Normal Organic Solvents Research Articles

Simultaneously reinforcing and toughening of shape-memory epoxy resin with carboxylated lignosulfonate: Facile preparation and effect mechanism

To improve the compatibility and reactivity of lignosulfonate (LS) with epoxy oligomers, the LS was firstly functionalized with anhydride via the carboxylation reaction. The carboxylated lignosulfonate (CLS) reinforced epoxy resin with excellent mechanical and shape memory performance was prepared facilely via distributing the CLS into the combined epoxy monomers of DGEBA and PEGDGE with the aid of water, rather than using the normal organic solvents. The incorporated CLS promoted the curing reaction of epoxy resin. A typical sea-island structure was formed in the cured sample at the CLS content of 5 phr, exhibiting the highest increases in tensile strength, modulus, elongation at break and toughness by 23.8 %, 18.2 %, 217 % and 113 %, respectively, relative to neat epoxy. Interestingly, the incorporation of CLS at a proper amount led to the simultaneous strengthening and toughing effects on cured epoxy resin, which could be attributed to the rigid structure of CLS covalently introduced in the epoxy resin network and the heterogeneous structure formed in the epoxy matrix. The rigid CLS component also restrained the movement of chain segments, consequently, the mechanical stability was enhanced and the fast shape recovery rate of epoxy resin network was slowed down to some extent.

Multipurpose conjugated block copolymers based on novel triphenylylamine derivatives and squaric acid for electrochromic and resistive memory devices

Here, we synthesized two kinds of novel conjugated block copolymers P1 and P2 by reacting squaric acid and three kinds of homemade diamine monomers. The polymers P1 and P2 can be dissolved in many normal organic solvents and form films by solution-cast method with high mechanical properties. In addition, when the 10% weight loss is selected as a reference point, the polymers P1 and P2 showed the thermal decomposition temperatures at around 309 and 312 °C, respectively. The polymer films exhibit high coloration efficiencies (CE) (262–282 cm2 C−1) and good cyclic stabilities. In addition, the ITO/polymer/Al sandwich memory devices exhibited non-volatile resistive switching behaviors with low write, erase voltages (more than −0.6 V and less than 3.1 V, respectively), good ON/OFF ratio (843 and 1435) and reliable cycling endurance (more than 30,000 cycles). These properties illustrate that the polymers could be considered as potential electrode materials for both electrochromic and resistive memory devices.

Tuning band gap, color switching, optical contrast, and redox stability in solution-processable BDT-based electrochromic materials

Abstract 2,6-bis(trimethylstannane)-4,8-bis(2-octyldecyloxy)benzo[1,2-b:4,5-b′]dithiophene coupled with 2,5-didecyloxy-1,4-dibromobenzene and 4,7-dibromo-5,6-dioctyloxy-2,1,3-benzothiadiazole using Stille-coupling polymerization to afford the non D-A type polymer P1 and D-A type polymer P2, respectively. Two polymers displayed excellent solubility in normal organic solvents, so series of chemical instrumental analysis, such as NMR, GPC and elemental analysis, were carried out to confirm the inner structure and composition of the polymers. Different structure types exerted great influence on polymer's optical, electrochemical and electrochromic properties. Compared with P1 film, the introduction of the strong electron-withdrawing group benzothiadiazole improved conjugate effect along the polymer backbone of P2, which caused the redshift of ultraviolet–visible absorption spectrum and significant reduction in energy band gap. In addition, electrochromic performance test results showed that the P1 polymer film can switch between the orange-yellow and gray, while P2 film changed from blue in the neutral state to light yellow in the oxidation state. Moreover, the optical contrasts and response times of the polymer films also showed great differences due to the different molecular structure types. Higher transmittance changes and less sensitivity to the step interval on optical contrast indicated the fast switching speed and the superior cycle stability of P2 film.

Bulky 4,6-disubstituted tetraphenylethene-naphthalimide dyad: synthesis, copolymerization, stimuli-responsive fluorescence and cellular imaging.

