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The employment of the hexyl-substituted anion [HexCB11 Cl11 ]- allowed the synthesis of a ZnII species, Zn[HexCB11 Cl11 ]2 , 3, in which the Zn2+ cation is only weakly coordinated to two carborate counterions and that is soluble in low polarity organic solvents such as bromobenzene. DOSY NMR studies show the facile displacement of at least one of the counterions, and this near nakedness of the cation results in high catalytic activity in the hydrosilylation of 1-hexene and 1-methyl-1cyclohexene. Fluoride ion affinity (FIA) calculations reveal a solution Lewis acidity of 3 (FIA=262.1 kJ mol-1 ) that is higher than that of the landmark Lewis acid B(C6 F5 )3 (FIA=220.5 kJ mol-1 ). This high Lewis acidity leads to a high activity in catalytic CO2 and Ph2 CO reduction by Et3 SiH and hydrogenation of 1,1-diphenylethylene using 1,4-cyclohexadiene as the hydrogen source. Compound 3 was characterized by multinuclear NMR spectroscopy, mass spectrometry, single crystal X-ray diffraction, and DFT studies.

Introduction: On account of the current COVID-19 pandemic, we have explored the importance of azithromycin and zinc in the treatment of the coronavirus disease by studying the interaction between the cation Zn++ and azithromycin with the tools of the semi-empirical quantum mechanics PM3 method. Methods: By this approach, the niche in which Zn++ is located was determined. Zn++ creates a strong clastic binding between an amine and a hydroxyl group located on the amino-hexose side-chain. Such an interaction serves as a shuttle and allows zinc cation to invade endocellular structures. Results: In this triple collaborative association, the role of hydroxychloroquine would be more that of a chaotropic agent at plasmic membranes, which facilitates access to the azithromycin-Zn++ equipage into key internal compartments. Conclusion: Finally, we show that both azithromycin and Zn++ are susceptible to play a direct role against the replication and the assembly of SARS-CoV-2 particles.

Aggregation-induced emission (AIE) compounds display a photophysical phenomenon in which the aggregate state exhibits stronger emission than the isolated units. The common term of “AIEgens” was coined to describe compounds undergoing the AIE effect. Due to the recent interest in AIEgens, the search for novel hybrid organic–inorganic compounds with unique luminescence properties in the aggregate phase is a relevant goal. In this perspective, the abundant, inexpensive, and nontoxic d10 zinc cation offers unique opportunities for building AIE active fluorophores, sensing probes, and bioimaging tools. Considering the novelty of the topic, relevant examples collected in the last 5 years (2016–2021) through scientific production can be considered fully representative of the state-of-the-art. Starting from the simple phenomenological approach and considering different typological and chemical units and structures, we focused on zinc-based AIEgens offering synthetic novelty, research completeness, and relevant applications. A special section was devoted to Zn(II)-based AIEgens for living cell imaging as the novel technological frontier in biology and medicine.

This work aims to study the impact of zinc cation and 2-mercaptobenzoxzole (MBO) on the corrosion protection of a silane sol-gel coating on mild steel. First, effectiveness of the organic and inorganic inhibitors on the corrosion of bare mild steel in a NaCl solution was shown to be linked to formation of a surface film. Using electrochemical data as well as results of surface analysis, a sharp inhibition synergism was found when an equal mole percentage of ZnCl 2 and MBO was added to the NaCl solution. Finally, electrochemical data indicated superior performance of the coating with the combination of inhibitors.

