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Abstract To address the problems of wall collapse, cuttings slurrying, and scaling on the inner wall of the drill pipe, which often occur in small-diameter diamond wireline core drilling, the inhibition properties of polyvinyl alcohol (PVA) was investigated, and the formulation of solids-free drilling fluid with PVA as the inhibitor were completed. PVA has the advantages of fast adsorption and easy regulation of rheological properties Firstly the inhibition effect of PVA was compared with that of common inorganic salts (sodium chloride, NaCl, potassium chloride, KCl) by bentonite dispersion test, linear swelling test, shale rolling recovery test and mud ball immersion test in this study. Then, the inhibition mechanism of PVA was analyzed with potentiometric particle size tests, Fourier transform infrared (FT-IR) and X-ray Diffraction (XRD) measurements. Based on the outstanding inhibition performance of PVA, tackifiers and filtration reducers were preferred through the compatibility test. And finally, the effects of various contaminants on the comprehensive performance of the formulated solids-free drilling fluids were evaluated. The results showed that PVA exhibited better inhibition of clay hydration and dispersion in shale recovery and linear swelling compared to NaCl and KCl, which was particularly evident in the mud ball immersion test. FT-IR and XRD tests revealed that the inorganic salts were used to replace the cations with larger radius and high degree of hydration in the clay layer by ion exchange ti achieve the effect of clay de-watering by reducing the spacing of the clay interlayer and the electrostatic repulsion between the particles. However, PVA is strongly adsorbed on the clay surface in the form of hydrogen bonds due to its unique multi-hydroxyl chain structure, forming a hydrophobic barrier to prevent water molecules from entering the clay layer, thus inhibiting the hydration and swelling of the clay. Using PVA as an inhibitor, compounded with xanthan gum, sulfonated lignite resin and sulfonated gilsonite (FT-1), the solids-free drilling fluid is promising for use in diamond wireline core drilling in complex formations.

Guanidine Sulphanilate (GSA) single crystal was grown by slow evaporation growth method. Single crystal X-ray diffraction studies show that the crystal grows in a centro symmetric monoclinic system and its space group is P21/c. Optical studies were carried out using UV visible spectroscopy and the grown crystal shows the the lower cutoff wavelength of 220 nm. Photoluminescence studies show that GSA crystals have good luminescence properties. Laser damage threshold was found to be 0.24GW/cm2. Nonlinear optical studies show green light emission.

In the title molecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, five-membered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitrogen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O—H...N and N—H...O hydrogen bonds plus C—H...π(ring) and weak π-stacking interactions.

In this paper, cellulose nanofiber (CNF)/ polyethylene glycol (PEG) composite aerogel phase change materials (CNPCMs) were prepared utilizing porous carrier support and freeze-drying. The solid-liquid phase change to solid-gel phase change was realized, which solved the problems of PEG flow, leakage, and shape instability. The physical properties and chemical compatibility of CNPCMs were studied, and the results showed that CNPCMs ensured the overall structure stability through internal hydrogen bonding, and they were only a physical bond with each other without chemical reaction. With the increase in PEG content, the thermal conductivity of CNPCMs increased from 0.22 W/m·K to 0.33 W/m·K. The thermal exposure experiment and thermogravimetric analysis (TGA) experiment have shown that CNPCMs have good shape stability at 75 ℃ and good thermal stability below 320 ℃. In summary, the experimental results indicated that the maximum content of PEG in CNPCMs was 78 % with an optimal content of 66.7 %. The sample corresponding to the optimal content was CNPCM2 with an enthalpy of 167.9 J/g for melting and 146.1 J/g for solidification. As a thermal storage material with good thermodynamic performance, CNPCM2 has enormous potential in the storage of solar collectors.

Chemical inhibition is one of the important measures for the prevention and control of coal spontaneous combustion. This paper proposed a quasi-ionic liquid inhibition method based on deep eutectic solvents (DES). First, seven kinds of room temperature deep eutectic solvents were prepared and screened using a heating method. The changes in the functional groups and thermodynamic characteristics of different DES-treated coal samples were analyzed. On this basis, the density functional theory was utilized to analyze the differences in the modification of coal's physicochemical properties by the hydrogen bond strength in the DES, and the inhibition mechanism of deep eutectic solvents and their optimal hydrogen bond strength were deduced. The results showed that after the DES treatment, the hydrogen bond network in coal was disrupted and rearranged. The relative abundance of aliphatic and aromatic hydrocarbons increased by 10%−37%, the content of aliphatic side chains decreased by 9.38%−20.65%, the relative abundance of oxygen-containing functional groups (C=O and C—O) decreased by 22.88%−56.94%, and free low-molecular compound and minerals were leached out. After the DES treatment, the mass loss during the evaporation and desorption stage of coal and the oxygen uptake during the oxygen absorption stage decreased. The heat release during the low temperature oxidation stage and the thermal decomposition stage was reduced by 8.94%−77.51% and 5.40%−26.20%, respectively. The stronger the electronegativity of the hydrogen bond acceptor site in the HBA, the greater the hydrogen bond strength formed between HBA and HBD. The hydrogen bond strength in the DES was positively correlated with the degree of destruction of the hydrogen bond network in coal, and was locally correlated with the oxygen uptake during the oxygen absorption stage, the heat release during low temperature oxidation, and the mineral removal rate. The DES weakened the low-temperature oxidation reactivity of coal by dissolving its active components, and increased the bond dissociation enthalpy of coal by promoting the rearrangement of hydrogen bonds into more thermally stable [OH]4 and OH—N hydrogen bonds. However, the excessive strong hydrogen bond strength would inhibit the removal and dissolution of active side chains. Therefore, the hydrogen bond strength of deep eutectic solvents used to inhibit coal spontaneous combustion should be controlled between 69.45 kJ/mol and 160.00 kJ/mol.