We report the design and synthesis of a tetraphenylethene substituted with naphthalimide at the 4, 6 positions, named NI-2TPE. NI-2TPE exhibits strong solvent-dependent emission properties with combined ICT and AIE characteristics in THF-H2O systems. This probe was used directly on test papers to distinguish normal organic solvents using their emission colours under UV light based on its AIE and ICT nature. Thanks to the vinyl group in NI-2TPE, we synthesized a copolymer of NIPAM and NI-2TPE, termed P(NIPAM-co-NI-2TPE). The resulting polymer is highly soluble and fluorescent in water (ΦF = 15.4%). Due to the well-known thermo-responsive character of NIPAM, P(NIPAM-co-NI-2TPE) exhibits an interesting fluorescence change in response to various temperatures. Due to the thermo-induced shrinking of the PNIPAM chain, the fluorescence intensity gradually increased from 20 to 34 °C. As the temperature further increased from 34 to 90 °C, the fluorescence intensity decreased sharply, which was caused by the well-known thermal effects. Furthermore, we synthesized a P(HEA-co-NI-2TPE-TPP acrylate) copolymer, in which HEA is a hydrophilic unit, TPP is a mitochondria label and NI-2TPE a fluorescent probe. The corresponding polymer probe is highly soluble in water with FLQY = 7% and we have further applied this probe as a mitochondria targeted imaging tracker in HeLa cells successfully.

Europium-containing ionic liquids and crystal complexes based on phosphine oxides

We synthesized two Eu-containing ionic liquids (ILs) [Eu(TOPO)4(NO3)2]NTf2 and [Eu(TBPO)4(NO3)2]NTf2, and a crystal [Eu(TPhPO)4(NO3)2]NTf2. In these complexes, TOPO (Tri-n-octylphosphine oxide) and TBPO (Tri-n-butylphosphine oxide) coordinate with Eu3+ constituting the cations, while NTf2− (bis(trifluoromethylsulfonyl)imide anion) acts as the counter anion. The crystal structure of [Eu(TPhPO)4(NO3)2]NTf2 showed the details of the coordinated condition. The infrared spectra of all the complexes exhibited some typical features of the phosphine oxides and two bidentate nitrates. [Eu(TRPO)4(NO3)2]+ (R=octyl and butyl) were proved to exist in the C2H2Cl2 solutions by 31P NMR of [Eu(TOPO)4(NO3)2]NTf2 and [Eu(TBPO)4(NO3)2]NTf2. The luminescence emissions also gave information about the same coordination environments. Thermogravimetric analyses (TGA) indicated that the NTf2− group determined the decomposition temperatures of the three complexes. These complexes are the first tetra-phosphine oxide complexes constituted by Eu(NO3)3 and phosphine oxides in the presence of NTf2−. The structural difference between [Eu(TRPO)4(NO3)2]NTf2 in this work and Eu(TRPO)3(NO3)3 formed in traditional organic solvent can help understand that new extraction species may exist in the NTf2−-based IL extraction system different from those in the normal organic solvent extraction system.

Purple Staining of Archaeological Human Bone: An Investigation of Probable Cause and Implications for Other Tissues and Artifacts

Excavations in the 1990s at the medieval Chapter House of Worcester Cathedral, UK, revealed medieval human skeletal remains, some of which exhibited a distinctive purple coloration. The nature of the colored bone was investigated using solvents for stain extraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray fluorescence (XRF), plane polarized (PPL) and cross-polarized (XPL) light microscopy, and auto fluorescence (AF) microscopy. Normal bone from the cemetery was used as a control. The color does not arise from a stain soluble in normal organic solvents. EDX and XRD analysis showed no significant difference between purple and normal bone. XRF analysis shows the presence of trace levels of iron, manganese, zinc, and copper in the affected material. This exhibited a pink color in acid phase and a blue color in alkaline phase. These two states were reversible. The alkaline phase gradually changed irreversibly to yellow over time. These data suggest that the coloration is consistent with the presence of high levels of purple acid phosphatase (PAP) enzyme. The presence of trace amounts of iron, manganese, zinc, and copper suggests a plant or fungal origin for the putative PAP, possibly a member of theAspergillus ficuumspecies.

