Formation Of Intermolecular Hydrogen Bonds Research Articles

Preparation of high temperature proton exchange membrane through covalent organic framework doped polyvinylidene fluoride nanofibers

Covalent organic framework (COF) exhibits the great potential to promote proton conduction under low relative humidity for proton exchange membranes (PEMs). In this research, quick and stable proton conduction has been achieved since the prepared COF and polyvinylidene fluoride (PVDF) nanofibers are believed to constitute successive proton conduction channels. The PVDF-COF nanofibers membrane is prepared through the in-situ growth of COF along PVDF nanofibers. The fine compatibility can drive the stable combination of COF with the PVDF nanofibers in PVDF-COF nanofibers. Most importantly, the fibrous PVDF nanofibers accelerate proton conduction through confining the proton conduction pathways. Additionally, ionic liquids of 1-butyl-3-methylimidazolium chloride (BmimCl) and 1-butyl-3-methylimidazole hexafluorophosphate (BmimPF6) as proton conduction carriers have been introduced to accelerate proton conduction in the prepared PVDF-COF/BmimCl/PA and PVDF-COF/BmimPF6/PA membranes. Phosphoric acid (PA) molecules are combined by COF and ionic liquid cations with the formation of intermolecular hydrogen bonds. As a result, the PVDF-COF/BmimPF6/PA membrane exhibits the proton conductivity of (1.81 ± 0.07) × 10−1 S/cm at 160 °C. The long-term proton conductivity stability is determined, deriving from the proton conductivities of 1.77×10−2 S/cm at 80 °C and 1.42×10−2 S/cm at 110 °C in the 400 h non-stop measurement. The single fuel cell equipped with the PVDF-COF/BmimPF6/PA membrane represents the open circuit voltage of 0.927 V and the peak power density of 178.8 mW/cm2 at 100 °C, 0.907 V and 326.5 mW/cm2 at 120 °C.

Programmable and flexible wood-based origami electronics

Natural polymer substrates are gaining attention as substitutes for plastic substrates in electronics, aiming to combine high performance, intricate shape deformation, and environmental sustainability. Herein, natural wood veneer is converted into a transparent wood film (TWF) substrate. The combination of 3D printing and origami technique is established to create programmable wood-based origami electronics, which exhibit superior flexibility with high tensile strength (393 MPa) due to the highly aligned cellulose fibers and the formation of numerous intermolecular hydrogen bonds between them. Moreover, the flexible TWF electronics exhibit editable multiplexed configurations and maintain stable conductivity. This is attributed to the strong adhesion between the cellulose-based ink and TWF substrate by non-covalent bonds. Benefiting from its anisotropic structure, the programmability of TWF electronics is achieved through sequentially folding into predesigned shapes. This design not only promotes environmental sustainability but also introduces its customizable shapes with potential applications in sensors, microfluidics, and wearable electronics.

Harvesting the tuning mechanism of strategic polychrome and white light emission in NapH dye based on excited state intermolecular proton transfer

Organic white light emitting (WLE) materials have sparked a research boom due to their promising applications in display devices, artificial lighting, and molecular sensors. However, the complex luminescence mechanism of full-spectra emitting materials has limited the development of white light materials with high stability and reproducibility. In this study, building on the full-spectra luminescent naphthimide dye (NapH) introduced by Xu et al., (Chin. Chem. Lett. 35(2024), 108348), we report the solvent-sensitive excited state proton transfer (ESPT) properties and white light emission mechanism in NapH. Our theoretical research results show that the ESPT process of NapH molecule is hindered in the low-polar solvent tetrahydrofuran (THF), so only the blue fluorescence from the Enol* is observed in the experiment. In contrast, in polar solvents such as water (H2O) and methanol (MeOH), the formation of strong intermolecular hydrogen bonds successfully initiates the ESPT process, leading to the dual fluorescence observed in experiments, with blue emission from the Enol* and red emission from the Nap anion. In essence, different solvent environments can adjust several emission colors. Furthermore, we theoretically verify that the optimal white light emission can be achieved when the mixed solvent ratio of dimethyl sulfoxide (DMSO) and dioxane (DIOX) is 5:5, which aligns well with experimental results. More importantly, we elucidate the specific WLE mechanism from multiple perspectives, including potential energy curves and electron spectra. Our work not only displays the interaction models of NapH molecule in various solvents, but also reveals the underlying luminescence mechanism, thus providing a valuable theoretical reference for the development and advancement of new white light materials.

