Kiryu hexose and pentose matrix: A comprehensive model of epimers, structures, and C-1/C-6 inversion products for hexoses and pentoses.

Effect of sugar alcohols on the reverse self-assembly of lecithin in diverse organic solvents

Effect of sugar or sugar alcohol with different spatial structures on the stability of paclitaxel/HS15/Tween80 micelles: Based on micellization thermodynamics

Comprehensive SummaryCross‐electrophile couplings (XEC), a crucial subset of cross‐coupling reactions, center on the formation of robust C—C bonds through the union of two electrophiles. Usually, such reactions have primarily been catalyzed by transition metals. However, with the steady advancements in photochemical and electrochemical technologies, XEC reactions have significantly progressed and broadened their scope, allowing for the utilization of a wider array of tolerable functional groups, thus revealing vast application prospects. This review aims to systematically summarize the current prevalent types of electrophiles and delve into their specific application examples within XEC reactions involving electrophiles with identical functional groups. Specifically, XECs between the same type of halides have received considerable attention, whereas carboxylic acids and alcohols are still in the early stages of investigation. Furthermore, certain other common electrophiles remain unexplored in this context. Moreover, this review underscores the remarkable contributions of photochemistry and electrochemistry in the field of XEC reactions, aiming to provide valuable insights and inspiration for researchers. Also, this review hopes to spark further interest in XEC reactions, thereby fueling the continuous development and advancement of this exciting area of research. Key ScientistsSince the 1960s, advancements in the XEC reaction have been substantial, driven primarily by the application of transition metal catalysts. In this area, many distinguished scientists have contributed their wisdom and efforts. Particularly noteworthy is that, during the systematic study of XEC reactions with the identical functional groups, in 2016, MacMillan achieved a photocatalytic XEC reaction between aryl bromides and alkyl bromides; in 2020, Weix successfully realized a nickel‐catalyzed XEC reaction between aryl chlorides and alkyl chlorides. Concurrently, contributions from researchers such as Mei, Wolf, Sevov, Lin, Shen, Browne, Zhang, and Qiu have expanded the scope of XEC reactions to various halides. By 2022, MacMillan and Baran achieved a significant milestone in the XEC between carboxylic acids, further broadening the scope of research in this area. Also, advancements in the XEC of alcohols have been noted, with researchers including Weix, Lian, Tu, and Stahl conducting pioneering work and successfully executing the XEC of protective groups. It is foreseen that the ongoing research endeavors will primarily concentrate on the expansion of diverse electrophiles.

An NADH-dependent l-xylulose reductase and the corresponding gene were identified from the yeast Ambrosiozyma monospora. The enzyme is part of the yeast pathway for l-arabinose catabolism. A fungal pathway for l-arabinose utilization has been described previously for molds. In this pathway l-arabinose is sequentially converted to l-arabinitol, l-xylulose, xylitol, and d-xylulose and enters the pentose phosphate pathway as d-xylulose 5-phosphate. In molds the reductions are NADPH-linked, and the oxidations are NAD(+)-linked. Here we show that in A. monospora the pathway is similar, i.e. it has the same two reduction and two oxidation reactions, but the reduction by l-xylulose reductase is not performed by a strictly NADPH-dependent enzyme as in molds but by a strictly NADH-dependent enzyme. The ALX1 gene encoding the NADH-dependent l-xylulose reductase is strongly expressed during growth on l-arabinose as shown by Northern analysis. The gene was functionally overexpressed in Saccharomyces cerevisiae and the purified His-tagged protein characterized. The reversible enzyme converts l-xylulose to xylitol. It also converts d-ribulose to d-arabinitol but has no activity with l-arabinitol or adonitol, i.e. it is specific for sugar alcohols where, in a Fischer projection, the hydroxyl group of the C-2 is in the l-configuration and the hydroxyl group of C-3 is in the d-configuration. It also has no activity with C-6 sugars or sugar alcohols. The K(m) values for l-xylulose and d-ribulose are 9.6 and 4.7 mm, respectively. To our knowledge this is the first report of an NADH-linked l-xylulose reductase.

Steam reforming of monohydric alcohols and polyalcohols: Influence of single or multiple hydroxyl group(s) on nature of the coke

The properties of carbohydrates are determined in part by the number and stereochemical arrangement of their hydroxyl groups. To facilitate their analysis, rapid methods are needed to identify and enumerate hydroxyl groups in sugars and polyalcohols, especially methods that are water-based. The present report details the results of an alternative method for identification and enumeration of hydroxyl groups in aqueous media. It employs vinyl acetate to selectively derivatize hydroxyl groups in analytes, followed by analysis of the reaction mixtures by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The method has been applied to several single and multi-component mixtures of monosaccharides and polyalcohols. The O-acetylated products were analyzed without chromatographic separation or purification by MALDI-TOF-MS. The mass spectra revealed consecutive ion peaks that are separated by 42 mass units as a consequence of displacement of one hydroxyl hydrogen by one acetyl group. A rapid and aqueous-based method is described to enumerate the hydroxyl groups in carbohydrates. The number of ion peaks due to derivatized products is determined by MALDI-TOF-MS, and corresponds to the number of free hydroxyl groups in the analyte. The method is applicable to both single and multi-component mixtures.

