Benzyl Ring 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).

Supramolecular Spring-Like Fe(II) Spin-Crossover Complexes Experiencing Giant and Anisotropic Thermal Expansion Across Two Distinct Temperature Regimes.

Dynamic molecules with tunable chemical and physical properties in response to external stimuli hold great potential for applications in information storage, smart molecular machines, and biomimetics. Among them, supramolecular springs and spin-crossover (SCO) complexes can both undergo visible macroscopic changes under heat or light stimulation. In this study, we synthesized a trinuclear Fe(II)-SCO complex, [(R-L)FeII{Au(CN)2}2] (R1), using a chiral chelating ligand decorated with rotatable benzyl rings. The [FeAu2] trinuclear molecules form a 21-helical supramolecular chain via elastic Au∙∙∙Au contacts. Interestingly, the synergy between the multiple dynamic factors (SCO event, rotation of the rings, and flexibility in Au∙∙∙Au distance) endows the complex with multiple switchings in both magnetism and structure, as well as the most intriguing characteristic of giant and anisotropic "breathing" feature in thermal expansion within two distinct temperature regimes. Specifically, complex R1 undergoes two hysteretic magnetic transitions: a non-spin transition and an unsymmetric SCO transition. Both transitions are triggered/accompanied by the rotation of the benzyl rings. Correspondingly, reversible spring-like motions of the helical chains are observed in the two distinct temperature regimes. This work demonstrates a significant success in incorporating both SCO and spring-like motion in one system, paving the way for designing multifunctional dynamic materials for future devices.

Supramolecular Spring‐Like Fe(II) Spin‐Crossover Complexes Experiencing Giant and Anisotropic Thermal Expansion Across Two Distinct Temperature Regimes

Dynamic molecules with tunable chemical and physical properties in response to external stimuli hold great potential for applications in information storage, smart molecular machines, and biomimetics. Among them, supramolecular springs and spin‐crossover (SCO) complexes can both undergo visible macroscopic changes under heat or light stimulation. In this study, we synthesized a trinuclear Fe(II)‐SCO complex, [(R‐L)FeII{Au(CN)2}2] (R1), using a chiral chelating ligand decorated with rotatable benzyl rings. The [FeAu2] trinuclear molecules form a 21‐helical supramolecular chain via elastic Au∙∙∙Au contacts. Interestingly, the synergy between the multiple dynamic factors (SCO event, rotation of the rings, and flexibility in Au∙∙∙Au distance) endows the complex with multiple switchings in both magnetism and structure, as well as the most intriguing characteristic of giant and anisotropic “breathing” feature in thermal expansion within two distinct temperature regimes. Specifically, complex R1 undergoes two hysteretic magnetic transitions: a non‐spin transition and an unsymmetric SCO transition. Both transitions are triggered/accompanied by the rotation of the benzyl rings. Correspondingly, reversible spring‐like motions of the helical chains are observed in the two distinct temperature regimes. This work demonstrates a significant success in incorporating both SCO and spring‐like motion in one system, paving the way for designing multifunctional dynamic materials for future devices.

Synthesis and Antifungal Activities of Glucosamine Aromatic Derivatives Against Four Phytopathogenic Fungi of Crops.

A series of diversified glucosamine derivatives (3a-3y) was synthesized and their antifungal activity was examined against four kinds of phytopathogens, Fusarium graminearum (F. graminearum), Fusarium moniliforme (F. moniliforme), Curvularia. lunata (C. lunata), and Rhizoctonia solani (R. solani) which cause seriously economic losses worldwide by affecting crops. The compound 3o showed remarkable antifungal activity against F. graminearum with EC50 value of 3.96 μg/mL, compared to the standard drug triadimefon (10.1 μg/mL). 3D-QSAR model with the statistically recommended values (r2=0.915, q2=0.872) showed that positive charge group or bulky group in the benzyl ring was favorable for the antifungal activity. Enzyme activity assays confirmed that 3o had a moderate inhibition of trehalase with inhibition rate of 51.4 % at 5 μg/mL, which is comparable to those of commercial inhibitor validamycin A with inhibition rate of 83.3 %. Molecular docking analysis revealed that 3o also had a hydrogen bond interaction with key amino acid residue compared to validoxylamine.