Development of multifunctional zein-based films engineered with gallic acid and Ag NPs loaded γ-CD-MOFs for pork preservation

The increasing emphasis on food quality and consumer safety has prompted researchers to explore green manufacturing techniques for packaging materials. In this study, γ-cyclodextrin metal-organic frameworks (γ-CD-MOFs) were prepared as promising nanocarriers for gallic acid (GA) and silver nanoparticles (Ag NPs). These nanocarriers (GA-Ag@CD-MOFs) were further incorporated into a zein matrix to fabricate multifunctional composite films, referred to as MOFs-Zein. Scanning electron microscopy (SEM) and atomic force microscope (AFM) analysis indicated that the fabricated composite film exhibited excellent biocompatibility, with GA-Ag@CD-MOFs uniformly dispersed within the film matrix. Fourier transform infrared spectroscopy (FT-IR) result revealed that the incorporation of GA-Ag@CD-MOFs facilitated the formation of intermolecular hydrogen bonds with the matrix polymer. The addition of GA-Ag@CD-MOFs enhanced the tensile strength of the composite film by 19.70 %, improved the water barrier performance by 57.76 %, and provided almost 100 % UV protection. The exceptional controlled release capability of γ-CD-MOFs for GA empowered the composite films to maintain their robust initial antioxidant capacity even after 100 days of storage. Moreover, the composite films performed high-efficiency antibacterial activity against Escherichia coli O157:H7 and Salmonella enterica. Acute toxicological studies showed no histopathology related toxicity was found in GA-Ag@CD-MOFs treated mice. When applied to fresh pork, the composite films significantly reduced the key quality indicators of raw meat, compared to the control film. Overall, this work presents a promising approach to fabricate the composite films as a sustainable and functional solution for green functional food packaging.

Enhancement of zein-based films for mango preservation using high-intensity ultrasound and castor oil plasticization

Zein-based films exhibit high efficiency in ethylene adsorption. However, its brittleness limits the practical applications. To address this issue, this study synergizes the plasticizing effects of high-intensity ultrasound (HIU) and castor oil (CO) to reduce the brittleness of zein-based films. The plasticizing mechanism was demonstrated through the formation of new intermolecular hydrogen bonds and electrostatic interactions, as evidenced by fourier transform infrared spectroscopy (FTIR) and zeta potential measurements. The tensile strength of 6 % CO-zein film increased eightfold. Additionally, the freshness of mangoes stored with 6 % CO-zein film significantly improved, extending their shelf life from 5 days to 15 days. Therefore, this study investigated the synergistic plasticization of zein-based films through the addition of CO, based on HIU. It also provides a theoretical basis for fruit packaging.

Pomegranate peel extract incorporated soy protein isolate/Artemisia sphaerocephala Krasch. gum composite films for fresh-cut apples preservation

