Aqueous DMSO Solution Research Articles

Acyl Transfer Reactions of 2,4-Dinitrophenyl Furoates: Comparative Effects of Nucleophiles and Non-Leaving Groups

This study investigated the acyl group transfer reactions of 2,4-dinitrophenyl 5-substituted-2-furoates, promoted by 4-substituted phenoxides/phenols in a 20 mol% DMSO aqueous solution at 25 °C. The reactions yielded nucleophilic substitution products and displayed second-order kinetics, with βacyl values ranging from −2.24 to −2.50, ρ(x) values between 3.18 and 3.56, and βnuc values of 0.81 to 0.84. These findings indicate an addition–elimination mechanism where the initial step is rate-determining. Comparative analysis with previous data revealed that the transition state structure remained largely consistent when altering the non-leaving group from thienyl to furyl under similar conditions. Notably, a shift in the rate-determining step was observed when changing the nucleophile from secondary amines/ammonium ions to 4-substituted phenoxides/phenols, highlighting the significant impact of nucleophile selection on the reaction kinetics and mechanisms in acyl transfer reactions.

Synthesis and characterization of 3,5-bis((2-hydroxybenzylidene)amino)-N-(2-hydroxyphenyl)benzamide and Zn(II) complex: Investigation of chromic, fluorescence and DPPH radical scavenging behaviours

Novel amido-Schiff base 3,5-bis((2-hydroxybenzylidene)amino)-N-(2-hydroxyphenyl)benzamide (2a) has been obtained by the reaction of Schiff base 1a with 2-hydroxyaniline in the presence of coupling agent N,N′-dicyclohexylcarbodiimide. Schiff base (1a) which serves as the starting compound in amide synthesis was produced from the condensation of 3,5-diaminobenzoic acid with salicylaldehyde in a 1:2 mol ratio. Tetrahedral geometry with 1:1 [M:L] stoichiometry Zn(II) complex (3a) was newly synthesized by the complexation reaction of ligand 2a with zinc(II) nitrate. 1a and 2a displayed a broad emission band at λem = 456 and 472 nm with a blue fluorescent in pure DMSO, while 3a emitted a strong greenish-blue fluorescent with the λem = 485 nm (λexc = 365 nm). The fluorescence efficiency of 1a was poor compared to the others. The λem in aqueous DMSO solution (v/v, 1:1) had ∼8–33 nm red-shift with respect to that of pure solution. The λem gave ∼1–15 nm red-shift with very low emission efficiency in acidic DMSO media. The results suggested that the aggregation caused quenching properties of 1a–3a in pure, aqueous, and acidic DMSO system with a 50 % water fraction. The fluorescence of the compounds appeared to be visibly very bright in basic DMSO media. All the compounds were also screened for antioxidant activity using UV–Vis spectroscopy. They were found to be not effective DPPH radical scavengers in DMSO.

Sensitive Detection and Cell Imaging of Ca2+ Based on a "Turn-On" Schiff Base Fluorescent Probe.

Ca2+ ion as a second messenger in signaling pathway plays many vital roles in many biological phenomena. Thus, it is of significance for developing effective probes to detect Ca2+ ion specifically. Herein, a new Schiff base fluorescent probe FPH, fluorescein monoaldehyde (2-aminomethylpyridine) hydrazone, was designed and synthesized to identify Ca2+ in DMSO aqueous solution. The probe FPH revealed significant responses to Ca2+ with a fluorescence enhancement at 540 nm, exhibiting an evident fluorescence change from ultraweak luminescence to bright green. Otherwise, the FPH displayed a good linear range of 0.67 × 10-6 to 3.33 × 10-6 mol/L with a lower detection limit at 7.02 × 10-8 mol/L. The probe FPH were further successfully utilized to detect Ca2+ in living cells by an increased bright green fluorescence.

