Donor-acceptor Interactions Research Articles

CRYOCHEMICAL SYNTHESIS OF HYBRID NANOFORMS BASED ON SILVER AND THE ANTIBACTERIAL DRUG SUBSTANCE DIOXIDINE

Hybrid nanoforms based on silver and antibacterial drug dioxidine (2,3-bis-(hydroxymethyl)quinoxaline 1,4-di-N-oxide) were prepared by the method of joint co-condensation of metal and ligand vapors on a liquid nitrogen cooled surface. The samples obtained by low temperature co-condensation were characterized by FTIR-, UV-Vis and XPS-spectroscopy, ТЕМ, SEM and powder X-ray phase analysis (ХРА). It was shown that cryomodified nanoforms preferably consist of anhydrous triclinic (T-phase) crystal phase of dioxidine, the dimensions of dioxidine particles ranges from 50 to 300 nm, the average size of included silver nanoparticles is (15±3) nm. Broadening of the diffraction patterns belonging to silver shows the transition of metallic silver to the nanoscale state. The FTIR results indicate for hybrid nanoforms stabilized by donor-acceptor interactions of surface silver atoms with hydroxyl groups and with donor N-atoms of quinoxaline cycles of dioxidine molecules.

Single crystal XRD, Hirshfeld surface analysis and computational approach for exploration of novel xanthene derivative

In order to study the structure-activity relationship of xanthene compound, hexahydro xanthene derivative was synthesized and characterized by single crystal X-rays diffraction. The molecular geometry was described in terms of dihedral angles between various rings present in structure. The stability of the supramolecular assembly was reinforced by multiple intermolecular interactions, which were inspected comprehensively via Hirshfeld surface analysis. DFT study revealed the excellent electronic properties and reactivity of synthesized compound. FMO is employed to uncover the orbitals energies and charge transfer within compound. The contribution of van der Waals forces is minor, while covalent nature of bonding is evidenced by the quantum theory of atoms in molecules (QTAIM) study. The electron transition from nonbonding orbitals (LP) to antibonding (LP*) are most prominent donor-acceptor interactions with significant stabilization energy. Ab-initio molecular dynamics reveals the kinetic and thermodynamic stability of present compound at room temperature. The excellent nonlinear optical properties and reactivity is revealed by its remarkable hyperpolarizability value.

Spatial Structure of Electron Interactions in High-entropy Oxide Nanoparticles for Active Electrocatalysis of Carbon Dioxide Reduction.

High-entropy oxides (HEOs) exhibit distinctive catalytic properties owing to their diverse elemental compositions, garnering considerable attention across various applications. However, the preparation of HEO nanoparticles with different spatial structures remains challenging due to their inherent structural instability. Herein, ultrasmall high-entropy oxide nanoparticles (less than 5nm) with different spatial structures are synthesized on carbon supports via the rapid thermal shock treatment. The low-symmetry HEO, BiSbInCdSn-O4, demonstrates exceptional performance for electrocatalytic carbon dioxide reaction (eCO2RR), including a lower overpotential, high Faraday efficiency across a wide electrochemical range (-0.3 to -1.6V), and sustained stability for over100h. In the membrane electrode assembly electrolyzer, BiSbInCdSn-O4 achieves a current density of 350mAcm-2 while maintaining good stability for 24h. Both experimental observations and theoretical calculations reveal that the electron donor-acceptor interactions between bismuth and indium sites in BiSbInCdSn-O4 enable the electron delocalization to facilitate the efficient adsorption of CO2 and hydrogenation reactions. Thus, the energy barrier of the rate-determining step is reduced to enhance the electrocatalytic activity and stability. This study elucidates that the spatial structure of metal sites in HEOs is able to regulate CO2 adsorption status for eCO2RR, paving the way for the rational design of efficient HEO catalysts.

Interstitial Optical Fiber-Mediated Multimodal Phototheranostics Based on an Aggregation-Induced NIR-II Emission Luminogen for Orthotopic Breast Cancer Treatment.

