Aliphatic Anion Exchange Ionomers with Long Spacers and No Ether Links by Ziegler–Natta Polymerization: Properties and Alkaline Stability

In this work we report the synthesis of poly(vinylbenzylchloride-co-hexene) copolymer grafted with N,N-dimethylhexylammonium groups to study the effect of an aliphatic backbone without ether linkage on the ionomer properties. The copolymerization was achieved by the Ziegler–Natta method, employing the complex ZrCl4 (THF)2 as a catalyst. A certain degree of crosslinking with N,N,N′,N′-tetramethylethylenediamine (TEMED) was introduced with the aim of avoiding excessive swelling in water. The resulting anion exchange polymers were characterized by 1H-NMR, FTIR, TGA, and ion exchange capacity (IEC) measurements. The ionomers showed good alkaline stability; after 72 h of treatment in 2 M KOH at 80 °C the remaining IEC of 76% confirms that ionomers without ether bonds are less sensitive to a SN2 attack and suggests the possibility of their use as a binder in a fuel cell electrode formulation. The ionomers were also blended with polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde. The water uptake of the blend membranes was around 110% at 25 °C. The ionic conductivity at 25 °C in the OH− form was 29.5 mS/cm.

Isolation and Structural Elucidation of Secondary Metabolites from New Zealand Marine Sponge Aaptos confertus

<p>This study reports on the spectroscopy-guided isolation and structural elucidation of secondary metabolites from the New Zealand marine sponge Aaptos confertus. An extraction of the sponge material, followed by several purification steps, led to the isolation of potential new compounds CJP02 20A, CJP02 20C and CJP02 04CB, a known 2,5-diketopiperzine cyclo(L-Phe-L-Pro), and a previously reported 3-((13-methylhexadecyl)oxy)propane-1,2-diol. Corrections to the ¹H NMR data reported for 3-((13-methylhexadecyl)oxy)propane-1,2-diol were also recorded. The relationship between the oceanic climate where a marine organism habituates and its production of secondary metabolites is discussed. The isolation of a diverse range of compounds, either novel or new to the genus, suggests that organisms originating in temperate climates are similar in value to those from tropical climates, where higher rates of predation (and therefore, selective pressure) are thought to produce superior diversity in their secondary metabolic distribution. In addition to the new compounds isolated, the diketopiperazine described is the first reported molecule of that class from the genus Aaptos. The significance of the isolated compounds is discussed, in the context of drug discovery and development. The potential of the branched-chain mono-glycerol ether 3-((13-methylhexadecyl)oxy)propane-1,2-diol as a lipid biomarker for the genus Aaptos was examined, as this compound has only been reported from species of that genera. In addition, it’s potential as an immunomodulatory drug is discussed, including the significance of the ether linkage in contrast to the more common ester linkage. The isolation of the 2,5-diketopiperazine cyclo(L-Phe-L-Pro) new to the genus was shown to support the potential in diversity of climate and geographical distribution. This class of molecule is generated through the shikimate biosynthetic pathway; a metabolic route used by bacteria, fungi and algae. A proposed symbiotic relationship between the sponge Aaptos confertus and a proximal bacteria, fungi or algae exemplifies the value of New Zealand’s diverse and unique marine organisms.</p>

Isolation and Structural Elucidation of Secondary Metabolites from New Zealand Marine Sponge Aaptos confertus

<p>This study reports on the spectroscopy-guided isolation and structural elucidation of secondary metabolites from the New Zealand marine sponge Aaptos confertus. An extraction of the sponge material, followed by several purification steps, led to the isolation of potential new compounds CJP02 20A, CJP02 20C and CJP02 04CB, a known 2,5-diketopiperzine cyclo(L-Phe-L-Pro), and a previously reported 3-((13-methylhexadecyl)oxy)propane-1,2-diol. Corrections to the ¹H NMR data reported for 3-((13-methylhexadecyl)oxy)propane-1,2-diol were also recorded. The relationship between the oceanic climate where a marine organism habituates and its production of secondary metabolites is discussed. The isolation of a diverse range of compounds, either novel or new to the genus, suggests that organisms originating in temperate climates are similar in value to those from tropical climates, where higher rates of predation (and therefore, selective pressure) are thought to produce superior diversity in their secondary metabolic distribution. In addition to the new compounds isolated, the diketopiperazine described is the first reported molecule of that class from the genus Aaptos. The significance of the isolated compounds is discussed, in the context of drug discovery and development. The potential of the branched-chain mono-glycerol ether 3-((13-methylhexadecyl)oxy)propane-1,2-diol as a lipid biomarker for the genus Aaptos was examined, as this compound has only been reported from species of that genera. In addition, it’s potential as an immunomodulatory drug is discussed, including the significance of the ether linkage in contrast to the more common ester linkage. The isolation of the 2,5-diketopiperazine cyclo(L-Phe-L-Pro) new to the genus was shown to support the potential in diversity of climate and geographical distribution. This class of molecule is generated through the shikimate biosynthetic pathway; a metabolic route used by bacteria, fungi and algae. A proposed symbiotic relationship between the sponge Aaptos confertus and a proximal bacteria, fungi or algae exemplifies the value of New Zealand’s diverse and unique marine organisms.</p>

