Naphthalene Molecules Research Articles

A novel 3D nitrogen-doped porous carbon supported Fe-Cu bimetallic nanoparticles composite derived from lignin: an efficient peroxymonosulfate activator for naphthalene degradation.

A novel 3D nitrogen-doped porous carbon supported Fe-Cu bimetallic nanoparticles composite (Fe-Cu-N-PC) was prepared via direct pyrolysis by employing black liquor lignin as a main precursor, and it was utilized as a novel catalyst for PMS activation in degrading naphthalene. Under the optimum experimental conditions, the naphthalene degradation rate was up to 93.2% within 60 min in the Fe-Cu-N-PC/PMS system. The porous carbon framework of Fe-Cu-N-PC could facilitate the quick molecule diffusion of reactants towards the inner bimetallic nanoparticles and enriched naphthalene molecules from the solution by a specific adsorption, which increased the odds of contact between naphthalene and reactive oxygen species and improved the reaction efficiency. The quenching reaction proved that the non-free radical pathway dominated by 1O2 was the main way in naphthalene degradation, while the free radical pathway involving SO4·- and ·OH only played a secondary role. Moreover, owing to its high magnetization performance, Fe-Cu-N-PC could be magnetically recovered and maintained excellent naphthalene degradation rate after four degradation cycles. This research will offer a theoretical basis for the construction of facile, efficient, and green technologies to remediate persistent organic pollutants in the environment.

Engineering of Aromatic Naphthalene and Solvent Molecules to Optimize Chemical Prelithiation for Lithium-Ion Batteries.

A cost-effective chemical prelithiation solution, which consists of Li+, polyaromatic hydrocarbon (PAH), and solvent, is developed for a model hard carbon (HC) electrode. Naphthalene and methyl-substituted naphthalene PAHs, namely 2-methylnaphthalene and 1-methylnaphthalene, are first compared. Grafting an electron-donating methyl group onto the benzene ring can decrease electron affinity and thus reduce the redox potential, which is validated by density functional theory calculations. Ethylene glycol dimethyl ether (G1), diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether solvents are then compared. The G1 solution has the highest conductivity and least steric hindrance, and thus the 1-methylnaphthalene/G1 solution shows superior prelithiation capability. In addition, the effects of the interaction time between Li+ and 1-methylnaphthalene in G1 solvent on the electrochemical properties of a prelithiated HC electrode are investigated. Nuclear magnetic resonance data confirm that 10-h aging is needed to achieve a stable solution coordination state and thus optimal prelithiation efficacy. It is also found that appropriate prelithiation creates a more Li+-conducing and robust solid-electrolyte interphase, improving the rate capability and cycling stability of the HC electrode.

The efficiency of micellar solubilization of naphthalene from aqueous solutions using rhamnolipid as a biological surfactant according to NMR diffusometry.

The micellar solubilization of naphthalene from its saturated aqueous solutions using the biosurfactant rhamnolipid was studied. Using the NMR diffusion method, selective measurements of the self-diffusion coefficients of molecules of all components of the solution-naphthalene, rhamnolipid, and water-were carried out at various rhamnolipid concentrations from 0.06 to 100 g/L. Based on the results of diffusometry, the distribution of naphthalene molecules between the states free in solution and states bound by micelles was found. With an increase in the concentration of rhamnolipids, the proportion of bound naphthalene molecules increases from 50% at CRL = 2g/L to 100% at CRL ≥ 50 g/L. The micelle-water partition coefficient Km and the molar solubilization ratio MSR were calculated.

Mechanistic Insights into the Excited-State Intramolecular Proton Transfer (ESIPT) Process of 2-(2-Aminophenyl)naphthalene.

