1H NMR Research Articles

Synthesis, spectroscopic characterization techniques of aromatic iminoaniline derived compound, along with the evaluation of its LNO properties using quantum chemistry

In this research work, we synthesized a Schiff base derivative, N,N-dimethyl-4-{[(4-nitrophenyl)imino]-methyl}aniline, denoted as (n1). The molecule (n1) was characterized using spectroscopic analyses, including FT-IR, NMR 1H, and 13C. Our compound (n1) is an unsaturated molecule, consisting of two benzylic rings connected by a methylimine bridge. The resulting system comprises seven alternating π bonds. At both ends of (n1) and in the para position, there are the N(CH3)2 group with a strong electron-donating effect and the NO2 group with a strong electron-accepting effect. The molecular structure of our compound prompted us to evaluate and study its properties in the field of NLO. The assessment of NLO properties is conducted by determining the Egap and employing density functional theory (DFT) quantum chemistry studies. The optical gap of (n1), measured using the Tauc method, is found to be 2.7 eV, serving as a reference value for the choice of the DFT functional in theoretical calculations. Quantum chemistry studies were carried out using Gaussian09 software, and the results were visualized with GaussView05. CAM-B3lyp functional was chosen for theoretical calculations due to its close agreement with experimental values. The studies confirm that (n1) exhibits significant NLO properties. Additionally, NBO (Natural Bond Orbital) analyses provide insight into the mechanism and trajectory of intramolecular charge transfer in (n1).

Unravelling the incorporation mechanisms of water in aluminous orthoenstatite: I. First-principles calculations

We performed first-principles calculations on the energy, and NMR and polarized infrared (IR) spectra for anhydrous and hydrous aluminous orthoenstatite (OEn) models to help clarify the incorporation mechanisms of Al and OH defects in OEn. Our calculations revealed that proton pairs in M2 vacancies ((2H)M2) adjacent to a tetrahedral Al (AlIV) are energetically more favorable than those remote from Al, and may contribute to the observed correlated 1H NMR peaks near 3.7 and 8.0 ppm, and IR bands near 3550–3570 and 3066 cm−1 (A4 band) for aluminous OEn. Coupled substitutions of AlVI (octahedral Al) + H for 2Mg were found to adopt multiple configurations, and may contribute to the observed IR bands near 3520, 3475 and 3320 cm−1. Coupled substitution of AlIV + H for 1Si may contribute to the observed IR band near 3380–3400 cm−1. 4H in SiB vacancies ((4H)SiB) adjacent to an AlVI were found to be energetically more favorable than those remote from Al, and may be the origin for an IR band observed near 3600–3620 cm−1. These results allow the incorporation mechanisms of water in synthetic and natural aluminous orthopyroxenes to be deciphered from the available NMR and IR data, and suggest that both (2H)M2 defects associated with Al and simultaneous coupled substitutions of Al + H for 2Mg and 1Si contribute to the observed correlation between Al and water incorporation, and the nearly unity AlIV/AlVI ratio. (4H)SiB defects associated with Al may also be present in some synthetic OEn and mantle-derived orthopyroxene.

HOST‐GUEST INTERACTIONS FACILITATED BY CHALCOGEN BONDING WITHIN SELENADIAZOLE FUNCTIONALISED PORPHYRIN NANOTUBES

The structural rigidity of tetrakis(4‐pyridyl)porphyrin (TPyP) has been utilised to prepare a robust novel porous coordination polymer of composition Cd2(TPyP)(sez)2 (TPyP = 5,10,15,20‐tetra(4‐pyridyl)porphyrin, sez = 1,2,5‐benzoselenadiazole‐5‐carboxylate). The coordination polymer may be described as a hexagonal porphyrin nanotube (PNT) and has the potential to bind guest molecules through chalcogen bonding. Single crystal X‐ray diffraction (SCXRD) data indicate an internal pore diameter ~9 Å which represents ~35% of the crystal volume. Immersion of the PNTs in solvents such as DMSO and CS2 result in the incorporation of these molecules within the nanotubes with chalcogen bonding between host and guest. The crystallographic guest‐inclusion investigations are complemented by solid‐state 77Se, 13C, 113Cd and 2H NMR studies which provide insights into dynamic behaviour. The porosity of the crystals was further explored using gas adsorption experiments, indicating the reversible uptake of CO2, CH4, H2 and N2. Structure‐function relationships are clearly established from complementary crystallographic, NMR and adsorption investigations.

