Zinc complexes with 1,2,4-triazole functionalized amino acid derivatives: Synthesis, structure and β-lactamase assay

Degradation of Penicillinic Antibiotics and β-Lactamase Enzymatic Catalysis in a Biomimetic Zn-Based Metal-Organic Framework

β-Lactam antibiotics are one of the most commonly prescribed drugs to treat bacterial infections. However, their use has been somehow limited given the emergence of bacteria with resistance mechanisms, such as β-lactamases, which inactivate them by degrading their four-membered β-lactam rings. So, a total knowledge of the mechanisms governing the catalytic activity of β-lactamases is required. Here, we report a novel Zn-based metal-organic framework (MOF, 1), possessing functional channels capable to accommodate and interact with antibiotics, which catalyze the selective hydrolysis of the penicillinic antibiotics amoxicillin and ceftriaxone. In particular, MOF 1 degrades, very efficiently, the four-membered β-lactam ring of amoxicillin, acting as a β-lactamase mimic, and expands the very limited number of MOFs capable to mimic catalytic enzymatic processes. Combined single-crystal X-ray diffraction (SCXRD) studies and density functional (DFT) calculations offer unique snapshots on the host-guest interactions established between amoxicillin and the functional channels of 1. This allows to propose a degradation mechanism based on the activation of a water molecule, promoted by a Zn-bridging hydroxyl group, concertedly to the nucleophilic attack to the carbonyl moiety and the cleaving of C-N bond of the lactam ring.

Novel 1D coordination polymers built from acyclic cryptate containing bis(1H-1,2,4-triazole) ligands and featuring coordinated counteranions

Two new coordination polymers, namely, ZnL₂(BF₄)₂ (1) and CuL₂(NO₃)₂ (2) were constructed from a new flexible acyclic cryptate-bis(1H-1,2,4-triazole) ligand.

Metal organic frameworks based on bioactive components

This review highlights the latest advances of Metal Organic Frameworks (MOFs) in the promising biomedical domain, from their synthesis to their biorelated activities.

Organic matrix-induced formation of a discrete cyclic [Cl2(H2O)2]2− cluster

Reaction of 6-NH₂-Py-2-NHC(S)NHP(S)(OiPr)₂ with DMFA·2HCl leads to the co-crystallization product of 2,6-di(4H-1,2,4-triazol-4-yl)pyridine and 2,6-diaminopyridinium chloride monohydrate (1) and N-(diisopropoxythiophosphoryl)-N′-(6-(4H-1,2,4-triazol-4-yl))pyridin-2-ylthiocarbamide (2).

Supramolecular homochiral helicity and zigzag hydrogen bonded chains in 1,2,4-triazole derived aminoester and aminoacid

Two new triazole ligands were synthesized, and their crystal structure analysis revealed unprecedented homochiral helical and 2D hydrogen bonded network structures.

A new Co(II) complex of diniconazole: synthesis, crystal structure and antifungal activity

A new Co(II) complex of diniconazole, namely diaqua[(E)-(RS)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl-κN(4))pent-1-en-3-ol]cobalt(II) dinitrate dihydrate, [Co(C15H17Cl2N3O)3(H2O)2](NO3)2·2H2O, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that the centrosymmetric Co(II) cation is coordinated by four diniconazole ligands and two water molecules, forming a six-coordinated octahedral structure. There are also two free nitrate counter-anions and two additional solvent water molecules in the structure. Intermolecular O-H...O hydrogen bonds link the complex cations into a one-dimensional chain. In addition, the antifungal activity of the complex against Botryosphaeria ribis, Gibberella nicotiancola, Botryosphaeria berengriana and Alternariasolani was studied. The results indicate that the complex shows a higher antifungal activity for Botryosphaeria ribis and Botryosphaeria berengriana than diniconazole, but a lower antifungal activity for Gibberella nicotiancola and Alternariasolani.

Spin transition sensors based on β-amino-acid 1,2,4-triazole derivative

A β-aminoacid ester was successfully derivatized to yield to 4H-1,2-4-triazol-4-yl-propionate (βAlatrz) which served as a neutral bidentate ligand in the 1D coordination polymer [Fe(βAlatrz)₃](CF₃SO₃)₂·0.5H₂O (1·0.5H₂O). The temperature dependence of the high-spin molar fraction derived from ⁵⁷Fe Mossbauer spectroscopy recorded on cooling below room temperature reveals an exceptionally abrupt single step transition between high-spin and low-spin states with a hysteresis loop of width 4 K (T_c^↑ = 232 K and T_c^↓ = 228 K) in agreement with magnetic susceptibility measurements. The material presents striking reversible thermochromism from white, at room temperature, to pink on quench cooling to liquid nitrogen, and acts as an alert towards temperature variations. The phase transition is of first order, as determined by differential scanning calorimetry, with transition temperatures matching the ones determined by SQUID and Mössbauer spectroscopy. The freshly prepared sample of 1·0.5H₂O, dried in air, was subjected to annealing at 390 K, and the obtained white compound [Fe(βAlatrz)₃](CF₃SO₃)₂ (1) was found to exhibit a similar spin transition curve however much temperature was increased by (T_c^↑ = 252 K and T_c^↓ = 248 K). The removal of lattice water molecules from 1·0.5H₂O is not accompanied by a change of the morphology and of the space group, and the chain character is preserved. However, an internal pressure effect stabilizing the low-spin state is evidenced.