In the title molecule, C21H23N3O3, the imidazolidine ring slightly deviates from planarity and the morpholine ring exhibits the chair conformation. In the crystal, N—H...O and C—H...O hydrogen bonds form helical chains of molecules extending parallel to the c axis that are connected by C—H...π(ring) interactions. A Hirshfeld surface analysis reveals that the most important contributions for the crystal packing are from H...H (55.2%), H...C/C...H (22.6%) and H...O/O...H (20.5%) interactions. The volume of the crystal voids and the percentage of free space were calculated to be 236.78 Å3 and 12.71%, respectively. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the nearly equal electrostatic and dispersion energy contributions. The DFT-optimized molecular structure at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined molecular structure in the solid state. Moreover, the HOMO–LUMO behaviour was elucidated to determine the energy gap.

In the title compound, C17H12N2O, the quinoxaline moiety shows deviations of 0.0288 (7) to −0.0370 (7) Å from the mean plane (r.m.s. deviation of fitted atoms = 0.0223 Å). In the crystal, corrugated layers two molecules thick are formed by C—H...N hydrogen bonds and π-stacking interactions.

The quinoxaline moiety in the title molecule, C13H13ClN2O3, is almost planar (r.m.s. deviation of the fitted atoms = 0.033 Å). In the crystal, C—H...O hydrogen bonds plus slipped π-stacking and C—H...π(ring) interactions generate chains of molecules extending along the b-axis direction. The chains are connected by additional C—H...O hydrogen bonds. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H...H (37.6%), H...O/O...H (22.7%) and H...Cl/Cl...H (13.1%) interactions.

The title compound, (C4H12N)[V(C12H8N4O2)O2]·H2O, was synthesized via aerial oxidation on refluxing picolinohydrazide with ethyl picolinate followed by addition of VIVO(acac)2 and diethylamine in methanol. It crystallizes in the triclinic crystal system in space group P\overline{1}. In the complex anion, the dioxidovanadium(V) moiety exhibits a distorted square-pyramidal geometry. In the crystal, extensive hydrogen bonding links the water molecule to two complex anions and one diethylammonium ion. One of the CH2 groups in the diethylamine is disordered over two sets of sites in a 0.7:0.3 ratio.

The title molecule, [Fe2(C5H5)2(C23H17ClN2)]·C3H7NO, is twisted end to end and the central N/C/N unit is disordered. In the crystal, several C—H...π(ring) interactions lead to the formation of layers, which are connected by further C—H...π(ring) interactions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (60.2%) and H...C/C...H (27.0%) interactions. Hydrogen bonding, C—H...π(ring) interactions and van der Waals interactions dominate the crystal packing.

In the title compound, C31H24N4O2, the quinoxaline units are distinctly non-planar and twisted end-to-end. In the crystal, C—H...O and C—H...N hydrogen bonds link the molecules into chains extending along the a-axis direction. The chains are linked through π-stacking interactions between inversion-related quinoxaline moieties.

In this study, chlorogenic acid-modified hyaluronic acid (HA-CGA) and phenylboric acid-modified ciprofloxacin (Cip-BPA) were synthesized and their structures were analyzed by 1HNMR and 13CNMR. Following, a dynamic borate and hydrogen bond crosslinked HCCB hydrogel was prepared by mixing HA-CGA and Cip-BPA solution. Its properties and gel formation mechanism were studied by means of ratio optimization, scanning electron microscopy, rheology, 11B-NMR and temperature-changing infrared spectroscopy. The basic properties and bioactivity of HCCB hydrogel were investigated by in vitro antibacterial experiment, in vitro anti-inflammatory oxidation experiment and biocompatibility test. We found that borate ester bond and hydrogen bond are important driving forces for the formation of HCCB hydrogels, and when the molar ratio of chlorogenic acid in HA-CGA and phenylboronic acid in Cip-BPA is 2:1, the properties of HCCB hydrogels formed are the best. It has excellent antibacterial properties, anti-inflammatory and antioxidant properties, good biocompatibility and pH/ROS response. The successful preparation of the gel and its excellent properties indicate that it has great potential in the treatment of some inflammation treatment.

α-Methyl groups play significant roles in the regulation of water molecules within both small molecular systems and bio-macromolecular systems. Systematically studying the influence of α-methyl on the dynamics of water molecules within hydrogel systems is therefore worthwhile. In this study, we prepared a series of hydrogen-bonded (H-bonded) hydrogels with varying densities of α-methyl groups by copolymerizing methacrylamide (MAm) with its α-methyl-absent analogue, acrylamide (Am). Introducing a small amount of Am (≤6 mol%) into the polymer chain resulted in significant shifts in the viscoelasticity of the hydrogels. The hydrogels exhibit a “time-temperature-α-methyl equivalence”, meaning that introduction of α-methyl-absent monomer has effects similar to elevating temperature and prolonging observation time on the dynamic properties. Based on low-field nuclear magnetic resonance spectroscopy and Raman scattering, a “hydrophilic defects-assisted H-bonds dissociation” mechanism is proposed, depicting that the α-methyl-absent monomer can disturb the rearrangement of water molecules surrounding the polymer chain and accelerate chain dissociation. These findings enabled the copolymer hydrogels with functions such as fast self-healing and tunable interface adhesion.

