Arylarsonate- and Phosphonate-Capped Polyoxomolybdates, [(RC6H4As)2Mo6O24]n- and [(R'C6H4P)2Mo5O21]n

We report on the synthesis and structural characterization of four arylarsonate- and phosphonate-capped polyoxomolybdates that exhibit different organic substituents in the para position of the phenyl group. The reaction of arylarsonates (RAsO₃, wherein R = 4-BrC₆H₄ or 4-N₃C₆H₄) with molybdate in aqueous pH 3.5 media resulted in the cyclic hexamolybdates [(BrC₆H₄As)₂Mo₆O₂₄]^4- (Mo₆As₂L_a) and [(N₃C₆H₄As)₂Mo₆O₂₄]^4- (Mo₆As₂L_b), whereas the reaction of arylphosphonates (R'PO₃, wherein R' = 4-O₂CC₆H₄ or 4-O₂CC₆H₄CH₂) with molybdate in aqueous pH 3 media resulted in the cyclic pentamolybdates [(O₂CC₆H₄P)₂Mo₅O₂₁]^6- (Mo₅P₂L_c) and [(HO₂CC₆H₄CH₂P)₂Mo₅O₂₁]^4- (Mo₅P₂L_d), respectively. Polyanions Mo₆As₂L_a and Mo₆As₂L_b comprise a ring of six MoO₆ octahedra that is capped on either side by an organoarsonate group, whereas Mo₅P₂L_c and Mo₅P₂L_d consist of a ring of five MoO₆ octahedra that is capped on either side by an organophosphonate group, with the organic arms protruding away from the metal-oxo core of the polyanions. All four polyanions Mo₆As₂L_a, Mo₆As₂L_b, Mo₅P₂L_c, and Mo₅P₂L_d have been characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analysis and in solution by multinuclear NMR (³¹P, ¹³C, and ¹H). The synthetic procedure of (4-bromophenyl)arsonic acid, BrC₆H₄AsO₃H₂, is reported here for the first time.

Laser-induced twisting of phosphorus functionalized thiazolotriazole as a way of cholinesterase activity change

Herein, the synthesis, design, and the physicochemical characterization of phosphorus functionalized thiazolotriazole (PFT) compound are presented. The PFT tests on the biological activity revealed butyrylcholinesterase inhibition that was confirmed and explained with molecular docking studies. The pronounced reduction of optical density and biological activity was found as a result of irradiation of the PFT water solution with laser beam at wavelength 266 nm. The observed phenomenon was explained on the base of molecular dynamics, docking, and density functional theory modeling by the formation of PFT conformers via laser-induced phosphonate group twisting. The reorganization of the PFT geometry was found to be a reason of butyrylcholinesterase inhibition mechanism change and the site-specificity loss. These results demonstrate that PFT combines photoswitching and bioactive properties in one molecule that makes it promising as a molecular basis for the further design of bioactive substances with photosensitive properties based on the mechanism of the phosphonate group phototwisting.

High Throughput Methods in the Synthesis, Characterization, and Optimization of Porous Materials

Porous materials are widely employed in a large range of applications, in particular, for storage, separation, and catalysis of fine chemicals. Synthesis, characterization, and pre- and post-synthetic computer simulations are mostly carried out in a piecemeal and ad hoc manner. Whilst high throughput approaches have been used for more than 30 years in the porous material fields, routine integration of experimental and computational processes is only now becoming more established. Herein, important developments are highlighted and emerging challenges for the community identified, including the need to work toward more integrated workflows.

New Directions in Metal Phosphonate and Phosphinate Chemistry

In September 2018, the First European Workshop on Metal Phosphonates Chemistry brought together some prominent researchers in the field of metal phosphonates and phosphinates with the aim of discussing past and current research efforts and identifying future directions. The scope of this perspective article is to provide a critical overview of the topics discussed during the workshop, which are divided into two main areas: synthesis and characterisation, and applications. In terms of synthetic methods, there has been a push towards cleaner and more efficient approaches. This has led to the introduction of high-throughput synthesis and mechanochemical synthesis. The recent success of metal–organic frameworks has also promoted renewed interest in the synthesis of porous metal phosphonates and phosphinates. Regarding characterisation, the main advances are the development of electron diffraction as a tool for crystal structure determination and the deployment of in situ characterisation techniques, which have allowed for a better understanding of reaction pathways. In terms of applications, metal phosphonates have been found to be suitable materials for several purposes: they have been employed as heterogeneous catalysts for the synthesis of fine chemicals, as solid sorbents for gas separation, notably CO2 capture, as materials for electrochemical devices, such as fuel cells and rechargeable batteries, and as matrices for drug delivery.

