The work in this paper presents syntheses, characterizations, crystal structures, electrochemical measurements and magnetic properties of two iron(III) compounds Fe super(IIIL(H) sub(2)O)(MeOH)(ClO ...sub(4) (1) and Fe) super(I)IIL(H sub(2O)) sub(2)(NO sub(3) times H) sub(2)O (2) derived from the Schiff base compartmental ligand N,N\'-o-phenylenebis(3-ethoxysalicylaldimine) (H sub(2L). The two compounds are characterized by elemental analyses, IR, electrospray ionization mass (ESI-MS positive), UV-Vis spectra and conductance values. The structures of 1 and 2 show that these are mononuclear compounds having the metal ion in the N) sub(2)O sub(2 compartment. Two mononuclear moieties in both the compounds are self-assembled due to bifurcated hydrogen bonds involving coordinated water molecule and O(phenoxo)/O(ethoxy) oxygen atoms. The neighboring dimeric self-assemblies in 2 are further interlinked due to hydrogen bonds involving coordinated and solvated water molecules and nitrate anions to generate a one-dimensional topology. Variable-temperature (2-300 K) magnetic susceptibility measurements reveal that iron(III) centers in 1 and 2 belong to high-spin state and there exist weak antiferromagnetic interactions (J = -0.25 cm) super(-)1 for 1 and -0.20 cm super(-1 for 2) between the metal centers in the dimeric self-assembly. Cyclic voltammetric and square wave voltammetric studies of the two compounds reveal that compounds 1 and 2 undergo reversible Fe(II)/Fe(III) reduction process at E) sub(1)/2 = -312 mV and -311 mV, respectively.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A template condensation of alpha -diketones (biacetyl, benzile and 2,3-pentanedione) with 2-methyl-3-amino-(3H)-quinazolin-4-one (AMQ) in the presence of CuX sub(2 (X = Cl) super(-), Br super(-, ...inline image or inline image) resulted in the formation of tetradentate Schiff base copper(II) complexes of the type CuLXX and CuLX) sub(2). Structural characterization of the complex species was achieved by several physicochemical methods, namely elemental analysis, electronic spectra, IR, ESR, molar conductivity, thermal analysis (TAG & DTG), and magnetic moment measurements. The stereochemistry, the nature of the metal chelates, and the catalytic reactivity are markedly dependent upon the type of counter anions and the ligand substituent within the carbonyl moiety. A square planar monomeric structure is proposed for the perchlorate, nitrate, and bromide complexes, in which the counter anions are loosely bonded to copper(II) ion. For the chloride complexes, the molar conductivities and the spectral data indicated that they have square-pyramidal environments around copper(II) center. The reported copper(II) complexes exhibit promising tyrosinase catalytic activity towards the hydroxylation of phenol followed by the aerobic oxidation of the resulting catechol. A linear correlation almost exists between the catalytic reactivity and the Lewis-acidity of the central copper(II) ion created by the donating properties of the parent ligand. The steric considerations could be accounted to clarify the difference in the catalytic activity of these functional models.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The persistent efforts to reveal the formation and evolution mechanisms of solid electrolyte interphase (SEI) are of fundamental significance for the rational regulation. In this work, through ...combined theoretical and experimental model investigations, we elucidate that the electric double layer (EDL) chemistry at the electrode/electrolyte interface beyond the thermodynamic stability of electrolyte components predominately controls the competitive reduction reactions during SEI construction on Li metal anode. Specifically, the negatively‐charged surface of Li metal will prompt substantial cation enrichment and anion deficiency within the EDL. Necessarily, only the species participating in the solvation shell of cations could be electrostatically accumulated in proximity of Li metal surface and thereafter be preferentially reduced during sustained dynamic cycling. Incorporating multi‐valent cation additives to more effectively drag the favorable anionic SEI enablers into EDL is validated as a promising strategy to upgrade the Li protection performance. The conclusions drawn herein afford deeper understandings to bridge the EDL principle, cation solvation, and SEI formation, shedding fresh light on the targeted regulation of reactive alkali metal interfaces.