Arsenate Stabilization via Dynamic Covalent Chemistry

AbstractWe report the synthesis of arsenic heterocycles derived from saccharides 2–4 and AsCl3. Compounds 5 and 6 are stable in aqueous solutions, DMSO, or methanolic solutions. However, NMR and HPLC studies revealed that intramolecular trans‐esterification processes leads to dynamic equilibria. Theoretical studies revealed that three arsenates and two arsoranes participate in these intramolecular equilibria and account for the experimental spectroscopy and HPLC results. Through the correlation between the experimental and theoretical 13C NMR spectra, we proposed the speciation of arsenic Compounds 5 and 6. Moreover, experimental and theoretical IR spectra demonstrated that arsenates 5 A and 6 A predominate in the solid state. QTAIM studies were performed to explain the chemical shifts in the 13C NMR spectra. Biological studies suggest that the structural flexibility of Compounds 5 and 6 increase the cytotoxic and antiproliferative activities of these compounds.

Influence of hydrogen bonds on state diagrams of cryoprotectant solutions

BACKGROUND: Transformation of state diagrams of cryoprotectant solutions under the influence of weak intramolecular interactions was considered. MATERIALS AND METHODS: Phase states of aqueous glycerol and DMSO solutions within temperature range +25???−150 °?? were studied using method of volumetric scanning tensodilatometry. Temperatures below which hydrogen bonds significantly affect crystallization-melting kinetics of such solutions were determined. RESULTS: Principles for plotting of state diagram for binary solutions with weak intermolecular interaction of the components were set up. The study demonstrates that in such solutions formation of clusters based on ice microcrystals and cryoprotectant occurs. Based on the obtained results, state diagrams for glycerol and DMSO aqueous solutions were plotted. These diagrams include area of cluster phase existence and differ fundamentally from those describing eutectic crystallization. CONCLUSION: Nanostructures occurring in cryoprotectant solutions during their cooling were analyzed. Difference between these structures and classical solid phase eutectics were demonstrated.

Ion diffusion captures composition-dependent anomalies in water-DMSO binary mixtures.

Aqueous dimethyl sulfoxide (Aq-DMSO) binary mixture exhibits many fascinating composition-dependent anomalies that are explained by using the peculiarities of the water-DMSO hydrogen bond. Ions can couple strongly to these composition-dependent anomalies to produce exotic dynamics of their own. We carry out theoretical studies using computer simulations to understand the structural and dynamical aspects of rigid monovalent cations (Li+, Na+, K+, Rb+, and Cs+) in aqueous DMSO solutions, with chloride as the counterion. We uncover a number of composition-dependent ion diffusion anomalies, which can be traced back to the interplay between the size-dependent charge density of the ion and the resulting difference in interactions of the ion with water and DMSO molecules. Size and composition dependence of the diffusion coefficients of the five ions exhibit fascinating variations that can be explained partially.

A reaction based carbazole-indolium conjugate probe for the selective detection of environmentally toxic ions.

A nucleophilic addition based chemodosimeter was designed and synthesized with a carbazole donor and an indole acceptor. The addition of a cyanide ion to an electron-deficient indole moiety disrupts the acceptor-donor relationship, resulting in noticeable color shifts and spectrum differences in both the absorption and emission profiles. The design has a D-π-A molecular arrangement. Selectivity was investigated in 90% aqueous DMSO solution of probe CI with various anions such as SCN-, PF6-, NO3-, N3-, I-, HSO4-, CN-, H2PO4-, F-, HS-, ClO4-, Cl-, Br-, and AcO-. An intermolecular charge transfer (ICT) band at 506 nm in the UV-visible spectra vanished and the intensity of emission was quenched at 624 nm upon the addition of CN- ions. These outcomes demonstrate the effective nucleophilic addition of cyanide ions to the electron-deficient indole moiety of the probe, resulting in the formation of a new adduct in which the ICT transition is interrupted when π conjugation is blocked. The Job plot, 1H NMR spectroscopy, and HRMS analysis confirmed the formation of a new product. An outstanding response was shown by paper test strips made using probe molecules for the easy detection of cyanide ions in aqueous solutions. Besides, the probe selectively senses cyanide ions in different water samples.

Water-Soluble Squaramide-Functionalised Copolymers for Anion Recognition.