Design, Synthesis, Antibacterial, and Antifungal Evaluation of a New Series of Quinazoline - Thiazole and/or Quinazoline - Triazole Hybrids as Bioactive Heterocycles.

Herein, a one-pot reaction between cyclohexanone, thiourea, and 2,5-dimethoxybenzaldehyde allowed to prepare hexahydroquinazoline-2(1H)-thione4 firstly, which followed by reacting with hydrazine hydrate to produce the corresponding 2-hydrazinylhexahydroquinazoline 6. Interesting analogs of thiazolo[3,2-a]quinazoline 713 where obtained when hexahydroquinazoline-2(1H)-thione 4 reacted with 1,2-dibromoethane, chloroacetyl chloride, bromoacetic acid, bromoacetic acid/4-chlorobenzaldehyde, 2-bromopropionic acid, ethyl bromo cyanoacetate, and/or bromomalononitrile; respectively. While triazolo[4,3-a] quinazoline 14-16 were created when 2-hydrazinylhexahydroquinazoline 6 reacted with triethyl orthoformate, acetic anhydride, and carbon disulfide respectively. Numerous spectroscopy tests, including FT-IR, NMR (1H &13 C), and MS spectrum, proved all the newly produced analogs. Additionally, the new analogs were examined for their antibacterial and antifungal properties against Escherichia coli, Staphylococcus aureus, and Candida albicans. It was discovered that triazolo[4,3-a] quinazoline analogs 14-16 have superior bacterial and fungal activity when compared to the corresponding conventional doses of Streptomycin andGriseofulvin. Towards Candida albicans; compounds 14, 15, and 16 increase activity with 1.14 %, 1.15 %, and 1.21 %, respectively more than griseofulvin.While, for Staphylococcus aureus; compounds 14, 15, and 16 increase activity with 1.5 %, 1.5 %, and 1.7 %, respectively more than streptomycin. Morever, for Escherichia coli; compounds 14, 15, and 16 increase activity with 1.19 %, 1.21 %, and 1.22 %, respectively more than streptomycin. Finally, structure activity relationships show that quinazoline derivatives exhibit higher activity when fused to pyrazole ring 14-16 as compared when fused thiophene ring 7-13.

A Unique Synthetic Route toward a 1,2‐Dihydrodigermene via Formal α‐Elimination of Bromo and Silyl Groups from a Bromo(phenylsilyl)germane

AbstractA 1,2‐dihydrodigermene bearing Tbb {4‐t‐butyl‐1,3‐bis[bis(trimethylsilyl)methyl]phenyl} groups was successfully synthesized and isolated via formal α‐elimination of bromo and silyl groups from the corresponding Tbb‐substituted boromo(phenylsilyl)germane. This novel synthetic method is conducted under mild conditions, representing a significant advantage in the field concerned. The synthesized 1,2‐dihydrodigermene was characterized by NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray crystallography. In the 1H NMR spectrum, the Ge−H unit was found to be less electronically affected from the substituents compared to that of the previously reported 1,2‐dihydrodigermene. Moreover, the UV/vis spectra at various temperatures indicated the formation of the isomeric (dihydrogermyl)germylene. In fact, the 1,2‐dihydrodigermene once isolated reacted with DMAP in solution to afford the corresponding complex of the (dihydrogermyl)germylene.

Chalcogen Bond-Driven Alkylations: Selenoxide-Pillar[5]arene As A Recyclable Catalyst For Displacement Reactions In Water.

