A new series of 3D lanthanide phenoxycarboxylates: synthesis, crystal structure, magnetism and photoluminescence studies

A new series of 3D Ln-carboxylates was synthesized, where the Tb one shows antiferromagnetic coupling and the Dy one shows ferromagnetic interaction, and with emission spectra combining the intra-4f emission of the Ln ions and that of the ligand.

Lipase-Catalyzed Chemoselective Ester Hydrolysis of Biomimetically Coupled Aryls for the Synthesis of Unsymmetric Biphenyl Esters

Lipases are among the most frequently used biocatalysts in organic synthesis, allowing numerous environmentally friendly and inexpensive chemical transformations. Here, we present a biomimetic strategy based on iron(III)-catalyzed oxidative coupling and selective ester monohydrolysis using lipases for the synthesis of unsymmetric biphenyl-based esters under mild conditions. The diverse class of biphenyl esters is of pharmaceutical and technical relevance. We explored the potency of a series of nine different lipases of bacterial, fungal, and mammalian origin on their catalytic activities to cleave biphenyl esters, and optimized the reaction conditions, in terms of reaction time, temperature, pH, organic solvent, and water–organic solvent ratios, to improve the chemoselectivity, and hence control the ratio of unsymmetric versus symmetric products. Elevated temperature and increased DMSO content led to an almost exclusive monohydrolysis by the four lipases Candida rugosa lipase (CRL), Mucor miehei lipase (MML), Rhizopus niveus lipase (RNL), and Pseudomonas fluorescens lipase (PFL). The study was complemented by in silico binding predictions to rationalize the observed differences in efficacies of the lipases to convert biphenyl esters. The optimized reaction conditions were transferred to the preparative scale with high yields, underlining the potential of the presented biomimetic approach as an alternative strategy to the commonly used transition metal-based strategies for the synthesis of diverse biphenyl esters.

A Lead Carboxylate-Azolate Metal-Organic Framework Based on Hexanuclear Clusters: Luminescence and Accelerating the Thermal Decomposition of Ammonium Perchlorate

A lead carboxylate-azolate framework, [Pb₃ (μ₄ -O)(L)₂ (H₂ O)] ⋅ 2H₂ O (1), has been constructed from the reaction of 2-methyl-4-(1H-tetrazol-5-yl) benzoic acid (H₂ L) and Pb(NO₃ )₂ under solvothermal conditions. Compound 1 contains an unprecedented hexanuclear cluster [Pb₆ (μ₄ -O)₂ (COO)₄ (CN₄ )₂ ], which as an 8-connected node is connected by 3-connected L linkers to give rise to a three-dimensional framework with an uncommon (3,8)-connected tfz-d; UO₃ topology. Framework 1 possesses strong solid-state yellow luminescence (563 nm), which stems from ligand-to-metal charge transfer (LMCT), however, the removal of water molecules in 1 lead to the significant luminescent decrease of the sample. Importantly, in the presence of 1, the thermal decomposition of ammonium perchlorate is significantly accelerated.

Cd(II) and Zn(II) thiocyanate coordination compounds with 3-ethylpyridine: synthesis, crystal structures and properties

Reaction of Cd(NCS)2 and Zn(NCS)2 with 3-ethylpyridine leads to the formation of compounds of compositions M(NCS)2(3-ethylpyridine)4 (M=Cd, 1-Cd; Zn, 1-Zn) and M(NCS)2(3-ethylpyridine)2 (M=Cd, 2-Cd; Zn, 2-Zn). 1-Cd and 1-Zn are isotypic and form discrete complexes in which the metal cations are octahedrally coordinated by two trans-coordinating N-bonded thiocyanate anions and four 3-ethylpyridine co-ligands. In 2-Cd the cations are also octahedrally coordinated but linked into chains by pairs of μ-1,3-bridging anionic ligands. 2-Zn is built up of discrete complexes, in which the Zn cation is tetrahedrally coordinated by two N-bonded thiocyanate anions and two 3-ethylpyridine co-ligands. Compounds 1-Cd, 2-Cd and 2-Zn can be prepared in a pure state, whereas 1-Zn is unstable and transforms on storage into 2-Zn. If 1-Cd and 1-Zn are heated, a transformation into 2-Cd, respectively 2-Zn is observed. Luminescence measurements reveal that 1-Cd, 2-Cd and 2-Zn emit light in the blue spectral range with maxima at, respectively, 21724, 21654 and 22055 cm−1, assigned to ligand-based luminescence.

Preparation of spherical metal-organic frameworks encapsulating ag nanoparticles and study on its antibacterial activity

A metal-organic frameworks (CuTCPP MOFs) were synthesized with Cu(NO₃)₂·3H₂O and 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) by the solvothermal method. The structure and morphology of the CuTCPP MOFs were characterized by UV-vis absorption spectra, X-ray diffraction (PXRD), energy dispersive spectra, scanning electron microscopy (EDS-SEM) and transmission electron microscopy (TEM). The structure of the as-synthesized MOF includes copper ions and copper metalloporphyrin (Cu-TCPP) by UV-vis absorption spectra and PXRD. The SEM and TEM images of the as-synthesized MOF showed the morphology of the CuTCPP MOFs were spherical. The as-synthesized spherical MOFs as the carriers were used to encapsulate the Ag nanoparticles and prepared Ag-CuTCPP MOFs. The Ag-CuTCPP MOFs was also characterized by UV-vis, PXRD, SEM and TEM. The Ag nanoparticles were completely encapsulated into the CuTCPP MOFs and no surface absorption, which have been confirmed by comparing TEM and SEM-EDS of Ag-CuTCPP MOFs before crushing with that of Ag-CuTCPP MOFs after crushing. In addition, the release of Ag ions from Ag-CuTCPP MOFs was also investigated by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Furthermore, the antimicrobial activities and cytotoxicity of Ag-CuTCPP MOFs were performed by in vitro and in vivo experiment. In vitro, the antibacterial effect of Ag-CuTCPP MOFs was even better than that of the penicillin as the positive control and the cytotoxicity of Ag-CuTCPP MOFs was significantly lower than that of naked Ag nanoparticles and Ag ions; in vivo, Ag-CuTCPP MOFs not only exhibited the excellently antibacterial effect and extremely low cytotoxicity but also effectively promoted the wound healing.

Unique anisotropic optical properties of a highly stable metal–organic framework based on trinuclear iron(iii) secondary building units linked by tetracarboxylic linkers with an anthracene core

A highly stable metal–organic framework, [{Fe₃(ACTBA)₂}X·6DEF]_n (1; X = monoanion), is reported.

The Biginelli reaction under batch and continuous flow conditions: catalysis, mechanism and antitumoral activity

Biginelli scaffolds have been synthesized using two new coordination polymer as catalysts under batch or continuous flow conditions. The mechanism of the reaction and the antitumoral activity of the obtained DHPMs were also evaluated.

Three sra topological lanthanide–organic frameworks built from 2,2′-dimethoxy-4,4′-biphenyldicarboxylic acid

The first neutral 3D sra-LOF built from a 1D inorganic rod-shaped chain [Ln(CO₂)₂(HCO₂)]_n (Ln = Eu, Gd, Dy) was synthesized.

Synthesis, structure and luminescence properties of a cadmium(ii)-based coordination polymer with (S)-4,4′-bis(4-carboxyphenyl)-2,2′-bis(diphenylphosphinoyl)-1,1′-binaphthyl as chiral linker

[{Cd₂(L)₂(H₂O)}·18 dmf]_n forms a two-dimensional chiral coordination polymer.