Solubility In Organic Media Research Articles

Iron(III) Sulfate-Mediated Synthesis of 2,5-Furandicarboxylic Acid Dimethyl Ester from Galactaric Acid

2,5-furandicarboxylic acid (FDCA) is one of the most studied bio-based monomers, being considered the best substitute for fossil-derived terephthalic acid in plastic production. FDCA is employed in the preparation of polyethylene furanoate (PEF), demonstrating superior mechanical and thermal proprieties compared to the widely used polyethylene terephthalate (PET). Nevertheless, FDCA synthesis mostly relies on the oxidation of the bio-based platform chemical hydroxymethyl furfural (HMF), whose notoriously instable nature renders FDCA yield and industrial scale-up production complicated. On the contrary, FDCA esters are less studied, even though they have greater solubility in organic media, which would favor their isolation and potential application as monomers for PEF. On these premises, we report herein an alternative green synthetic approach to FDCA methyl ester (FDME) using galactaric acid as the substrate, dimethyl carbonate (DMC) as the green media, and Fe2(SO4)3 as the heterogeneous Lewis acid. Optimization of the reaction conditions allowed the selective production of FDME in a 70% isolated yield; product purification was achieved via flash column chromatography over silica. Furthermore, it was possible to employ up to 5.0 g of galactaric acid in a single reaction, leading to a good isolated yield of FDME.

Enhanced Visible Light Absorption and Photophysical Features of Novel Isomeric Magnesium Phthalocyaninates with Cyanophenoxy Substitution

Novel metal-free and Mg(II) [3/4-(3,4-dicyanophenoxy)phenoxy]-substituted phthalocyanines were obtained and characterized using NMR, IR, UV-vis spectroscopy, and mass spectrometry. This substitution provided compounds with good solubility in organic media, and thus their spectroscopic and fluorescent properties were studied. The formation of the investigated phthalocyanine complexes with central magnesium ions led to the stabilization of macrocyclic molecules in solution, preventing aggregation through specific and universal solvation. From meta-substitution to para-substitution, insignificant spectroscopic changes were observed. The complexes exhibited higher values of molar light absorption coefficients and fluorescence quantum yields (up to 55%) compared to ligands. The efficiency of both the fluorescence-quenching and singlet oxygen generation processes in the case of magnesium [3/4-(3,4-dicyanophenoxy)phenoxy]phthalocyaninates was found to exceed that of the unsubstituted zinc phthalocyaninate, which suggests the potential applicability of these compounds as PDT sensitizers.

Synthesis and Physicochemical Properties of Cryptophazane—A Soluble and Functionalizable C1‐Symmetrical Cryptophane

AbstractThe first example of a cryptophazane, a cryptophane functionalized with a nitrogen atom replacing one of the methylene bridges, is obtained with a 28 % overall yield over 8 steps, through the preparation of a C1‐symmetrical aza‐cyclotriveratrylene (aza‐CTV). Herein, we demonstrate that the introduction of a nitrogen atom on this part of the cryptophane core enhances the solubility in organic media of both the cryptophane and the synthetic intermediates, while presenting the same conformation as known cryptophanes. Cryptophazane was prepared on a multigram scale and easily functionalized. We also investigated its ability to encapsulate xenon atoms using hyperpolarized 129Xe (HP 129Xe) NMR spectroscopy. We found that both its affinity and exchange kinetics were in the appropriate range for applications in 129Xe magnetic resonance imaging (MRI). Combined with the wide range of possible functionalization, this makes cryptophazane an excellent candidate for targeted HP 129Xe MRI.

Synthesis and Physicochemical Properties of Cryptophazane-A Soluble and Functionalizable C1 -Symmetrical Cryptophane.

The first example of a cryptophazane, a cryptophane functionalized with a nitrogen atom replacing one of the methylene bridges, is obtained with a 28 % overall yield over 8 steps, through the preparation of a C1 -symmetrical aza-cyclotriveratrylene (aza-CTV). Herein, we demonstrate that the introduction of a nitrogen atom on this part of the cryptophane core enhances the solubility in organic media of both the cryptophane and the synthetic intermediates, while presenting the same conformation as known cryptophanes. Cryptophazane was prepared on a multigram scale and easily functionalized. We also investigated its ability to encapsulate xenon atoms using hyperpolarized 129 Xe (HP 129 Xe) NMR spectroscopy. We found that both its affinity and exchange kinetics were in the appropriate range for applications in 129 Xe magnetic resonance imaging (MRI). Combined with the wide range of possible functionalization, this makes cryptophazane an excellent candidate for targeted HP 129 Xe MRI.