A comprehensive study of the promoting effect of manganese on white rot fungal treatment for enzymatic hydrolysis of woody and grass lignocellulose

Background The efficiency of biological systems as an option for pretreating lignocellulosic biomass has to be improved to make the process practical. Fungal treatment with manganese (Mn) addition for improving lignocellulosic biomass fractionation and enzyme accessibility were investigated in this study. The broad-spectrum effect was tested on two different types of feedstocks with three fungal species. Since the physicochemical and structural properties of biomass were the main changes caused by fungal degradation, detailed characterization of biomass structural features was conducted to understand the mechanism of Mn-enhanced biomass saccharification. Results The glucose yields of fungal-treated poplar and wheat straw increased by 2.97- and 5.71-fold, respectively, after Mn addition. Particularly, over 90% of glucose yield was achieved in Mn-assisted Pleurotus ostreatus-treated wheat straw. A comparison study using pyrolysis gas chromatography mass spectrometry (Py-GC/MS) and two-dimensional 1H–13C heteronuclear single quantum coherence (2D HSQC) nuclear magnetic resonance (NMR) spectroscopy was conducted to elucidate the role of Mn addition on fungal disruption of the cross-linked structure of whole plant cell wall. The increased Cα-oxidized products was consistent with the enhanced cleavage of the major β-O-4 ether linkages in poplar and wheat straw lignin or in the wheat straw lignin–carbohydrate complexes (LCCs), which led to the reduced condensation degree in lignin and decreased lignin content in Mn-assisted fungal-treated biomass. The correlation analysis and principal component analysis (PCA) further demonstrated that Mn addition to fungal treatment enhanced bond cleavage in lignin, especially the β-O-4 ether linkage cleavage played the dominant role in removing the biomass recalcitrance and contributing to the glucose yield enhancement. Meanwhile, enhanced deconstruction of LCCs was important in reducing wheat straw recalcitrance. The findings provided not only mechanistic insights into the Mn-enhanced biomass digestibility by fungus, but also a strategy for improving biological pretreatment efficiency of lignocellulose. Conclusion The mechanism of enhanced saccharification of biomass by Mn-assisted fungal treatment mainly through Cα-oxidative cleavage of β-O-4 ether linkages further led to the decreased condensation degree in lignin, as a result, biomass recalcitrance was significantly reduced by Mn addition. Graphic abstract

Effective absorption of SO2 by imidazole-based PILs with multiple active sites: Thermodynamic and mechanical studies

In view of the environmental hazards caused by SO2, the development of efficient SO2 capture technology has important practical significance. In this work, a low viscosity protic ionic liquids containing imidazole, ether linkage, and tertiary amine structure, was synthesized by acid-base neutralization of tris(3,6-dioxaheptyl)amine (TMEA) and imidazole (Im) for SO2 absorption. The results showed that the solubility of SO2 in [TMEA][Im] reached 12.754 mol·kg-1 at 298.2 K and 100 kPa and the ideal selectivity of SO2/CO2(1/1) and SO2/H2S(1/1) are 141.6 and 11.8 at 100 kPa, respectively. Furthermore, [TMEA][Im] can be reused and the SO2 absorption performance was not significantly reduced after five cycles. In addition, the absorption of low-concentration SO2 (2000 ppm) in [TMEA][Im] was also tested. Further spectroscopic research and thermodynamic analysis suggested that the high SO2 uptake by [TMEA][Im] was caused by the synergistic effect of physical and chemical absorption.