Follower sealant can be widely used in many fields because it has a strong sealing effect on liquids. However, most follower sealants often have a short sealing cycle and poor thermal stability. Herein, the hydrophilic and hydrophobic SA-NSiO2 Janus nanoparticles were synthesized via the emulsion interfacial synthesis method using stearic acid (SA) and silanized SiO2 (NSiO2) as raw materials. The characteristic peaks of Janus nanoparticles were clearly seen in Fourier-transform infrared, while snowman-like Janus nanoparticles were clearly observed in scanning electron microscopy and transmission electron microscopy, and the successful synthesis of Janus particles (SA-NSiO2) was indicated in both energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The synthesized SA-NSiO2 (Janus nanoparticles) was added to the follower sealant PDMS/PPG@SA-NSiO2 (PPSN for short) composed of polydimethylsiloxane (PDMS)/poly-(propylene glycol) (PPG), which was found to have excellent thermal stability and sealing performance even under high temperature and negative pressure, and the sealing cycle was increased by 300%, a long time of efficient sealing was also achieved, and the high and low temperature viscosity ratio was reduced from 2 to 1.5, with a 50% increase in centrifugal negative pressure capability. MS simulation results showed that the high sealing performance of PPSN was attributed to the entanglement of the hydrophobic phase of SA-NSiO2 with the hydrophobic chain of PDMS, and the hydrophilic phase was hydrogen-bonded and cross-linked with the hydrophilic group of PPG in PPSN. This study provides an effective method for realizing nanoparticle-enhanced follower sealants, which are sustainable as well as environmentally friendly, giving them great potential for industrial processing. [ABSTRACT FROM AUTHOR]

We studied the morphology of yarns obtained from Manila hemp (also known as Abacá) fiber bundles to find a possible correlation with the enhancement in mechanical properties of yarns relative to the original natural fiber bundle. Long Manila hemp fiber bundles had lignin and hemicelluloses removed, twisted and dried to form yarns. Scanning electron micrography revealed that the collapse of lumens inside the fibers leads to densification and consequent increase of tensile properties of the yarns. The densification occurs after the chemical removal of noncellulosic substances from the interstices of cellulose fibrils. These cellulosic elements are then bridged by hydrogen bonds during the drying step of yarn fabrication. [ABSTRACT FROM AUTHOR]

The crystal structure of 4-methylcatechol (4MEC) has, to date, never been solved, despite its very simple chemical formula C7O2H8 and the many possible applications envisaged for this molecule. In this work, this gap is filled and the structure of 4MEC is obtained by combining X-ray powder diffraction and first principle calculations to carefully locate hydrogen atoms. Two molecules are present in the asymmetric unit. Hirshfeld analysis confirmed the reliability of the solved structure, since the two molecules show rather different environments and H-bond interactions of different directionality and strength. The packing is characterised by a peculiar hydrogen bond network with hydroxyl nests formed by two adjacent octagonal frameworks. It is noteworthy that the observed short contacts suggest strong inter-molecular interactions, further confirmed by strong inter-crystalline aggregation observed by microscopic images, indicating the growth, in many crystallization attempts, of single aggregates taller than half a centimetre and, often, with spherical shapes. These peculiarities are induced by the presence of methyl group in 4MEC, since the parent compound catechol, despite its chemical similarity, shows a standard layered packing alternating hydrophobic and polar layers. Finally, the complexity and peculiarity of the packing and crystal growth features explain why a single crystal could not be obtained for a standard structural analysis. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a polymer hydrogel(PPNS), which features multiple hydrogen bonds through copolymerization, by using N -isopropylacrylamide, polyvinyl alcohol, and octadecyl polyoxyethylene ether acrylate (SGA 15) as raw materials. The PPNS hydrogel demonstrated outstanding high-resolution, repeatable recording capabilities, enabling reversible recording, encryption, and decryption of information using anhydrous ethanol as the inducer. Due to their responsive and dynamic nature of PPNS hydrogels are positions them as promising candidates for use as innovative information storage platforms. [Display omitted] Smart hydrogel materials, known for their sensitivity to external stimuli, exhibit a reversible dynamic response and find applications in diverse fields, particularly in information storage. Despite significant efforts in this domain, developing a hydrogel with high-resolution, repeatable recording, and robust information encryption/decryption capabilities still remains a challenge. In this study, we synthesized a polymer hydrogel, namely polyvinyl alcohol- n -isopropylacrylamide-octadecyl polyoxyethylene ether acrylate hydrogel (PPNS), which features multiple hydrogen bonds through copolymerization, by using N -isopropylacrylamide, polyvinyl alcohol, and octadecyl polyoxyethylene ether acrylate (SGA 15) as raw materials. The PPNS hydrogel demonstrated outstanding high-resolution, repeatable recording capabilities, enabling reversible recording, encryption, and decryption of information using anhydrous ethanol as the inducer. Varying the SGA 15 monomer concentration revealed that the PPNS-2% hydrogel, prepared with 2% SGA 15 , outperformed the other hydrogels in terms of information recording and encryption/decryption when immersed in anhydrous ethanol and deionized water. Furthermore, the PPNS-2% hydrogel exhibited the ability to undergo multiple information cycles while maintaining excellent mechanical properties even after 25 cycles. Notably, ethanol served as a specialized ink for inscribing different patterns on the hydrogel surface for information recording. The recorded information could be erased through water wiping or ethanol volatilization, enabling reversible information recording, encryption, and decryption. Due to their responsive and dynamic nature of PPNS hydrogels are positions them as promising candidates for use as innovative information storage platforms. [ABSTRACT FROM AUTHOR]