Harmonizing Between Chemical Functionality and Surface Area of Porous Organic Polymeric Nanotraps for Tuning Carbon Dioxide Capture.

The energy sector has demonstrated significant enthusiasm for investigating post-combustion CO2 capture, storage, and separation. However, the practical application of current porous adsorbents is impeded by challenges related to cost competitiveness, stability, and scalability. Intregation of heteroatoms in the porous organic polymers (POPs) dispense it more susceptible for CO2 adsorption to attenuate green house gases. In this regard, two hydroxy rich hypercrosslinked POPs, namely Ph/Tt-POP have been developed by one-pot condensation polymerization using a facile synthetic strategy. The high surface areas of both the Ph/Tt-POP (1057 and 893 m2g-1, respectively), and the heteroatom functionality in the POP framework instigated us to explore our material for CO2 adsorption study. The CO2 uptake capacities in Ph/Tt-POP are found to be 2.45 and 2.2 mmol g-1, at 273 K respectively. Further, in-situ static 13C NMR experiment shows that CO2 molecules in Tt-POP appear to be less mobile than those in Ph-POP which probably due to the presence of triazine functional groups along with high abundant -OH groups in the Tt-POP framework. An in-depth study of the CO2 adsorption mechanism by density functional theory (DFT) calculations also shows that CO2 adsorption at the cages formed by two benzyl rings represents the most stable interaction and CO2 molecule is more favorably adsorbed on the Ph-POP with the more negative interaction energies values compared to that of Tt-POP. Further, Non-covalent interaction (NCI) plot reveals that CO2 molecules adsorb more on the Ph-POP than Tt-POP, which can be explain by hydrogen bond formation in case of Tt-POP repeating units turning aside CO2 molecule to interact with the Ph component. Overall, our present study reflects the comprising effects of surface area of the solid adsorbents as well as their functionality can be beneficial for developing efficient hypercrosslinked porous polymers as solid CO2 adsorbent.

Natural α-Methylene-γ-Butyrolactone Analogues: Synthesis and Evaluation of Isoaurone Derivatives as Antifungal Agents.

In order to develop novel, efficient and green fungicides, a series of novel isoaurone derivatives were designed and synthesized, which were characterized by 1H and 13C NMR, high-resolution mass spectra and melting points. The target compounds showed different inhibitory activities against seven plant pathogenic fungi. Compounds 1, 12, 17, 20, 22, 24 and intermediate A showed more than 90% inhibition rates against S. s at 50 mg/L. Interestingly, compound 22 and intermediate A showed the great inhibitory effect against S. s with EC50 values of 4.65 and 4.24 mg/L, which were better than the lead compound isoaurone (EC50 = 15.62 mg/L). The EC50 values of compounds 17 and 24 against B. c were 13.94 and 22.13 mg/L. Moreover, compound 19 displayed significant antifungal activity against G. g with the EC50 value of 11.88 mg/L. Theoretical calculations by DFT revealed that the α, β-unsaturated carbonyl bond and the benzyl ring are very importantly linked to the strength of the fungicidal activity. Therefore, this study identified a valuable antifungal lead compound for further development of green fungicides.

Design, synthesis, and in vitro and in silico study of 1-benzyl-indole hybrid thiosemicarbazones as competitive tyrosinase inhibitors.

Developing new anti-tyrosinase drugs seems crucial for the medical and industrial fields since irregular melanin synthesis is linked to the resurgence of several skin conditions, including melanoma, and the browning of fruits and vegetables. A novel series of N-1 and C-3 substituted indole-based thiosemicarbazones 5(a-r) are synthesized and further analyzed for their inhibition potential against tyrosinase enzyme through in vitro assays. The synthesized compounds displayed very good to moderate inhibition with half maximal inhibitory concentration in the range of 12.40 ± 0.26 μM to 47.24 ± 1.27 μM. Among all the derivatives 5k displayed the highest inhibitory activity. According to SAR analysis, the derivatives with 4-substitution at the benzyl or phenyl ring of the thiosemicarbazones exhibited better inhibitory potential against tyrosinase. In silico analysis (including ADMET prediction and molecular docking) was conducted and compared with the standard drug (kojic acid). These findings may help the hunt for new melanogenesis inhibitors that the food and cosmetics industries may find valuable.