The electric double layer chemistry and structure are identified to play a predominate role in governing the competitive reactions during solid electrolyte interphase formation on lithium‐metal anodes. This knowledge affords critical guidance on the targeted interface design to enable a stable working lithium anode.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Purpose: The aim of the present work was to perform the labelling of granulocytes by their engulfment with chitosan-coated magnetic super(64)Cu nanoparticles (MNPs) in order to obtain a ...radiopharmaceutical suitable for dual imaging (PET-MRI) of inflammatory/infective diseases. Procedures: Specimens of 5-20 mg MNPs were washed with saline-isotonic solution and recuperated by magnetic decantation; 15-58 mu g Cu super(2+) (CuCl sub(2).H sub(2)O) in 50 mu l of acidified (pH 5.5) saline solution was added to the MNPs re-suspended saline-isotonic solution; 10 mg MNPs was allowed to react with 16 mu g super(64)Cu super(64)Ni(p,n) at 12-9 MeV followed by anion exchange chromatography with a specific activity of 56 MBq/ mu g. Pellets of granulocytes were obtained from peripheral blood; MNPs engulfment by granulocytes was obtained and granulocyte-engulfed viability was assessed by the trypan blue exclusion (TBE) test performed at 5 min, 2 h and 4 h; assessment of the release of super(64)Cu from labelled granulocytes in plasma was performed by measuring the radioactivity of both the cellular pellet and the supernatant solution. Results: Our data showed the binding capacity of chitosan-coated MNPs for cationic metal. The amount of Cu super(+2) chelated captured per milligram of MNPs was constant and independent of the reagent concentrations. In all cases, more than 90% of the engulfed granulocytes were positive to the TBE test. The MNPs were localised within the cells. Conclusion: In our in vitro model, MNPs are taken up by granulocytes through phagocytosis, whereas previously described methods were based on the use of a chelating agent that permit Cu to cross the cell membrane. Moreover, the super(64)Cu-engulfed granulocytes showed a high stability of up to 80% of retained radioactivity after 24 h of incubation.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
Cationic frameworks can selectively trap anions through ion exchange, and have applications in ion chromatography and drug delivery. However, cationic frameworks are much rarer than anionic or ...neutral ones. Herein, we propose a concept, preemptive coordination (PC), for targeting positively charged metal–organic frameworks (P‐MOFs). PC refers to proactive blocking of metal coordination sites to preclude their occupation by neutralizing ligands such as OH−. We use 20 MOFs to show that this PC concept is an effective approach for developing P‐MOFs whose high stability, porosity, and anion‐exchange capability allow immobilization of anionic nucleotides and coenzymes, in addition to charge‐ and size‐selective capture or separation of organic dyes. The CO2 and C2H2 uptake capacity of 117.9 cm3 g−1 and 148.5 cm3 g−1, respectively, at 273 K and 1 atm, is exceptionally high among cationic framework materials.
New traps for bio‐anions. Using a preemptive coordination approach, highly porous cationic frameworks were made that allow immobilization of anionic nucleotides and coenzymes, in addition to charge‐ and size‐selective capture and separation of organic dyes.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this communication experimental and theoretical results are reported affording strong evidence that interactions between electron rich atoms and the metal of tetroxide anions of group 7 elements ...are a new case of attractive and σ‐hole interactions. Single crystal X‐ray analyses, molecular electrostatic potentials, quantum theory of atoms‐in‐molecules, and noncovalent interaction plot analyses show that in crystalline permanganate and perrhenate salts the metal in Mn/ReO4− anion can act as electron acceptors, the oxygen of another Mn/ReO4− anion can act as the donor and supramolecular anionic dimers or polymers are formed. The name matere bond (MaB) is proposed to categorize these noncovalent interactions and to differentiate them from the classical metal‐ligand coordination bond.