Ligand modulation of the electrical properties and surface solvation plays a crucial role in the development of functionalized colloidal quantum dots (CQDs) inks for solution‐processed optoelectronics. While inorganic halide ionic ligands can facilitate the n‐type doping of PbS CQDs and establish an electrical double layer in polar solvents for stable high‐concentration n‐type CQD inks, a plausible solvation strategy is still lacking to stabilize p‐type PbS CQDs, thereby resulting in a tedious multi‐step deposition involving short‐chain dithiol molecular ligands for advanced heterojunction CQD solar cells. Here an effective hydrogen bonding solvation strategy is proposed using 2‐mercaptoethanol (ME) ligands to realize stable p‐type PbS CQD ink. This strategy enables DMSO to form a dense solvation layer surrounding the ME‐modified PbS CQDs. With this approach, the PbS‐ME CQD ink exhibits a photoluminescence quantum yield of 52.03%, which is the highest record for PbS CQD inks. Finally, one‐step deposition of a p‐type PbS‐ME layer for PbS CQD photovoltaics is successfully achieved with an impressive power conversion efficiency (PCE) of 10.91%. This p‐type solar ink facilitates the fabrication of ready‐to‐use devices, enabling extensive applications in large‐scale and flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

Aqueous fluoride ion batteries (FIBs) have garnered attention for their high theoretical energy density, yet they are challenged by sluggish fluorination kinetics, active material dissolution, and electrolyte instability. Here, we present a room temperature rocking‐chair aqueous FIBs featuring KOAc‐KF binary salt electrolytes, enabling concurrent fluorination and defluorination reactions at both cathode and anode electrodes. Experimental and theoretical results reveal that acetate ions in the electrolyte compete with fluoride ions in hydrogen bonding formation, weakening the excessively strong solvation between H2O and F− ions. This results in the suppression of detrimental HF formation and a reduced desolvation energy of F− ions, enhancing the electrochemical reaction kinetics. The bismuth‐based cathode exhibits direct conversion in the optimized electrolyte, effectively suppressing the detrimental disproportionation reactions from Bi2+ intermediates. Additionally, zinc anode undergoes a typical fluorination process, forming solid KZnF3 as the electrode product, minimizing the risks of hydrogen evolution. The proposed aqueous FIBs with the optimized electrolyte demonstrate high discharge capacity, long‐term cycling stability and excellent rate capabilities. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) composite films were synergistically modified by adding corn starch (CS) and peach gum (PG). The effects of PVA molecular weight, different CS addition, and the PG incorporation with the same CS addition on the moisture and heat resistance of PVA/CS/PG composite film were investigated. The results show that the hydroxyl groups of CS and PG interact with PVA chains by hydrogen bonding. The crystal size of PVA in the PVA/CS/PG composite film decreases, while the crosslinking density increases. At the same time, with the increase of CS and PG content, the network mesh size of the composite film gradually decreases, and the thermal stability can be improved. The water vapor permeability test shows that as w(CS)=2% and w(PG)=2%, the water content of PG/CS/PVA composite film increases by 11.5%, while the water vapor permeability decreases by 43%. [ABSTRACT FROM AUTHOR]

Photosystem I (PS I) is a photosynthetic pigment–protein complex that absorbs light and uses the absorbed energy to initiate electron transfer. Electron transfer has been shown to occur concurrently along two (A- and B-) branches of reaction center (RC) cofactors. The electron transfer chain originates from a special pair of chlorophyll a molecules (P700), followed by two chlorophylls and one phylloquinone in each branch (denoted as A−1, A0, A1, respectively), converging in a single iron–sulfur complex Fx. While there is a consensus that the ultimate electron donor–acceptor pair is P700+A0−, the involvement of A−1 in electron transfer, as well as the mechanism of the very first step in the charge separation sequence, has been under debate. To resolve this question, multiple groups have targeted electron transfer cofactors by site-directed mutations. In this work, the peripheral hydrogen bonds to keto groups of A0 chlorophylls have been disrupted by mutagenesis. Four mutants were generated: PsaA-Y692F; PsaB-Y667F; PsaB-Y667A; and a double mutant PsaA-Y692F/PsaB-Y667F. Contrary to expectations, but in agreement with density functional theory modeling, the removal of the hydrogen bond by Tyr → Phe substitution was found to have a negligible effect on redox potentials and optical absorption spectra of respective chlorophylls. In contrast, Tyr → Ala substitution was shown to have a fatal effect on the PS I function. It is thus inferred that PsaA-Y692 and PsaB-Y667 residues have primarily structural significance, and their ability to coordinate respective chlorophylls in electron transfer via hydrogen bond plays a minor role. [ABSTRACT FROM AUTHOR]

Reversible networks of epoxidized natural rubber (ENR) mixed with dicarboxylic acid were studied. ENR is a bio-based polymer, commercially available, and capable of sulphur vulcanisation. In addition, ENR has been already reported to exhibit self-healing characteristics after ionisation by adding ionic groups to the epoxide group. The reversible network structure plays an essential role for self-healing behaviour, which cannot be obtained for elastomers with irreversible sulphur network. In this study, dicarboxylic acid was used to construct the reversible network. The reversible hydrogen bonds were established in such a way that firstly one carboxyl group of di-carboxylic acid (DA) is reacted to ENR and secondary the other carboxyl group of DA interacts with residual carboxyl group to form hydrogen bonds in carboxylic dimer. The self-healing behaviour was evaluated for ENR with DA by tensile tests. This self-healing system provides new insights for sustainable and natural-based materials. [ABSTRACT FROM AUTHOR]

Synchrotron radiation plays a crucial role in the analysis of valence states which play an important role in the function of materials. In this paper, the development and application of the analysis using synchrotron-radiation-based soft X-rays are outlined, and the research expected in the next generation synchrotron radiation NanoTerasu is commented. [ABSTRACT FROM AUTHOR]