Human urine-derived stem cells in combination with polycaprolactone/gelatin nanofibrous membranes enhance wound healing by promoting angiogenesis.

BackgroundDespite advancements in wound healing techniques and devices, new treatments are needed to improve therapeutic outcomes. This study aimed to evaluate the potential use of a new biomaterial engineered from human urine-derived stem cells (USCs) and polycaprolactone/gelatin (PCL/GT) for wound healing.MethodsUSCs were isolated from healthy individuals. To fabricate PCL/GT composite meshes, twin-nozzle electrospinning were used to spin the PCL and gelatin solutions in normal organic solvents. The morphologies and hydrophilicity properties of PCL/GT membranes were investigated. After USCs were seeded onto a PCL/GT, cell adhesion, morphology, proliferation, and cytotoxicity were examined. Then, USCs were seeded on a PCL/GT blend nanofibrous membrane and transplanted into rabbit full-thickness skin defects for wound repair. Finally, the effect of USCs condition medium on proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) were performed in vitro.ResultsUSCs were successfully isolated from urine samples and expressed specific mesenchymal stem cells markers and could differentiate into osteoblasts, adipocytes, and chondrocytes. PCL/GT membrane has suitable mechanical properties similar with skin tissue and has good biocompatibility. USCs-PCL/GT significantly enhanced the healing of full-thickness skin wounds in rabbits compared to wounds treated with PCL/GT membrane alone or untreated wounds. USCs-PCL/GT-treated wounds closed much faster, with increased re-epithelialization, collagen formation, and angiogenesis. Moreover, USCs could secrete VEGF and TGF-β1, and USC-conditioned medium enhanced the migration, proliferation, and tube formation of endothelial cells.ConclusionUSCs in combination with PCL/GT significantly prompted the healing of full-thickness skin wounds in rabbits. USCs based therapy provides a novel strategy for accelerating wound closure and promoting angiogenesis.

Perchloroetylene and Dibutyltin Dichloride Removal from Packed Column by Surfactant Solution

Surfactant enhanced remediation is viewed as a potential method for removing organometallic compounds from contaminated aquifers. Dibutyltin dichloride (DBT), as a representative organometallic compound, was applied in sand packed columns to observe its solubilization behavior compared to that of perchloroetylene (PCE), a normal organic solvent. Ottawa sand was used as the porous media. A mixture of DBT and PCE was applied as the contaminant. The tracer study exhibited the plug flow condition with a retention time of 79.9 min. The surfactant solution was a mixture of 3.6 wt% SDHS and 0.4 wt% C16DPDS with various concentrations of CaCl2.The column experiments were carried out by single and gradient surfactant systems. The effluent exhibited a general solubilization pattern for PCE, governed by a rate limiting mechanism. However, the concentration of DBT in the effluent observed in every experiment was just a slice of its solubilization capacity.The adsorption of DBT on the sand was suspected to be the cause of the problem. The solubilization of DBT by a surfactant was ineffective at removing DBT from the contaminated media. It may be concluded that DBT exhibits the properties of both an organic and inorganic compound; it could be solubilized by a surfactant and absorbed strongly on sand. Nevertheless, the results indicate that trapped DBT could be removed by mobilization in the form of a PCE-DBT mixture and that adsorption could be prevented by a very low pH condition.

Synthetic and structural studies of piperidine carboxamide uranyl ion complexes

New piperidine based ligands of the type [C5H10NCONR2] (where R=CH3 (L1), C2H5 (L2) and iC3H7 (L3)) have been prepared and characterized. The complex chemistry of these ligands with uranyl chloride, bromide, nitrate and β-diketonates has been studied using IR and NMR spectroscopic methods. Crystal structures for the complexes [UO2Cl2(L3)2] (1), [UO2Br2(L3)2] (2) [UO2(NO3)2(L3)2] (5) and [UO2(C4H3SCOCHCOCF3)2(L3)] (8) have been determined by the X-ray diffraction method. The structures of 1 and 2 show that the uranyl ion is surrounded by two of the ligands and two halogen atoms in an octahedral geometry. The structure of 5 shows that the uranyl group is surrounded by two nitrate groups and two ligands in a hexagonal bipyramidal geometry. The structure of 8 shows that the uranyl group is surrounded by two β-diketonates and one ligand in a pentagonal bipyramidal geometry. The structures show that the carboxamide ligands are strongly bonded to the uranyl group, showing a near linear geometry for the U–O–C bond (angle 150–159°). The prepared chloro and bromo compounds are air and moisture stable and show good solubility in normal organic solvents.

