A Simulation Model for the Non-Electrogenic Uniport Carrier-Assisted Transport of Ions across Lipid Membranes

Impressive work has been completed in recent decades on the transmembrane anion transport capability of small synthetic transporters from many different structural classes. However, very few predicting models have been proposed for the fast screening of compound libraries before spending time and resources on the laboratory bench for their synthesis. In this work, a new approach is presented which aims at describing the transport process by taking all the steps into explicit consideration, and includes all possible experiment-derived parameters. The algorithm is able to simulate the macroscopic experiments performed with lipid vesicles to assess the ion-transport ability of the synthetic transporters following a non-electrogenic uniport mechanism. While keeping calculation time affordable, the final goal is the curve-fitting of real experimental data—so, to obtain both an analysis and a predictive tool. The role and the relative weight of the different parameters is discussed and the agreement with the literature is shown by using the simulations of a virtual benchmark case. The fitting of real experimental curves is also shown for two transporters of different structural type.This research was funded by the University of Cagliari (FIR 2020). Financial support from MIUR (PRIN 2017 project 2017EKCS35), Fondazione di Sardegna (FdS Progetti Biennali di Ateneo, annualità 2018 and 2020) is also gratefully acknowledged

reactivity of the drug methimazole and its iodine adduct with elemental zinc

The reactivity of zinc complexes with N,S-donor molecules may be of relevance to the study of Zn-metalloproteins and -metalloenzymes. In this context, the zinc complex [Zn(MeImSH)2I2] was synthesised by the reaction of zinc powder with the 1:1 iodine adduct of the drug methimazole [(MeImSH)·I2]. The molecular structure of the complex, elucidated by X-ray diffraction analysis, showed a tetrahedral zinc(II) centre coordinated by two neutral methimazole units (through the sulfur atoms) and two iodides. From the reaction of MeImSH and Zn powder, the complex [Zn(MeImSH)(MeImS)2] (MeImS = deprotonated form of methimazole) was separated and characterised. An analysis of the crystal packing of the neutral complexes [Zn(MeImSH)2X2] (X = I, Br and Cl) and the ionic complex [Zn(MeImSH)3I]I showed that in all of the complexes the sulfur atom, in addition to binding to the metal centre, contributes to the formation of 1-D chains built via C(4)–H⋯S and N–H⋯X interactions in the neutral complexes, and via C(4)–H⋯S and N–CH3⋯S interactions in the ionic complex [Zn(MeImSH)3I]I. The deprotonation/protonation of the coordinated methimazole units can modulate the coordination environment at the Zn core. From the reaction of complex [Zn(MeImSH)3I]I with a strong non-coordinating organic base, we have shown that, as a consequence of the NH deprotonation of methimazole S-coordinated to zinc(II), the ligand coordination mode changes from S-monodentate to N,S-bridging. Correspondingly, in the complex [Zn(MeImSH)(MeImS)2], the MeImS that displays the N,S-bridging mode at zinc can be N-protonated and thereby changes to the S-monodentate coordination

Stabilization of caesium ions by simple organic molecules: crystal structures of Cs(OXL) (OXL = oxalurate anion), and CsOH/cyanuric acid co-crystal Cs3(CYH3)4(OH)3 (CYH3 = cyanuric acid)

The reaction in water between CsOH and parabanic acid (PBH2) leads to the formation of the caesium salt of the oxalurate anion Cs(OXL), while the reaction with cyanuric acid (CYH3) leads to the formation of the CsOH co-crystal of cyanuric acid Cs3(CYH3)4(OH)3. The X-ray crystal structures of these compounds show that both the organic moieties OXL and CYH3 form robust homomeric ribbons based on strong and articulated N–HO hydrogen bonds. The stabilization of the Cs+ ions can occur regardless of whether the ribbon of organic units is negatively charged or neutral. In Cs(OXL), each cation displays nine-fold coordination with Cs–O distances in the range of 2.975(3)–3.601(4) Å; in Cs3(CYH3)4(OH)3, two of the Cs+ cations (Cs1 and Cs2) display a nine-fold coordination with Cs–O distances in the range of 3.007(9)–3.823(13) Å and one (Cs3) is ten-fold coordinated with Cs–O distances in the range of 3.161(14)– 3.653(17) Å. The molecular electrostatic potential maps of OXL and di-OXL anions have been reported and discussed