Valorization of Rice Straw via Hydrotropic Lignin Extraction and Its Characterization

Rice straw hydrotropic lignin was extracted from p-Toluene sulfonic acid (p-TsOH) fractionation with a different combined delignification factor (CDF). Hydrotropic lignin characterization was systematically investigated, and alkaline lignin was also studied for the contrast. Results showed that the hydrotropic rice straw lignin particle was in nanometer scopes. Compared with alkaline lignin, the hydrotropic lignin had greater molecular weight. NMR analysis showed that β-aryl ether linkage was well preserved at low severities, and the unsaturation in the side chain of hydrotropic lignin was high. H units and G units were preferentially degraded and subsequently condensed at high severity. High severity also resulted in the cleavage of part β-aryl ether linkage. 31P-NMR showed the decrease in aliphatic hydroxyl groups and the increasing carboxyl group content at high severity. The maximum weight loss temperature of the hydrotropic lignin was in the range of 330–350 °C, higher than the alkaline lignin, and the glass conversion temperature (Tg) of the hydrotropic lignin was in the range of 107–125 °C, lower than that of the alkaline lignin. The hydrotropic lignin has high β-aryl ether linkage content, high activity, nanoscale particle size, and low Tg, which is beneficial for its further valorization.

Cherbonolides M and N from a Formosan Soft Coral Sarcophyton cherbonnieri

Two new isosarcophine derivatives, cherbonolides M (1) and N (2), were further isolated from a Formosan soft coral Sarcophyton cherbonnieri. The planar structure and relative configuration of both compounds were established by the detailed analysis of the IR, MS, and 1D and 2D NMR data. Further, the absolute configuration of both compounds was determined by the comparison of CD spectra with that of isosarcophine (3). Notably, cherbonolide N (2) possesses the unique cembranoidal scaffold of tetrahydrooxepane with the 12,17-ether linkage fusing with a γ-lactone. In addition, the assay for cytotoxicity of both new compounds revealed that they showed to be noncytotoxic toward the proliferation of A549, DLD-1, and HuCCT-1 cell lines. Moreover, the anti-inflammatory activities of both metabolites were carried out by measuring the N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-induced generation of superoxide anion and elastase release in the primary human neutrophils. Cherbonolide N (2) was found to reduce the generation of superoxide anion (20.6 ± 6.8%) and the elastase release (30.1 ± 3.3%) in the fMLF/CB-induced human neutrophils at a concentration of 30 μM.

Synthesis of Polyanionic C5-Modified 2′-Deoxyuridine and 2′-Deoxycytidine-5′-Triphosphates and Their Properties as Substrates for DNA Polymerases

Modified 2′-deoxyribonucleotide triphosphates (dNTPs) have widespread applications in both existing and emerging biomolecular technologies. For such applications it is an essential requirement that the modified dNTPs be substrates for DNA polymerases. To date very few examples of C5-modified dNTPs bearing negatively charged functionality have been described, despite the fact that such nucleotides might potentially be valuable in diagnostic applications using Si-nanowire-based detection systems. Herein we have synthesised C5-modified dUTP and dCTP nucleotides each of which are labelled with an dianionic reporter group. The reporter group is tethered to the nucleobase via a polyethylene glycol (PEG)-based linkers of varying length. The substrate properties of these modified dNTPs with a variety of DNA polymerases have been investigated to study the effects of varying the length and mode of attachment of the PEG linker to the nucleobase. In general, nucleotides containing the PEG linker tethered to the nucleobase via an amide rather than an ether linkage proved to be the best substrates, whilst nucleotides containing PEG linkers from PEG6 to PEG24 could all be incorporated by one or more DNA polymerase. The polymerases most able to incorporate these modified nucleotides included Klentaq, Vent(exo-) and therminator, with incorporation by Klenow(exo-) generally being very poor.