Synthesis of Mesylated and Tosylated α-Hydroxy-Benzylphosphonates; Their Reactivity and Cytostatic Activity.

α-Hydroxyphosphonates and their acylated and phosphorylated derivatives may be of significant biological activity including cytotoxic effects. To extend the pool of the potentially bioactive species, new methane- and arenesulfonyloxyphosphonates were synthesized by the sulfonylation of differently substituted α-hydroxy-benzylphosphonates using methanesulfonyl chloride or p-toluenesulfonyl chloride at 25 °C in the presence of triethylamine in toluene. The new sulfonyl derivatives were obtained in 54-80% yields. In the case of the 4- or 2-methoxy substituent in the aromatic ring, surprisingly the corresponding α-chlorophosphonates were the exclusive products, whose formation was explained assuming a quinoid intermediate and supported by theoretical calculations. With a 3-methoxyphenyl substituent, the expected mesylation of the hydroxy group took place. Attempted alcoholyses of the diethyl α-methanesulfonyloxy-benzylphosphonates with different substituents in the benzyl ring at ∼140 °C in the presence of triethylamine under microwave irradiation left the P-function intact under the conditions applied, instead, the mesyloxy group was substituted by an alkoxy unit in a selective new reaction. The α-alkoxy-benzylphosphonates were isolated in 60-77% yields. While α-chloro- or α-bromo-benzylphosphonates proved to be rather inefficient in the Michaelis-Arbuzov reaction with triethyl phosphite, according to a new possibility, the α-methansulfonyloxy-benzylphosphonates underwent an efficient Arbuzov fission using the phosphite in excess at 135 °C. The arylmethylenebisphosphonates were obtained in yields of 76-81%. Bioactivity studies with the members of the phosphonate library revealed pronounced in vitro cytostatic effect of the α-hydroxy- and α-mesyloxy-3,5-di-tert-butylbenzylphosphonates on human breast carcinoma cell culture with IC50 values of 16.4 and 28.0 μM, respectively. The mesyloxy species was also cytostatic on melanoma cells (IC50 = 34.9).

Synthesis of New Chroman-4-one Based 1,2,3-Triazole Analogues as Antioxidant and Anti-Inflammatory Agents.

A library of new chroman-4-one based 1,2,3-triazole analogues were synthesized involving a series of condensation, cyclization, Suzuki coupling and copper catalysed click chemistry protocols. The newly synthesized compounds 8a-l were screened for their invitro antioxidant and anti-inflammatory activities by employing Ascorbic acid and Diclofenac as reference drugs respectively. The compound without any substituent on benzyl ring (8a), compound with -Cl substituent in para position of benzyl ring (8i), and compound with ethoxy substituent in para position of benzyl ring (8k) exhibited potent antioxidant and anti-inflammatory activities with higher percentage of inhibition. To understand their binding affinities, molecular docking study of these three compounds performed against NADPH oxidase with presented outstanding docking scores and promising binding interactions like H-bond and hydrophobic.

A chiral zeolite material with improved enantioselective catalytic properties prepared from readily accessible ephedrine alkaloids

Substituted-benzyl-containing N-methyl-ephedrinium derivatives (BMEP), prepared from the highly-accessible (1R,2S)- or (1S,2R)-ephedrine alkaloids, have been found to act as efficient structure-directing agents for the synthesis of chiral zeolite GTM-4 with –ITV framework structure, promoting the enantio-enrichment in one of the chiral crystalline polymorphs as a function of the organic handedness. Results of a systematic variation of substituents in the benzyl ring attached to the ephedrine core (with methyl-, fluoro- or chloro-groups in the different positions of the aromatic ring) revealed that F-containing SDAs brought about an improvement in the structure-directing ability toward the –ITV framework, giving asymmetric zeolite acid-catalysts that yielded notable enantiomeric excesses in the range of 40–45 % for the trans-stilbene oxide ring-opening with 1-butanol. Interestingly, the incorporation of a methyl group in ortho-position (oMBMEP) had a double positive effect: on the one hand, this SDA prevented the crystallization of the competing BEC phase, allowing the crystallization of the -ITV structure at higher temperature and with higher crystallinity, and on the other, it drove to GTM-4 asymmetric catalysts that yielded enantiomeric excesses up to 60 %, resulting in the chiral GTM catalysts with the best enantioselective properties found so far. Remarkably, our catalytic results show the same chiral activity (in terms of zeolite handedness) for GTM-4 materials prepared from benzyl-containing (1S,2S)-N-methyl-pseudoephedrinium (BMPS) and (1S,2R)-N-methyl-ephedrinium (BMEP) derivatives, thus suggesting that the host-guest transfer of chirality during crystallization with these chiral organic aromatic agents is imposed by the absolute configuration of the C1 atom to which the OH group is attached. The relatively high enantiomeric excess of 60 % achieved, combined with the high accessibility of the ephedrine chiral precursors used for the synthesis that enables the production of both crystalline handedness of the –ITV framework, bring these materials closer to a potential application as heterogeneous asymmetric catalysts for the synthesis of chiral compounds of interest.