A novel strategy to catalyze alkylation reactions through chalcogen bond interaction using a supramolecular structure is presented herein. Utilizing just 1.0 mol% of selenoxide-pillar[5]arene (P[5]SeO) as the catalyst we achieved efficient catalysis in the cyanation of benzyl bromide in water. Our approach demonstrated high efficiency and effectiveness, with the results supported by designed control experiments and theoretical models, highlighting the catalytic effect of the pillar[5]arene through noncovalent interactions. Quantum-chemical calculations (ωB97X-D/def2-TZVP@SMD) pointed out that the catalyzed cyanation reaction followed an SN2-like mechanism, with energy barriers (ΔH‡) ranging from 16.7 to 18.2 kcal mol-1, exhibiting dissociative character depending on the para-substituent. 1H NMR analysis revealed that P[5]SeO acted as a catalyst through inclusion complex formation, facilitating the transfer of the electrophilic substrate to the aqueous solution for nucleophilic displacement. Our reaction protocol proved applicable to various substrates, including aromatic and alpha-carbonyl derivatives. The use of sodium azide as the nucleophile was also feasible. Importantly, our method allowed scalability, and the catalyst P[5]SeO could be recovered and reused effectively for multiple reaction cycles, showcasing sustainability.

Combining the Strengths of MS and NMR in Biochemometrics: A Case Study on Buddleja officinalis.

Biochemometrics has emerged as promising strategy for the targeted identification of bioactive constituents from natural sources. It is based on the correlation of bioactivity data with chemical data to reveal constituents contributing to activity. Providing complementary data and structural information, MS- and NMR-based biochemometric approaches have both been separately applied in the past. The herein presented study is dedicated to the evaluation of a combined MS- and NMR-based biochemometric workflow for the unambiguous identification of bioactives. As an example, a flower extract of Buddleja officinalis Maxim. was selected to unravel bioactive constituents in the context of dry eye disease pathology. While NMR-based biochemometrics relies on heterocovariance analysis (HetCA) of 1H NMR spectra using the previously established ELINA approach, a biochemometric molecular network was generated for the MS-based approach. Both analyses were performed in parallel and were ultimately combined to increase their power to identify the bioactive constituents from the complex mixture. As a result, phenylethanoid glycosides and triterpene saponins were discovered as main contributors for the antioxidant and cytotoxic effects of the extract. This article illustrates the advantages, opportunities, and limitations of MS and NMR in the context of biochemometrics.

Luminescent Anthracene-based Elastic Mixed Molecular Crystals for Flexible and FRET-Assisted Optical Waveguides

Abstract Optical waveguides based on elastic molecular crystals are of interest as flexible and compact optical communication materials. Low emission efficiency is often a problem in terms of communication signal strength, and an increase in the loss factor α due to fluorescence reabsorption in the crystal reduces the photon transport efficiency. Here, we report the development and improvement of Förster resonance energy transfer (FRET)-assisted optical waveguides using anthracene-based elastic mixed molecular crystals. 9,10-Dicyanoanthracene was selected as the dopant for solution-grown crystallization of 9,10-dibromoanthracene. 1H NMR measurements of the obtained crystals showed that the acceptor doping to be 1%-5%. Elastic behavior was observed even when doped with a few percent of the acceptor. The quantum efficiency was 0.016, a dramatic improvement over the previous luminescent EMMC (0.004). The α value (92 dB/cm) of this crystal containing 1%-doped 9,10-dicyanoanthracene is much lower than that of the crystal consisting of only 9,10-dibromoanthracene (1258 dB/cm) due to the reduced reabsorption in the FRET system. We have demonstrated a practical approach towards developing improved fluorescent, highly efficient, and flexible optical waveguides by constructing the mixed crystal structure by selecting appropriate acceptor molecules and their low doping ratios.

Nanoconjugate Carrying pH-Responsive Transferrin Receptor-Targeted Hesperetin Triggers Triple-Negative Breast Cancer Cell Death through Oxidative Attack and Assemblage of Pro-Apoptotic Proteins.