The objective of this study was to prepare an active packaging film using phosphorylated soy protein isolate (PPS) and Artemisia sphaerocephala Krasch. gum (ASKG) as film matrices, with the incorporation of pomegranate peel extract (PPE) to preserve fresh-cut apples. The results showed that PA-PPE (PPS/ASKG-PPE) films significantly increased thickness by 24.47 %, tensile strength by 58.76 %, and elongation at break by 30.48 %. Additionally, water vapor permeability and oxygen permeability decreased significantly to 6.17 × 10−13 and 0.62 × 10−13 Kg•m•m−2•s−1•Pa−1, respectively. FTIR, XRD, and SEM analyses confirmed the formation of intermolecular hydrogen bonds between PPS, ASKG, and polyphenols extracted from pomegranate peel, indicating excellent compatibility. Furthermore, radical scavenging activity experiments demonstrated that these films exhibited a remarkable ability to scavenge DPPH and ABTS+ radicals up to 70.44 % and 74.28 %, respectively, when the PPE content was at 3 wt%. Moreover, PPS could achieve a sustained release effect on polyphenols with a relatively low release rate (63.83 %) even after seven days' time elapsed. Finally, the PA-PPE film displayed superior performance in reducing the weight loss and browning index of fresh-cut apples within 24 h of storage. The development of PA-PPE film could promote sustainable resource protection and demonstrate promising prospects in the field of fresh-cut fruit packaging.

PREPARATION OF DEEP EUTECTIC SOLVENTS FOR MAKING AN OIL-DISPLACING COMPOSITION BASED ON TETRAHYDROXY ALCOHOL, CARBAMIDE, QUATERNARY AMMONIUM SALT, AND A SURFACTANTS

The binary systems of deep eutectic solvents (DESs) have been synthesised and investigated: tetraxydroxy alcohol - a salt of a quaternary ammonium base (DES1), tetrahydroxy alcohol - carbamide (DES2), a salt of a quaternary ammonium base - carbamide (DES3), and the ternary system tetrahydroxy alcohol - a salt of a quaternary ammonium base - carbamide (DES4). Eutectic compositions of binary systems DES1, DES2 and DES3 are characterised by significantly lower pour/melting points than those of the initial components. The lowest pour point among the binary mixtures is that of eutectic composition DES3. The ternary system is characterised by an even lower melting point (-14 °C), which is associated with the formation of intermolecular donor-acceptor hydrogen bonds within the system. An aqueous solution of DES4 with the concentration of 26 wt% was prepared, and its pH value was determined depending on temperature during preparation. At room temperature, pH of three-component DES is 6.6-7.1, but after thermostating for 6 h at 150 °C pH increases to 9.2 due to carbamide hydrolysis. It is assumed that further on, using DES4 as the basis for an alkaline oil-displacing composition directly in the reservoir, under the influence of the temperature of injected heat carrier, CO2 is formed, along with the ammonia buffer system with the maximal buffer capacity within the pH range 9-10. Resulting carbon dioxide, dissolving predominantly in oil, will cause a decrease in its viscosity, on the one hand, while the formed alkaline medium, being most favourable for surfactant performance due to a decrease in interfacial tension, liquefaction of high-viscosity layers or films at the oil-water-rock boundaries, on the other hand, will ensure efficient use of this system for oil displacement. In addition, the oil-displacing composition based on DES4 will be low-solidifying, which opens the possibility of its transportation and use in the northern regions and the Arctic zone.

Additive-Assisted Forming High-Quality Thin Films of Sn-Oxo Cluster for Nanopatterning.

Recently, metal-oxo clusters (MOCs) have attracted significant interest in fabricating nanoscale patterns in semiconductors via lithography. However, many MOCs are highly crystalline, making it difficult for them to form films and hindering subsequent nanopatterning processes. In this study, we developed a novel and simple method to enhance the film-forming ability of aromatic tetranuclear Sn-oxo clusters by adding additives. Theoretical calculations and Fourier-transform infrared (FTIR) analysis revealed the formation of intermolecular hydrogen bonds between the Sn-oxo clusters and additives, which induced a crystal-gel phase transition at -20 °C, thereby inhibiting the easy crystallization of the Sn-oxo clusters. High-quality and uniform thin films with surface roughness below 0.3 nm were prepared via spin coating. The obtained thin films exhibited good lithographic performance under deep ultraviolet (DUV), electron beam, and extreme-ultraviolet irradiation without a photo acid generator/photoinitiator, and 13- and 21 nm-wide line patterns were obtained on the films via electron-beam and extreme-ultraviolet lithographies. This study will pave the way for the further investigation of novel MOCs for advanced lithography and other thin-film applications.