The 2-(2-aminophenyl)naphthalene molecule attracted much attention due to excited-state intramolecular proton transfer (ESIPT) from an amino NH2 group to a carbon atom of an adjacent aromatic ring. The ESIPT mechanisms of 2-(2-aminophenyl)naphthalene are still unclear. Herein, the decay pathways of this molecule in vacuum were investigated by combining static electronic structure calculations and nonadiabatic dynamics simulations. The calculations indicated the existence of two stable structures (S0-1 and S0-2) in the S0 and S1 states. For the S0-1 isomer, upon excitation to the Franck-Condon point, the system relaxed to the S1 minimum quickly, and then there exist four decay pathways (two ESIPT ones and two decay channels with C atom pyramidalization). In the ESIPT decay pathways, the system encounters the S1S0-PT-1 or S1S0-PT-2 conical intersection, which funnels the system rapidly to the S0 state. In the other two pathways, the system de-excited from the S1 to the S0 state via the S1S0-1 or S1S0-2 conical intersection. For the S0-2 structure, the decay pathways were similar to those of S0-1. The dynamics simulations showed that 75 and 69% of trajectories experienced the two ESIPT conical intersections for the S0-1 and S0-2 structures, respectively. Our simulations showed that the lifetime of the S1 state of S0-1 (S0-2) is estimated to be 358 (400) fs. Notably, we not only found the detailed reaction mechanism of the system but also found that the different ground-state configurations of this system have little effect on the reaction mechanism in vacuum.

In silico analyses of solvent effects, toxicity, NBO, homo-lumo and hole-electron transfer of 7-hydroxy-2-nitrofluoranthene

7-Hydroxy-2-nitrofluoranthene (7H2NF) is a fused polynuclear aromatic molecule. A naphthalene molecule is fused with a benzene ring through a five-membered ring. Since it is aromatic, it has conjugated double bonds. In this molecule, an electron-donor and an electron-acceptor are placed in different corners. Hence, electrons can flow from electron-donor to acceptor through π-linkers. DFT/B3LYP/6-311 G method is adopted to perform the calculations. The electronic structure, Frontier energy gap, Mulliken charge analysis, stability, theoretical IR, and UV are investigated with the help of Gaussian 16W software. The NCI study reveals that it has steric and Van der Waals forces. The shaded surface with a projection of LOL indicates that it has electron depleted areas. The hole-electron transfer analysis suggests that it has a CT type excitation at the S6 level. Multiwfn 3.8 is used for these investigations. Toxicity is predicted. Solvent effects are calculated for FMO, MEP, etc.

Shpol’skii effect: new interpretation for the nature of the spectral multiplet structure and Bethe-splitting

New approach to the interpretation of the multiplet structure in the Shpol’skii spectra based on the symmetry consideration of the impurity molecule and crystal matrix is proposed. The reasons and peculiarities of doublet structure formation in the spectra of molecules without inversion center and highly symmetric molecules are considered. It is shown that the structure of electron density distribution in the naphthalene molecule causes a doubly degenerate of the electronic level of its ground state. The calculated data are compared with the experimental results. The main research stages and directions in the field of narrow-line spectroscopy of organic molecules are marked.

Modulating molecular plasmons in naphthalene via intermolecular interactions and strong light-matter coupling.

We conducted a theoretical investigation on the modulation of plasmon-like resonances in naphthalene - the so-called molecular plasmons - through intermolecular interactions and strong light-matter coupling. The configuration interaction with single excitations (CIS) approach and its quantum electrodynamics extension (QED-CIS-1) are used to describe the molecular plasmon states under these interactions. We detail the effects of changing intermolecular distances of the naphthalene dimer and incorporating the naphthalene molecule into optical cavities, both allowing for precise control of naphthalene's plasmonic responses. Our results show significant shifts of the plasmon peak in the absorption spectra of naphthalene, depending on the spatial configuration of the dimer and cavity parameters such as polarization, frequency, and coupling strength. Further investigation of the naphthalene dimer in a cavity reveals a synergistic effect on the plasmon peak when the two types of interactions are combined. This research provides insights into the plasmonic behavior of simple polyacenes like naphthalene and opens up possibilities for plasmon modulation in more complex systems.