Triple-negative breast cancer (TNBC) is recognized as a major aggressive subtype of breast cancer due to its expeditious worsening growth, extensive metastatic capability, and recalcitrance to standard current treatments. Hesperetin (HSP), a natural bioflavonoid from citrus fruits, demonstrates pronounced anticancer efficacy, but its hydrophobicity limits its clinical development. The present study reports the fabrication of a biocompatible and pH-responsive transferrin (TF) receptor-targeted HSP-loaded poly(lactic-co-glycolic acid) (PLGA) nanobioconjugate (PLGA-HSP-TF NPs) and the exploration of its in vitro and in vivo antineoplastic potential. PLGA nanoparticles (NPs), PLGA-HSP NPs, and PLGA-HSP-TF NPs were synthesized and characterized by DLS, FTIR, FE-SEM, and 1H NMR spectroscopy. The stability and in vitro release profile of nanoparticles were inspected, and anticancer efficacy was scrutinized in terms of in vitro cytotoxicity, oxidative stress and apoptosis biomarkers, and cell cycle arrest. In vivo tumor regression and host survival studies were executed in Ehrlich ascites carcinoma (EAC) cell-bearing Swiss albino mice. The drug uptake of highly stable PLGA-HSP-TF NPs was accomplished effectively in MDA-MB-231 cells and showed the pH-dependent intracellular release of HSP, which generated excessive intracellular reactive oxygen species (ROS) that led to oxidative assault to the TNBC cells. This elevated ROS dropped the mitochondrial membrane potential and triggered apoptosis-mediated cell death by arresting the cell cycle at the G0/G1 phase. Furthermore, PLGA-HSP-TF NPs unveiled significant in vivo Ehrlich ascites carcinoma regression and host survival compared to free HSP with minimum toxicity at a minimum dose of 20 mg/kg body weight. The study divulges that PLGA-HSP-TF NPs may be an astounding anticancer nanocandidate for aggressive triple-negative breast cancer therapy.

Tetratellura[36]octaphyrin(1.1.1.1.1.1.1.1) Metalation: From Dynamic Behavior to Rigid Chiral Figure-of-Eight Molecule; Activation of the C-Te Bond by Ruthenium.

The large expanded telluraporphyrin, tetratellura[36]octaphyrin(1.1.1.1.1.1.1.1), was synthesized in 7% yield by acid-catalyzed condensation of pyrrole with 2,5-bis(phenylhydroxymethyl)tellurophene and subsequent oxidation. The macrocycle acquires the chiral figure-eight conformation with two alternative spatial arrangements of the heterocyclic rings. The molecule exhibits dynamic behavior in solution, which was studied by means of 1H NMR spectroscopy. The reaction with chlorine led to a reversible oxidative addition at two distant tellurium atoms, which altered the preferred conformations. Metalation of the tetratellura[36]octaphyrin with triruthenium dodecacarbonyl selectively activated two of the eight Te-C bonds, resulting in the formation of an organometallic diruthenium compound. During the reaction, two tellurophene rings were converted to 1-ruthena-2-telluracyclohexadiene units containing octahedral ruthenium(II) centers. The rigid structure of this chiral complex allowed the separation of enantiomers.

One-Pot Divergent Synthesis of a 13-Ring Triquinone and its Facile Conversion to a [4.4.4]Tridecastarphene.