Supramolecular Chemistry: Young Talents and their Mentors

Celebrating Supramolecular Chemistry and Mentoring: ChemPlusChem is pleased to publish a Special Collection on Supramolecular Chemistry: Young Talents and their Mentors, guest‐edited by Anna McConnell, Cally Haynes, Claudia Caltagirone, and Jennifer Hiscock. The Special Collection features recent developments in supramolecular chemistry and highlights mentoring relationships between emerging investigators and their mentor

Simple isophthalamides/dipicolineamides as active transmembrane anion transporters

Eight N,N´-diarylisophthalamide/dipicolineamide derivatives have been synthesised and fully characterised, both in solution and in the solid state. The transmembrane anion transport properties of these compounds have been studied by chloride-selective electrode and fluorescence experiments. The substitution pattern of the aromatic moieties determines the transport properties of these systems, with those containing electron-withdrawing groups in their structures being the most active ones of the series.Consejería de Educación de la Junta de Castilla y León (project BU075G19

Bis(2-pyridylmethyl)alkyl(thioalkyl)diamines as promising scaffolds for the construction of fluorescent and redox chemosensors for transition and post-transition metal ions

Abstract N , N ′- Bis (2-pyridylmethyl)propylendiamine ( 1 ) and N , N ′- bis (2-pyridylmethyl)-1,5-diamino-3-thiapentane ( 2 ) have been functionalised at the secondary nitrogen atoms with dansylamidoethyl ( L 1 , L 3 ), 2-quinolinylmethyl ( L 2 , L 4 ) and ferrocenylmethyl ( L 6 , L 7 ) pendant arms with the intention to study their potentiality as receptor units in molecular sensors. The optical response of L 1 – L 4 to the presence of the metal ions Cu 2+ , Zn 2+ , Cd 2+ , Hg 2+ and Pb 2+ has been investigated in MeCN/H 2 O (4:1 v/v) solution. The electrochemical response of L 6 and L 7 to the presence of the same metal ions has been investigated in anhydrous MeCN/CH 2 Cl 2 10:1 (v/v) solution. Results are compared and discussed with the aim to clarify the mutual role played by the bis (2-methylpyridyl)alkyl(thioalkyl)diamines and the signalling units attached to them in reaching the selectivity of the responses observed

Advances in applied supramolecular technologies

Supramolecular chemistry is a comparatively young field that to date has mainly been focused on building a foundation of fundamental understanding. With much progress in this area, researchers are seeking to apply this knowledge to the development of commercially viable products. In this review we seek to outline historical and recent developments within the field of supramolecular chemistry that have made the transition from laboratory to market, and to bring to light those technologies that we believe have commercial potential. In doing so we hope we may illuminate pathways to market for research currently being conducted

Fluorescent asymmetric bis-ureas for pyrophosphate recognition in pure water

Three fluorescent asymmetric bis-urea receptors (L1–L3) have been synthesised. The binding properties of L1–L3 towards different anions (fluoride, acetate, hydrogencarbonate, dihydrogen phosphate, and hydrogen pyrophosphate HPpi3?) have been studied by means of 1H-NMR, UV-Vis and fluorescence spectroscopy, single crystal X-ray diffraction, and theoretical calculations. In particular, a remarkable affinity for HPpi3? has been observed in the case L1 (DMSO-d6/0.5% H2O) which also acts as a fluorimetric chemosensor for this anion. Interestingly, when L1 is included in cetyltrimethylammonium (CTAB) micelles, hydrogen pyrophosphate recognition can also be achieved in pure water

A pilot study on brain plasticity of functional connectivity modulated by cognitive training in mild Alzheimer's disease and mild cognitive impairment

Alzheimer's disease (AD) alters the functional connectivity of the default mode network (DMN) but also the topological properties of the functional connectome. Cognitive training (CT) is a tool to slow down AD progression and is likely to impact on functional connectivity. In this pilot study, we aimed at investigating brain functional changes after a period of CT and active control (AC) in a group of 26 subjects with mild AD (mAD), 26 with amnestic mild cognitive impairment (aMCI), and a control group of 29 healthy elderly (HE) people. They all underwent a CT and AC in a counterbalanced order following a crossover design. Resting-state functional MRI and neuropsychological testing were acquired before and after each period. We tested post-CT and post-AC changes of cognitive abilities, of the functional connectivity of the DMN, and of topological network properties derived from graph theory and network-based statistics. Only CT produced functional changes, increasing the functional connectivity of the posterior DMN in all three groups. mAD also showed functional changes in the medial temporal lobe and topological changes in the anterior cingulum, whereas aMCI showed more widespread topological changes involving the frontal lobes, the cerebellum and the thalamus. Our results suggest specific functional connectivity changes after CT for aMCI and mAD