One-for-all phototheranostics based on a single molecule is recognized as a convenient approach for cancer treatment, whose efficacy relies on precise lesion localization through multimodal imaging, coupled with the efficient exertion of phototherapy. To unleash the full potential of phototheranostics, advancement in both phototheranostic agents and light delivery methods is essential. Herein, an integrated strategy combining a versatile molecule featuring aggregation-induced emission, namely tBuTTBD, with a modified optical fiber to realize comprehensive tumor diagnosis and "inside-out" irradiation in the orthotopic breast tumor, is proposed for the first time. Attributed to the intense donor-acceptor interaction, highly distorted conformation, abundant molecular rotors, and loose intermolecular packing upon aggregation, tBuTTBD can synchronously undergo second near-infrared (NIR-II) fluorescence emission, photothermal and photodynamic generation under laser irradiation, contributing to a trimodal NIR-II fluorescence-photoacoustic (PA)-photothermal imaging-guided phototherapy. The tumor treatment is further carried out following the insertion of a modified optical fiber, which is fabricated by splicing a flat-end fiber with an air-core fiber. This configuration aims to enable effective in situ phototherapy by maximizing energy utilization for therapeutic benefits. This work not only enriches the palette of NIR-II phototheranostic agents but also provides valuable insight for exploring an integrated phototheranostic protocol for practical cancer treatment.

Investigation of spectroscopic characterization, crystal structure, and antitumor activity of a novel 2ATP molecule

In this section, the spectroscopic characteristics of 2-amino-toysl-pyridine (2ATP) are fully examined, using both experimental and computational investigations guided by density functional theory (DFT). It will facilitate our computational research using the B3LYP approach to use the basis set 6–311++G(d,p). Comprehensive assignments of vibrational modes were obtained from the vibrational spectra, which comprised FT-Raman and FT-IR spectroscopy and were recorded in the region of 3500–400 cm−1 and 4000–500 cm-1, respectively, using the Vibrational Energy Distribution Analysis (VEDA) approach. The net atomic charges inside the molecule were ascertained by using Mulliken population analysis, natural atomic charges, and electrostatic potentials (CHELPG). The structural conformations of 2ATP were determined using NMR spectroscopy in a CDCl3 solvent. The donor-acceptor interactions of the 2ATP molecule at the 6–311++G(d,p) level were studied by means of a Natural Bond Orbital (NBO) study. Studies of the ultraviolet (UV) spectrum in ethanol were used to assess the effects of the solvent. An assessment was made of the energy difference between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) in order to understand charge transfer processes that suggest the molecule may have biological activity. Molecular electrostatic potential (MEP) surfaces were used to predict the nucleophilic and electrophilic sites in molecules. The non-covalent interactions were evaluated using the reduced density gradient (RDG) approach. The Multiwfn software was used to analyze the topological properties of the 2ATP, including the Localized Orbital Locator (LOL) and Electron Localization Function (ELF). Further attention was drawn to the compound's exceptional pharmacological potential when its ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) characteristics were evaluated. Not to add, molecular docking experiments were carried out to evaluate the feasibility of 2ATP as a bioactive material with possible uses in the pharmaceutical business.

π-Bridge Regulates Donor–Acceptor Interactions for Long-Wavelength Photoacoustic Imaging and Enhanced Photothermal Therapy

π-Bridge Regulates Donor–Acceptor Interactions for Long-Wavelength Photoacoustic Imaging and Enhanced Photothermal Therapy

Open-cage metallo-azafullerenes as efficient single-atom catalysts toward oxygen reduction reaction.