Synthesis of 5-Benzylamino and 5-Alkylamino-Substituted Pyrimido[4,5-c]quinoline Derivatives as CSNK2A Inhibitors with Antiviral Activity.

A series of 5-benzylamine-substituted pyrimido[4,5-c]quinoline derivatives of the CSNK2A chemical probe SGC-CK2-2 were synthesized with the goal of improving kinase inhibitor cellular potency and antiviral phenotypic activity while maintaining aqueous solubility. Among the range of analogs, those bearing electron-withdrawing (4c and 4g) or donating (4f) substituents on the benzyl ring as well as introduction of non-aromatic groups such as the cyclohexylmethyl (4t) were shown to maintain CSNK2A activity. The CSNK2A activity was also retained with N-methylation of SGC-CK2-2, but α-methyl substitution of the benzyl substituent led to a 10-fold reduction in potency. CSNK2A inhibition potency was restored with indene-based compound 4af, with activity residing in the S-enantiomer (4ag). Analogs with the highest CSNK2A potency showed good activity for inhibition of Mouse Hepatitis Virus (MHV) replication. Conformational analysis indicated that analogs with the best CSNK2A inhibition (4t, 4ac, and 4af) exhibited smaller differences between their ground state conformation and their predicted binding pose. Analogs with reduced activity (4ad, 4ae, and 4ai) required more substantial conformational changes from their ground state within the CSNK2A protein pocket.

Degradation of the strobilurin fungicide mandestrobin in illuminated water-sediment systems.

The degradation behavior of mandestrobin (1) was investigated in aerobic aquatic water-sediment systems exposed to continuous artificial sunlight (λ>290 nm). [14C]mandestrobin uniformly labeled at the phenoxy or benzyl ring was individually applied to the overlying water of the system at a rate equivalent to 262.5 g a.i./ha. The transformation of 1 was mainly proceeded via photoinduced bond cleavage at the benzyl phenyl ether and the subsequent rearrangement reaction. Interestingly, some of the photodegradates and microbial metabolites of 1 observed in the aquatic photodegradation and water-sediment (dark) studies, respectively, were never detected. Furthermore, the observed photoproducts were less formed and were steadily degraded or metabolized to carbon dioxide or strongly adsorbed to bottom sediment. The fate of 1 and its degradates in illuminated water-sediment systems was considered to reflect realistic conditions more precisely, as it accounts for various effects attributed to sunlight.

Solvatochromism, optical and electronic properties of thiosemicarbazone derivatives in solution phase

The electronic structure, solvatochromic and some optoelectronic properties of five different thiosemicarbazone (TSCs) derivatives with different substituents consisted from indole ring, benzyl ring and conjugated thiosemicarbazide have been investigated in detail. UV–vis. absorption spectra of TSC compounds have been analyzed in solvent media with different polarity. The spectral changes are observed to forming of solvent effects and substituents. Spectral behaviors and electronic transitions are interpreted based on the UV-Vis. spectra. Solvatochromic behaviors were defined by linear solvation energy relationships via multiple linear regression analysis by using Kamlet-Abboud-Taft and Catalán parameters. In addition, the correlations of electronic absorption transition energy with Marcus optical dielectric parameter and Reichardt-Dimroth parameter were also determined. Some optoelectronic parameters such as forbidden band gap energy and refractive index have been determined in different solvent medium. Thiosemicarbazone derivatives have a global electronic absorption transition energy of about 3.351 eV. According to LSER calculations, polarizability-induction of electronic transitions of the investigated molecules is effective. The (E)-4-(4-nitrobenzyl)-1-(2-oxo-2H-indol-3(3aH)-ylidene)thiosemicarbazide (TSC-B) compound that does not a methoxy group and contain nitro group substituent and has the highest forbidden energy range.