Acenes are notable for their optoelectronic properties and applications in organic electronics. Starphenes are structurally related molecules possessing three acene arms that radiate linearly from a central benzene ring (i. e., linearly annellated triphenylenes). Large starphenes have been prepared using convergent syntheses involving transition metal catalyzed cyclotrimerizations of either preformed acenes or arynes. Here, we report a one-pot divergent synthesis of a 13-ring triquinone that is readily converted to a [4.4.4]tridecastarphene derivative. The one-pot procedure involves the sequential reactions of three 1,4-anthraquinones with o-quinodimethane derivatives that are generated sequentially from a stable, trisulfone precursor. The resulting [4.4.4]tridecastarphene derivative bearing p-(t-butyl)phenyl substituents was characterized by 1H NMR, 13C NMR and UV-vis spectroscopies, as well as mass spectrometry, cyclic voltammetry and differential pulse voltammetry. Theoretical and experimental studies reveal a relatively high-lying HOMO orbital (about -4.70 to -4.86 eV) and a relatively small HOMO-LUMO gap (2.1 eV), suggesting utility as a p-type organic semiconductor. Our [4.4.4]tridecastarphene derivative photooxidizes in a CH2Cl2 solution exposed to ambient light and air with a half-life of 150 minutes at room temperature, but shows no sign of degradation after 12 months in the solid-state. Our [4.4.4]tridecastarphene derivative also shows excellent solubility in a number of organic solvents including dichloromethane, chloroform and toluene, potentially enabling printed electronic applications.

A facile and green procedure in preparing dibenzo-chromeno-phenazine-diones using an effectual and recyclable Brønsted acidic ionic liquid

First, a Brønsted acid ionic liquid (BAIL) in the role of a double acid-base called 1,3-n-propyl-bipyridinium bisulfonic acid-ditrifluoroacetate (PBPBSDT) was produced, and its skeleton was determined via TGA, mass, 13C NMR, 19F NMR, 1H NMR and FT-IR data. Further, it was successfully applied in the preparation of dibenzo-chromeno-phenazine-dione derivatives (1a-12a, 9–15 min, 90–98%) via one-pot multicomponent domino reaction among 2 mmol 2-hydroxynaphthalene-1,4-dione, 1 mmol benzene-1,2-diamine, and 1 mmol aldehydes under optimal conditions (5 mol% of PBPBSDT, solvent-free, 60 °C). The proper reproducibility of the PBPBSDT homogeneous catalyst (5 times), solvent-free medium, reasonable TON (Turnover Number) and TOF (Turnover Frequency) numbers, the non-metallic framework of the catalyst, and the formation of C-N, C = N, C-C, C = C, C-O bonds in a single operation are the distinct advantages of this protocol.

Synthesis, Spectroscopy and Biological Studies of Copper and Silver Complexes Derived from 2-Substituted Amino Propanoic Acid

Synthesis of copper and silver complexes were prepared from novel Schiff base ligand. These synthesized ligand and their metal complexes were characterized by elemental analysis, FT-IR, 1H NMR, UV-Vis and Mass spectrometry. The coordination of amino nitrogen, phenolic oxygen, and carboxylato oxygen atoms is shown by the infrared spectra.The Schiff bases and its complexes were screened for their in vitro antibacterial and antifungal studies against the bacteria Pseudomonas Aeruginosa (PA, Gram -ve), Bacillus Cirroflagellosus (BC, Gram +ve), Penicillium Notatium (PN) and Aspergillus Niger (AN) strains. The results of the antibacterial investigation show that the copper and silver complexes possess more potent bactericide and fungicide properties than the ligand.

Structural Elucidation and Complete NMR Spectral Assignments of Monascus Monacolin Analogs.

One new monacolin analog, monacolin V (1), together with two new monacolin-like natural products, 6-hydroxyl monacolin P (2) and 3-keto monacolin S (3), were isolated from the ethyl acetate portion of red yeast rice ethanol extract. Their structures were identified by HRESIMS and NMR experiments, and the complete assignments of 1H and 13C NMR data for three compounds were obtained by the aid of HSQC, HMBC, 1H-1H COSY, and NOESY data. This is the first time that the NMR data of compounds 2 and 3 have been fully assigned.

Reaction Kinetics of the Benzylation of Adenine in DMSO: Regio-Selectivity Guided by Entropy.