Very recently, open-cage metallo-azafullerenes PbC100N4H4 and Pb2C100N4H4 containing one Pb-N4-C moiety have been synthesized via the electron beam. Herein, we utilized density functional theory calculations in combination with abinitio molecular dynamics (AIMD) simulations to study the geometric and electronic structures, bonding properties, thermodynamic stability, and catalytic performance of MC100N4H4 and M2C100N4H4 (M = Ge, Sn, Pb). Metal-nitrogen distances and metal-metal distances increase along with the metal radius while the metal atom is positively charged. Energy decomposition analysis revealed that the bonding interactions between M and the C100N4H4 fragment could be described as the donor-acceptor interaction between M(ns0(n-1)d10np4) and C100N4H4 fragment, in which the orbital interactions terms contribute more than the electrostatic interactions. AIMD simulations demonstrate that those metallo-azafullerenes exhibit thermodynamic stability at room temperature. These metallo-azafullerenes, which could serve as typical carbon-supported single-atom catalysts, possess enhanced catalytic performance toward the oxygen reduction reaction (ORR) compared to the planar catalysts, which is attributed to the curvature of metallo-azafullerenes. GeC100N4H4 and SnC100N4H4 exhibit high catalytic performance in the 4e-ORR pathway to H2O, whereas only PbC100N4H4 is suitable for the 2e-ORR reaction pathway because of the difficulty in obtaining electrons. All M2C100N4H4 favors the 4e-reaction pathway due to the presence of the axial metal atom. Our finding of open-cage metallo-azafullerenes as efficient single-atom catalysts holds profound implications for both fundamental research in catalysis and practical applications in fuel cells and other electrochemical devices.

Mechanochromism and aggregation-induced emission in a fluorene-fumaronitrile-based molecular system: The influence of supramolecular control on donor-acceptor interactions

Effective control and reversible switching of solid-state luminescence in organic molecules are crucial for optoelectronic applications. This study presents a novel molecular system based on fluorene-diphenylfumaronitrile-fluorene (FDF), which exhibits mechanochromism and aggregation-induced emission (AIE). The design utilizes fluorene as the donor, leveraging its high photoluminescent quantum yield, thermal stability, and optimal solubility. The diphenylfumaronitrile moiety, used as the acceptor, is characterized by antiparallel dipoles, which align orthogonally with the chromophore's long axis, promoting effective self-assembly and supramolecular control of interchromophore interactions, in association with the cooperative hydrogen bonding of the amide end-functional groups. FDF demonstrates significant mechanochromic properties, in which mechanical stress induces a reversible shift from greenish-yellow to red emission due to alterations in molecular packing and hydrogen bonding. Additionally, FDF exhibits pronounced AIE behavior in DMF/water mixtures, transitioning from non-emissive in DMF to highly fluorescent upon nanoparticle formation. The investigation reveals that the control over donor-acceptor interactions is critical in modulating these luminescent properties, offering potential applications in stress sensing, bioimaging, and optoelectronic devices. These findings provide deeper insights into the molecular mechanisms underlying mechanochromism and AIE, highlighting the dual-functional nature of FDF and its applicability in advanced materials sciences.

Calcium oxide adsorption of gas phase PCDD/Fs and its impact on the adsorption properties of activated carbon

Calcium oxide (CaO), utilized in semi-dry/dry desulfurization systems at municipal solid waste incineration (MSWI) plants, demonstrates some capability to remove polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study assessed the gas-phase PCDD/F removal performance of CaO, activated carbon (AC) and CaO-AC mixtures. Alone, CaO achieved removal efficiencies of only 31.9% for mass and 50.8% for I-TEQ concentration. However, CaO-AC mixtures exhibited significantly higher efficiencies, reaching 96.0% and 92.5% for mass and I-TEQ concentrations, respectively, surpassing those of AC alone, which were 74.7% and 58.5%. BET analysis indicated that CaO's limited surface area and pore structure are major constraints on its adsorption performance. Density functional theory (DFT) calculations revealed that the π-π electron donor-acceptor (EDA) interaction enhances the adsorption between AC and PCDD/F, with adsorption energies ranging from −1.02 to −1.24 eV. Additionally, the induced dipole interactions between CaO and PCDD/F contribute to adsorption energies ranging from −1.13 to −1.43 eV. Moreover, with increasing chlorination levels, PCDD/F molecules are more predisposed to accept electron transfers from the surfaces of AC or CaO, thereby facilitating adsorption. The calculation for mixed AC and CaO showed that CaO modifies AC's properties, enhancing its ability to adsorb gas phase PCDD/Fs, with the higher adsorption energy and more electrons transfer, aligning with gas phase PCDD/Fs adsorption experiments. This study provides a comprehensive understanding of how CaO influences the PCDD/F adsorption performance of AC.