Reversible Complexation Mediated Living Radical Polymerization Using Tetraalkylammonium Chloride Catalysts.

This work reports the first use of organic chloride salts as catalysts for reversible complexation mediated living radical polymerization. Owing to the strong halogen-bond forming ability of Cl- , the studied four tetraalkylammonium chloride catalysts (R4 N+ Cl- ) successfully control the polymerizations of methyl methacrylate, yielding polymers with low dispersities up to high monomer conversion (>90%). Benzyldodecyldimethylammonium chloride is further exploited to other methacrylates and yields low-dispersity block copolymers. The advantages of the chloride salt catalysts are wide monomer scope, good livingness, accessibility to block copolymers, and good solubility in organic media. Because of the good solubility, the use of the chloride salt catalysts can prevent agglomeration of catalysts on reactor walls in organic media, which is an industrially attractive feature. Among halide anions, chloride anion is the most abundant and least expensive halide anion, and therefore, the use of the chloride salt catalysts may lower the cost of the polymerization.

Synthesis, structure and antibacterial properties of a mononuclear Ag(I) complex, [Ag(OBz)(PTA)2] (OBz = benzoate, PTA = 1, 3, 5-triaza-7-phospadamantane)

A new silver complex, namely [Ag(OBz)(PTA)2] (where OBz = benzoate and PTA = 1, 3, 5-triazaphospadamantane) has been synthesized and structurally characterized. The silver center resides in a triangular coordination environment, noticeably deviated from the plane defined by three ligands. [Ag(OBz)(PTA)2] has excellent aqueous solubility and also moderate solubility in organic media. Antibacterial studies indicated the effectiveness of this complex towards growth inhibition of three nosocomial pathogens, namely, B. cereus, S. aureus and P aeruginosa. The MIC and IC50 values clearly suggested that the complex induced more significant antibacterial activity against the Gram (+) strains compared to the Gram (−) variety.

Получение и свойства аминиевых солей (1-гидроксиэтилиден)дифосфоновой кислоты

An overview of the preparation methods and properties of (1-hydroxyethylidene) diphosphonic acid aminium salts is presented. (1-Hydroxyethylidene) diphosphonic acid with monoethanolamine forms a crystalline compound, which, according to the elemental analysis and XRD data, is ternary C(CH3)(OH)[P(O)O-NH3+CH2CH2OH]3[P(O)(OH)] amine salt. A characteristic feature of the derivatives of (1-hydroxyethylidene) diphosphonic acid and tris (hydroxymethyl)aminomethane is the formation of glassy and resinous products. Their composition Н4L∙4NH2C(CH2OH)3 corresponds to 4 base molecules per 1 tetrabasic acid molecule. The addition of 4 molecules of the primary amine occurs both when the ratio of the initial reagents is 1: 4 and 1: 3. The polymer structure and the presence of strong hydrogen bonds in the Н4L∙4NH2C(CH2OH)3 compound lead to its very low solubility in organic media and good solubility in water. The solubility of Н4L∙4NH2C(CH2OH)3 in methanol is 1.8 g per 100 mL. The reaction of (1-hydroxyethylidene)diphosphonic acid with para-aminobenzoic acid leads to the formation of bis(4-carboxyphenylamine)(1-hydroxyethylidene)diphosphonate C(CH3)(OH)[P(O)(OH)O-NH3+C6H4С(О)ОН]2. In a crystal, this compound consists of the anion of the double-deprotonated (1-hydroxyethylidene)diphosphonic acid C(CH3)(OH)[P(OH)(O)O-]2 and two amine cations NH3+C6H4С(О)ОН. The tetrabasic acid binds 3 molecules of morpholine, giving tris(morpholinium)(1-hydroxyethylidene)diphosphonate H4L•3HN(CH2CH2)2O in the form of a white powder that dissolves well in water, methyl and ethyl alcohols. The solid complex of morpholine with (1-hydroxyethylidene)diphosphonic acid does not crystallize from various solvents, which may be caused by the oligomeric form of morpholine included in the molecule of the complex with H4L.

