Barrel-Shaped-Polyoxometalates Exhibiting Electrocatalytic Water Reduction at Neutral pH: A Synergy Effect.

Two copper-based barrel-shaped polyoxometalates (POMs), namely, [{HO}{Na(HO)}][{Cu (HO)}{Cu (HO)}{B-α-BiWO}]·7HO () and Li[{NH}{HO}{Li(HO)}][{Cu(SH)}{(CuCu)(B-α-BiWO)}]·9HO () have been synthesized and structurally characterized. The single-crystal X-ray diffraction analyses of and reveal the presence of penta- and hexa-nuclear copper wheels per formula units, respectively; these copper wheels are sandwiched between two lacunary Keggin anions {B-α-BiWO} (BiW) to form the barrel-shaped title POM compounds. In both the compounds and , the mixed-valent copper centers are present in their respective penta- and hexa-nuclear copper wheels, established by X-ray photoelectron spectroscopy (XPS) as well as by bond valence sum (BVS) calculations.

Discovery of ( ±)-3-(1H-pyrazol-1-yl)-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4] thiadiazine derivatives with promising in vitro anticoronavirus and antitumoral activity.

A new series of ( ±)-(3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-phenyl-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-7-yl)(phenyl)methanones were efficiently synthesized starting from 4-amino-5-hydrazinyl-4H-1,2,4-triazole-3-thiol 1, acetyl acetone 2, various aromatic and heterocyclic aldehydes 3 and phenacyl bromides 4. All the newly synthesized compounds were tested for their antiviral and antitumoral activity. It was shown that subtle structural variations on the phenyl moiety allowed to tune biological properties toward antiviral or antitumoral activity.

Carbonate encapsulation from dissolved atmospheric CO into a polyoxovanadate capsule.

An aqueous synthesis, involving the reduction of the VO anion in a mild alkaline pH in the presence of α-BiO, led to the formation of a fully reduced polyoxovanadate (POV) capsule, with CO anion encapsulation in its internal cavity, in the compound [Na(HO)][HVO(CO)]·3NH·10HO (1). This CO anion encapsulation, the source of which is absorbed aerial CO in the pertinent aqueous alkaline reaction mixture, occurs only in the presence of α-BiO. Compound 1 crystals, upon exposure to HCl acid vapor, exclude CO gas that can react with the Grignard reagent (PhMgBr) to form triphenylcarbinol and benzoic acid; during this solid-vapor interface reaction, compound 1 itself transforms into an amorphous material that includes the Cl anion but could not be characterized unambiguously.

Accelerated hydration reaction of an unsymmetrical tolan evidenced by a Hg(ii)-trapped macrocycle and its application as a Hg(ii)-selective indicator.

Hg(ii)-mediated hydration reactions of unsymmetrical quinoline type tolans were studied. The observed accelerated reactions of the tolans rely on the additional binding motifs of the tolan, as supported by the X-ray structure of the macrocycle (2b). The analyte-specific reaction allows us to detect Hg(ii) in buffered media.

cis-{MoO2}(2+) assisted Mannich-type addition of acetylacetonate methine to the azomethine of tridentate Schiff bases: racemic complexes with chiral transformed ligands.

Reactions of [MoO2(acac)2] (acac(-) = acetylacetonate) with the potential N2O-donor 5,5-membered fused chelate rings forming Schiff bases 2-(2-pyridylaldimine)ethanol (HL(1)) and 4/5-R-2-(2-pyridylaldimine)phenols (HL(n); n = 2-5 for R = H, 4-Cl, 4-Me and 5-Me, respectively) lead to the facile formation of racemic complexes of the general formula cis-[MoO2(acacL(1-5))] () in 80-85% yield. Here, (acacL(n))(2-) represents a chiral N2O2-donor ligand system formed by a novel Mannich-type reaction that involves acetylacetonate and the azomethine fragment of HL(n) both coordinated to the cis-{MoO2}(2+) unit. The characterization of has been performed with the help of microanalytical (CHN), spectroscopic (ESI-MS, IR, UV-Vis and (1)H- and (13)C-NMR) and electrochemical measurements.

(Methanol-κO)-cis-dioxido{(4Z,N'E)-N'-[(Z)-4-oxido-4-phenyl-but-3-en-2-yl-idene]iso-nicotino-hydrazidato}molybdenum(VI).

In the title complex, [Mo(C16H13N3O2)O2(CH3OH)], the deprotonated Schiff base (E)-N'-[(Z)-4-oxido-4-phenyl-but-3-en-2-yl-idene]isonicotinohydrazide coordinates in a meridional fashion through the enolate O-, imine N- and amidate O-atom donors to the Mo atom of a cis-[MoO2](2+) core. The sixth coordination site of molybdenum is occupied by the O atom of a methanol mol-ecule. In this complex, the NO5 coordination sphere adopts a distorted octa-hedral coordination geometry.