A series of ethylene glycol-based squaramide-containing copolymers were synthesised via a post-polymerisation functionalisation strategy. Conversion of polymeric amines to squaramides was found to proceed in good yields, representing a versatile method of incorporating squaramides into polymers for anion recognition. Analysis of the polymers by UV-Vis and fluorescence spectroscopy revealed that anion binding takes place similarly to that of small-molecule squaramides. The presence of a fluorescent sensing group on polymer-bound squaramides allowed for a fluorescent sensing mechanism for anions that followed a similar trend in selectivity in aqueous DMSO solution, with selectivity observed for H2 PO4 - , AcO- and SO4 2- over other common anions tested. The anion response and selectivity towards anions was similar to that of analogous small-molecule squaramides, however polymeric squaramides exhibited a greater resistance to deprotonation by more basic anions, which was attributed to the closer proximity of individual squaramides on a macromolecule. The squaramide containing polymers exhibited good water solubility, overcoming a common problem for anion sensors which are typically not sufficiently soluble in water to function in many required applications. Despite no anion binding being observed in water, this represents a simple and effective method of creating fully water-soluble anion receptors which may be adapted to give improved binding affinity and selectivity depending on the anion binding moiety. This article is protected by copyright. All rights reserved.

In ovo exposure of F-ions and organo-fluoride insecticide (Bifenthrin) cause developmental anomalies of eye in chick embryos

ObjectiveThe developmental abnormalities of the in-ovo exposure of Fluoride ions (F-ions) and Bifenthrin (BF) on the embryonic chick eye were investigated. Materials and methods165 fresh fertilized eggs of zero day and 40–50 g weight were divided into three groups (55 eggs each) on the basis of inter-vitelline treatment of eggs on zero day of study: 1) Control group (CG); 0.1 ml of 5 % DMSO aqueous solution 2),3) Fluoride group (FG), and Bifenthrin group (BFG); 0.01 mg/kg F-ions (from NaF) and 0.01 mg/kg BF in 0.1 ml of 5 % DMSO aqueous solution respectively. After incubation for 14 days at 37 ± 0.5 °C embryos were externalized. Eyes of each embryo were removed for micro-anatomical, micrometric and histopathological studies. ResultsThe histological sections have shown denser and enlarged marginal mitotic region of the developing eye lenses in FG and BFG. In vertical sections of the eye lenses the nuclei of the crystalline cells in FG and BFG show a highly depressed bow shaped arrangement. Moreover, the nuclei of the core crystalline cells of the lens were apparently smaller in FG and BFG than CG. Out of the six anatomical layers of the retina the nuclear and the plexiform layers were highly enlarged in FG and BFG, similarly the three corneal cell layers (endothelial, parenchymal and epithelial) were enlarged in FG and BFG than CG. The morphometric, histometric and micrometric estimations also show significant variations in FG and BFG than CG. ConclusionThe results indicate subtle developmental anomalies of the eyes attributable to the F-ions and BF exposure indicating their developmental neuro-optic disruption potentials. Results further revealed higher toxicity of BF as compared to F-ions.

Crystallization Selectivity of Ribavirin Solution and Amorphous Phase.

Crystallization selectivity is an important principle in polymorph control. Ribavirin Form I, Form II, DMSO solvate, and amorphous ribavirin are prepared, and the short-range order similarities between these solid forms and ribavirin aqueous solution and DMSO solution are compared via mid-frequency Raman difference spectra (MFRDS). The crystallization process from amorphous ribavirin to Form I and from solution to amorphous phase is explained. Reasons for the difficulty in preparing the DMSO solvate are proposed. The rationale provided for the crystallization selectivity provides a foundation for the synthesis of metastable phases with a robust and convenient method.

