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International Journal of Molecular... Jun 2022The synthesis and structural characterization of a series of supramolecular complexes of bicyclic cationic pyridine-fused 1,2,4-selenodiazoles with various anions is...
The synthesis and structural characterization of a series of supramolecular complexes of bicyclic cationic pyridine-fused 1,2,4-selenodiazoles with various anions is reported. The binding of trifluoroacetate, tetrachloroaurate, tetraphenylborate, perrhenate, and pertechnetate anions in the solid state is regarded. All the anions interact with selenodiazolium cations exclusively via a pair of "chelating" Se⋯O and H⋯O non-covalent interactions, which make them an attractive, novel, non-classical supramolecular recognition unit or a synthon. Trifluoroacetate salts were conveniently generated via novel oxidation reaction of 2,2'-dipyridyl diselenide with bis(trifluoroacetoxy)iodo)benzene in the presence of corresponding nitriles. Isolation and structural characterization of transient 2-pyridylselenyl trifluoroacetate was achieved. X-ray analysis has demonstrated that the latter forms dimers in the solid state featuring very short and strong Se⋯O and Se⋯N ChB contacts. 1,2,4-Selenodiazolium trifluoroacetates or halides show good solubility in water. In contrast, (AuCl), (ReO), or (TcO) derivatives immediately precipitate from aqueous solutions. Structural features of these supramolecular complexes in the solid state are discussed. The nature and energies of the non-covalent interactions in novel assembles were studied by the theoretical methods. To the best of our knowledge, this is the first study that regards perrhenate and pertechnetate as acceptors in ChB interactions. The results presented here will be useful for further developments in anion recognition and precipitation involving cationic 1,2,4-selenodiazoles.
Topics: Anions; Cations; Models, Theoretical; Salts; Sodium Pertechnetate Tc 99m; Trifluoroacetic Acid; Water
PubMed: 35742815
DOI: 10.3390/ijms23126372 -
Proceedings of the Japan Academy.... 2023The aromaticity and synthetic application of "heavy benzenes", i.e., benzenes containing a heavier Group 14 element (Si, Ge, Sn, and Pb) in place of skeletal carbon,... (Review)
Review
The aromaticity and synthetic application of "heavy benzenes", i.e., benzenes containing a heavier Group 14 element (Si, Ge, Sn, and Pb) in place of skeletal carbon, have been the targets of many theoretical and synthetic studies. Although the introduction of a sterically demanding substituent enabled us to synthesize and isolate heavy aromatic species as a stable compound by suppressing their high reactivity and tendency to polymerize, the existence of a protection group is an obstruction to the development of functional materials based on heavy aromatics. This review will delineate the most recent topics in the chemistry of heavy aromatics, i.e., the chemistry of "metallabenzenyl anions", which are the heavier Group 14 element analogs of phenyl anions stabilized by taking advantage of charge repulsion instead of steric protection.
Topics: Benzene; Anions; Carbon
PubMed: 38072454
DOI: 10.2183/pjab.99.027 -
Molecules (Basel, Switzerland) Jun 2020Polyhydroborate salts represent the important class of energy materials attracting significant recent attention. Some of these salts exhibit promising hydrogen storage... (Review)
Review
Polyhydroborate salts represent the important class of energy materials attracting significant recent attention. Some of these salts exhibit promising hydrogen storage properties and/or high ionic conductivities favorable for applications as solid electrolytes in batteries. Two basic types of thermally activated atomic jump motion are known to exist in these materials: the reorientational (rotational) motion of complex anions and the translational diffusion of cations or complex anions. The present paper reviews recent progress in nuclear magnetic resonance (NMR) studies of both reorientational and diffusive jump motion in polyhydroborate salts. The emphasis is put on sodium and lithium -borates exhibiting high ionic conductivity and on borohydride-based systems showing extremely fast reorientational motion down to low temperatures. For these systems, we discuss the effects of order-disorder phase transitions on the parameters of reorientations and diffusive jumps, as well as the mechanism of low-temperature rotational tunneling.
Topics: Anions; Bromates; Cations; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Conformation; Salts
PubMed: 32604750
DOI: 10.3390/molecules25122940 -
Nature Communications Oct 2022Transmembrane ion transport is a key process in living cells. Active transport of ions is carried out by various ion transporters including microbial rhodopsins (MRs)....