Cooperativity in Molecular Recognition of Porphyrin Clefts

The electron-rich cleft cavities of porphyrin-based molecular tweezers encapsulate various electron-deficient guest molecules via π-π stacking and donor-acceptor interactions. In this presentation, we will describe negative cooperativity in the molecular recognition of a trisporphyrin host molecule possessing two cleft cavities. A 1:2 host-guest complexation of the trisporphyrin host with various electron-deficient guest molecules showed strong negative cooperativity. The quantitative discussion of the negative cooperativity was provided by a detailed analysis using isothermal titration calorimetry.1) Hisano, N.; Kodama, T.; Haino, T., Chem. Eur. J. 2023, 29, e2023001072) Hisano, N.; Haino, T., J. Org. Chem. 2022, 87, 4001-4009. Figure 1

N self-doping hierarchical porous biochar from Chinese medicine residues for efficient removal of malachite green: Critical contribution of N doping to π-π electron donor-donor interactions

N self-doping hierarchical porous biochars are prepared from three kinds of Chinese medicine residues (Lophatherum Gracile (LG), Licorice Radix (LR) and Radix Isatidis (RI)) using KHCO3 as a foaming agent. Among them, LGC shows the best adsorption performance with a maximum adsorption capacity of 3791.5 mg g−1 at 298 K for malachite green (MG). Significant differences of the biochar adsorption behavior are found and the main reason are attributed to differences in sp2 conjugated carbon (ID/IG = 1.46–1.50) and heteroatomic nitrogen (pyridinic-N, pyrrolic-N and graphitic-N) doping. The quasi-secondary kinetic and Langmuir isothermal models are more suitable for describing the adsorption process of biochar towards MG. Further characterization and density functional theory (DFT) calculations showed that the good adsorption of MG by biochar increased with increasing specific surface area (SSA) and pyrrolic-N content. Pore filling effect and π-π electron donor-acceptor (EDA) interactions have been demonstrated to be the predominant driving force of adsorption. Among them, pyridinic-N and graphitic-N further enhance the adsorption performance through the π-π stacking and π-π EDA interactions between MG and biochar, respectively. Pyrrolic-N and other surface functional groups (-COOH, -OH) promote the hydrogen bonding effect. In addition, the good recycling efficiency (close to 70 % after four cycles), excellent multifunctionality and low fabrication cost (13.01 US$ kg−1) of the LGC reveal the potential for practical applications. In addition, all biochar has a wide range of pH suitability (pH = 2.0–10.0). This study provides new ideas for the rapid removal of MG using biochar. In addition, the effects of N self-doping and microscopic N species on the adsorption of biochar provide theoretical guidance for enhancing the adsorption of other macromolecular dyes.

Calculation of the formation enthalpies of charge-transfer complexes with iodine from the binding constants at 298.15 K