Divalent metal phosphonates – new aspects for syntheses, in situ characterization and structure solution

Divalent metal phosphonates are promising hybrid materials with a broad field of application. The rich coordination chemistry of the phosphonate linkers enables the formation of structures with different dimensionalities ranging from isolated complexes and layered structures to porous frameworks incorporating various functionalities through the choice of the building blocks. In brief, metal phosphonates offer an interesting opportunity for the design of multifunctional materials. Here, we provide a short review on the class of divalent metal phosphonates discussing their syntheses, structures, and applications. We present the advantages of the recently introduced mechanochemical pathway for the synthesis of divalent phosphonates as a possibility to generate new, in certain cases metastable compounds. The benefits of

Transition metal phosphonates with supramolecular structures: syntheses, structures, surface photovoltage and luminescence properties

Four new transition metal phosphonates with 2D and 3D supramolecular structures have been hydrothermally synthesized. The surface photovoltage and luminescence properties of the title compounds have also been studied.

Two fluorescent lead phosphonates for highly selective sensing of nitroaromatics (NACs), Fe3+ and MnO4− ions

Two novel lead(ii) phosphonates have been hydrothermally synthesized. The luminescence properties of compounds 1 and 2 have been investigated. Meanwhile, the selective fluorescent sensing properties of compounds 1 and 2 for p-NP, Fe³⁺ and MnO₄⁻ have also been demonstrated.

Cadmium phenylphosphonates: preparation, characterisation and in situ investigation

New and known cadmium phenylphosphonates were prepared mechanochemically and their synthesis mechanism was determined in situ.

Guest molecule-responsive functional calcium phosphonate frameworks for tuned proton conductivity

We report the synthesis, structural characterization, and functionality (framework interconversions together with proton conductivity) of an open-framework hybrid that combines Ca(2+) ions and the rigid polyfunctional ligand 5-(dihydroxyphosphoryl)isophthalic acid (PiPhtA). Ca2[(HO3PC6H3COOH)2]2[(HO3PC6H3(COO)2H)(H2O)2]·5H2O (Ca-PiPhtA-I) is obtained by slow crystallization at ambient conditions from acidic (pH ≈ 3) aqueous solutions. It possesses a high water content (both Ca coordinated and in the lattice), and importantly, it exhibits water-filled 1D channels. At 75 °C, Ca-PiPhtA-I is partially dehydrated and exhibits a crystalline diffraction pattern that can be indexed in a monoclinic cell with parameters close to the pristine phase. Rietveld refinement was carried out for the sample heated at 75 °C, Ca-PiPhtA-II, using synchrotron powder X-ray diffraction data, which revealed the molecular formula Ca2[(HO3PC6H3COOH)2]2[(HO3PC6H3(COO)2H)(H2O)2]. All connectivity modes of the "parent" Ca-PiPhtA-I framework are retained in Ca-PiPhtA-II. Upon Ca-PiPhtA-I exposure to ammonia vapors (28% aqueous NH3) a new derivative is obtained (Ca-PiPhtA-NH3) containing 7 NH3 and 16 H2O molecules according to elemental and thermal analyses. Ca-PiPhtA-NH3 exhibits a complex X-ray diffraction pattern with peaks at 15.3 and 13.0 Å that suggest partial breaking and transformation of the parent pillared structure. Although detailed structural identification of Ca-PiPhtA-NH3 was not possible, due in part to nonequilibrium adsorption conditions and the lack of crystallinity, FT-IR spectra and DTA-TG analysis indicate profound structural changes compared to the pristine Ca-PiPhtA-I. At 98% RH and T = 24 °C, proton conductivity, σ, for Ca-PiPhtA-I is 5.7 × 10(-4) S·cm(-1). It increases to 1.3 × 10(-3) S·cm(-1) upon activation by preheating the sample at 40 °C for 2 h followed by water equilibration at room temperature under controlled conditions. Ca-PiPhtA-NH3 exhibits the highest proton conductivity, 6.6 × 10(-3) S·cm(-1), measured at 98% RH and T = 24 °C. Activation energies (Ea) for proton transfer in the above-mentioned frameworks range between 0.23 and 0.4 eV, typical of a Grothuss mechanism of proton conduction. These results underline the importance of internal H-bonding networks that, in turn, determine conductivity properties of hybrid materials. It is highlighted that new proton transfer pathways may be created by means of cavity "derivatization" with selected guest molecules resulting in improved proton conductivity.

Two novel oxovanadium–organophosphonate hybrids with a 3D supramolecular structure: synthesis, crystal structures, surface photovoltage and luminescent properties

Two novel oxovanadium–organophosphonates with a 3D supramolecular structure, [{M(1,10–phen)}(VO)(OH)(hedp)]·H₂O (M = Cu (1), Zn (2)), have been hydrothermally synthesized. The surface photovoltage and luminescent properties of the two compounds have been studied.