Design and Synthesis of Novel Diphenyl Ether Carboxamide Derivatives To Control the Phytopathogenic Fungus Sclerotinia sclerotiorum.

Sclerotinia stem rot (SSR) caused by the phytopathogenic fungus Sclerotinia sclerotiorum has led to serious losses in the yields of oilseed rape and other crops every year. Here, we designed and synthesized a series of carboxamide derivatives containing a diphenyl ether skeleton by adopting the scaffold splicing strategy. From the results of the mycelium growth inhibition experiment, inhibition rates of compounds 4j and 4i showed more than 80% to control S. sclerotiorum at a dose of 50 μg/mL, which is close to that of the positive control (flubeneteram, 95%). Then, the results of a structure-activity relationship study showed that the benzyl scaffold was very important for antifungal activity and that introducing a halogen atom on the benzyl ring would improve antifungal activity. Furthermore, the results of an in vitro activity test suggested that these novel compounds can inhibit the activity of succinate dehydrogenase (SDH), and the binding mode of 4j with SDH was basically similar to that of the flutolanil derivative. Morphological observation of mycelium revealed that compound 4j could cause a damage on the mycelial morphology and cell structure of S. sclerotiorum, resulting in inhibition of the growth of mycelia. Furthermore, in vivo antifungal activity assessment of 4j displayed a good control of S. sclerotiorum (>97%) with a result similar to that of the positive control at a concentration of 200 mg/L. Thus, the diphenyl ether carboxamide skeleton is a new starting point for the discovery of new SDH inhibitors and is worthy of further development.

Semisynthesis and Cytotoxic Evaluation of an Ether Analogue Library Based on a Polyhalogenated Diphenyl Ether Scaffold Isolated from a Lamellodysidea Sponge.

The known oxygenated polyhalogenated diphenyl ether, 2-(2',4'-dibromophenoxy)-3,5-dibromophenol (1), with previously reported activity in multiple cytotoxicity assays was isolated from the sponge Lamellodysidea sp. and proved to be an amenable scaffold for semisynthetic library generation. The phenol group of 1 was targeted to generate 12 ether analogues in low-to-excellent yields, and the new library was fully characterized by NMR, UV, and MS analyses. The chemical structures for 2, 8, and 9 were additionally determined via single-crystal X-ray diffraction analysis. All natural and semisynthetic compounds were evaluated for their ability to inhibit the growth of DU145, LNCaP, MCF-7, and MDA-MB-231 cancer cell lines. Compound 3 was shown to have near-equivalent activity compared to scaffold 1 in two in vitro assays, and the activity of the compounds with an additional benzyl ring appeared to be reliant on the presence and position of additional halogens.

Shape and interactions of the synthetic repellent DEET.

N,N-Diethyl-3-methylbenzamide (DEET) is the most widely used insect repellent, exhibiting high efficiency against a wide variety of species. In this work, a comprehensive isolated-molecule investigation of DEET was conducted using chirp-excitation Fourier transform microwave (CP-FTMW) spectroscopy within the frequency range of 7-14 GHz. Four out of the eight theoretically predicted conformers were detected and grouped in pairs based on their rotational constants and planar moments of inertia. We also studied the non-covalent interactions of DEET by characterizing the attractive and repulsive forces, which could explain the energetic ordering of the four conformers. In addition, DEET has a methyl top bound to the benzyl ring which is predicted to rotate almost freely with respect to the molecular framework.

Leishmanicidal activity and 4Dquantitative structure-activity relationship and molecular docking studies of vanillin-containing 1,2,3-triazole derivatives.