In Stationary Regime, Electron Transfer Rates in RTIL Media Are Diffusion Controlled: Experimental Evidence from Pulse Radiolysis Study

We report electron transfer (ET) process from the long-lived radical anions of pyrene and benzophenone to molecular acceptors, e.g., benzophenone and fluorenone, respectively, in two RTIL media, namely, [BMIM][PF6] and [BMIM][BF4], as well as a few other conventional organic solvents using the nanosecond pulse radiolysis technique. Decay of the donor radical anion and concomitant formation of the acceptor radical anion ensure a bimolecular ET process. The rate constants for the bimolecular ET process in both normal organic solvents and RTILs have been found to be nearly equal to diffusion controlled rate calculated for the corresponding solvent. For long-lived anions, having lifetimes longer than a few hundred nanoseconds, quenching occurs mainly in the stationary regime. In this regime, the ET rate is fully controlled by the rate of diffusion of the reactive species in those solvents. To the best of our knowledge, this is the first experimental evidence of the diffusion controlled ET process occurring in the stationary regime in RTIL media.

Review: Recent Application of Chiral Liquid Chromatography-Tandem Mass Spectrometric Methods for Enantiomeric Pharmaceutical and Biomedical Determinations

The technology of analyzing the pharmacological and toxicological properties of chiral drugs has become more commonly utilized since the knowledge of the biological actions of enantiomers has been gradually acquired during the last few decades. This work reviews the applications of chiral liquid chromatography coupled to tandem mass spectrometry (LC-MS) for the analysis of chiral pharmaceuticals since 2005. The enantioselective determinations in pharmaceutical and biomedical fields with LC-MS are classified based on three mobile phase modes, including normal phase, reversed phase and polar organic solvent, in terms of their compatibility with various ionization sources and specific applications.

Studies on Chemical Modification of Porous Silicon‐Based Graded‐Index Optical Microcavities for Improved Stability Under Alkaline Conditions

AbstractPreparation of graded‐index optical microcavities based on porous silicon is demonstrated, and chemical modifications for obtaining improved stability under alkaline conditions are studied. Four surface modification methods for stabilizing the samples are examined, and the effects on the optical properties are verified. Two different thermal carbonization treatments resulting in hydrophilic and hydrophobic surfaces are employed. In addition, modification with undecylenic acid is performed on as‐prepared and thermally hydrocarbonized porous silicon surfaces. Stability and sensing capabilities of the modified samples are examined by subjecting them to different concentrations of methylamine and trimethylamine vapors. Vapor induced changes in the reflectance spectra are used for evaluating sensitivity and stability. Sensitivity towards ethanol vapor is also measured in order to compare the sensitivity to a normal organic solvent. The results show that the two carbonization treatments and the undecylenic acid functionalization of the hydrocarbonized surface result in greatly improved stability. In contrast, derivatization of as‐prepared porous silicon with undecylenic acid does not protect the surface sufficiently against oxidation under the highly basic conditions produced by the amine vapors. Surface chemistry is also shown to have a large effect on sensitivity towards the examined vapors. X‐ray photoelectron spectroscopy was used to assess changes in elemental composition of sample surface. The results suggest that thermally promoted addition of undecylenic acid on hydrocarbonized porous silicon is an effective method for producing highly stable optical structures with a carboxyl group functionalization.

New Hyperbranched Polytriazoles Containing Isolation Chromophore Moieties Derived from AB4 Monomers through Click Chemistry under Copper(I) Catalysis: Improved Optical Transparency and Enhanced NLO Effects

By modifying a synthetic procedure, two new hyperbranched polytriazoles (HP1 and HP2) containing isolation chromophores were synthesized successfully through click chemistry reactions under copper(I) catalysis. For the first time, these two polymers were derived from an AB(4)-type monomer, although they contain different end-capping chromophores. They are soluble in normal polar organic solvents and are well characterized. Thanks to the presence of the isolation chromophore, the two polymers demonstrate good nonlinear optical (NLO) properties and optical transparency, making them promising candidates for practical applications.