New anthracene-based Cu(I) dithiocarbamates as AIEgens

The syntheses and structural characterizations of a series of anthracene-tethered Cu(I) phosphine dithiocarbamate complexes, [CuL(PPh3)2], are described in this article. All complexes were readily prepared from corresponding ligands with various acyclic and cyclic N-alkyl substituents and [Cu(PPh3)2(NO3)]. Steric hindrance imposed on the anthracenyl rings by dithiocarbamate, N-alkyl substituents and triphenylphosphine moieties in complexes 1-6 are not detected, as evidenced by the sharp aromatic resonances in 1H NMR spectra. X-ray crystallography reveals distorted tetrahedral chelation environments around the Cu(I) centers in 2 and 3 as well as extensive C–S···π and C–H···π intermolecular interactions in their solid state packings. The complexes display characteristic anthracene-based absorption and emission properties. The emission quantum yields of the complexes are poor (1.0–2.7 × 10−2) but the aggregation-induced emission effects are perceived in aqueous DMSO solutions. Especially, 6 with N-substituted cyclohexyl group displays the largest increase in emission intensity (ca. 7 times).

Effects of water molecules on luminescence in europium and terbium coordination polymers with p-fluorobenzoic acid as ligand

Our previous experimental observations show that the crystal structure of lanthanide luminescent complexes synthesized in aqueous solution usually contains a large number of coordination water molecules or free water molecules. In order to probe the influence of water molecules on luminescent processes of lanthanide complexes, the photoluminescence properties of Ln-FBA (Ln = Eu and Tb, FBA = p-fluorobenzoic acid) coordination polymers at different ambient temperatures, in different solvents and aqueous DMSO solutions with different volume concentrations were systematically investigated. The experiment results show that the presence of water molecules can promote the energy transfer from FBA ligand to Ln3+, at the same time, can cause luminescent non-radiation quenching of lanthanide ions. In addition, the variation of emission intensity ratio of 615 nm/591 nm peaks of Eu3+ with increasing the volume concentration of H2O can be potentially used for the quantitatively detection of water traces in organic solvents. In order to suppress the non-radiation quenching caused by the water molecules, Ln-FBA (Ln = Eu and Tb) coordination polymers were embedded into the PVP matrix to prepare Ln-FBA@PVP hybrid materials. The photoluminescence investigation indicates that PVP can not only block the quenching effect of water molecules on luminescence, but also effectively sensitize Eu3+ and Tb3+ luminescence. These experimental conclusions are useful for probing the influence of water molecules on luminescent processes of lanthanide complexes, quantitatively detecting water traces in organic solvents and enhancing the photoluminescence intensity in lanthanide complexes.

Novel PDMS-based transparent suspensions suitable for fluid flow characterization by optical techniques

Optical measurement techniques, such as µPIV and LDV are widely used in experimental fluid dynamics to investigate pure fluids or suspension flows. Optical access is a major concern in suspension experimentation. The suspended particle material must have a refractive-index matching those of the base fluid and wall set-up. This work reports a novel refractive-index-matched transparent suspension. The particulate matter is comprised of sub-10 µm spherical PDMS particles. PMDS is a widely used material to manufacture microchannels due to its low-refractive-indexand non-toxicity. PDMS microparticles were produced and suspended in a refractive-index matching base fluid (DMSO aqueous solution) and two transparent suspension concentrations were formulated [∼ 10% and ∼ 18% (w/w)]. Suspension rheology was characterized, andoptical properties analysed. μPIV successfully measured the velocity flow of the transparent suspensions in a circular-section microchannel, and the velocity profiles agreed well with the analytical solution.

2D-IR Spectroscopy of Nitrosyl Stretch of Sodium Nitroprusside Reveals the Elusive Two Anomalous Regions in the DMSO–Water Mixture