Kinetics of CH2=CHCH2OCF2CF2H with atmospheric oxidants

&lt;p&gt;As industries transition towards greener business models, many mass-produced chemicals are being replaced by low-global warming potential (GWP) alternatives. Allyl 1,1,2,2-tetrafluoroethyl ether (CH&lt;sub&gt;2&lt;/sub&gt;=CHCH&lt;sub&gt;2&lt;/sub&gt;OCF&lt;sub&gt;2&lt;/sub&gt;CF&lt;sub&gt;2&lt;/sub&gt;H) represents a potential replacement candidate. This molecule contains an olefinic bond, several abstractable hydrogen atoms, an ether linkage and a non-perfluorinated side-chain. As such it can react with various atmospheric oxidants in a variety of degradation mechanisms, each of which may serve to reduce its atmospheric lifetime and its impact upon the environment. Before widespread usage, it is crucial that these environmental sinks are quantified such that the risk that CH&lt;sub&gt;2&lt;/sub&gt;=CHCH&lt;sub&gt;2&lt;/sub&gt;OCF&lt;sub&gt;2&lt;/sub&gt;CF&lt;sub&gt;2&lt;/sub&gt;H poses to the environment can be thoroughly assessed. We present measurements of gas-phase relative rates with hydroxyl radicals (OH), atomic chlorine (Cl), ozone (O&lt;sub&gt;3&lt;/sub&gt;) and nitrate radical (NO&lt;sub&gt;3&lt;/sub&gt;) carried out in HELIOS simulation chamber at CNRS (Orl&amp;#233;ans, France) as described by Ren &lt;em&gt;et al&lt;/em&gt;.&lt;sup&gt;1&lt;/sup&gt; and references within. Although previous measurements are available for OH&lt;sup&gt;2&lt;/sup&gt; and Cl,&lt;sup&gt;3&lt;/sup&gt; we find some discrepancies in comparison to our new determinations. In the case of O&lt;sub&gt;3&lt;/sub&gt; and NO&lt;sub&gt;3&lt;/sub&gt;, these represent the first such measurements of which we are aware. Furthermore, we have determined the absolute rate coefficient of CH&lt;sub&gt;2&lt;/sub&gt;=CHCH&lt;sub&gt;2&lt;/sub&gt;OCF&lt;sub&gt;2&lt;/sub&gt;CF&lt;sub&gt;2&lt;/sub&gt;H + OH using a pulsed-laser photolysis&amp;#8211;laser-induced fluorescence technique between 273 and 363 K performed at the Physical Chemistry department of UCLM (Ciudad Real, Spain) as described by Bl&amp;#225;zquez &lt;em&gt;et al&lt;/em&gt;.&lt;sup&gt;4&lt;/sup&gt; and references within, representing the first temperature-dependent kinetic measurements for this molecule with OH radicals. In addition, the infrared absorption cross section is quantified between 400 and 4000 cm&lt;sup&gt;-1&lt;/sup&gt;, in an extended range of wavenumbers with respect to the previously reported ones&lt;sup&gt;5&lt;/sup&gt;. Combining each these observations, we are able to provide an improved estimate for the GWP of this molecule and its likely environmental fate.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;&lt;span&gt;1. Ren, Y.; McGillen, M. R.; Da&amp;#235;le, V.; Casas, J.; Mellouki, A. Science Total Environ. &lt;/span&gt;&lt;strong&gt;2020&lt;/strong&gt;&lt;span&gt;, 749, 141406.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;2. Heathfield, A. E.; Anastasi, C.; Pagsberg, P.; McCulloch, A. Atmos. Environ. &lt;strong&gt;1998,&lt;/strong&gt; 32, 711&amp;#8211;717.&lt;/p&gt;&lt;p&gt;3. Papadimitriou, V. C.; Kambanis, K. G.; Lazarou, Y. G.; Papagiannakopoulos, P. J. Phys. Chem. A &lt;strong&gt;2004,&lt;/strong&gt; 108, 2666&amp;#8211;2674.&lt;/p&gt;&lt;p&gt;4. Bl&amp;#225;zquez, S.; Anti&amp;#241;olo, M.; Nielsen, O. J.; Albaladejo, J.; Jim&amp;#233;nez, E. Chem. Phys. Lett. &lt;strong&gt;2017&lt;/strong&gt;, 687, 297&amp;#8211;302.&lt;/p&gt;&lt;p&gt;5. Heathfield, A. E.; Anastasi, C.; McCulloch, A.; Nicolaisen, F. M. Atmos. Environ. &lt;strong&gt;1998&lt;/strong&gt;, 32, 2825&amp;#8211;2833.&lt;/p&gt;