There is a continuing interest in charge-transfer complex chemistry, particularly in their formation thermodynamics. Nowadays, the binding constants and Gibbs energies of formation are available for many complexes. However, the experimental determination of the complexation enthalpies is a more difficult procedure, as it usually requires the establishment of the temperature dependence of the binding constant. Our recent studies of the compensation relationship in the thermodynamics of solvation in hydrogen-bonded systems opened the way to the calculation of the enthalpies of specific (i.e., localized donor-acceptor) interactions (Δint(sp)H) directly from the Gibbs energies at 298.15 K (Δint(sp)G). The calculation procedure is based on the following equation: Δint(sp)G/(kJ·mol−1) = 0.66·Δint(sp)H/(kJ·mol−1) + 2.5n (n corresponds to the coordination number of a solute).In the present work, we checked whether the above relation can be applied to the complex formation between halogens (primarily iodine) and organic electron donors. For 152 complexes with aromatics, nitrogen, oxygen, sulfur, selenium, and phosphor-containing compounds, the formation enthalpies were estimated using the data on equilibrium constants at 298.15 K. In most cases, agreement with the experimental binding enthalpies within the expected measurement error was observed (RMS = 1.4 kJ·mol−1, AD = –0.4 kJ·mol−1).

Single-electron transfer between sulfonium and tryptophan enables site-selective photo crosslinking of methyllysine reader proteins.

The identification of readers, an important class of proteins that recognize modified residues at specific sites, is essential to uncover the biological roles of post-translational modifications. Photoreactive crosslinkers are powerful tools for investigating readers. However, existing methods usually employ synthetically challenging photoreactive warheads, and their high-energy intermediates generated upon irradiation, such as nitrene and carbene, may cause substantial non-specific crosslinking. Here we report dimethylsulfonium as a methyllysine mimic that binds to specific readers and subsequently crosslinks to a conserved tryptophan inside the binding pocket through single-electron transfer under ultraviolet irradiation. The crosslinking relies on a protein-templated σ-π electron donor-acceptor interaction between sulfonium and indole, ensuring excellent site selectivity for tryptophan in the active site and orthogonality to other methyllysine readers. This method could escalate the discovery of methyllysine readers from complex cell samples. Furthermore, this photo crosslinking strategy could be extended to develop other types of microenvironment-dependent conjugations to site-specific tryptophan.

Synthesis, crystal structure, and DFT studies of NHC mediated Pd-PEPPSI complex: Application for Suzuki reaction

A novel air and moisture resistant Pd-PEPPSI (pyridine-enhanced precatalyst preparation, stabilization, and initiation) complex was synthesized via the reaction of benzimidazolium salt, PdCl2, KBr, K2CO3, and pyridine. The structure was characterized by spectroscopic methods such as 1H and 13C NMR, FT-IR, UV–vis. and single X-ray diffraction techniques. In order to evaluate the synthesized Pd complex in a detailed manner in terms of structural, bonding, electronic, and thermodynamic characteristics, DFT-based calculations were carried out at the B3LYP/6-311++G (d, p)/LANL2TZ theory level. Natural bond orbital (NBO) analysis was implemented to provide more insights about the possible donor-acceptor interactions and types of hybridization. Also, TD-DFT calculations were performed to rationalize the nature of the observed electronic transitions. The complex showed high catalytic activity in the Suzuki–Miyaura cross coupling of aryl chlorides with phenylboronic acid. Aryl chlorides bearing either electron- donating or withdrawing substituents afforded a wide range of biaryl derivatives that were isolated in the range of 55–97 % yields (7 examples). The reactions were carried out at very low catalyst loading (0.25 mol%) in the presence of air using a green water-based solvent (ipr:H2O/ 1:3). The palladium complex was found to be efficient for the coupling of aryl chlorides with arylboronic acids under aerobic conditions, affording the corresponding biaryls in high yields.

Polyurea-urethane Temperature-responsive Hydrogels for Sustained Delivery of Anti-VEGF Therapeutics.