Exploring the AC conductivity and dielectric properties of PVA films doped with Erythrosin B

Erythrosin B (EB) doped in PVA film was processed utilizing the casting procedure, and the structure was investigated via the Fourier Transformation infrared technique (FTIR). FTIR analysis presented a strong formation of intermolecular hydrogen bonds among PVA and EB hydroxyl groups (OH). Characteristic temperature and frequency variation of dielectric behavior and AC electrical conductivity for films of PVA doped with Erythrosin B were analyzed at (293–383 K) temperature and (102–106 Hz) frequency. The AC conductivity dependency indicates that the predominant conduction mechanism in PVA doped with Erythrosin B films follows the correlated barrier hopping (CBH) model. The charge carriers’ hopping involving localized states causes a relaxation process. Estimates were made for the AC conductivity activation energy and the conductivity relaxation energy. Frequency and temperature affect the dielectric constant (ε′) and the dielectric loss (ε″). The complex impedance spectrum (Z′ versus Z″) showed single semicircular arcs with a decreased radius with increasing temperature. The relaxation peaks in the electric modulus representation are clearly defined, and the relaxation period has been calculated.

Structural Characterization of Pyruvic Acid Dimers Formed inside Helium Nanodroplets by Infrared Spectroscopy and Ab Initio Study.

The structural arrangements of α-keto acid complexes hold significant interest across various fields of chemistry such as enzyme modeling, drug design, or polymer blending. Herein, we report mass-selective infrared (IR) spectra of pyruvic acid monomers and dimers in the range 1720-1820 cm-1 recorded in helium nanodroplets at 0.37 K. The monomer features IR bands at 1807.1 and 1734.5 cm-1, which are assigned to the carboxylic and ketonic C═O stretching vibrations, respectively. Furthermore, the pyruvic acid dimers generated inside the helium nanodroplets are characterized by carboxylic and ketonic C═O stretch vibrations appearing at 1799.2 and 1737.0 cm-1, respectively. This frequency shift of ±7 cm-1 for both C═O stretching bands from the monomer to the dimer demonstrates that the structural motif of the monomer is maintained upon dimer aggregation in helium nanodroplets. The structural assignments were supported by a comparison of the MP2/aug-cc-pVDZ-predicted harmonic vibrational spectra at the C═O stretching region with the experiments. The global minimum monomer structure with an intramolecular hydrogen bond and its dimer stabilized by both inter- and intramolecular hydrogen bonding interactions reproduce the experimental spectra from the monomer and dimer. This assigned dimer structure lies ca.11 kJ/mol above the corresponding global minimum and is favored in helium nanodroplets due to the long-range realignment of molecules via dipole-dipole interaction, followed by short-range stabilization upon intermolecular hydrogen bond formation. The barrier for reconfiguration of the precooled monomer conformer leading to the formation of the most stable dimer structure is around 58 kJ/mol, which is infeasible at 0.37 K.

3-Pentadecylphenol (PDP) as a Novel Compatibilizer for Simultaneous Toughened and Reinforced PA10,12 Composites.