ChemInform Abstract: An Improved Acid Chloride Preparation via Phase-Transfer Catalysis.

Phase transfer catalysis has been found to be effective for the rapid conversion of carboxylic acids in high yield to the corresponding acid chlorides. The procedure is well suited for acids that exhibit low solubilities in normal organic solvents

Hindered Intramolecular Electron Transfer in Room-Temperature Ionic Liquid

Three perylene tetracarboxylic diimide (PDI) compounds, namely, N,N'- di(2-N'',N''-dimethylamino)ethylperylene-3,4:9,10-tetracarboxylic diimide (1), N,N'-di(2-N'',N''-dimethylamino)propylperylene-3,4:9,10-tetracarboxylic diimide (2), and N,N'- dicyclohexyl-1,7-pyrrolidinylperylene-3,4:9,10-tetracarboxylic diimide (3), have been designed and prepared. Their photophysical properties in room-temperature ionic liquid (RTILs) were studied by steady-state absorption and emission spectra and fluorescence lifetime measurements. The intramolecular photoinduced electron transfer from dimethylamine to PDI in 1 and 2 has been efficiently hindered because of the solvation of RTILs. A two-conformation mechanism for the PET in 1 and 2 is proposed, which explains the results of the fluorescence lifetime measurements well. The solvation of RTILs to 3 resembled that of a normal polar organic solvent with polarity larger than that of DMF.

A Practical Approach for the Preparation of Regioregular Poly(3-hexylthiophene)

Scheme 1. Preparation of monomer Polythiophenes have been intensively studied over the last three decades. And major studies have been focused on poly 3-alkylthiophene especially poly 3-hexylthiophene (P3HT), which has shown very unique properties in conducting polymer applications. Of these, the most notable property is electrical conductivity, which is contributed to the delocalization of πelectrons through overlap of π-orbitals. In addition to this, since it is very soluble in normal organic solvents, a good processability has been observed. In general, preparation of P3HT could be achieved by either chemical or electrochemical method. For electrochemical polymerization including FeCl3 catalyzed polymerization, a potential was applied to a solution containing monomer and electrolyte. Chemical synthesis was performed by metal-mediated polymerization of monohalogenated and/or dihalogenated thiophene derivatives under appropriate conditions. An advantage in chemical polymerization over electrochemical method is that this method generally affords a highly regioregular polymer in excellent yields. Since regioregularity of P3HT is a critical element for the application of this polymer, a lot of different procedures have been developed especially in chemical synthetic methods. Generally accepted methods include metal (Ni) catalyzed self-condensation of thienyl organozinc and thienyl Grignard reagents. A big breakthrough for the preparation of regioregular P3HT has been reported by Rieke and McCullough, separately. From these works, high regioregular (> 98%) head-to-tail P3HT has been achieved with reasonable molecular weight. As mentioned above, 2,5-dibromo-3-alkylthiophenes have been extensively used as a monomer in the chemical synthetic method. However, only a few examples of using 2-bromo-5iodo-3-alkylthiopenes have been appeared in the chemical method. Recently, Knochel and co-workers introduced the application of commercially available and relative cheap zinc powder to organic synthesis. This work prompted us immediately to study the possibility of using zinc powder in the preparation of P3HT. To this end, 2-bromo-5-iodo-3-alkylthiopene could be the most proper candidate since zinc dust showed excellent insertion reactivity to carbon-iodine bond. Here, we wish to report the first result obtained from the application of the activated zinc dust to the preparation of regioregular P3HT.