Dynamic Covalent Polymerization of Chalcogenide Hybrid Inorganic/Organic Polymer Resins with Norbornenyl Comonomers

Elemental sulfur (S8) is an inexpensive chemical feedstock for polymeric materials but has the disadvantages of poor solubility in organic media and inferior physical properties in the elemental form. We report on the preparation of organosulfur chalcogenide hybrid inorganic/organic polymer (CHIPs) based on bifunctional norbornene comonomers using dynamic covalent polymerization (DCP). A poly(sulfur-random-styrene) (p(S-r-Sty)) resin was utilized to address the limited solubility/ miscibility of norbornene-containing comonomers in liquid sulfur. This report demonstrated the ability to expand the scope of organic comonomers to prepare organosulfur CHIPs from elemenatal sulfur using a combination of inverse vulcanization and dynamic covalent polymerization.

Thioxanthone-based amidine: An efficient nonionic photobase generator for thiol-based click polymerization under visible LED light

With the fast development of the long-wavelength irradiation sources, such as light emitting diodes (LED), which possess advantages regarding irradiation safety and energy utilization efficiency, it is highly desired to develop efficient photobase generators (PBGs) sensitive to visible light. Currently, the reported efficient visible light PBGs mainly undergo photodecarboxylation to generate the super bases, while the released CO2 can potentially cause bubbles and cracks in the cured materials. Moreover, these ionic PBGs generally have poor solubility in organic media and limited thermal stability. In the present work, we have investigated a nonionic amidine PBG TX-DBN, which contains thioxanthone as a chromophore and a reduced form of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) as a latent base species. TX-DBN, with a strong absorption above 380 nm, showed excellent solubility in most organic solvents and commercial monomers/oligomers. Under irradiation with an LED lamp at 405 nm, TX-DBN undergoes a CN bond cleavage followed by a fast hydrogen transfer, leading to the generation of the super base DBN without the generation of CO2. The as-released active species, namely super bases and active free radicals, can trigger thiol-epoxy and thiol-ene polymerization to fabricate hybrid network.

Tuning Merocyanine Photoacid Structure to Enhance Solubility and Temporal Control: Application in Ring Opening Polymerization

AbstractHerein we report the development of a merocyanine‐based photoacid with improved solubility in organic media and enhanced switching kinetics that can be used to impart temporal control over ring opening polymerization. The effect of the structural modification on solubility, thermal relaxation kinetics and activation energy were evaluated using 1H NMR and pump‐probe absorption spectroscopies. Overall, the new merocyanine based photoacid provides access to a wider range of chemical and material applications with improved solvent compatibility and temporal control.

New Magnesium(II), Aluminum(III), and Gallium(III) 12-Crown-4-Porphyrinates: Synthesis, Structure, and Luminescent Properties

New meso-tetra(benzo-12-crown-4)-substituted magnesium(II), aluminum(III), and gallium(III) porphinates are obtained. The structure of complexes is established using the data of electron absorption spectroscopy and MALDI TOF mass spectrometry. Comparative analysis of luminescent properties (energies of fluorescent transitions and fluorescence quantum efficiency) of metal porphyrinates and free meso-tetra(benzo-12-crown-4)-substituted porphyrin in a dimethylformamide solution at 25°C. It is found that the obtained metal porphyrinates are characterized by rather intense fluorescent radiation, as well as solubility in organic media of very different polarities, which allows considering new complexes as potential luminescent sensors for metal cations and as luminescent agents of metal cation interphase transfer.

Extraction of Cesium-137 and Americium-241 by Calix[n]arenes from Carbonate-Alkaline Media

Trends of cesium-137 and americium-241 extraction from carbonate–alkaline media with p-tert-butylcalix[n]arenes with macrocycles of different size (n = 4, 6, 8), including monofunctional derivatives with lipophilic substituents for increasing their solubility in organic media, were studied. It was demonstrated that O-n-octyl ethers of p-tert-butylcalix[6]arene appeared to be the most efficient extractants for Cs(I) cations, while it was p-tert-butylthiacalix[4]arene for and americium(III) cations.