Combustion derived carbon with ultrahigh-mesoporosity and moderate surface affinity towards reversible low-volatile gas capture

Capturing naphthalene as a valuable chemical from waste gases via adsorption on porous sorbent materials is a promising approach to tackle such an environmental health issue with additional economic benefits. However, very few sorbents have simultaneously high adsorption capacity and good regenerability for the large-molecular and low-volatile naphthalene. Here we attempt to address this challenge by integrating key fabrication elements of a layer-by-layer network, rational mesoporosity, and highly reversible sites into a carbonaceous adsorbent (ECSC) using a facile and fast eruptive solution combustion synthesis method. Adsorption breakthrough and temperature-programmed desorption experiments show that the ECSC achieves all-round superior naphthalene capture performance with unprecedented high capacity, fast kinetics, and low desorption energy. The combination of in situ DRIFTS, XPS, and DFT calculations reveals the moderate adsorption affinity of mitigated π–π stacking bonding between tilted naphthalene molecule and surface pyridinic N. This work affords new insights for designing next-generation adsorbents for naphthalene removal and presents a way of overcoming the adsorption–desorption dilemma for gas purification.

On-surface synthesis of aromatic cyclo[10]carbon and cyclo[14]carbon.

All-carbon materials based on sp2-hybridized atoms, such as fullerenes1, carbon nanotubes2 and graphene3, have been much explored due to their remarkable physicochemical properties and potential for applications. Another unusual all-carbon allotrope family are the cyclo[n]carbons (Cn) consisting of two-coordinated sp-hybridized atoms. They have been studied in the gas phase since the twentieth century4-6, but their high reactivity has meant that condensed-phase synthesis and real-space characterization have been challenging, leaving their exact molecular structure open to debate7-11. Only in 2019 was an isolated C18 generated on a surface and its polyynic structure revealed by bond-resolved atomic force microscopy12,13, followed by a recent report14 on C16. The C18 work trigged theoretical studies clarifying the structure of cyclo[n]carbons up to C100 (refs. 15-20), although the synthesis and characterization of smaller Cn allotropes remains difficult. Here we modify the earlier on-surface synthesis approach to produce cyclo[10]carbon (C10) and cyclo[14]carbon (C14) via tip-induced dehalogenation and retro-Bergman ring opening of fully chlorinated naphthalene (C10Cl8) and anthracene (C14Cl10) molecules, respectively. We use atomic force microscopy imaging and theoretical calculations to show that, in contrast to C18 and C16, C10 and C14 have a cumulenic and cumulene-like structure, respectively. Our results demonstrate an alternative strategy to generate cyclocarbons on the surface, providing an avenue for characterizing annular carbon allotropes for structure and stability.

Infrared spectroscopic and gravimetric analysis of the dicyclobutylaminemetal(II) tetracyanonickellate(II) host-aromatic guest complexes

M(cyclobutylamine)2Ni(CN)4 (M = Ni or Co) host and M(cyclobutylamine)2Ni(CN)4.nG (M = Ni or Co; cba = cyclobutylamine; G = benzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene and naphthalene; n=the number of guest) host-guest compounds were synthesized and characterized by infrared spectroscopy. The spectral results were found to be consistent with the structure of the Hofmann-dma-type hosts. The absorption and release studies of certain aromatic guests (benzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, and naphthalene) molecules in the host complexes were investigated by gravimetric and spectroscopic methods at room temperature. The liberation of guest molecule benzene against time has been examined. The structures of M(cyclobutylamine)2Ni(CN)4 host do not affect when the guest molecule is included and liberated. It is thought that the host compounds will guide as sorbents for isomeric separations.

Cationic complex-enhanced C-H stimulated Raman scattering in naphthalene-benzene solution.