A new case: Single crystal X‐ray analyses, molecular electrostatic potentials, quantum theory of atoms‐in‐molecules, and noncovalent interaction plot index analyses show that Mn/Tc/ReO4− anions self‐assemble in the solid and in solution and afford dimers and supramolecular polyanionic infinite chains thanks to the matere bond (MaB, Ma=Mn, Tc, Re, (Bh)), a new entry in the palette of σ‐hole interactions.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The asymmetric unit of the title compound consists of two crystallographically independent, but structurally identical, HP2Mo5O235− anions, ten guanidinium cations and five water molecules. Each ...singly protonated diphosphopentamolybdate(VI) anion retains the typical geometry of a ring of five edge‐sharing MoO6 octahedra Mo...Mo = 3.3265 (8)–3.4029 (10) Å, except for one corner‐sharing link Mo...Mo = 3.6642 (7) and 3.6826 (8) Å. Two capping PO4 tetrahedra share corners with the five octahedra. Despite being surrounded by an extensive network of hydrogen bonds, predominantly from the guanidinium cations, short P—O—H...O=P contacts O...O = 2.519 (7) and 2.457 (7) Å associate the anions into infinite columns generated by the c‐glide. In addition to their heavy involvement in hydrogen bonding, with all N—H donors being utilized, the guanidinium cations assemble into extensive π‐stacked columns with an average interplanar spacing of 3.53 Å.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Correction for ‘A topological path to the formation of a quasi-planar B70 boron cluster and its dianion’ by Pinaki Saha et al., Phys. Chem. Chem. Phys., 2024, https://doi.org/10.1039/d2cp05452c.
Summary
Guard cells control the opening of stomatal pores in the leaf surface, with the use of a network of protein kinases and phosphatases. Loss of function of the CBL‐interacting protein kinase 23 ...(CIPK23) was previously shown to decrease the stomatal conductance, but the molecular mechanisms underlying this response still need to be clarified.
CIPK23 was specifically expressed in Arabidopsis guard cells, using an estrogen‐inducible system. Stomatal movements were linked to changes in ion channel activity, determined with double‐barreled intracellular electrodes in guard cells and with the two‐electrode voltage clamp technique in Xenopus oocytes.
Expression of the phosphomimetic variant CIPK23T190D enhanced stomatal opening, while the natural CIPK23 and a kinase‐inactive CIPK23K60N variant did not affect stomatal movements. Overexpression of CIPK23T190D repressed the activity of S‐type anion channels, while their steady‐state activity was unchanged by CIPK23 and CIPK23K60N.
We suggest that CIPK23 enhances the stomatal conductance at favorable growth conditions, via the regulation of several ion transport proteins in guard cells. The inhibition of SLAC1‐type anion channels is an important facet of this response.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Following up on scattered reports on interactions of conventional chaotropic ions (for example, I−, SCN−, ClO4−) with macrocyclic host molecules, biomolecules, and hydrophobic neutral surfaces in ...aqueous solution, the chaotropic effect has recently emerged as a generic driving force for supramolecular assembly, orthogonal to the hydrophobic effect. The chaotropic effect becomes most effective for very large ions that extend beyond the classical Hofmeister scale and that can be referred to as superchaotropic ions (for example, borate clusters and polyoxometalates). In this Minireview, we present a continuous scale of water–solute interactions that includes the solvation of kosmotropic, chaotropic, and hydrophobic solutes, as well as the creation of void space (cavitation). Recent examples for the association of chaotropic anions to hydrophobic synthetic and biological binding sites, lipid bilayers, and surfaces are discussed.
Chaos reigns: The unexpectedly high affinity of large anions to macrocyclic hosts, proteins, membranes, colloids, and interfaces results from a generic driving force for association in aqueous solution, namely the chaotropic effect. It is most effective for superchaotropic anions, positioned between chaotropic and hydrophobic ions on an expanded Hofmeister scale.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
PDF