DMSO-water mixtures provide an intriguing hydrogen-bonding environment which has been a subject of various theoretical and experimental investigations. The structural dynamics of aqueous DMSO solutions has been investigated, using nitrosyl stretch of sodium nitroprusside (SNP, Na2[Fe(CN)5NO]) as a local vibrational probe, with the help of infrared (IR) absorption spectroscopy, vibrational pump-probe spectroscopy, and two-dimensional IR spectroscopy (2D-IR). Fourier transform infrared spectra of the nitrosyl stretch of SNP reveals that both the peak position and spectral broadening are very sensitive to the composition of the DMSO-water mixture and the subsequent structural changes occurring due to the addition of DMSO to water. The vibrational lifetime of the nitrosyl stretch displays two different linear variation regimes as a function of mole fraction of DMSO which has been assigned presumably to two different predominant structures at these compositions. However, the rotational depolarization measurements show that the reorientational times follow a bell-shaped profile, imitating the changes in the composition-dependent physical properties (viscosity) of DMSO-water solvent mixtures. To get a holistic picture of the system, 2D-IR spectroscopy of the NO stretch of SNP has been employed to study time scales of hydrogen-bond reorganization dynamics existing at different compositions. The analysis of frequency-frequency correlation function (FFCF) decay times reveal that the dynamics gets slower in intermediate DMSO concentrations than that of pure DMSO or pure water. A careful analysis reveals two anomalous regions of hydrogen-bond dynamics: XDMSO ∼0.2 and 0.4, which indicates that different hydrogen-bonded structures exist in these regions that can be effectively probed by SNP which has remained mostly elusive to previous vibrational probe-based investigations.

Near-infrared fluorescent turn-on probe for hydrazine detection: environmental samples and live cell imaging.

An acetoxy naphthaldehyde conjugated benzophenoxazinium chloride chromophore-based-donor-π-acceptor (D-π-A) fluorescent probe BPN (benzophenoxazinium naphthoxy imine) displaying near-infrared (NIR) emission was reported for hydrazine detection. The chosen water-soluble benzophenoxazinium chloride chromophore has excellent photostability, a high molar extinction coefficient and fluorescence quantum yield (Φ = from 0.0075 to 0.6193), higher selectivity towards hydrazine and a longer fluorescence lifetime. In the presence of hydrazine, BPN exhibits near infrared fluorescence emission at 725 nm along with color change from light blue to red, as detected by the naked eye. Moreover, the BPN probe can selectively detect hydrazine (DL = 4.5 × 10-10 M) in a 90% aqueous DMSO solution without interfering with other analytes. As proof of real samples, the probe is successfully applied to sense hydrazine in thin layer chromatography (TLC) paper strips (both solution and vapor phases) and water and soil samples, suggesting its significant potential application. Also, due to its NIR emission and aqueous solubility, the BPN probe can be successfully used in live cell imaging with low cytotoxicity.

Solvent directed fluorometric discrimination of Cu2+ and Ni2+ ions by a quinoline-based glucopyranosyl derivative

The reversible fluorescence sensor 1 has been reported for the discrimination of metal ions in aqueous medium after excitation at a higher wavelength. Sensor 1 showed specific sensing properties towards Cu2+ and Ni2+ in aqueous solutions of DMSO and CH3CN. The discrimination of Cu2+ and Ni2+ions was carried out by controlling the testing media. Sensor 1 exhibited high selectivity and excellent sensitivity (LOD: 0.17 µM for Cu2+ and 0.18 µM for Ni2+) towards Cu2+ and Ni2+ in two different analytical techniques (absorbance and fluorescence). The 1:1 complexation for both Cu2+ and Ni2+ was established from Job plots and ESI-mass spectra of the complexes. Model compound 2 and FTIR spectroscopy were used to know the binding mechanism of sensor 1 with Cu2+ and Ni2+ ions. Finally, DFT calculations were performed to establish the binding mode of 1 with Cu2+ and Ni2+.

Indole alkaloid ellipticine as efficient multitarget compound

First isolated from the tropical plant Oschrosia elliptica, indole alkaloid ellipticine provoked huge interest since it demonstrated antitumor activity was demonstrated along with limited toxic side effects and a complete lack of hematological toxicity. In this work, a five-step Cranwell and Saxton synthesis was used for obtaining ellipticine (Ell). Ellipticine hydrochloride salt (Ell×HCl) was also synthesized. Detailed in vitro studies of anticancer, antimalarial, and leishmanicidal activities were performed. Antiproliferation assay using DU145 cancer cell line treated with Ell showed a consistent reduction in cell proliferation and cell viability when treated with 5 μmol Ell. Anti-proliferation activity was more pronounced for the Ell×HCl solutions. Both the Ell and Ell×HCl revealed moderate activity in vitro against Leishmania amazonensis promastigotes, which is related to insufficient solubility of the drugs. IC50 values of Ell and Ell×HCl were determined in vitro against multidrug resistant Plasmodium falciparum strain K1. The Ell×HCl was shown to be almost three times more potent than the Ell in DMSO. Upon dilution with water, Ell solubility and activity drops down, while the activity and solubility of Ell×HCl is enhanced up to 10 times in 50:50 aqueous DMSO solutions