The zinc cation in the structure has a N2O3 coordination set, arranged in a trigonal–bipyramidal configuration. The bridging mode of the organic ligands leads to the formation of a polymeric layer structure parallel to the ab plane., The crystal structure of the title polymer, {[Zn(C8H4O6S)(C10H8N2S)(H2O)]·0.26H2O}n, is characterized by a layered arrangement parallel to the ab plane. The zinc cation is five-coordinated in a slightly distorted trigonal–bipyramidal coordination environment defined by two pyridine ligands, two carboxyl­ate groups of two thio­phene di­carboxyl­ate ligands, and by one water mol­ecule. The ethyl­ene bridge in the dioxine ligand is disordered over two sets of sites [occupancy ratio 0.624 (9):0.376 (9)]. Several hydrogen-bonding inter­actions of the types O—H⋯O, C—H⋯O, C—H⋯S and C—H⋯N ensure the cohesion within the crystal structure.

A new imidazolium macrocycle based on tetraphenylethylene (TPE) has been synthesized. This positively charged macrocycle showed a typical aggregation-induced emission (AIE) effect but fluorescence emission could not be induced by common inorganic anions in aqueous solution, including pyrophosphate bearing four negative charges. However, in the presence of a half equivalent of zinc(II) ions, the addition of pyrophosphate anions could arouse a strong fluorescence while other common inorganic anions gave almost no response. The macrocycle has an inherent cavity with the correct size for binding a pyrophosphate anion, so that the pyrophosphate anion can be easily aggregated together with the macrocycle and a zinc cation, which selectively triggers a turn-on fluorescence.

International audience; We report the solid-state structure of an unexpected trinuclear zinc dimeric porphyrin complex resulting of zinc insertion into a single strap porphyrin. The latter bears an overhanging carboxylic acid which usually interacts with metal cations either in out-of-plane (OOP) or in hanging-atop (HAT) coordination mode by changing its location above the porphyrin coordination site. However, in the present studies, the overhanging carboxylic group acts as a bidentate ligand and binds the OOP-bound zinc cation together with another zinc cation bridging two porphyrin units.

Direct voltammetric determination of oxytetracycline (OTC) at a zinc cation-exchanged montmorillonite modified glassy carbon electrode (Zn-Mt/GCE) was described. The OTC yielded one well-defined oxidation peak at the Zn-Mt/GCE. The experimental parameters, which influence the voltammetric responses of OTC, e.g., the pH value, scan rate and accumulation condition, were optimized. The oxidation peak current changed with the OTC concentration over the range from 0.80 to 40 μM. The detection limit was 0.12 μM for an accumulation time of 4 min. The coefficient of variation, determined at 10 μM OTC, was 3.4% (n = 10). Using this method, OTC in the real food and feedstuff samples was determined.

Multi cage-like zinc oxides were prepared via a facile hydrothermal method. The as-synthesized materials were characterized by means of XRD, TG-DTA, SEM, EDS, and N2 adsorption. The results indicate that the molar ratio of glucose to zinc cation has a significant effect on the morphology, surface area, pore size and distribution of the obtained products. This method is attractive for its merits such as simplicity, commercial feasibility, environmentally benign, surfactant-free, and good potential for scale-up.

A new 3D porous zinc phosphonate, Zn6(HL)4 · 6H2O 1 (H4L = C6H11N(CH2PO3H2)2) has been synthesized by hydrothermal reaction at 180 °C and structurally characterized by X-ray diffraction as well as by infrared spectroscopy, elemental and thermogravimetric analysis. The structure of compound 1 features a 3D open-framework built from ZnO4 tetrahedra linked together by bridging phosphonate groups. Each zinc cation is tetrahedrally coordinated by four phosphonate oxygen atoms from four ligands, each of which connects with six zinc atoms, resulting in channel systems of different size.