Conjugated ethynylene-fluorenepolymers with electro-donating TTF as pendant groups: Synthesis, electrochemical and spectroscopic properties

A series of conjugated ethynylene-fluorene polymers with electro-donating TTF as pendant groups (P2–P4) were synthesized by using Sonogashira coupling reaction, and two functionalization methods, i.e. prepolymerization and postpolymerization, were developed. The composition and purity of the corresponding products were analyzed by 1H NMR. The results proved the functionalization of P2 (pre) and P2 (post) were 40% and 100%, respectively. The results also indicated that the postpolymerization method would be a better approach to prepare TTF-pendant conjugated ethynylene-fluorene polymers. The postpolymerization methodology could be extended to synthesize other conjugated fluorene-based polymers bearing TTF units (P3 and P4). The polymers mentioned above exhibited good solubility in normal organic solvents and higher conductivity (neutral conductivity ∼2–4 × 10−6 S cm−1; doped conductivity ∼1–3 × 10−3 S cm−1). Moreover, the fluorescence intensity of P2 (post) could be modulated by the oxidation of TTF units, which makes it an attractive candidate for the fluorescence switch.

Hydrocarbon Metallosurfactants for CO2

Cobalt and nickel salts of the highly branched trichain anionic surfactant sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulfonate (TC14) are shown to be soluble in dense CO(2) at concentrations up to 6 wt % at 500 bar pressure. This is a remarkably high solubility for such hydrocarbon transition metal surfactants in CO(2). High-pressure small-angle neutron scattering (HP-SANS) has been used to study the surfactant aggregates in a normal organic solvent, cyclohexane, dense CO(2), and also mixtures of these two pure solvents. The results show that transition metal TC14 derivatives are viable compounds for incorporating reactive and functional metal ions into CO(2).

Efficient Preparation of Separable Pseudo[n]rotaxanes by Selective Threading of Oligoalkylammonium Salts with Cucurbit[7]uril

We describe the efficient preparation of well-defined, homogeneous pseudo[n]rotaxanes (n = 2, 3, 4, 5) by the selective threading of oligoalkylammonium salts with cucurbit[7]uril (CB[7]) and the subsequent simple separation of the pure pseudo[n]rotaxanes from the complicated system. A series of well-defined oligoalkylammonium salts were prepared by stepwise synthesis and their molecular recognition and self-assembly with a solution of CB[7] in CF(3)CO(2)D/D(2)O (1:1 v/v) were investigated. As a result of the high affinity of CB[7] to the p-xylene diammonium units (-NH(2)(+)CH(2)C(6)H(4)CH(2)NH(2)(+)-) in the oligoalkylammonium salts, the CB[7] rings threaded onto these cationic threads to form pseudorotaxane structures. Interestingly, due to the repulsive dipole-dipole electrostatic interactions between the CB[7] units and steric hindrance, the threading process exhibited a high selectivity and a unique self-assembling mode was discovered in which two CB[7] units cannot bind the same ammonium site. The as-formed well-defined pseudo[n]rotaxanes can be easily separated as pure compounds from the mixture by simple counterion exchange with NH(4)PF(6) and the pure pseudo[n]rotaxanes are stable and partially soluble in normal organic solvents. Such facile preparation and separation are mainly ascribed to the high binding constant between CB[7] and the oligoalkylammonium salts and the unique solubility of CB[7] in protonic acid. As most pseudorotaxanes reported in the literature exist as a dynamic mixture and their separation is usually difficult, our research represents one good example in which pure pseudo[n]rotaxanes (n = 2, 3, 4, 5) can be obtained by a simple "threading-followed-by-precipitation" method.

Solubilizing polycarbonate-modified single-walled carbon nanotubes by simultaneously attaching octadecylamine

To dissolve polycarbonate-modified single-walled carbon nanotubes, octadecylamine was simultaneously attached to carbon nanotubes by ammonification. The functionalized carbon nanotubes are soluble in highly or normal polar organic solvents due to different polycarbonates: the poly (butylene-co-ε-caprolactone carbonate) and octadecylamine-modified carbon nanotubes can dissolve in highly polar organic solvents such as dimethyl sulfoxide and dimethylformamide; the poly[(propylene oxide)-co-(carbon dioxide)-co-(maleic anhydride)] and octadecylamine-modified carbon nanotubes can dissolve in normal polar organic solvents such as chloroform and dichloromethane. The so-obtained composites were characterized using Fourier-transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and thermogravimetric analysis.