Ring skeleton vibrations of aromatic series are dominant in Raman spectroscopy compared with the C-H stretching vibrations. When a laser-induced plasma (LIP) was generated in a mixed solution of naphthalene and benzene, an anomalous enhancement was observed in stimulated Raman scattering (SRS) of aromatic C-H stretching vibrations of naphthalene (3055 cm-1). However, SRS of C-H stretching vibrations of benzene at 3060 cm-1 disappeared. The LIP produced electrons and cations, and the transient production of ionized material contributed to the enhancement of SRS of C-H vibrations of naphthalene. Density functional theory calculations showed that the C-H Raman activity of the naphthalene molecules in (naphthalene-benzene)+ heterodimer was significantly enhanced compared with neutral naphthalene. In addition, SRS pulse durations were better compressed in pure benzene and naphthalene due to the self-focusing effect.

An analytical expression for temperature-dependent infrared intensities in fully coupled anharmonic molecular systems

We present the analytical expression for determining the temperature evolution of absolute integrated infrared (IR) intensities of fundamental bands in fully coupled anharmonic molecular systems. Only harmonic frequencies and integrated IR intensities (within the double harmonic approximation) are needed to predict the absolute temperature-dependent IR intensities of the fundamental bands. These quantities can be readily obtained from ab initio electronic structure calculations for relatively large molecules. In order to illustrate the accuracy of the expression we compare the results from this formula using harmonic frequencies and intensities from a tight-binding potential energy surface with the results from semiclassically prepared molecular dynamics (SCP-MD) simulations on the same potential energy surface for the naphthalene molecule. For a favorable comparison with experimental data we use the same analytical expression with the more accurate B3LYP/cc-pVDZ harmonic frequencies and intensities. We conclude that the IR intensity changes that our proposed formula predicts in the fundamental vibrational bands are mainly due to intramolecular vibrational energy redistribution (IVR).

Energy Component Analysis for Electronically Excited States of Molecules: Why the Lowest Excited State Is Not Always the HOMO/LUMO Transition

The ability to tune excited-state energies is crucial to many areas of molecular design. In many cases, this is done based on the energies of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). However, this viewpoint is incomplete neglecting the many-body nature of the underlying excited-state wave functions. Within this work, we highlight the importance of two crucial terms, other than orbital energies, that contribute to the excitation energies and show how to quantify them from quantum chemistry computations: a Coulomb attraction and a repulsive exchange interaction. Using this framework, we explain under which circumstances the lowest excited state of a molecule, of either singlet or triplet multiplicity, is not accessed via the HOMO/LUMO transition and show two paradigmatic examples. In the case of the push-pull molecule ACRFLCN, we highlight how the lowest triplet excited state is a locally excited state lying below the HOMO/LUMO charge transfer state due to enhanced Coulomb binding. In the case of the naphthalene molecule, we highlight how the HOMO/LUMO transition (the 1La state) becomes the second excited singlet state due to its enhanced exchange repulsion term. More generally, we explain why excitation energies do not always behave like orbital energy gaps, providing insight into photophysical processes as well as methodogical challenges in describing them.

Long Lived Delayed Fluorescence of Ternary Naphthalene–β-Cyclodextrin–Cyclohexane Complexes at Room Temperature

Long-lived delayed fluorescence of dispersions of microcrystals of naphthalene–β-cyclodextrin–cyclohexane ternary complexes has been studied. It has been established that the delayed fluorescence is due to the T–T annihilation process. The kinetics of delayed fluorescence has a nonexponential character; the average lifetime is 0.68 s. The shape of the decay rate curves of delayed fluorescence does not depend on the intensity of excitation light. The nonexponential nature of the delayed fluorescence is presumably associated with the presence in the crystals of paired naphthalene molecules with different mutual positions and pair formation energies.