Temperature-responsive hydrogels, or thermogels, have emerged as a leading platform for sustained delivery of both small molecule drugs and macromolecular biologic therapeutics. Although thermogel properties can be modulated by varying the polymer's hydrophilic-hydrophobic balance, molecular weight and degree of branching, varying the supramolecular donor-acceptor interactions on the polymer remains surprisingly overlooked. Herein, to study the influence of enhanced hydrogen bonding on thermogelation, we synthesized a family of amphiphilic polymers containing urea and urethane linkages using quinuclidine as an organocatalyst. Our findings showed that the presence of strongly hydrogen bonding urea linkages significantly enhanced polymer hydration in water, in turn affecting hierarchical polymer self-assembly and macroscopic gel properties such as sol-gel phase transition temperature and gel stiffness. Additionally, analysis of the sustained release profiles of Aflibercept, an FDA-approved protein biologic for anti-angiogenic treatment, showed that urea bonds on the thermogel were able to significantly alter the drug release mechanism and kinetics compared to usage of polyurethane gels of similar composition and molecular weight. Our findings demonstrate the unrealized possibility of modulating gel properties and outcomes of sustained drug delivery through judicious variation of hydrogen bonding motifs on the polymer structure.

Enhanced Adsorption of Gaseous Naphthalene by Activated Carbon Fibers at Elevated Temperatures.

This study utilized activated carbon fibers (ACFs) as adsorbents to investigate the removal efficiency of naphthalene and toluene at elevated temperatures and their competitive adsorption behavior. Three types of ACFs, inlet concentrations of naphthalene (343, 457, and 572 mg·Nm-3), and toluene (2055, 2877, and 4110 mg·Nm-3) were investigated to determine the adsorption capacities of naphthalene and toluene. To study the reaction mechanisms of naphthalene and toluene on the ACFs, the BET, SEM, FTIR, and TGA methods were used to examine the physical and chemical characteristics of ACFs. Results showed ACF-A's superior adsorption capacity for naphthalene that was attributed to its mesoporous structure and hydrophobicity. Adsorption equilibrium studies indicated multilayer adsorption behavior. Competitive adsorption experiments demonstrated the displacement of toluene by naphthalene on ACF-A, highlighting its higher selectivity for naphthalene. Functional group analysis revealed changes in ACF surfaces after naphthalene adsorption, suggesting π-π dispersion and electron donor-acceptor interactions. Overall, this study underscores the importance of pore structure and surface properties in designing ACFs for the efficient adsorption of high-boiling-point organic pollutants.

Self-coupling of electron acceptor units in conjugated microporous polymers strengthening local donor-acceptor interaction for improving photocatalytic activity

The partial self-coupling of donor or acceptor unit during donor-acceptor (D-A) type CMPs synthesis is often overlooked for the effect on photocatalytic activity. Herein, we developed three D-A type CMPs, named SATE-CMP-n (n=1–3), which were constructed from triazine (TEPT) unit (A) and three salen units (D). With the rigidity of salen units increasing (the rigidity: salen-1 <salen-2 <salen-3), the self-coupling proportion of TEPT decreases. The experiments and DFT calculations reveal that salen-1 has the stronger electron-donating ability compared to salen-2 and salen-3, and that the self-coupling of TEPT units also enhances the electron-accepting ability. Therefore, SATE-CMP-1 exhibits the strongest D-A interaction and the highest separation and transfer efficiency of charge carriers, and has been used a photocatalyst for S−S and S−N coupling reactions. This work proves that the self-coupling of monomers in the construction of CMPs is not overlooked for adjusting the photocatalytic activity of catalyst.

Upscaling Brønsted acid intercalation and exfoliation of graphite into graphene by polyoxometalate clusters for sodium-ion battery application

Non-oxidative intercalation of graphite avoids damage to graphene lattices and is a suitable method to produce high-quality graphene. However, the yield of exfoliated graphene is low in this process due to the poor delamination efficiency of guest species. In this study, a Brønsted acid intercalation protocol is developed involving polyoxometalate (POM) clusters (H6P2W18O62) as guests and intercalation of graphite is realized at the sub-nanometer scale. Theoretical simulation based on DFT elucidates the stepwise intercalation mechanism of Brønsted acid molecules and clusters. Unlike common molecules/ionic guests, intercalation of POM clusters induces large expansion and extensive donor–acceptor interactions among graphite interlayers. This significantly weakens the van der Waals forces and promotes exfoliation efficiency of graphene layers. The exfoliated graphene possesses outstanding features of large lateral size, thin thickness, and high purity, and shows excellent performance as the anode for high power sodium-ion batteries. This work proffers a new pathway toward non-oxidative intercalation of graphite for large-scale production of graphene.