Transmembrane ion transport is a key process in living cells. Active transport of ions is carried out by various ion transporters including microbial rhodopsins (MRs). MRs perform diverse functions such as active and passive ion transport, photo-sensing, and others. In particular, MRs can pump various monovalent ions like Na, K, Cl, I, NO. The only characterized MR proposed to pump sulfate in addition to halides belongs to the cyanobacterium Synechocystis sp. PCC 7509 and is named Synechocystis halorhodopsin (SyHR). The structural study of SyHR may help to understand what makes an MR pump divalent ions. Here we present the crystal structure of SyHR in the ground state, the structure of its sulfate-bound form as well as two photoreaction intermediates, the K and O states. These data reveal the molecular origin of the unique properties of the protein (exceptionally strong chloride binding and proposed pumping of divalent anions) and sheds light on the mechanism of anion release and uptake in cyanobacterial halorhodopsins. The unique properties of SyHR highlight its potential as an optogenetics tool and may help engineer different types of anion pumps with applications in optogenetics.
Topics: Anion Transport Proteins; Halorhodopsins; Rhodopsins, Microbial; Synechocystis; Anions; Sulfates
PubMed: 36309497
DOI: 10.1038/s41467-022-34019-9 -
Chemphyschem : a European Journal of... Jan 2023Modulation and fine-tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors...
Modulation and fine-tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors includes both a urea motif and a tetrazine motif. The synthetic sequence towards three receptors is detailed. Impacts of H-bond strength and linker length between urea and tetrazine on chloride complexation are studied. Binding properties of the chloride anion are examined in both the ground and excited states using a panel of analytical methods (NMR spectroscopy, mass spectrometry, UV/Visible spectroscopies, and fluorescence). A ranking of the receptors by complexation strength has been determined, allowing a better understanding of the structure-properties relationship on these compounds.
Topics: Urea; Chlorides; Hydrogen Bonding; Anions
PubMed: 36111796
DOI: 10.1002/cphc.202200524 -
Molecules (Basel, Switzerland) Sep 2022Besides their extremely useful properties as solvent, ionic liquids (ILs) are now considered to be highly instructive tools for enhancing the rates of chemical... (Review)
Review
Besides their extremely useful properties as solvent, ionic liquids (ILs) are now considered to be highly instructive tools for enhancing the rates of chemical reactions. The ionic nature of the IL anion and cation seems to be the origin of this fascinating function of ILs as organocatalyst/promoter through their strong Coulombic forces on other ionic species in the reaction and also through the formation of hydrogen bonds with various functional groups in substrates. It is now possible to tailor-make ILs for specific purposes as solvent/promoters in a variety of situations by carefully monitoring these interactions. Despite the enormous potentiality, it seems that the application of ILs as organocatalysts/promoters for chemical reactions have not been fully achieved so far. Herein, we review recent developments of ILs for promoting the nucleophilic reactions, focusing on fluorination. Various aspects of the processes, such as organocatalytic capability, reaction mechanisms and salt effects, are discussed.
Topics: Anions; Halogenation; Hydrogen Bonding; Ionic Liquids; Solvents
PubMed: 36080470
DOI: 10.3390/molecules27175702 -
Chemistry (Weinheim An Der Bergstrasse,... Aug 2021Synthetic anion transporters show much promise as potential anti-cancer agents and therapeutics for diseases associated with mis-regulation of protein anion channels. In...
Synthetic anion transporters show much promise as potential anti-cancer agents and therapeutics for diseases associated with mis-regulation of protein anion channels. In such applications high activity and anion selectivity are crucial to overcome competing proton or hydroxide transport which dissipates cellular pH gradients. Here, highly active bidentate halogen bonding and chalcogen bonding anion carriers based on electron deficient iodo- and telluromethyl-triazole derivatives are reported. Anion transport experiments in lipid bilayer vesicles reveal record nanomolar chloride transport activity for the bidentate halogen bonding anion carrier, and remarkably high chloride over proton/hydroxide selectivity for the chalcogen bonding anionophore. Computational studies provide further insight into the role of sigma-hole mediated anion recognition and desolvation at the membrane interface. Comparison with hydrogen bonding analogues demonstrates the importance of employing sigma-hole donor motifs in synthetic anionophores for achieving both high transport activity and selectivity.
Topics: Anions; Chalcogens; Chlorides; Halogens; Humans; Hydrogen Bonding
PubMed: 34014001
DOI: 10.1002/chem.202101681 -
Journal of Chemical Information and... Sep 2021Herein, it is shown how anion recognition in highly polar solvents by neutral metal-free receptors is feasible when multiple hydrogen bonding and anion-π interactions...
