Seven-Coordinate Group 6 Metal Hydrides Obtained by H Activation at B(CF) Adducts of N Complexes: Frustrated Lewis Pair-Type Reactivity of The B-N Linkage.

The adducts 2 of general formula trans-[(L)M{RP(CH)PR}{NB(CF)}] (L=ø or N, M=Mo or W, R=Et or Ph), formed from Lewis acid-base pairing of B(CF) to a dinitrogen ligand of zero-valent group 6 bis(phosphine) complexes trans-[M{RP(CH)PR}(N)] are shown to react with dihydrogen to afford hepta-coordinated bis(hydride) complexes [M(H){RP(CH)PR}{NB(CF)}] 3 which feature the rare ability to activate both dinitrogen and dihydrogen at a single metal center, except in the case where M=Mo and R=Ph for which fast precipitation of insoluble [Mo(H)(dppe)] (dppe=1,2-bis(diphenylphosphino)ethane) occurs. The frustrated Lewis pair (FLP)-related reactivity of the B-N linkage in compounds 3 was explored and led to distal N functionalization without involvement of the hydride ligands. It is shown in one example that the resulting bis(hydride) diazenido compounds may also be obtained through a sequence involving first FLP-type N-functionalization followed by oxidative addition of H.

Antibacterial and antibiofilm properties of two cyclic dipeptides produced by a new desert Streptomyces sp. HG-17 strain against multidrug-resistant pathogenic bacteria.

Introduction: The emergence of multidrug-resistant bacteria and biofilms requires discovering new antimicrobial agents from unexplored environments.

Objectives: This study aims to isolate and characterize a new actinobacterial strain from the Hoggar Mountains in southern Algeria and evaluate its ability to produce bioactive molecules with potential antibacterial and antibiofilm activities.

Methods: A novel halotolerant actinobacterial strain, designated HG-17, was isolated from the Hoggar Mountains, and identified based on phenotypic characterizations, 16S rDNA sequence analysis, and phylogenetic analysis.

From Stilbenes to carbo-Stilbenes: an Encouraging Prospect.

Beyond previously described carbo-naphthalene and carbo-biphenyl, a novel type of bis-carbo-benzenic molecules is envisaged from the stilbene parent. The synthesis, structure, spectroscopic and electrochemical properties of two such carbo-stilbenes are described at complementary experimental and computational DFT levels. In the selected targets, the bare skeletal carbo-mer of carbo-stilbene is decorated by 8 or 10 phenyl groups, 0 or 2 tert-butyl groups, and 2 n-octyl chains, the later substituents being introduced to compensate anticipated solubility issues.

Acetate exchange mechanism on a Zr oxo hydroxo cluster: relevance for reshaping Zr-carboxylate coordination adaptable networks.

The kinetics and mechanism of the acetate ligand exchange with free acetic acid in [ZrO(OH)(OCCH)], used as a molecular model of crosslink migration in [ZrO(OH)(carboxylate)(OH)]-based coordination adaptable networks with vitrimer-like properties, has been thoroughly investigated by dynamic H NMR and DFT calculations. The compound maintains its -symmetric Zr structure in CDCl and CD, while it splits into its Zr subunits in CDOD and DO. In the Zr structure, the topologically different acetates (3 chelating, 6 belt-bridging, 2 intercluster-bridging and 1 inner-face-bridging) of the Zr subunits behave differently in the presence of free CHCOOH: very fast exchange for the chelating (coalesced resonance at room temperature), slower exchange for the belt-bridging (line broadening upon warming), no observable exchange up to 65 °C (by EXSY NMR) for the intercluster- and inner-face-bridging.

Mechanochemical Studies on Coupling of Hydrazines and Hydrazine Amides with Phenolic and Furanyl Aldehydes-Hydrazones with Antileishmanial and Antibacterial Activities.

Hydrazone compounds represent an important area of research that includes, among others, synthetic approaches and biological studies. A series of 17 hydrazones have been synthesized by mechanochemical means. The fragments chosen were phenolic and furanyl aldehydes coupled with 12 heterocyclic hydrazines or hydrazinamides.