Comparative roles of Zr4+ and Ni2+ Wells-Dawson hetero-metal substituted polyoxometalates on oxidation of chemical contaminants

Rapid oxidation of a persistent organophosphate chemical warfare agent (CWA) analogue by aqueous 15wt% hydrogen peroxide solutions containing hetero-metal substituted Wells-Dawson polyoxometalates (POMs), [Zr(α2-P2W17O61)2]16− and [Ni(α2-P2W17O61)]8−, was accomplished. A novel decontamination method was employed in which oxidation reactions were performed via direct application of aqueous POM solutions onto the CWA analogue, notably without the use of surfactants to promote POM solubility in organic media. POM facilitated reactions occurred at the interface of the aqueous decontamination solution and organic contaminant, the biphasic nature of which affords easy separation and recovery of the POM catalyst for future use. Oxidation of Demeton-S with 15wt% hydrogen peroxide alone was slow with a reaction half-life of 40.9min. Incorporation of Ni2+ and Zr4+ POMs increased the oxidation rate significantly and reduced the reaction half-lives to 20.5 and 2.2min, respectively. The Ni2+ POM increased the rate of reactive species formation by decomposing hydrogen peroxide. The Zr4+ POM when dissolved in 15wt% hydrogen peroxide resulted in a beneficial in situ structural rearrangement, generating the Zr4+ POM species [Zr(H2O)3(α2-P2W17O61)]6− and the Venturello complex ([PO4{W(O)(O2)2}4]3−), with other tungsten peroxo species. The combination of these highly active compounds in solution increased the reaction rate 20-fold over hydrogen peroxide alone, with a half-life of 2.2min.

Cohelical Crossover Network by Supramolecular Polymerization of a 4,6-Acetalized β-1,3-Glucan Macromer.

Natural polysaccharides represent a renewable resource whose effective utilization is of increasing importance. Chemical modification is a powerful tool to transform them into processable materials but usually sacrifices the original structures and properties of value. Here we introduce a chemical modification of Curdlan, a β-1,3-glucan, via 4,6-acetalization. This modification has successfully combined a helix-forming ability of Curdlan with new solubility in organic media. Furthermore, it has operationalized efficient cohelical crossovers (CCs) among the helices to demonstrate the formation of an extensive supramolecular network that goes well beyond the nanoscopic regime, allowing for preparation of flexible self-supporting films with macroscopic dimensions. This protocol, which is now viewed as supramolecular polymerization of a helical polysaccharide macromer, can add a new dimension to "polysaccharide nanotechnology", opening a door for the creation of unconventional polymer materials based on the cohelical crossover network (CCN).

Induced cholesteric solutions of highly soluble bis-salicylaldiminate Cu(II) metallomesogens and their rheological behaviour

Copper(II) complexes containing chiral centres and functionalised with citronellyl end groups were synthesised. Isomerisation of citronellyl double bond was exploited to decrease the melting temperature of the complexes and improve their solubility in organic media. The chiral metallomesogens were successfully used to produce induced cholesteric solutions in commercial nematic liquid crystals also in high concentrations. Transparent and coloured thin films were easily obtained showing good reflective properties across the visible spectrum. The rheological behaviour of the nematic and the cholesteric phases was investigated. The nematic system showed the characteristics of a tumbling phase with a very peculiar transient behaviour. The cholesteric samples also showed a very unusual, flow-history-dependent transient behaviour. The viscosity trend presumably indicates a flow-induced orientation of the cholesteric superstructure, thus opening the way to the possibility of tuning the yield stress level of the material. The results support the potentiality of these compounds for applications in light reflecting technology.

Single-walled carbon nanotubes decorated with a pyrene–fluorenevinylene conjugate

Single-walled carbon nanotubes are noncovalently functionalized using a pyrene–fluorenevinylenedye and the resulting nanohybrids are isolated from the free molecules. The tubes modifiedby means of this noncovalent approach show enhanced solubility in organic media. Thestructure and morphology of this hybrid material are fully characterized using absorption,infrared and Raman spectroscopies as well as atomic force and scanning electronmicroscopies. Steady state fluorescence measurements reveal that significant quenching ofthe pyrene derivative excited state takes place through an energy transfer mechanism.