Complexes between TiO 2 and sugar alcohol molecules or polyol molecules were prepared by heating the mixture of titanium isopropoxide (TIP) and ethylene glycol, glycerin, meso-erythritol, or D-mannitol aqueous solution at 368 K for 24 h. The degree of crystallization of TiO 2 in the obtained TiO 2 -sugar alcohol or polyol complex depended on the concentration of the polyol and sugar alcohol aqueous solution. When the TiO 2 -sugar alcohol or polyol complex was prepared by using the same concentration of the sugar alcohol or polyol aqueous solution, the degree of crystallization of the TiO 2 in the complex decreased with increase in the number of OH groups per molecule. According to the results of the DTA measurements and the element analysis, the strength of the interaction between Ti 4+ ions and polyol or sugar alcohol molecules increased with increases in the number of OH groups in the molecules. The heat treatment of TiO 2 -D-mannitol complex in 0.5 mol/l HNO 3 aqueous solution at more than 318 K enabled to obtain TiO 2 -D-mannitol complex nanoparticles by breaking the bonds between the D-mannitol molecules and Ti 4+ ions. The obtained TiO 2 -D-mannitol complex nanoparticles had large surface area which was more than 300 m 2 /g and showed photocatalytic activity. Furthermore, the complex nanoparticles can be dispersed into the distilled water with high stability.

Additivity of the lanthanide induced chemical shifts in rigid compounds with two identical functional groups

Chemical cross-linking—a process forming covalent bonds between different molecules (intermolecular) or parts of a molecule (intramolecular)—has proven successful in combination with mass spectrometry [1, 2] as a tool for low-resolution structure determination [3, 4]. It is a fast procedure with low material consumption offering the opportunity to gain further insight into three-dimensional structures of proteins or protein complexes under native conditions. The goal of performing intramolecular chemical cross-linking of a protein is to get hints on its threedimensional structure [5], whereas the aim of intermolecular cross-linking between different proteins is to elucidate which components interact and how and where they physically contact each other [6]. Of the hundreds of cross-linking reagents described in the literature [7, 8] or offered commercially [9], most utilize common organic chemical principles that can be reduced to a few primary reactions. Homobifunctional cross-linking reagents contain identical functional groups at both reactive sites, which are connected with a carbon chain spacer bridging a defined distance. Therefore, identical functional groups in the proteins (e.g., amine or sulfhydryl groups) can be cross-linked. In contrast, heterobifunctional cross-linkers possess two different reactive sites. The number of cross-linking reagents has increased dramatically during the past 20 years, and today, a wide variety of reagents are commercially available possessing different spacer lengths and reactivities [9]. N-Hydroxysuccinimide (NHS) esters, targeting amine groups, are probably the most widely applied reagents for chemical cross-linking of proteins. As examples, Table 1 shows the two homobifunctional, water-soluble sulfoNHS esters sulfo-DST (sulfo-disuccinimidyl tartrate) and BS (bis(sulfosuccinimidyl)suberate). The smallest available reagent systems for chemical cross-linking are ‘zero-length’ cross-linkers, such as EDC (1-ethyl-3-(3dimethylaminopropyl)carbodiimide). These compounds mediate cross-linking between two proteins by creating a bond without an intervening linker and have proven beneficial especially for intermolecular cross-linking between proteins [6]. EDC is mostly applied in combination with N-hydroxysulfosuccinimide (sulfo-NHS) (Table 1). The advantage of adding sulfo-NHS to EDC consists in increasing the stability of the active intermediate, which ultimately reacts with the amine group. However, the cross-linking approach possesses some apparent limitations, since cross-linking conditions have to be specifically established for each protein or protein complex under investigation, and identification of crosslinking products is often a laborious procedure due to the complexity of the created cross-linking reaction mixtures. Fourier transform ion cyclotron resonance (FTICR) mass spectrometry [10] represents an attractive tool for analyzing cross-linking reaction mixtures. Its high mass accuracy serves as an additional constraint in the identification of cross-linking reaction products. Additionally advantageous is that FTICRMS allows a ‘gas-phase’ purification and subsequent fragmentation of cross-linking products in the ICR cell. In general, chemical cross-linking in combination with FTICR mass spectrometry for protein structure characterization can be divided into two groups:

Single-crystal structures of five lanthanide-erythritol complexes are reported. The analysis of the chemical compositions and scrutinization of structural features in the single-crystal data of the complexes led us to find that unexpected deprotonation occurs on the OH group of erythritol of three complexes. Considering these complexes were prepared in acidic environments, where spontaneous ionization on an OH group is suppressed, we suggest metal ions play an important role in promoting the proton transfer. To find out why the chemically inert OH is activated, the single-crystal structures of 63 rare-earth complexes containing organic ligands with multiple hydroxyl groups (OLMHs) were surveyed. The formation of μ2-bridges turns out to be directly relevant to the occurrence of deprotonation. When an OH group from an OLMH molecule participates in the formation of a μ2-bridge, the polarization ability of the metal ions becomes strong enough to promote the deprotonation on the OH group. The above structural characteristics may be useful in the rational design of catalysts that can activate the chemically inert OH group and promote the relevant chemical conversions.