This Perspective starts with the discussion of the properties of an interesting metalloenzyme (carbonic anhydrase, CA) that performs extremely successfully the activation of carbon dioxide. Conclusions from that are important for many synthetic procedures and include experimental and theoretical investigation (DFT calculations) of such metal mediated processes in the condensed and in the gas phase in which the zinc cation plays a dominant role. This is extended to the bio-analogue activation of further heterocumulenes such as COS, an important atmospheric trace gas, and CS(2). Novel metal complexes which serve as useful catalysts for the reactions (copolymerisations and cyclisation) of CO(2) and oxiranes are discussed subject to the inclusion of recently published DFT calculations. We continue with the discussion of the very general aspect of the insertion of CO(2) into metal-nitrogen bonds (formation of carbamates). This again is closely related to many biological or bio-analogue processes. We describe the synthesis and mechanistic aspects of characteristic metal carbamates of a wide variety of metals and include a discussion of the mechanistic aspects, especially for the formation of Mg(2+) and Li(+) carbamates and the formation of related cyclic products after addition of the heterocumulenes CO(2), Ph-NCO or CS(2) to novel ligands, the 4H-pyridin-1-ides which finally result in the formation of e.g. 1,3-thiazole-5(2H)-thiones.

The synthesis of four new tetraamido-type p-tert-butylcalix[4]arenes presenting two proximal binding subunits is reported. Complexation of alkalimetals and zinc picrates with these ligands have been carried out and monitored by 1H-NMR inCDCl3. It is shown that hard cations are included in the tetraamido cavity while thezinc cation is chelated to the pyridine rings of one of the ligands. The formation of a 1:1:1heterobinuclear complex is also described

1,1-Diacetates were produced from a variety of aromatic aldehydes using Zn-montmorillonite as a catalyst. The procedure generally resulted in good yields (98%) of aromatic aldehydes including those carrying electron donating- or withdrawing substituents. The great advantage of the application of Zn-montmorillonite catalyst is that the reaction takes place under mild conditions. In addition, the zinc cation exchanged form of montmorillonite has a minimal environmental impact.

The structure of the title complex, [ZnCl2(C11H9N3)2], comprises two 2-(phenyldiazenyl)pyridine ligands coordinating to a central ZnIIdichloride unitviathe pyridyl N-atom donors, resulting in a slightly distorted tetrahedral geometry. The complex exhibits twofold rotation symmetry, with the rotation axis bisecting the zinc cation. The structure is stabilized by weak intermolecular C—H...Cl interactions [C...Cl = 3.411 (2) and 3.675 (2) Å], connecting neighbouring molecules into layers perpendicular to thecaxis.

From a solution of [Zn(H2O)6](NO3)2 and acetyl­enedicarb­oxylic acid in deionized water, single crystals of zinc acetyl­ene­dicarboxyl­ate dihydrate, {[Zn(C4O4)(H2O)2]}n, were obtained by slow evaporation of the solvent. The asymmetric unit consits of one zinc cation which is located on a centre of symmetry, half of an acetyl­enedicarboxyl­ate anion, the anion lying on a twofold axis, and one water mol­ecule in a general position. Thus, zinc is octa­hedrally coordinated by four O atoms of acetyl­enedicarboxyl­ate anions and two water mol­ecules in trans positions. These octa­hedra are connected by dicarboxyl­ate ligands into a three-dimensional network.

Di-aza-benzo crown etherp-tert-butyl calix[4]arene (1) has been prepared by hydrogenating the already known Schiff-base precursor (2). The metal ion complexing ability of (1) toward zinc cation is presented. The formation of a 2:1 (Zn: (1) complex and the location of zinc cations were deduced from1H-NMR investigations.

In diacetato-O,O',-O-(2,9-dimethyl-1,10-phenanthroline-N,N')zinc(II), [Zn(C 2 H 3 O 2 ) 2 (C 14 H 12 N 2 )], the zinc cation has a pentacoordinated environment consisting of the two N atoms of 2,9-dimethyl-1,10-phenanthroline, one O atom from a monodentate acetate group and two O atoms from a bidentate acetate group.

The zinc cation (Zn2+) binding to human serum albumin (HSA) was studied using a non-equilibrium approach in order to prove two HSA binding sites. The effect of the bulk solvent pH and column temperature T on this binding and the corresponding thermodynamic data were also investigated. It appeared that the association process can be divided into two pH value ranges due to a predominant Zn2+ interaction with either HSA site I or site II. It was also demonstrated that the Zn2+ affinity for the site II was weakly affected by modifying the mobile phase pH whereas for the site I, the affinity constant increased strongly with increasing the pH of the bulk solvent.