Living Radical Polymerizations with Germanium, Tin, and Phosphorus Catalysts − Reversible Chain Transfer Catalyzed Polymerizations (RTCPs)

A novel class of living radical polymerizations with germanium, tin, and phosphorus catalysts were developed. The polymerizations are based on a new reversible activation mechanism, Reversible chain Transfer (RT) catalysis. Low-polydispersity (M(w)/M(n) approximately 1.1-1.3) polystyrene, poly(methyl methacrylate), poly(glycidyl methacrylate), and poly(2-hydroxyethyl methacrylate) with predicted molecular weight were obtained with fairly high conversion in a fairly short time. The pseudo-first-order activation rate constant kact for the styrene/GeI4 (catalyst) system was large enough, even with a small amount of GeI4, explaining why the system provides low-polydispersity polymers from an early stage of polymerization. The retardation in the polymerization rate observed for the styrene/GeI4 system was kinetically proven to be mainly due to the cross-termination between the propagating radical with GeI3*. Attractive features of the germanium, tin, and phosphorus catalysts include their high reactivity hence small amounts (1-10 mM) being required under relatively mild conditions (at 60-100 degrees C), high solubility in organic media without ligands, insensitivity to air hence sample preparation being allowed in the air, and minor color and smell. The germanium and phosphorus catalysts may also be attractive for their low toxicity. The phosphorus catalysts may also be attractive for their low cost.

Germanium‐ and Tin‐Catalyzed Living Radical Polymerizations of Styrene and Methacrylates

AbstractSummary: Ge and Sn (non‐transition‐metal) catalyzed living radical polymerizations were developed. Low‐polydispersity (Mw/Mn ∼ 1.1–1.3) polystyrenes, poly(methyl methacrylate)s, poly(glycidyl methacrylate)s, and poly(2‐hydroxyethyl methacrylate) with predicted molecular weights were obtained with a fairly high conversion in a fairly short time. The pseudo‐first‐order activation rate constant kact for the styrene/GeI4 (catalyst) system was large enough, even with a small amount of GeI4, to explain why the system provides low‐polydispersity polymers from an early stage of polymerization. The retardation in the polymerization rate observed for the styrene/GeI4 system was kinetically proved to be mainly due to the cross‐termination between the propagating radical with GeI. Attractive features of the Ge and Sn catalysts include their high reactivity hence small amounts (1–5 mM) being required under a mild condition (at 60–80 °C), high solubility in organic media without ligands, insensitivity to air hence sample preparation being allowed in the air, and minor color and smell. The Ge catalysts may also be attractive for their low toxicity.

Dendrimer Complexes Based on Fine-Controlled Metal Assembling

Abstract A series of novel dendrimers composed of dendritic phenylazomethines (DPAs) were synthesized with several types of functional cores. The metal assembling to the DPAs is stepwise by the layers, therefore, they can be used as a scaffold for the precise hybridization between metal ions and organic macromolecules. Because of uniform structure of the dendrimer, there is no structural dispersion in the macromolecule–metal hybrid of the DPAs. Also, the number of metal ions loaded in one dendrimer should have no statistical distribution in principle due to the precise metal assembling. A rigid π-conjugating backbone structure contributes not only to the stepwise metal assembly, but also to the solid-state stability under high temperature. Development of this property without any reduction in solubility in organic media enabled the easy preparation of homogeneous amorphous films in which the metal and macromolecule are precisely hybridized. As a result, the thin solid of the metal-assembling dendrimer acts as an excellent organic semiconductor in the hole-transport layer of a light-emitting diode. Metal-assembling DPAs also enhance the electron-transfer reaction as a protein-like catalyst. The DPA having a cobalt porphyrin core-could catalyze the CO2 reduction at an applied overpotential 1.1 V lower than that needed for the catalysis by a model compound of the porphyrin core (CoTPP). Reversible encapsulation/release of multiple irons is also demonstrated as a mimic of the iron storage protein (Ferritin). The switching between these two coordinating states can be completely controlled by the redox states of the iron (FeII/FeIII). The finding of these unique dendritic ligands will afford new insight into molecular design for finely controlled macromolecule–metal hybrid materials.

5‐(Pyrrolidin‐2‐yl)‐1H‐tetrazole and 5‐[(Pyrrolidin‐2‐yl)methyl]‐1H‐tetrazole: Proline Surrogates with Increased Potential in Asymmetric Catalysis

Catalytic enantioselective methodology has dramatically been enriched by the re-discovery of the simple amino acid proline as a chiral catalyst in the year 2000. Although no catalyst offers such a simple and broad access to quite complex reaction products, as does proline, its synthetic potential is not unrestricted, what is especially connected to its poor solubility in organic media. Exchange of the carboxylic moiety by a tetrazole unit leads to proline surrogates, that by far outperform proline with respect to yield, enantioselectivity, reaction time, substrate and solvent scope, catalyst loading, and stoichiometry of the compounds used in excess. These factors are discussed and critically compared with selected representative proline-catalyzed reactions.