4-Methylbenzylammonium hydrogen succinate (4MLBAHS) was synthesized and successfully grown via a slow solvent evaporation process. The structure was solved and the space group identified as P 1 ¯ . In the 4MLBAHS molecule, 4-methylbenzylammonium and hydrogen succinate are linked by O–H···O and N–H···O bonds. Functional group vibrations were revealed through vibrational analysis. UV–Vis–NIR analysis was used to determine the transparency bandwidth range from 260 nm to 1100 nm. 1H and 13C nuclear magnetic resonance (NMR) spectroscopy established the carbon–hydrogen network in 4MLBAHS. In 1H NMR, the chemical shift for the NH2 group of 4-methylbenzylamine was revealed at 1.42 ppm. This was shifted to 8.094 ppm in 4MLBAHS, owing to the origination of the N–H···O bond between the 4-methylbenzylammonium cation and hydrogen succinate anion. The third-order nonlinear optical characteristics were analysed using Z-scan analysis. χ3 was established as 3.0879 × 10−5 esu. The presence of hydrogen bond interactions in the 4MLBAHS crystal enhanced the χ3 value. [ABSTRACT FROM AUTHOR]

Isobutylammonium hydrogen oxalate hemihydrate (IHOH), an organic nonlinear optical (NLO) crystal, is developed in this work using a solvent evaporation process. The single-crystal XRD (SCXRD) study reveals the monoclinic system and centrosymmetric space group C2/c of IHOH. The highly crystalline nature of IHOH is confirmed by the presence of well-defined peaks in the powder x-ray diffraction (PXRD) pattern. The presence of various functional groups in IHOH is ascertained by vibrational analysis. The lower cutoff wavelength of IHOH is 223 nm, and it is transparent up to 1100 nm. The refractive index (n), extinction coefficient (k), optical absorption coefficient (α) and optical bandgap (Eg) are determined. Nuclear magnetic resonance (NMR) spectral analysis establishes the molecular structure of IHOH. Z-scanning is employed to analyse the NLO characteristics of IHOH crystal. The crystal demonstrates saturable absorption and a self-defocusing nature. The third-order NLO susceptibility (χ3) of IHOH is calculated as 2.6718 × 10−7 esu. The presence of N–H···O and O–H···O bonds in the IHOH crystal is the reason for the high χ3 value. The photoluminescence (PL) spectrum reveals violet and blue emission from the crystal. The decomposition of IHOH is investigated using thermogravimetry/differential thermal analysis (TG/DTA analysis. The results reveal the suitability of IHOH for Q-switching, optical pulse shortening, optical sensors, and photonic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Cocrystals with three π‐components, which were a π‐cation, a π‐anion acting as a hydrogen‐bond acceptor, and a π‐molecule acting as a hydrogen‐bond donor, were prepared by the solution‐growth methods. The first and second components were ion pairs of 1‐methylpyridinium or 1‐methylquinolinium p‐toluenesulfonate derivatives, and the third components were dihydric phenol derivatives, like hydroquinone, 1,4‐naphthalenediol, 4,4'‐biphenol, and 1,1'‐bi‐2‐naphthol, or benzoic acid derivatives with hydroxy or amino group at the para position. Among 23 cocrystals found from 35 possible combinations of five ion‐pairs and seven hydrogen‐bond donors, 20 cocrystals were investigated by the X‐ray crystallographic analyses. Some of them also contained solvent molecules. In these cocrystals, hydrogen‐bond sequences composed of p‐toluenesulfonate and the hydrogen‐bond donors were observed, and ionic bonds between the first and second components and hydrogen bonds between the second and third components were found to be responsible for three‐π‐component cocrystals. When the cations were 4‐cyanopyridinium or quinolinium derivatives, the cocrystals showed charge‐transfer absorption bands due to electronic interaction between the cations and the hydrogen‐bond donors. To the mixture of quinolinium p‐toluenesulfonate and 1,1'‐bi‐2‐naphthol forming the three‐π‐component cocrystals, tetrathiafulvalene were added to form four‐π‐component cocrystals with ethanol or water molecules. [ABSTRACT FROM AUTHOR]

Non‐covalent interactions play an important role in all sub‐fields of chemistry, including catalysis, where interactions of different natures can work together to improve reactivitiy and selectivity. Several families of molecules that incorporate both hydrogen bond (HB) and halogen bonding (XB) donors have already been studied. However, there is a lack of data on how grafting HB donors to iodoazolium salts could impact their association and reactivity properties. Herein, we disclose the synthesis of a library of iodoazolium salts bearing varied HB donors, along with a study of their physico‐chemical properties using different techniques (X‐ray diffraction, 31P NMR, ITC) and their behavior in catalysis. Even though no clear‐cut evidence of cooperation between XB and HB could be obtained through physico‐chemical evaluations, a iodoazolium salt bearing a urea function displayed better conversion and product selectivity in a Ritter reaction than all other activators lacking one or the other function. [ABSTRACT FROM AUTHOR]

Exfoliation into a 2D nanosheet structure can lead to enhanced surface activity and unique optical and electronic properties in polymeric carbon nitride (PCN). In this study, four common exfoliation strategies (liquid ultrasonication, thermal oxidation, hydrothermal oxidation, and chemical oxidation) were adopted, and their effects on the structural and electronic changes in PCN were analyzed in detail. This allows us to understand the relationship between the exfoliation mechanism and the structural/optical properties. Here, we demonstrate that the thermal and ultrasonic exfoliation methods can effectively reduce the thickness of PCN while preserving its original structure. In contrast, the chemical and hydrothermal treatments can strongly affect the morphology and structure of PCN, leading to a decreased performance in phenol photodegradation. Therefore, depending on the employed exfoliation method, the surface area, functionalization, band edge positions, charge carrier generation, and mobility are influenced differently up to the point where semiconducting behavior is entirely lost. Our results allow conclusions about the applicability of the different exfoliation methods to obtain distinct material properties for photocatalytic applications. [ABSTRACT FROM AUTHOR]