Herein, it is shown how anion recognition in highly polar solvents by neutral metal-free receptors is feasible when multiple hydrogen bonding and anion-π interactions are suitably combined. A neutral aromatic molecular tweezer functionalized with azo groups is shown to merge these two kinds of interactions in a unique system and its efficiency as an anion catcher in water is evaluated using first-principles quantum methods. Theoretical calculations unequivocally prove the high thermodynamic stability in water of a model anion, bromide, captured within the tweezer's cavity. Thus, static calculations indicate anion-tweezer interaction energies within the range of covalent or ionic bonds and stability constants in water of more than 10 orders of magnitude. First-principles molecular dynamics calculations also corroborate the stability through the time of the anion-tweezer complex in water. It shows that the anion is always found within the tweezer's cavity due to the combination of the tweezer-anion interactions plus a hydrogen bond between the anion and a water molecule that is inside the tweezer's cavity.
Topics: Anions; Hydrogen Bonding; Solvents; Thermodynamics; Water
PubMed: 34396775
DOI: 10.1021/acs.jcim.1c00595 -
International Journal of Molecular... Jan 2023In searching for a tool for optimizing the band gap of a hybrid compound capable of serving as a light-harvesting material in lead-free photovoltaics, we synthesized a...
Synthesis, Crystal, and Electronic Structure of (HpipeH)[SbI](I), with I Molecules Linking SbX Dimers into a Polymeric Anion: A Strategy for Optimizing a Hybrid Compound's Band Gap.
In searching for a tool for optimizing the band gap of a hybrid compound capable of serving as a light-harvesting material in lead-free photovoltaics, we synthesized a new polyiodoantimonate (HpipeH)[SbI](I) and analyzed its crystal and electronic structure by application of X-ray crystal structure analysis, Raman and diffuse reflectance spectroscopies, and quantum chemical calculations. It was demonstrated that I molecules link SbI edge-sharing octahedra into zig-zag chains, whereas the organic cations link inorganic anionic chains into a 3D structure featuring a complex pattern of covalent bonds and non-covalent interactions. Overall, these features provide the background for forming the electronic structure with a narrow band gap of 1.41 eV, therefore being a versatile tool for optimizing the band gap of a potential light-harvesting hybrid compound.
Topics: Polymers; Anions; Electronics; Serogroup
PubMed: 36768523
DOI: 10.3390/ijms24032201 -
The New Phytologist Aug 2019We investigated the molecular basis and physiological implications of anion transport during pollen tube (PT) growth in Arabidopsis thaliana (Col-0). Patch-clamp...
We investigated the molecular basis and physiological implications of anion transport during pollen tube (PT) growth in Arabidopsis thaliana (Col-0). Patch-clamp whole-cell configuration analysis of pollen grain protoplasts revealed three subpopulations of anionic currents differentially regulated by cytoplasmic calcium ([Ca ] ). We investigated the pollen-expressed proteins AtSLAH3, AtALMT12, AtTMEM16 and AtCCC as the putative anion transporters responsible for these currents. AtCCC-GFP was observed at the shank and AtSLAH3-GFP at the tip and shank of the PT plasma membrane. Both are likely to carry the majority of anion current at negative potentials, as extracellular anionic fluxes measured at the tip of PTs with an anion vibrating probe were significantly lower in slah3 and ccc mutants, but unaffected in almt12 and tmem16 . We further characterised the effect of pH and GABA by patch clamp. Strong regulation by extracellular pH was observed in the wild-type, but not in tmem16 . Our results are compatible with AtTMEM16 functioning as an anion/H cotransporter and therefore, as a putative pH sensor. GABA presence: (1) inhibited the overall currents, an effect that is abrogated in the almt12 and (2) reduced the current in AtALMT12 transfected COS-7 cells, strongly suggesting the direct interaction of GABA with AtALMT12. Our data show that AtSLAH3 and AtCCC activity is sufficient to explain the major component of extracellular anion fluxes, and unveils a possible regulatory system linking PT growth modulation by pH, GABA, and [Ca ] through anionic transporters.
Topics: Anions; Arabidopsis; Arabidopsis Proteins; Calcium; Cell Membrane; Chlorides; Electrophysiological Phenomena; Hydrogen-Ion Concentration; Ion Channels; Ion Transport; Models, Biological; Mutation; Nitrates; Pollen; Pollen Tube; Protoplasts; Symporters; gamma-Aminobutyric Acid
PubMed: 31132313
DOI: 10.1111/nph.15863