and MOF 2 were analyzed in detail, allowing to identify a topologically unique 4,5,5,6-connected net in 1 or a very rare 4,4-connected net with the isx topology in 2. Thermal stability and solid-state luminescent behavior of 1 and 2 were also investigated. Apart from revealing a notable topological novelty, both compounds also represent the first structurally characterized Pb(II) and Zn(II) derivatives assembled from H3cpta, thus opening up the application of this unexplored pyridine-tricarboxylate block in the design of new metal-organic architectures.

Influence of different metal ions on the assembly, structures, and properties of two complexes based on the semi-rigid bis(pyridyl)-bis(amide) ligand and 4,4′-oxybis(benzoic acid)

Two transitional metal complexes, [Zn(oba)(3-bpcd)] n (1) and [Cd(oba)(3-bpcd)0.5] n (2) [H2oba= 4,4′-oxybis(benzoic acid), 3-bpcd=N,N′-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide], have been hydrothermally synthesized and structurally characterized by elemental analyses, infrared spectra, powder X-ray diffraction, thermogravimetric and single-crystal X-ray diffraction. Complex 1 possesses a three-fold interpenetrating network based on layers with a 4-connected sql topology. Complex 2 is a layered framework constructed by the oba anions and 3-bpcd ligands, which represents a binodal (3,4)-connected {62.10}{6} topology. The adjacent layers of complex 2 are further linked by hydrogen bonding interactions to build a three-dimensional supramolecular architecture. The differences of metal ions in coordination modes show a significant effect on the final structures of the Zn(II)/Cd(II) complexes. The photocatalytic activities and the fluorescence sensing properties of complexes 1 and 2 were investigated.

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.

A new series of Co, Ni, Zn, and Cd metal–organic architectures driven by an unsymmetrical biphenyl-tricarboxylic acid: hydrothermal assembly, structural features and properties

Twelve new Zn(ii), Ni(ii), Co(ii), and Cd(ii) coordination compounds with diverse dimensionalities were assembled using 3′-nitro-biphenyl-2,4,4′-tricarboxylic acid as a main building block.