Unconventional gas-phase preparation of the prototype polycyclic aromatic hydrocarbon naphthalene (C10H8) via the reaction of benzyl (C7H7) and propargyl (C3H3) radicals coupled with hydrogen-atom assisted isomerization.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the interstellar medium and in meteorites such as Murchison and Allende and signify the missing link between resonantly stabilized free radicals and carbonaceous nanoparticles (soot particles, interstellar grains). However, the predicted lifetime of interstellar PAHs of some 108 years imply that PAHs should not exist in extraterrestrial environments suggesting that key mechanisms of their formation are elusive. Exploiting a microchemical reactor and coupling these data with computational fluid dynamics (CFD) simulations and kinetic modeling, we reveal through an isomer selective product detection that the reaction of the resonantly stabilized benzyl and the propargyl radicals synthesizes the simplest representative of PAHs - the 10π Hückel aromatic naphthalene (C10H8) molecule - via the novel Propargyl Addition-BenzAnnulation (PABA) mechanism. The gas-phase preparation of naphthalene affords a versatile concept of the reaction of combustion and astronomically abundant propargyl radicals with aromatic radicals carrying the radical center at the methylene moiety as a previously passed over source of aromatics in high temperature environments thus bringing us closer to an understanding of the aromatic universe we live in.

Modeling Impurity-Mediated Crystal Growth and Morphologies of Centrosymmetric Molecules

Foreign molecules in solution often disrupt crystal growth mechanisms and alter the crystal morphology. In this article, we predict crystal morphologies for molecules of interest by combining step velocity model theory, kinetic Monte Carlo simulations, and existing visualization frameworks. We first validate the methodology by comparing simulation results to verified step velocity models for crystal growth systems without impurities present. We then introduce impurities (both thermoneutral and energetically attractive/repulsive) to the system and examine the change in step behavior to inform impurity-mediated crystal growth models. We demonstrate the approach with a visualization of morphology for the centrosymmetric molecule naphthalene grown under a variety of growth conditions, including from impure solutions. We comment on the applicability of this approach for more complex structures, including noncentrosymmetric molecular growth units.

One-Step Pyrolysis of Nitrogen-Containing Chemicals and Biochar Derived from Walnut Shells to Absorb Polycyclic Aromatic Hydrocarbons (PAHs)

The pyrolysis of biomass is an efficient means of utilizing biomass resources. Biomass can be converted into various high-performance chemicals and functional materials through pyrolysis. However, current pyrolysis technologies suffer from low conversion rates and single products, so the preparation of nitrogen compounds with high economic value remains a challenge. The walnut shell was soaked in three nitrogen-containing compound solutions before carbonization to produce high-value-added nitrogen-containing chemicals (with a nitrogen content of 59.09%) and biochar for the adsorption of polycyclic aromatic hydrocarbons (PAHs). According to biochar analysis, biochar has a porous structure with a specific surface area of 1161.30 m2/g and a high level of rocky desertification. The surface forms a dense pyrrole structure, and the structure produces π-π interactions with naphthalene molecules, exhibiting excellent naphthalene adsorption with a maximum capacity of 214.98 mg/g. This study provides an efficient, rapid, and environmentally friendly method for producing nitrogen-containing chemicals with high-added value and biochar.

Study on the structure regulation and electrochemical properties of imidazole-based MOFs by small molecules