Ab initio molecular orbital methods in combination with DFT calculations were used to study the structural and thermodynamic properties of 17 complexes containing zinc cation and four first-shell ligands as models of active site of metalloenzymes (e.g. angiotensin converting enzyme, thermolysin). The geometry of the complexes was relaxed by complete optimization by ab initio molecular orbital methods at Hertree-Fock level with 3-21G* basis set. Following single point calculation with tight SCF criteria at the B3LYP level with 6-311+G(2d,p) basis set was used to calculate accurate interaction enthalpies. The structure and thermodynamics of optimized complexes are discussed from the point of view of their biological importance.

Recently, cadmium-containing additives for plastics have been designated as undesirable environmentally. Prior to this adverse characterization of cadmium derivatives most flexible vinyl in the United States involving severe stabilizer demand during processing or service utilized metal blends based on cadmium salts. As a result many vinyl formulators have been forced to find suitable alternatives. Replacement of a stabilizer composed of specific levels of barium/cadmium salts in flexible vinyl with another containing the same levels of barium/zinc has been found to give dramatically reduced performance in heat stability tests. Results of this study has shown that satisfactory replacement of barium/cadmium/zinc or barium/cadmium systems in flexible vinyl is possible with barium/zinc stabilizers. This replacement appears to depend on higher barium-to-zinc ratios than those utilized in barium/cadmium analogs, use of special ligands that compensate for the smaller sized zinc cation; and prevention of their destruction by inadvertent addition of competitors.

The title compound, [Zn(NO3)(C8H8N2O)2]NO3·H2O, consists of a tris-chelated zinc cation and a nitrate anion, along with an uncoordinated water mol­ecule. These inter­act through O—H⋯O and N—H⋯O hydrogen bonds, giving rise to a three-dimensional network structure. The ZnII ion has an octa­hedral coordination.

The title compound, [Zn(C8H4N4O2)]n, is a coordination polymer prepared by the hydro­thermal reaction of zinc chloride and 3-(1H-tetrazol-5-yl)­benzoic acid. The zinc cation is tetrahedrally coordinated by two N atoms and two O atoms from four ligands, resulting in a three-dimensional framework encapsulating one-dimensional channels.

ZnAPO-34 and MnZnAPO-34 materials were synthesised hydrothermally in the presence of tetraethylammonium hydroxide as a template. Rietveld refinement and EXAFS studies indicate the incorporation of zinc cation into tetrahedral framework sites of AlPO 4 -34 and imply the presence of extra-framework manganese atoms located in cavities.

The asymmetric unit of the title compound, [Zn(NCSe)(2)(C(4)H(4)N(2))(2)](n), consists of one Zn(2+) cation located on a special position with site symmetry 2/m, one seleno-cyanate anion on a mirror plane and one pyrimidine ligand on a twofold rotation axis. The zinc cation is coordinated by six N atoms of four pyrimidine ligands and two N-bonded seleno-cyanate anions in mutually trans orientations within a slightly distorted octa-hedral coordination environment. The Zn atoms are μ-1,3-bridged via the pyrimidine ligands into a polymeric layer extending parallel to (100).

Elastomere de masse moleculaire 8000 neutralise avec: Ca 2+ , Sr 2+ , Ni 2+ , Zn 2+ et Cd 2+

Theoretical ab initio pseudopotential SCF computations performed on a model of the Glu 106 – Thr 199 – water H-bonded chain, free and bound to the zinc cation at the active site of carbonic anhydrase show that whereas the Glu – Thr – water form of the unbound chain is stable, the same chain, when bound to zinc, is more stable in the Glu - Thr - OH form, and the proton-relay process to that form occurs with no barrier.