The utilization of polyamide 10,12 (PA10,12) composites in various industries has been limited constrained by their inherent low toughness, making it a challenge to achieve a balance between toughness and structural integrity through conventional elastomer addition strategies. Herein, we introduce a straightforward method for the concurrent toughening and reinforcement of PA10,12 composites. This is accomplished by blending polyolefin elastomer (POE) and 3-pentadecylphenol (PDP) with the PA10,12 matrix. The incorporation of 5 wt% PDP effectively blurred the PA10,12/POE interface due to PDP's role as a compatibilizer. This phenomenon is attributed to the formation of intermolecular hydrogen bonds, as evidenced by Fourier Transform Infrared Spectroscopy (FTIR) analysis. Further investigation, using differential scanning calorimetry (DSC), elucidated the crystallization thermodynamics and kinetics of the resulting binary PA10,12/POE and ternary PA10,12/POE/PDP composites. Notably, the crystallization temperature (Tc) was observed to decrease from 163.1 °C in the binary composite to 161.5 °C upon the addition of PDP. Increasing the PDP content to 10% led to a further reduction in Tc to 159.5 °C due to PDP's capacity to slow down crystallization. Consequently, the ternary composite of PA10,12/POE/PDP (92/3/5 wt%) demonstrated a synergistic improvement in mechanical properties, with an elongation at break of 579% and a notch impact strength of 61.54 kJ/m2. This represents an approximately eightfold increase over the impact strength of unmodified PA10,12. Therefore, our work provides the potential of PDP as a compatibilizer to develop nylon composites with enhanced stiffness and toughness.

In-depth research on azole corrosion inhibitors - effect of N atoms position and quantity on copper corrosion inhibition performance in alkaline environments: Experimental evaluation and theoretical analysis

Copper's superior electrical properties make it ideal for multi-layer interconnections in integrated circuits. Chemical mechanical polishing (CMP) is the main method for achieving copper wiring flatness. However, copper is susceptible to corrosion in glycine-based alkaline polishing solutions. This study examines benzimidazole, indazole, and benzotriazole as corrosion inhibitors for copper in an alkaline environment (pH=9), focusing on the impact of nitrogen atom arrangement on inhibition efficiency. Through electrochemical, contact angle, static corrosion, and surface characterization tests, it's demonstrated that these inhibitors protect copper surfaces effectively. The adsorption of these inhibitors follows the Langmuir equation with a mixed adsorption mode. X-ray photoelectron spectroscopy (XPS), UV–vis spectroscopy tests, and density functional theory calculations elucidate the adsorption configuration and corrosion inhibition mechanism. The scope of this research extends beyond merely analyzing the performance of the three corrosion inhibitors; more importantly, it has yielded novel insights that are broadly applicable to the field of corrosion inhibitors. The findings are as follows: 1. The coupled structure of dinitrogen and trinitrogen facilitates charge accumulation, manifesting as the formation of additional Cu-N bonds, which prevents desorption; 2. The multi-nitrogen coupled structures provide sites for the formation of intermolecular hydrogen bonds, which is essential for the establishment of an orderly and dense passivation layer. It is expected that this study will provide valuable insights into the development and design of new and efficient copper corrosion inhibitors.

Simultaneously enhancing the mechanical and thermoelectric properties of diketopyrrolopyrrole-thiophene based conjugated polymers through dynamic hydrogen-bonding

Remarkable progress has been made in the development of thermoelectric materials based on diketonepyrrolopyrrole-thiophene (DPPT). However, achieving DPPT polymers with both high thermoelectric and mechanical properties remain a challenge. In this study, thymine groups, which are beneficial for the formation of intermolecular hydrogen bonds, were introduced into the side chains of DPPT, and a series of polymers (PDPPT-x) with different amount of thymine groups (x is the molar ratio of thymine side chains) were synthesized and characterized. The introducing thymine groups can regulate the self-assembly of conjugated polymers, effectively enhancing the crystallinity and molecular packing order, and thereby improve the charge carrier mobility. Additionally, the formed dynamic hydrogen-bonding networks by the thymine groups possess a moderate strength that can alleviate applied pressure and enhance the flexibility. Among these polymers, PDPPT-5 exhibited superior performance with excellent flexibility demonstrated by its elongation at break (up to 19.8 %), surpassing that of PDPPT-0 by a power factor of 2.2. In addition, the incorporation of 5 % amount of thymine groups can enhance the interchain interactions, thereby improving the crystallinity of the polymers and consequently enhancing the carrier mobility (4.26 × 10-3 cm2 V−1 s−1 for PDPPT-5 compared to 1.14 × 10-3 cm2 V−1 s−1 for PDPPT-0). Upon doping with FeCl3 at room temperature, the power factor of PDPPT-5 is about twice that of PDPPT-0. These results suggest that incorporating hydrogen bonding is a highly effective strategy for enhancing both the thermoelectric and mechanical properties of conjugated polymer-based thermoelectric materials.