Comprehensive SummaryMost of the known open‐cage fullerene derivatives contain carbonyl and other relatively inert groups on the rim of the orifice. It is difficult to rationally design further reactions and attach other functional groups on to these open‐cage derivatives. In the present work, two molecules of difunctional 1,4‐benzenediamine have been incorporated into the rim of an open‐cage C60 derivative through one amino group leaving the other amino group free for further functionalization. The difunctional 4‐aminophenol reacted analogously to form an open‐cage derivative with a free OH group each on the two phenyl rings. The amino and hydroxyl groups on the phenyl ring above the rim of the orifice showed similar reactivity as aniline and phenol. One of the carbonyl groups on the rim of the orifice could be selectively reduced by NaBH4 and P(OEt)3. The reduction reactions were reversible and the reduced products could be readily converted back to the carbonyl precursor. Thus, this redox process acts as a tool to fine tune the size of the orifice for host‐guest studies.

Electrolytes hold the key to realizing reliable zinc (Zn) anodes. Divergent organic molecules have been proven effective in stabilizing Zn anodes; however, irrational comparisons exist due to the uncontrolled molecular weights and functional group amounts. In this work, two “isomeric molecules”: 1,2-dimethoxyethane (DME) and 1-methoxy-2-propanol (PM), with identical molecular weights but different functional groups, have been studied as co-solvents in electrolytes, which have delivered distinct electrochemical performance. Experimental and simulative study indicates the dipole moment induced by the hydroxyl groups in PM (higher molecular polarity than ether groups in DME) reconstructs the space charge region, enhances the concentration of Zn²⁺ in the vicinity of Zn anodes, and <em>in-situ</em> derives different solid electrolyte interphase (SEI) models and electrode–electrolyte interfaces, resulting in exceptional cycling stability. Remarkably, the Zn||Cu cell with PM worked over 2000 cycles with high Coulombic efficiency (CE) of 99.7%. The Zn||Zn symmetric cell cycled over 2000 h at 1 mA·cm⁻², and showed excellent stability at an ultrahigh current density of 10 mA·cm⁻² and capacity of 20 mAh·cm⁻² over 200 h (depth of discharge, DOD of 70%). The Zn||sodium vanadate pouch cell with a high mass loading of 6.3 mg·cm⁻² and a high capacity of 24 mAh demonstrates superior cyclability after 570 h. This work can be a good starting point to provide reliable guidance on electrolyte design for practical aqueous Zn batteries.

Rosin is a natural resin from the coniferous tree sap, which separated from its oil content (terpenes). Rosin is brittle. Therefore modifications are needed to improve its mechanical properties. The main content of rosin is abietic acid which has a carboxylic group, so it can form an ester group when reacted with polyhydric alcohol (polyalcohol) such as glycerol. The research aimed to study the kinetics of the esterification reaction between the hydroxyl group in glycerol and the carboxylic group in abietic acid from rosin at various reaction temperatures and reactant compositions. This reaction is carried out in a three-neck flask at atmospheric pressure without a catalyst. The reaction temperatures used were 180˚C, 200˚C, and 220˚C, and the ratio of rosin and glycerol was 1:1, 1:3, and 1:5. The reaction kinetics calculations were analyzed with acid number data over the reaction time using three different models. The calculations showed that this reaction involves positioning a hydroxyl group on glycerol, which the primary and secondary hydroxyl groups contribute to forming a rosin ester (glycerolabietate). The rate of reaction constants of primary hydroxyl of glycerol and abietic acid were in the range 6.25x10-4 - 3.90x10-3 g/(mgeq.min), while reaction rate constants of secondary hydroxyl and abietic acid were in the range 1.06x10-5 - 1.15x10-4 g/(mgeq.min). FTIR analysis showed a change in the hydroxyl, carboxylate, and ester groups which were assigned by a shift of wavenumber and a difference of intensity at 3200-3570 cm-1, 1697.36 cm-1, and 1273.02 cm-1.

This paper reports the detection of gas molecules with an identical functional group, but in different lengths due to varying numbers of CH 2 backbone units, by utilizing a nano-gap gas sensor. Significance of such a gas sensor lies on its ability to distinguish molecular lengths by down to 0.15nm in this testing. The fabricated nano-gap sensor, after being functionalized by a specific linker on the surface, successfully captured all three target gas molecules of 2-CH 2 -diamine (0.3nm), 3-CH 2 -diamine (0.45nm) and 5-CH 2 -diamine (0.75nm). The capture of each target molecules demonstrated significant differences in both resistance and capacitances, resulting in successful identification of 2-CH 2 -diamine (0.3nm), 3-CH 2 -diamine (0.45nm) and 5-CH 2 -diamine (0.75nm) by producing different on/off resistance ratios of 105, 2905 and 3832 and capacitance changes of 4.45pF, 16.21pF and 26.64pF, indicating the capability of identifying multiple gas molecules in different lengths despite identical functional groups.

Reinforcement mechanism of silica surface hydroxyl: The opposite effect