Synthesizing high-performance of gel polymer electrolytes (GPEs) with simple methods and common materials has long been a crucial concern for lithiumion batteries. Here, the poor mechanical properties of polyethylene oxide (PEO) based GPEs were overcome by introducing strong hydrogen bond between PEO and polyacrylic acid (PAA). Easy-available PEO/PAA membranes were prepared though hot processing approach without use of organic solvent during all processes. The mechanical properties and crystalline of dry composites could be tuned by the addition content of PAA. After quick absorbing electrolyte in 30 min, the tensile strength and elongation at break of the GPEs composites are ranged from 0.07 to 0.63 MPa, and 525% to 722%. Moreover, the lithium-ion conductivity and transference number with 30 wt% addition of PAA reach up to 1.66 and 0.58 mS/cm, respectively. After 500 cycling at 0.5 C, the discharge specific capacity and the capacity retention rate are still up to 134.1 mAh/g and 88.7%, respectively. This research proves the great possibility of applying environmentally friendly method, low cost, and high electrochemical performances of PEO/PAA based GPEs in the lithium batteries. [ABSTRACT FROM AUTHOR]

The article focuses on supported atomically dispersed palladium (Pd) catalysis for direct alkoxylation and allylic alkylation, emphasizing the catalyst's efficiency and unique mechanism. It discusses the utilization of atomically dispersed Pd on titanium dioxide (TiO2) nanosheets for direct allylic alkylation from allylic alcohols, highlighting the role of hydrogen bonding at the organic-inorganic interface in facilitating the reaction.

Herein, we report an asymmetric two-component alkenyl Catellani reaction for the construction of C--N axial chirality through a palladium/chiral norbornene cooperative catalysis and an axial-to-axial chirality transfer process. Various partially aromatic iodinated 2-pyridones, quinolones, coumarin and uracil substrates react with 2,6-disubstituted aryl bromides with a tethered amide group, to afford a wide variety of polycyclic C--N atropisomers (38 examples, up to 97% e.e.). The obtained C--N axial chirality originates from the preformed transient C--C axial chirality with high fidelity. The synthetic utility of this chemistry is demonstrated by facile preparation of complex quinoline and pyridine based C--N atropisomers through a N-deprotection and aromatization sequence. In addition, a remote axial-to-central diastereoinduction process dictated by C--N axial chirality is observed with excellent diastereocontrol. [ABSTRACT FROM AUTHOR]

[Carbonatotetraamminecobalt(III)] permanganate monohydrate was synthesized first in the metathesis reaction of [Co(NH3)4CO3]NO3 and NaMnO4 in aqueous solution. Its thermal dehydration at 100 °C resulted in phase-pure [Co(NH3)4CO3]MnO4 (compound 1). Compounds 1 and 2 (i.e., the hydrated form) were studied with IR, far-IR, and low-temperature Raman spectroscopies, and their vibrational modes were assigned. The lattice parameters were determined by powder X-ray diffraction (PXRD) and single crystal X-ray diffraction (SXRD) methods for the triclinic and orthorhombic compounds 1 and 2, respectively. The detailed structure of compound 2 was determined, and the role of hydrogen bonds in the structural motifs was clarified. UV studies on compounds 1 and 2 showed the distortion of the octahedral geometry of the complex cation during dehydration because of the partial loss of the hydrogen bonds between the crystal water and the ligands of the complex cation. The thermal decomposition consists of a solid phase quasi-intramolecular redox reaction between the ammonia ligands and permanganate anions with the formation of ammonia oxidation products (H2O, NO, N2O, and CO2). The solid phase reaction product is amorphous cobalt manganese oxide containing ammonium, carbonate (and nitrate) anions. The temperature-controlled thermal decomposition of compound 2 in toluene at 110 °C showed that one of the decomposition intermediates is ammonium nitrate. The decomposition intermediates are transformed into Co1.5Mn1.5O4 spinel with MnCo2O4 structure upon further heating. Solid compound 2 gave the spinel at 500 °C both in an inert and air atmosphere, whereas the sample pre-treated in toluene at 110 °C without and with the removal of ammonium nitrate by aqueous washing, gave the spinel already at 300 and 400 °C, respectively. The molten NH4NO3 is a medium to start spinel crystallization, but its decomposition stops further crystal growth of the spinel phase. By this procedure, the particle size of the spinel product as low as ~4.0 nm could be achieved for the treatments at 300 and 400 °C, and it increased only to 5.7 nm at 500 °C. The nano-sized mixed cobalt manganese oxides are potential candidates as Fischer-Tropsch catalysts. [ABSTRACT FROM AUTHOR]

It is widely recognized that electrostatics plays a central role in the intermolecular interactions in condensed phases, as evidenced by the "electrostatics + Lennard-Jones" form of the potential functions that are commonly used in classical molecular dynamics simulations. Then, do we understand all about electrostatics in condensed phases? In this review, recent theoretical advances in relation to this topic will be discussed: (1) vibrational spectroscopic probing of the electrostatics in condensed phases, and (2) some phenomena affected by deviation from the scheme of isotropic fixed atomic partial charges, i.e., anisotropy and intermolecular transfer of electron distributions. A theoretical basis for better understanding on them and some theoretical models for practical calculations will be shown with some typical example cases of hydrogen- and halogen-bonded systems. [ABSTRACT FROM AUTHOR]