The factors governing the regio-selectivity of the alkylation of adenine have been of interest for many years due to the biological importance of adenine derivatives, however, no reaction kinetic studies have been conducted. Herein, we report the rate constants and activation parameters of the benzylation of adenine under basic conditions in DMSO in the absence and presence of 15-crown-5 ether using real-time 1H NMR spectroscopy. The reaction is second-order for the formation of the N9- and N3-benzyladenine products, with a regio-selectivity factor 2.3 in favour of the N9-adduct. The Gibbs free energy of activation amounts to 87±2 kJ mol-1 for both reactions. The formation of the N9-adduct is more activated by 7 kJ mol-1, but its effect is offset by a less negative activation entropy, demonstrating that the long-contested reason for the regioselectivity in the benzylation of adenine is dominated by compensation of entropy and enthalpy in the transition state. The kinetic parameters obtained in the presence of the 15-crown-5 ether indicate that the crown ether forms a complex with an adenine-sodium ion-pair, increasing the activation barrier. However, the Gibbs free energy in the absence and presence of the crown ether remains constant.

Novel Glycidyl Carbamate Functional Epoxy Resin Using Hydroxyl-Terminated Polybutadiene

Herein, a novel glycidyl carbamate functional epoxy resin (GCE) is synthesized by the additional reaction of the isocyanate group of tolylene diisocyanate (TDI) with the hydroxyl group of hydroxyl-terminated polybutadiene (HTPB) and glycidol. The successful synthesis of the GCE is confirmed by FT-IR and 1H NMR spectroscopy. Furthermore, a dual-curing adhesive system is developed using acrylic acid and trimethylolpropane triacrylate with varying GCE contents, and its adhesive performance is assessed by testing adhesive strength, pencil hardness, and surface energy. As a result, the dual-cure adhesive containing 0.2 mol of GCE demonstrates an impressive adhesive strength of 11.1 MPa, a pencil hardness of B, and surface energy comparable to that of standard polycarbonate film.

Absolute Quantification of Phenylbutanoids in Zingiber cassumunar Roxb. Rhizome by Quantitative 1H NMR.

Quantitative determination of pharmacologically active constituents in medicinal plants is critical for quality control. Due to the chemical complexity of the crude plant extracts, the presence of interfering compounds is often problematic for the unambiguous quantitation of the designed bioactive compounds. Considering the method of quantification, quantitative NMR spectroscopy (qNMR) has gained substantial popularity as a powerful and effective technique for both qualitative and quantitative analyses of natural products. The aim of this study is to develop a quantitative NMR method for quantifying the bioactive phenylbutanoids in Zingiber cassumunar rhizome crude extract. Quantitative 1H NMR (qHNMR) measurements were performed on a 600 MHz NMR spectrometer using an internal standard for the determination of the absolute quantities of four phenylbutanoids in Z. cassumunar rhizome crude extract. The direct quantification of four characteristic phenylbutanoids, i.e., (E)-1-(3',4'-dimethoxyphenyl)butadiene (DMPBD), (E)-1-(2',4',5'-trimethoxyphenyl)butadiene (TMPBD), (E)-4-(3',4'-dimethoxyphenyl)but-3-en-1-ol, and (E)-4-(3',4'-dimethoxyphenyl)but-3-en-1-yl acetate, in crude extract by qHNMR using an internal standard was achieved, with high specificity and sensitivity. The selected 1H NMR signals could unambiguously be assigned and did not overlap with other resonances, including the highly similar compounds DMPBD and TMPBD. The method is linear in the concentration range of 0.70-14.52 mg/mL, with a limit of quantification of 0.46-0.68 mg/mL. The RSD values of intraday and interday precisions are in the range of 0.23%-0.74% and 0.29%-0.52%, respectively. The average recoveries are 99.54%-100.18%. A rapid, accurate, and precise method using 1H NMR for the simultaneous quantitation of four phenylbutanoids in the crude extract of Z. cassumunar rhizome was developed and validated.

Structurally Diverse Duclauxins from a Coral-Derived Talaromyces sp. and Insight into Determining the Configuration at C-1 of Heptacyclic Duclauxins by 1H NMR.