In this work, four novel metal-organic frameworks (MOFs) were synthesized by the solvothermal reaction of the transition metal salts Co(NO3)2 with the mixed organic ligands 4,4′-sulfonyldibenzoic acid (H2SA) and 1,4-di(1H-imidazole-1-yl)-benzene (DIB) with the formula of [Co(DIB)0.5(SA)]•(DIB)0.5 (1), [Co(DIB)0.5(SA)] (2), [Co0.5(DIB)(HSA)]•(C10H8)0.5 (3) and [Co0.5(DIB)(HSA)]•(CH3CN) (4). Structural analysis manifested that complex 1 was assembled by the 2D Co-SA-DIB coordination networks constructed from the binuclear cobalt paddle-wheel secondary building units, while complex 3 was built from the 2D Co-DIB coordination networks based on the mononuclear cobalt center with the partially deprotonated HAS− ligand suspended on the two sides of the Co-DIB networks via the coordination between carboxylate and Co2+ cations. Furthermore, free DIB and naphthalene molecules functioned as the guest molecules to fill the pores in the structure of 1 and 3 respectively. More impressively, by just changing the used solvent, the free guest molecules DIB and naphthalene could be removed from the pores, and two novel MOFs, namely 2 and 4, could be obtained, whose framework architectures were identical to 1 and 3, respectively. In addition, the electrochemical properties of complexes 1–3 were checked as well and the results indicated that complex 3 exhibited the best electrocatalytic performance for the hydrogen evolution reaction (HER) with a low overpotential of 135 ​mV at the 10 ​mA ​cm−2 current density and a Tafel slope of 84 ​mV·dec−1. Moreover, it also possessed excellent stability with the maintainment of the current density up to 99.2% after 1000 cycles.

Comparative efficiency of polycyclic aromatic hydrocarbon removal by novel graphene oxide composites prepared from conventional and green synthesis

New materials have been developed based on the pillars of green chemistry; however, few studies compare the potential of these materials with that of conventional materials. In this study, two composites based on graphene oxide and magnetic chitosan were synthesized, one by the green route (G-mCS/GO) and the other by the conventional route (C-mCS/GO), using proanthocyanidin (PAS) and glutaraldehyde as crosslinking agents, respectively. Then, they were applied as adsorbents in the removal of polycyclic aromatic hydrocarbons (PAHs) from synthetic wastewater to compare their performance. Through XRD analysis, the crystallographic properties were obtained, FT-IR analyses indicated the presence of functional groups associated with graphene oxide, chitosan and Fe3O4 particles, and the magnetization curves indicated greater saturation magnetization for G-mCS/GO. Adsorption assays were performed at 298 K for 30 min at pH 6.5, an adsorbent dosage of 0.1 mg mL−1 and an initial PAH concentration of 0.01 mmol. L−1 showed a greater adsorptive capacity of G-mCS/GO for naphthalene (0.093 mmol g−1) and anthracene (0.089 mmol g−1), with removal efficiencies of 93.55% and 89.25%, respectively. On the other hand, C-mCS/GO showed a better removal efficiency for fluoranthene (0.076 mmol g−1), 76.07%. The results obtained through the molecular simulation indicated that naphthalene molecules have greater stability than anthracene and fluoranthene, which contributes to increasing the hydrophobic and π-π interactions between the PAH molecules and the adsorbent surface, thus inducing an increase in the adsorptive capacity. The results of this study indicate that G-mCS/GO is a potential and sustainable adsorbent for PAH removal from wastewater.

Penetration of Nonenergetic Hydrogen Atoms into Amorphous Solid Water and their Reaction with Embedded Benzene and Naphthalene

Chemical processes on the surface of icy grains play an important role in the chemical evolution in molecular clouds. In particular, reactions involving nonenergetic hydrogen atoms accreted from the gaseous phase have been extensively studied. These reactions are believed to effectively proceed only on the surface of the icy grains; thus, molecules embedded in the ice mantle are not considered to react with hydrogen atoms. Recently, Tsuge et al. suggested that nonenergetic hydrogen atoms can react with CO molecules even in ice mantles via diffusive hydrogenation. This investigation was extended to benzene and naphthalene molecules embedded in amorphous solid water (ASW) in the present study, which revealed that a portion of these molecules could be fully hydrogenated in astrophysical environments. The penetration depths of nonenergetic hydrogen atoms into porous and nonporous ASW were determined using benzene molecules to be >50 and ∼10 monolayers, respectively (1 monolayer ≈ 0.3 nm).