Chemical Behavior and Bioactive Properties of Spinorphin Conjugated to 5,5'-Dimethyl- and 5,5'-Diphenylhydantoin Analogs.

The discovery of new peptides and their derivatives is an outcome of ongoing efforts to identify a peptide with significant biological activity for effective usage as a possible therapeutic agent. Spinorphin peptides have been documented to exhibit numerous applications and features. In this study, biologically active peptide derivatives based on novel peptide analogues of spinorphin conjugated with 5,5'-dimethyl (Dm) and 5,5'-diphenyl (Ph) hydantoin derivatives have been successfully synthesized and characterized. Scanning electron microscopy (SEM) and spectral methods such as UV-Vis, FT-IR (Fourier Transform Infrared Spectroscopy), CD (Circular Dichroism), and fluorimetry were used to characterize the microstructure of the resulting compounds. The results revealed changes in peptide morphology as a result of the restructuring of the aminoacidic sequences and aromatic bonds, which is related to the formation of intermolecular hydrogen bonds between tyrosyl groups and the hydantoin moiety. Electrochemical and fluorescence approaches were used to determine some physicochemical parameters related to the biological behavior of the compounds. The biological properties of the spinorphin derivatives were evaluated in vivo for anticonvulsant activity against the psychomotor seizures at different doses of the studied peptides. Both spinorphin analog peptides with Ph and Dm groups showed activity against all three phases of the seizure in the intravenous Pentylenetetrazole Seizure (ivPTZ) test. This suggests that hydantoin residues do not play a crucial role in the structure of spinorphin compounds and in determining the potency to raise the seizure threshold. On the other hand, analogs with a phenytoin residue are active against the drug-resistant epilepsy test (6-Hz test). In addition, bioactivity analyses revealed that the new peptide analogues have the potential to be used as antimicrobial and antioxidant compounds. These findings suggest promising avenues for further research that may lead to the development of alternative medicines or applications in various fields beyond epilepsy treatment.

Quantitative lithium substitution of carboxyl hydrogens in polyacrylic acid binder enables robust SiO electrodes with durable lithium storage stability

The design of advanced binders plays a critical role in stabilizing the cycling performance of large-volume-effect silicon monoxide (SiO) anodes. For the classic polyacrylic acid (PAA) binder, the self-association of –COOH groups in PAA leads to the formation of intramolecular and intermolecular hydrogen bonds, greatly weakening the bonding force of the binder to SiO surface. However, strengthening the binder-material interaction from the perspective of binder molecular regulation poses a significant challenge. Herein, a modified PAA-Lix (0.25 ≤ x ≤ 1) binder with prominent mechanical properties and adhesion strength is specifically synthesized for SiO anodes by quantitatively substituting the carboxylic hydrogen with lithium. The appropriate lithium substitution (x = 0.25) not only effectively increases the number of hydrogen bonds between the PAA binder and SiO surface owing to charge repulsion effect between ions, but also guarantees moderate entanglement between PAA-Lix molecular chains through the ion–dipole interaction. As such, the PAA-Li0.25/SiO electrode exhibits exceptional mechanical properties and the lowest volume change, as well as the optimum cycling (1237.3 mA h g−1 after 100 cycles at 0.1 C) and rate performance (1000.6 mA h g−1 at 1 C), significantly outperforming the electrode using pristine PAA binder. This work paves the way for quantitative regulation of binders at the molecular level.