A chemical investigation of the coral-derived fungus Talaromyces sp. TJ403-AL05 led to the isolation of 18 duclauxin analogues (1-18), 14 of which, taladuxins A-N (1-14), are new and consist of the first example of duclauxin fused with one 1,6-dioxaspiro[4.5]decan-2-one moiety (1), as well as its biosynthetic product (2), and 12 6/6/6/5/6/6/6 heptacyclic derivatives (3-14). Comprehensive spectroscopic analyses, electronic circular dichroism (ECD) calculations, DP4+ probability analyses, single-crystal X-ray diffraction, and vibrational circular dichroism (VCD) calculations were employed to characterize their structures and revise the published structure of verruculosin B. An efficient 1H NMR method was established to discriminate 1R and 1S configurations at C-1 of 6/6/6/5/6/6/6 heptacyclic duclauxins according to chemical shift differences of diastereotopic methylene H2-11 or H2-12 (ΔδH-11 or ΔδH-12). Compounds 4, 7-8, 13-15, and 18 exhibited moderate inhibition of Arabidopsis thaliana 4-hydroxyphenylpyruvate dioxygenase (AtHPPD), with IC50 values ranging from 17.1 to 71.3 μM.

A Study on the Stability of High Drug Solubility Characteristics of Hydroxyphenyl Adhesives under the Interference of CPEs.

Novel hydroxyphenyl adhesives (HP-PSAs) could significantly increase drug solubility and control drug release through a doubly ionic hydrogen bond (DIH bond) in the patch. However, chemical penetration enhancers (CPEs) always destroy the performance of most adhesives. As a result, this work investigated the stability of both the HP-PSA features and the DIH bond under the interference of the CPEs. Donepezil (DON) was chosen as the model drug, and CPEs with hydroxyl, carboxyl, amido, and ester groups were selected as model CPEs. Unlike the commonly used neutral H-bond, the DIH bond between DON and the HP-PSA was still stable under the interference of the CPEs, resulting in the 2-3-fold drug solubility in the HP-PSA, which was higher than that in the nonfunctional PSA, which reduced the drug crystallization risk and the difficulty of formulation design. FT-IR, 1H NMR, XPS, dynamic simulation, and molecular docking revealed the mechanism of the stability feature of both the DIH bond and the high drug solubility of the HP-PSA, which was that the formed neutral H-bond interaction caused by CPEs is weaker than that of the DIH bond between DON and the HP-PSA. Furthermore, the drug release, skin permeation, and CPE release study showed that the newly formed weak H-bond and strong ionic H-bond interaction promoted or controlled both DON and CPE release, respectively, thereby influencing drug skin permeation, which provided a theoretical basis for drug release regulation. To summarize, besides the reversible, strong features of the DIH bond in our previous study, the stability of the interaction made the HP-PSA's high drug solubility potential to be applied in the TDDS.

Structural and Textural Characteristics of Municipal Solid Waste Incineration Bottom Ash Subjected to Periodic Seasoning

The objective of this study was to determine the structural and textural description of municipal solid waste incineration (MSWI) bottom ash that was subjected to a six-month seasoning process. Bottom ash samples, with a particle size fraction of 0.063–0.1 mm, were seasoned in a closed landfill and collected for laboratory analyses at monthly intervals. The research focused on determining the structural parameters, using methods such as nuclear magnetic resonance spectroscopy (1H NMR), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), and the textural parameters, using low-pressure nitrogen adsorption (LPNA) at −196.15 °C. The analyses of the porous structure of the bottom ash samples revealed differences in texture of ASH 1 to ASH 6, specifically in the pore volume (micro- and mesopores), specific surface area, and pore size distribution. Changes in the structural and porous characteristics of the samples were attributed to the duration of the seasoning process. The results of the structural analysis of the bottom ash suggest its application in the concrete industry, potentially enhancing the long-term mechanical strength of concrete. The results of the textural analysis indicate the possible use of MSWI bottom ash in environmental applications, as the internal surface area could be further developed.