Colorimetric analysis of palladium using thiocarbamate hydrolysis and its application for detecting residual palladium in drugs

In this research, we report a practical colorimetric method for the convenient analysis of residual palladium ions in drugs and drug intermediates. In a phosphate-buffered (pH 7.0) 50% aqueous DMSO solution, chlororhodol-based probe PP-1 demonstrated a prominent colorimetric (APP-1+Pd(II)/APP-1 at 531 nm is over 780) and turn-on type fluorescence signaling behavior (IPP-1+Pd(II)/IPP-1 at 561 nm is over 2000) toward palladium. The signaling was realized through the palladium-assisted hydrolysis of the thiocarbamate protecting moiety of the probe. Palladium-selective signaling was feasible in the presence of possibly interfering chemical species, and it was concluded within 7 min. The selective signaling was observed for palladium species with different oxidation states (Pd2+, Pd4+, and Pd0). The detection limit of the probe for palladium analysis was sufficiently sensitive to analyze the residual palladium in drugs and related products (LODPP-1 = 1.0 × 10–8 M, LODPP-2 = 4.3 × 10–8 M). In particular, palladium analysis could be performed in the presence of ibuprofen and 2-cyano-4′-methylbiphenyl, as the drug and drug intermediate, respectively.

Elucidation of molecular interactions between sugar alcohol and dimethyl sulfoxide in aqueous system: Volumetric and acoustic study

Sugar alcohols have a significant role in the pharmaceutical and food industry due to their dominant effect on blood glucose levels and as artificial sweeteners in dairy products. The volumetric and acoustic study of sugar alcohol is the easiest way to characterize the solvation behavior that is in demand to get better considerations about mechanisms of sweet taste chemoreception and give valuable information about protein stabilization, and solute–solvent interactions. Densities and sound speeds of meso-erythritol in water and water-DMSO mixtures were measured at 293.15 K, 298.15 K, 303.15 K, 308.15 K, and 313.15 K under ambient pressure. The experimental data was further used to calculate the apparent molar volume, apparent molar volume at infinite dilution, partial molar volume transfer (Δt∅Vo), apparent specific volume, expansibility, and compressibility to evaluate the solvation behavior and taste quality of investigated mixtures of meso-erythritol in an aqueous DMSO system. Apparent specific volume values i.e. 0.51–0.71 cm3/g can predict the taste quality which is consistent with their ability to evoke a pure sweet taste. Positive values of Hepler’s constant (∂2∅vo /∂T2) represent structure making capability of meso-erythritol in water and aqueous DMSO. The obtained parameters were used to get the different mixing effects due to the interactions between meso-erythritol in water and in aqueous DMSO solutions that characterize the hydration properties and solvation behavior of sugar alcohol.

Explanation for the selective crystallization from inosine solutions using mid-frequency Raman difference spectra analysis.

Mid-frequency Raman difference spectra (MFRDS) analysis can be used to reveal the selective crystallization from solutions through determining the degree of similarity of the short-range orders between the assemblies of small organic molecules in solutions and their solid phases. Four solid phases of inosine (IR) (α-anhydrous IR (α-IR), β-anhydrous IR (β-IR), IR dihydrate (IRD), and amorphous IR (AmIR)) and two IR solutions (aqueous and 70 vol% DMSO aqueous solution) were prepared and characterized using MFRDS here. The MFRDS analysis results indicate that the selective formation of IRD and AmIR from IR aqueous solution and β-IR from IR 70 vol% DMSO solution are originated from the high similarity of their short-range structures. Moreover, we propose that the formation of α-IR from IR aqueous solution benefits from the appearance of AmIR as an intermediate phase. MFRDS is a robust tool to explain and predict the possible precipitation products from various solutions of small organic molecules.