The level of fluoride ions (F−) in the human body is closely related to various pathological and physiological states, and the rapid detection of F− is important for studying physiological processes and the early diagnosis of diseases. In this study, the detailed sensing mechanism of a novel high-efficiency probe (PBT) based on 2-(2′-hydroxyphenyl)-benzothiazole derivatives towards F− has been fully investigated based on density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. F− attacks the O-P bond of PBT to cleavage the dimethylphosphinothionyl group, and the potential products were evaluated by Gibbs free energy and spectroscopic analyses, which ultimately identified the product as HBT-Enol1 with an intramolecular hydrogen bond. Bond parameters, infrared vibrational spectroscopy and charge analysis indicate that the hydrogen bond is enhanced at the excited state (S1), favoring excited state intramolecular proton transfer (ESIPT). The mild energy barrier further evidences the occurrence of ESIPT. Combined with frontier molecular orbital (FMO) analysis, the fluorescence quenching of PBT was attributed to the photoinduced electron transfer (PET) mechanism and the fluorescence turn-on mechanism of the product was attributed to the ESIPT process of HBT-Enol1. [ABSTRACT FROM AUTHOR]

A comparative study of the electrochemical behavior of various forms of the antitumor antibiotic doxorubicin (DOX), both free and encapsulated in micelle-like nanoparticles of the biocompatible amphiphilic copolymer of N-vinylpyrrolidone (VP) and methacrylic acid, viz., triethylene glycol dimethacrylate (TEGDM), is carried out in aqueous neutral buffers on a glassy carbon electrode. The hydrodynamic radii Rh of the copolymer and the DOX polymeric nanostructures are determined using dynamic light scattering. Using cyclic and square wave voltammetry, for both forms of DOX at pH 7.24, the two main redox transitions are revealed namely, the irreversible oxidation/rereduction in the potential interval from 0.2 to 0.6 V and the reversible reduction/reoxidation in the interval from –0.4 to –0.7 V (vs. saturated Ag/AgCl), and their redox potentials are determined. For both redox transitions, the potential difference between the corresponding peaks does not exceed several tens (20–30) mV; and, moreover, the oxidation of the encapsulated form proceeds easier as compared with the free form, whereas its reduction is somewhat more difficult. The analysis of the dependence of the reduction current of both DOX forms on the potential scan rate shows that the electron transfer to a free DOX molecule is largely determined by the rate of reagent accumulation in the adsorption layer, whereas the electron transfer to the encapsulated form is characterized by the mixed adsorption-diffusion control. Based on voltammetric data and the results of quantum chemical modeling, it is concluded that a hydrogen bond is formed between the oxygen-containing groups of copolymer's monomeric units and the H atoms in OH and NH2 groups of DOX. The bond energy in these structures is calculated and shown to be close to the classical values, assuming that the carbonyl group in the VP lactam ring in the encapsulating polymer is the electron donor, and the hydrogen atoms in OH and NH2 groups of DOX are the electron acceptors. At the same time, the bonds involving oxygen of the ester group in the TEGDM unit are extremely weak. [ABSTRACT FROM AUTHOR]

In this paper we would like to highlight the problems of conceiving the "Hydrogen Bond" (HB) as a real short-range, directional, electrostatic, attractive interaction and to reframe its nature through the non-approximated view of condensed matter offered by a Quantum Electro-Dynamic (QED) perspective. We focus our attention on water, as the paramount case to show the effectiveness of this 40-year-old theoretical background, which represents water as a two-fluid system (where one of the two phases is coherent). The HB turns out to be the result of the electromagnetic field gradient in the coherent phase of water, whose vacuum level is lower than in the non-coherent (gas-like) fraction. In this way, the HB can be properly considered, i.e., no longer as a "dipolar force" between molecules, but as the phenomenological effect of their collective thermodynamic tendency to occupy a lower ground state, compatible with temperature and pressure. This perspective allows to explain many "anomalous" behaviours of water and to understand why the calculated energy associated with the HB should change when considering two molecules (water-dimer), or the liquid state, or the different types of ice. The appearance of a condensed, liquid, phase at room temperature is indeed the consequence of the boson condensation as described in the context of spontaneous symmetry breaking (SSB). For a more realistic and authentic description of water, condensed matter and living systems, the transition from a still semi-classical Quantum Mechanical (QM) view in the first quantization to a Quantum Field Theory (QFT) view embedded in the second quantization is advocated. [ABSTRACT FROM AUTHOR]

Three cocrystals of acridine with 2,7-dihydroxynaphthalene (Ia and Ib) in two different polymorphs and 1,5-dihydroxynaphthalene (II) have been synthesized and characterized by single crystal X-ray diffraction method. Two polymorphs of acridine, 2,7-dihydroxynaphthalene cocrystal crystallizes in same space group with different unit-cell parameters. In (Ia) the O–H group form a syn-anti conformation whereas in (Ib) the O–H group form an anti-anti conformation leads to the polymorphic structure of acridine, 2,7-dihydroxynaphthalene. This study reveals that the influence of π⋯π and C–H⋯π interactions in the formation of one-, two-, and three-dimensional supramolecular frameworks when the classical hydrogen bonds such as O–H⋯N and C–H⋯O are limited to discrete motifs. The acridine molecules form continuous π⋯π stacking in the crystal structure of (Ia) and discrete π⋯π stacking in the crystal structure of (Ib) and (II). The conformational flexibility of the substituted hydroxy group has an influence in the supramolecular frameworks of the three-dimensional crystal structure. The intermolecular interaction energy calculation between the molecular pairs has been carried out to study the strength of the interaction and its dependence on the geometrical parameters. [ABSTRACT FROM AUTHOR]