Network and structural analysis of quail mucins with expression pattern of mucin 1 and mucin 4 in the intestines of the Iraqi common quail (Coturnix coturnix).

In avian and other species, mucins (MUCs) play a crucial role in the gastrointestinal tract (GIT), and constitute a large group of O-glycosylated glycoproteins, are glycoconjugate proteins. MUCs present in two forms: (1) membrane-attached on cell surfaces to repel external threats and (2) detachable, gel-forming proteins in the soluble form. In quail GIT, the specific types of MUCs that are expressed remain largely unknown. We investigated the expression of MUC1 and MUC4 MUCs in the GIT of Iraqi common quails and conducted network and structural analyses of all known MUC types across quail breeds. Histological and gene expression analyses of MUC1 and MUC4 were conducted using fresh small intestine and large intestine samples from 10 quails. Using the STRING Database, Chimera software, and PrankWeb-ligand binding site prediction tool, network and structural analyses of all reported types of quail MUCs were conducted. Most intestinal MUCs in quails were acidic, with few neutral MUCs detectable through Alcian blue and periodic acid-schiff stains. Acidic MUCs were more expressed in the duodenum, ileum, cecum, and colon, whereas neutral MUCs were more expressed in the jejunum. MUC1 and MUC4 messenger RNA expression was significantly higher in the jejunum and colon than in the duodenum and ileum. The analysis of the network revealed that MUC 1, 15, 16, and 24 formed homologous networks, while MUC 2, 4, 5, and 6 formed heterologous networks. Specific MUC combinations, including MUC5A-MUC6, MUC5A-MUC5B, and MUC5B-MUC6, show higher intermolecular hydrogen bond formation affinity. MUC15, MUC16, and MUC24 showed minimal interaction with other MUC types. Among the analyzed MUCs, MUC5B, and MUC6 had the highest probability for binding, while MUC2, MUC4, and MUC5A showed lower probabilities despite greater numbers of binding sites. This study's results offer significant insights into quails' MUCs' composition, expression, network interactions, and binding sites, advancing knowledge of MUC-related processes in gastrointestinal physiology and their potential connection to gastrointestinal diseases.

Spectroscopic characterization and quantum chemical calculations on Favipiravir-Guanine biomolecular complex

Favipiravir, a medication, has drawn a lot of interest recently as a possible therapeutic option for viral illnesses such as the COVID-19 pandemic. In the current work, Favipiravir + Guanine combination is being spectroscopically characterized using Fourier Transformed Infrared Spectroscopy, Raman, and Surface-Enhanced Raman Spectroscopy tools. Density functional theory along with the Becke 3-Parameter, Lee-Yang-Parr method and the basis set 6-311++ G(d,p) is used to explore the molecular interactions between the monomers of Guanine and Favipiravir. The stability of the complex resulting from the charge delocalization is thoroughly examined by natural bond orbital analysis that demonstrates the C=O∙∙∙H intermolecular hydrogen bond formation. The nature of the intermolecular hydrogen bond is described using atoms in molecules analysis. Molecular electrostatic potential mapping depicts various regions of electrostatic potential for the molecules, characterizing their reactive nature. The complex’s frontier molecular orbital gap of 2.39 eV indicates a higher possibility of electronic charge transfer, which in turn enhances the chemical reactivity of the complex. An analysis of the complex’s hyperpolarizability reveals a good non-linear optical response. The antiviral activity of the Favipiravir + Guanine complex is demonstrated by its molecular docking against the 6LU7 receptor (−5.61 kcal/mol).

Lysine-Triggered Polymeric Hydrogels with Self-Adhesion, Stretchability, and Supportive Properties.