Aim: The assessment of the antileishmanial potential of 22 vanillin-containing 1,2,3-triazole derivatives against Leishmania braziliensis is reported. Materials & methods: Initial screening was performed against the parasite promastigote form. The most active compound, 4b, targeted parasites within amastigotes (IC50=4.2±1.0μmol l-1), presenting low cytotoxicity and a selective index value of 39. 4D quantitative structure-activity relationship and molecular docking studies provided insights into structure-activity and biological effects. Conclusion: A vanillin derivative with significant antileishmanial activity was identified. Enhanced activity was linked to increased electrostatic and Van der Waals interactions near the benzyl ring of the derivatives. Molecular docking indicated the inhibition of the Leishmania amazonensis sterol 14α-demethylase, using Leishmania infantum sterol 14α-demethylase as a model, without affecting the human isoform. Inhibition was active site competition with lanosterol.

Aryl azoles based scaffolds for disrupting tumor microenvironment

Thirty-nine aryl azoles, thirteen triazoles and twenty-seven tetrazoles, have been synthetized and biologically evaluated to determine their activity as tumor microenvironment disruptors. Antiproliferative studies have been performed on tumor cell lines HT-29, A-549 and MCF-7 and on non-tumor cell line HEK-293. It has been studied in HT-29 the expression levels of biological targets which are involved in tumor microenvironment processes, such as PD-L1, CD-47, c-Myc and VEGFR-2. In addition, antiproliferative activity was evaluated when HT-29 were co-cultured with THP-1 monocytes and the secretion levels of IL-6 were also determined in these co-cultures. The angiogenesis effect of some selected compounds on HMEC-1 was also evaluated as well as their action against vasculogenic mimicry on HEK-293. Compounds bearing an amino group in the phenyl ring and a halogen atom in the benzyl ring showed promising results as tumor microenvironment disrupting agents. The most outstanding compound decrease dramatically the population of HT-29 cells when co-cultured with THP-1 monocytes and the levels of IL-6 secreted, as well as it showed moderate effects over PD-L1, CD-47 and c-Myc.

Phenyl-quinoline derivatives as lead structure of cholinesterase inhibitors with potency to reduce the GSK-3β level targeting Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder that leads to cognitive decline and memory loss. Unfortunately, there is no effective treatment for this condition, so there is a growing interest in developing new anti-AD agents.In this research project, a series of phenyl-quinoline derivatives were designed as potential anti-AD agents. These derivatives were substituted at two different positions on benzyl and phenyl rings. The structures of the derivatives were characterized using techniques such as IR spectroscopy, 1H NMR, 13C NMR, and elemental analysis. During the in vitro screening, the derivatives were tested against both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). It was observed that most of the derivatives showed higher selectivity against BChE compared to AChE. Among the derivatives, analog 7n (with a methoxy group at R1 and a 4-bromine substituent at R2 exhibited the highest potency, with a 75-fold improvement in the activity compared to the positive control. Importantly, this potent analog demonstrated no toxicity at the tested concentration on SH-SY5Y cells, indicating its potential as a safe anti-AD agent. The level of GSK-3β was also reduced after treatments with 7n at 50 μM.Overall, this study highlights the design and evaluation of phenyl-quinoline derivatives as promising candidates for developing novel anti-AD agents.

Operando FTIR-ATR with molecular dynamic simulations to understand the diffusion mechanism of waste tire-derived pyrolytic oil for asphalt self-healing

Recent research proves that pyrolytic oils from waste tires are effective in restoring the chemical and rheological properties of aged asphalt binders. Nonetheless, the role of oil-binder molecular interactions and bindeŕs aging degree on the diffusional behavior of the pyro-oils is still unclear. In this study, authors propose integrating operando Fourier Transformed Infrared Spectroscopy (FTIR) measurements with molecular dynamics (MD) simulations as a novel approach to unravel the diffusion mechanisms of pyro-oils in asphalt binders with self-healing purposes. The produced pyro-oils contains aliphatic and single-ring alkyl aromatic compounds as the most abundant species (ca. 80%). The operando FTIR measurements were correlated by a Fickian model, resulting in diffusion coefficients (D0) between 10-12 and 10-11 m2s−1. Moreover, MD simulations, with a molecular model of aged asphalt containing benzylic rings, sulfoxides, and hydroxyl functional groups, demonstrated that interactions of functional groups in the pyro-oil with the binder, hinder the diffusion behavior of the pyro-oil. The D0 estimated from the MD simulations agreed with those calculated from experimental data and previous reports for petro- and bio-derived rejuvenators. The predictive performance of the MD simulations developed in this study confirms to design of more resilient self-healing asphalt binders using a bottom-up strategy.