In this paper, the structure and properties of interpolymer complexes (IPC) based on sodium carboxymethylcellulose with a linear carbopol were studied. Interpolymer complexes were obtained by mixing aqueous solutions of Na-CMC and carbopol components in various ratios of components and pH of the medium. The structure of the obtained products was determined using the methods of IR spectroscopy and X-ray diffraction analysis. IR spectra in the range of 400-4000 cm-1 were recorded on spectrophotometers "NIKOLET Magna-560 IR" and "Specord-75 IR" (Karl Zeiss, GDR). X-ray diffraction analysis of IPС films was carried out on a Rigaku X-Ray installation with an X-ray generator with a rotating copper anode, at a voltage of 40 kV, with a current strength of 15 mA and using characteristic Cu-Ka radiation in the area of angles 0 <2θ <40. IR spectroscopic data show that the interpolymer complexes based on Na-CMC and carbopol obtained in moderately acidic regions are stabilized due to the cooperative hydrogen bond between the carboxyl groups of Na-CMC and the carbonyl groups of carbopol. X-ray diffraction analysis has shown that a change in the composition of the interpolymer complex leads to a change in the structure, which depends on the structure and nature of the interchain bonds. It is ascertained that an increase in the number of hydrogen bonds leads to a more ordered state of the resulting interpolymer complex. It is revealed that the formation of an interpolymer complex due to hydrogen bonds provides additional stability. This can serve as one of the means of controlling the structure and properties of the IPC of sodium carboxymethylcellulose with carbopol. [ABSTRACT FROM AUTHOR]

Chitosan (CS) was selected as the carbon source, and the Chitosan/dicyandiamide (CS/DCDA) precursors with hydrogen bonding interactions were prepared by freeze-drying and normal drying, and the carbon-Chitosan/graphite carbon nitride (C-CS/g-C3N4) composites were obtained after calcination. The results show that the freeze-drying process can produce more hydrogen bonding interaction between chitosan and dicyandiamide (DCDA) and more pores through recrystallization. More composite carbon is formed in the C-CS/g-C3N4-2 composite obtained after calcination. More hydrogen bonds are broken, releasing more N lone pairs of electrons, which not only facilitates the n−π* electron leap, but also facilitates the separation and photogenerated electron-hole, and provides a large number of reactive sites for photocatalytic degradation of pollutants. This results in better photocatalytic performance of C-CS/g-C3N4-2. [ABSTRACT FROM AUTHOR]

In the title molecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, fivemembered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitrogen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O--H...N and N--H...O hydrogen bonds plus C--H...π(ring) and weak π-stacking interactions. [ABSTRACT FROM AUTHOR]

Copyright of China Surfactant Detergent & Cosmetics (2097-2806) is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, interest in polyphenol-containing composite adhesives for various biomedical applications has been growing. Tannic acid (TA) is a polyphenolic compound with advantageous properties, including antioxidant and antimicrobial properties. Additionally, TA contains multiple hydroxyl groups that exhibit biological activity by forming hydrogen bonds with proteins and biomacromolecules. Furthermore, TA-containing polymer composites exhibit excellent tissue adhesion properties. In this study, the gelation behavior and adhesion forces of TA/Pluronic F127 (TA/PluF) composite hydrogels were investigated by varying the TA and PluF concentrations. PluF (above 16 wt%) alone showed temperature-responsive gelation behavior because of the closely packed micelle aggregates. After the addition of a small amount of TA, the TA/PluF hydrogels showed thermosensitive behavior similar to that of PluF hydrogels. However, the TA/PluF hydrogels containing more than 10 wt% TA completely suppressed the thermo-responsive gelation kinetics of PluF, which may have been due to the hydrogen bonds between TA and PluF. In addition, TA/PluF hydrogels with 40 wt% TA showed excellent tissue adhesion properties and bursting pressure in porcine intestinal tissues. These results are expected to aid in understanding the use of mixtures of TA and thermosensitive block copolymers to fabricate adhesive hydrogels for versatile biomedical applications. [ABSTRACT FROM AUTHOR]

Guanidine Sulphanilate (GSA) single crystal was grown by slow evaporation growth method. Single crystal X-ray diffraction studies show that the crystal grows in a centro symmetric monoclinic system and its space group is P21/c. Optical studies were carried out using UV visible spectroscopy and the grown crystal shows the the lower cutoff wavelength of 220 nm. Photoluminescence studies show that GSA crystals have good luminescence properties. Laser damage threshold was found to be 0.24GW/cm² . Nonlinear optical studies show green light emission. [ABSTRACT FROM AUTHOR]

Abstract—Using the molecular dynamics method features of the formation of the microstructure of ionic liquids based on a mesylate anion and ammonium cations containing different number of propyl groups are studied. Structural changes of a liquid with a change in the cation size are analyzed. Probabilities of the formation of hydrogen bonds between the cation and anion and the average numbers of hydrogen bonds are calculated. The influence of solvation effects on the structural models of ionic liquids which were previously predicted using the quantum chemical method is considered. [ABSTRACT FROM AUTHOR]

Although S‐nitrosylation of cysteines is a common protein posttranslational modification, little is known about its three‐dimensional structural features. This paper describes a systematic survey of the data available in the Protein Data Bank. Several interesting observations could be made. (1) As a result of radiation damage, S‐nitrosylated cysteines (Snc) are frequently reduced, at least partially. (2) S‐nitrosylation may be a protection against irreversible thiol oxidation; because the NO group of Snc is relatively accessible to the solvent, it may act as a cork to protect the sulfur atoms of cysteines from oxidation by molecular oxygen to sulfenic, sulfinic, and sulfonic acid; moreover, Snc are frequently found at the start or end of helices and strands and this might shield secondary structural elements from unfolding. [ABSTRACT FROM AUTHOR]