Hydrogels, recognized for their flexibility and diverse characteristics, are extensively used in medical fields such as wearable sensors and soft robotics. However, many hydrogel sensors derived from biomaterials lack mechanical strength and fatigue resistance, emphasizing the necessity for enhanced formulations. In this work, we utilized acrylamide and polyacrylamide as the primary polymer network, incorporated chemically modified poly(ethylene glycol) (DF-PEG) as a physical crosslinker, and introduced varying amounts of methacrylated lysine (LysMA) to prepare a series of hydrogels. This formulation was labeled as poly(acrylamide)-DF-PEG-LysMA, abbreviated as pADLx, with x denoting the weight/volume percentage of LysMA. We observed that when the hydrogel contained 2.5% w/v LysMA (pADL2.5), compared to hydrogels without LysMA (pADL0), its stress increased by 642 ± 76%, strain increased by 1790 ± 95%, and toughness increased by 2037 ± 320%. Our speculation regarding the enhanced mechanical performance of the pADL2.5 hydrogel revolves around the synergistic effects arising from the co-polymerization of LysMA with acrylamide and the formation of multiple intermolecular hydrogen bonds within the network structures. Moreover, the acid, amine, and amide groups present in the LysMA molecules have proven to be instrumental contributors to the self-adhesion capability of the hydrogel. The validation of the pADL2.5 hydrogel's exceptional mechanical properties through rigorous tensile tests further underscores its suitability for use in strain sensors. The outstanding stretchability, adhesive strength, and fatigue resistance demonstrated by this hydrogel affirm its potential as a key component in the development of robust and reliable strain sensors that fulfill practical requirements.

Effect of Hydrogen Bonding and Chirality in Star-Shaped Molecules with Peripheral Triphenylamines: Liquid Crystal Semiconductors and Gels.

Organic semiconductors with well-defined architectures pose a suitable alternative to amorphous silicon-based inorganic semiconductors. Encouraged by the development of organic semiconductors based on columnar liquid crystals, herein, we report on a family of C3-symmetric star-shaped mesogens based on triphenylamine (TPA), a functional unit with strong electron donor character. Highly stable columnar phases with high hole mobility values were obtained out of this nonplanar functional unit, and this was achieved by using flexible amide spacers to join the TPA units to a tris(triazolyl)triazine (T) star-shaped core, allowing the formation of intermolecular hydrogen bonds. The presence of hydrogen bonds results in a stabilization of the columnar architectures either in bulk or in the presence of solvents by reinforcing π-stacking and van der Waals interactions, as deduced by Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) studies. Furthermore, the introduction of a stereogenic center in the flexible spacer prompts the formation of chiral aggregates in the liquid crystal state and in the organogel formed in 1-octanol, as demonstrated by circular dichroism spectroscopy.

Guest-induced supramolecular helices and its application in L-Arg detection and L-Arg controlled reversible morphology modulation

A novel AIE supramolecular polymer (BPK) was synthesized by bis(2-hydroxy-1-naphthaldehyde) terephthalo hydrazone functionalized pillar [5]arene and cross-linked using a bis(4.4-dipyridinium salt)cross-linker via host-guest complexation. BPK exhibited strong aggregation-induced emission (AIE) in binary solutions of DMSO/H2O. BPK could be an AIE-based sensor with specific fluorescence sensing ability for L-Arg in water. The detection limit of BPK for L-Arg was 3.95 × 10−7 M, and other amino acids did not interfere with the sensing process. Moreover, in a pure DMSO solvent, BPK can self-assemble into a fibrous structure of the right-hand spiral by guest-induced supramolecular helices. At 80 % water content, BPK undergoes a morphological transformation into supramolecular polymer. Intriguingly, BPK exhibits a reversible transformation from a polymer to a nanosphere through the alternating addition of trifluoroacetic acid and arginine. Additionally, the fluorescence of BPK demonstrates an "on-off" switch. This phenomenon is attributed to the formation and disruption of intermolecular hydrogen bonds. The reversible manipulation of polymer materials' morphology and optical properties holds significant potential in biomedicine and smart materials.