Influence of supramolecular self-assembly of oppositely charged Co- and Sn-porphyrins on the their spectral-luminescent properties in aqueous and aqueous micellar media of ionic surfactants

The processes of supramolecular self-assembly of Co(III)-meso-tetra-(4-trimethylammoniophenyl)porphyrin (CoP) and bis-(4-(1-imidazolyl)-phenol)-Sn(IV)-meso-tetra(4-sulfophenyl)porphyrin (SnP) were studied using electronic, steady-state and time-resolved fluorescence, one- and two-dimensional NMR spectroscopy in aqueous media. The main product of such interaction at a 2:1 M ratio of Co and Sn porphyrinates was found to be supramolecular porphyrin trimer CoP–SnP–CoP formed due to donor-acceptor, hydrogen and electrostatic interactions. The distinctive features of the resulting trimer are: significant distortion of the spatial structure of the Co-porphyrin fragments and strong quenching of the Sn-porphyrin macrocycles fluorescence (by 70 %). The distortion of the spatial structure of Co porphyrinates is in good agreement with the quantum chemical calculations as well as with the electronic and NMR spectroscopy data. Adding surfactants – both anionic (Cetyltrimethylammonium bromide - CTAB) and cationic (Sodium dodecyl sulfate - SDS) – even at concentrations below the critical micelle concentration (CMC) leads to the supramolecular trimer destruction. In solutions of ionic surfactants, supramolecular trimer destruction is caused by the interaction of either the peripheral macrocycles of the trimer (CoP) with SDS micelles (premicellar aggregates) or the central macrocycle (SnP) with CTAB micelles (premicellar aggregates). This process is prolonged and the rate of trimer destruction depends on the surfactant concentration. The sizes of the CTAB and SDS micelles solubilized with porphyrin molecules were established by dynamic light scattering. In general, surfactant additions lead to an increase in the SnP fluorescence at least due to the destruction of the supramolecular self-assembly, as well as due to the changes in the state of its microenvironment.

Innovative hybrid and bifunctional rare earth complexes as corrosion inhibitors for AA2024 Alloy: Electrochemical and surface analysis enhanced by DFT/MD simulation

The hybrid inorganic–organic compounds, RE-thioglycolates (RE = Ce, Nd, Sm), were analyzed as effective green corrosion inhibitors of AA2024 alloy in 0.1 M NaCl solution. Utilizing Electrochemical Impedance Spectroscopy the protective inhibitory film on the alloy’s surface was affirmed, alongside the persistence of a natural oxide layer over time. These complexes demonstrated notable corrosion inhibition efficiency over immersion from 1 h to 3 days, with Sm-thiog retaining the high inhibition efficiency of over 95 % during 72 h. All RE-thioglycolates are mixed-type inhibitors, imparting resistance against both general and pitting corrosion.The presence of a protective inhibitory film on the AA2024 surface in NaCl solution has been substantiated through various analytical techniques including FTIR, SEM/EDS and XPS. A detailed examination of the differential inhibition exhibited by these bifunctional complexes is elucidated through theoretical calculations. The smallest difference of HOMO and LUMO orbitals for Sm-thiog of 3.21 eV indicates that this inhibitor attains the strongest donor–acceptor interactions with the metal surface. Predictions generated by Density Functional Theory/Molecular Dynamics simulations suggest the potential formation of diverse inhibitory species within the electrolyte. The corrosion inhibition mechanism proposed for RE-thioglycolates is grounded in electrochemical and theoretical insights, and subsequently validated through surface analysis methods.