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The adsorption of molecules usually increases capacity and/or strength with the doping of surfaces with transition metals; furthermore, carbon nanostructures, i.e., graphene, carbon nanotubes, fullerenes, graphdiyne, etc., have a large specific area for gas adsorption. This review focuses on the reports (experimental or theoretical) of systems using these structures decorated with transition metals for mainly pollutant molecules' adsorption. Furthermore, we aim to present the expanding application of nanomaterials on environmental problems, mainly over the last 10 years. We found a wide range of pollutant molecules investigated for adsorption in carbon nanostructures, including greenhouse gases, anticancer drugs, and chemical warfare agents, among many more.

RESUMO

Abstract We report on the synthesis of C60 and C70 monoadducts at room temperature through the Bingel reaction; employing acetylacetone as ligand; in presence of DBU (1,8-Diazabicyclo [5.4.0] undec-7-ene), carbon tetrabromide (CBr4), and o-dichlorobenzene. Diacetylmethane-[C60-Ih]-fullerene-[5,6] and diacetylmethane-[C70-D5h]-fullerene-[5,6] monoadducts were obtained with yields of 69% and 44%, respectively. The products were purified by column chromatography (CC, on silica gel, using hexane, carbon disulfide, and chloroform as eluents at room temperature) and characterized by Nuclear Magnetic Resonance ('H and 13C), Fourier-Transform Infrared (FT-IR) and UV-Visible spectroscopies, Matrix-assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) Mass spectrometry, Cyclic Voltammetry (CV), and Osteryoung Square Wave Voltammetry (OSWV). Both compounds showed irreversible reduction peaks controlled by diffusion, with LUMO energy levels of -3.09 eV, -3.13 eV for C60, and C70 monoadducts, respectively. These values are comparable with the -3.99 eV of PC61BM. The synthetized adducts were incorporated into inverted-type perovskite solar cells and were used as electron transporting materials (ETM) obtaining power conversion efficiencies (PCE) of 8.5% and 14.0% for the C60 and C70 monoadducts, respectively. When C60 is replaced by a lower symmetrical fullerene such as C70 an improved light absorption in the visible region is observed.

Resumen Reportamos la síntesis de monoadductos de C60 y C70 a temperatura ambiente a través de la reacción de Bingel, empleando acetilacetona como ligando, en presencia de DBU (1,8-diazabiciclo [5.4.0] undec-7-eno), tetrabromuro de carbono (CBr4) y o-diclorobenceno. Se obtuvieron monoadductos de diacetilmetano-[C -I.]-fullereno-[5,6] y diacetilmetano-[C70-D5h]-fullereno-[5,6] con rendimientos del 69% y 44%, respectivamente. Los productos se purificaron por cromatografía en columna (CC, usando silica gel, hexano, disulfuro de carbono y cloroformo como fase móvil, a temperatura ambiente) y se caracterizaron por resonancia magnética nuclear (1H y 13C), infrarrojo con transformada de Fourier (FT-IR), espectroscopia UV-Visible, espectrometría de masas, desorción/ionización láser asistida por matriz - tiempo de vuelo (MALDI-TOF), voltametría cíclica (CV) y voltametría de onda cuadrada de Osteryoung (OSWV). Ambos compuestos mostraron picos de reducción irreversibles controlados por difusión, con niveles de energía LUMO de -3,09 eV y -3,13 eV para los monoadductos C60 y C70, respectivamente. Estos valores son comparables con el -3,99 eV de PC61BM. Los aductos sintetizados se incorporaron a las células solares de perovskita de tipo inversa y se usaron como materiales de transporte de electrones (ETM) obteniendo eficiencias de conversión de energía (PCE) de 8,5% y 14,0% para los monoaductos C60 y C70, respectivamente. Cuando el C60 se reemplaza por un fullereno menos simétrico como el C70, se observa una absorción de luz mejorada en la región visible.

Resumo Reportamos a sínteses de monoadutos de C60 e C70 a temperatura ambiente através da reação de Bingel, utilizando acetilacetona como ligando, na presença de DBU (1,8-diazabiciclo [5.4.0] undec-7-eno), tetrabromuro de carbono (CBr4) e o-diclorobenzeno. Foram obtidos monoadutos de diacetilmetano-[C60-IJ-fulereno-[5,6] e diacetilmetano-[C70-D5J-fulereno-[5,6] com rendimentos de 69% e 44%, respectivamente. Os produtos se purificaram por cromatografia em coluna (CC, usando sílica gel, hexano, dissulfeto de carbono e clorofórmio como fase móvel à temperatura ambiente ) e se caracterizaram por ressonância magnética nuclear OH e 13C), infra-vermelho com transformada de Fourier (FT-IR), espectroscopia UV-Visível, espectrometria de massas, ionização e dessorção a laser assistida por matriz-tempo de voo (MALDI-TOF), voltametria cíclica (CV) e voltametria de onda quadrada de Osteryoung (OSWV). Ambos compostos mostraram picos de redução irreversíveis controlados por difusão, com níveis de energia LUMO de -3,09 eV, -3,13 eV para os monoadutos C60 e C70, respectivamente. Estos valores são comparáveis com -3,99 eV de PC61BM. Os adutos sintetizados se incorporaram nas células solares de perovskita de tipo inversa e se usaram como materiais de transporte de eletrões (ETM) obtendo eficiências de conversão de energia (PCE) de 8,5% e 14,0% para os monoadutos C60 e C70, respectivamente. Quando o C60 se substitui por um fulereno menos simétrico como o C70, se observa uma absorção de luz melhorado na região visível.

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We report the synthesis and characterization of a fullerene-steroid hybrid that contains H2 @C60 and a dehydroepiandrosterone moiety synthesized by a cyclopropanation reaction with 76 % yield. Theoretical calculations at the DFT-D3(BJ)/PBE 6-311G(d,p) level predict the most stable conformation and that the saturation of a double bond is the main factor causing the upfield shielding of the signal appearing at -3.13 ppm, which corresponds to the H2 located inside the fullerene cage. Relevant stereoelectronic parameters were also investigated and reinforce the idea that electronic interactions must be considered to develop studies on chemical-biological interactions. A molecular docking simulation predicted that the binding energy values for the protease-hybrid complexes were -9.9 kcal/mol and -13.5 kcal/mol for PLpro and 3CLpro respectively, indicating the potential use of the synthesized steroid-H2 @C60 as anti-SARS-Cov-2 agent.

Assuntos

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With the rapid growth of industrialization, diverse pollutants produced as by-products are emitted to the air-water ecosystem, and toxic contamination of water is one of the most hazardous environmental issues. Various forms of carbon have been used for adsorption, electrochemical, and ion-exchange membrane filtration to separation processes for water treatment. The utilization of carbon materials has gained tremendous attention as they have exceptional properties such as chemical, mechanical, thermal, antibacterial activities, along with reinforcement capability and high thermal stability, that helps to maintain the ecological balance. Recently, engineered nano-carbon incorporated with polymer as a composite membrane has been spotlighted as a new and effective mode for water treatment. In particular, the properties of zero-dimensional (0D) carbon forms (fullerenes and carbon dots) have encouraged researchers to explore them in the field of wastewater treatment through membrane technologies as they are biocompatible, which is the ultimate requirement to ensure the safety of drinking water. Thus, the purpose of this review is to highlight and summarize current advances in the field of water purification/treatment using 0D carbon-polymer-based nanocomposite membranes. Particular emphasis is placed on the development of 0D carbon forms embedded into a variety of polymer membranes and their influence on the improved performance of the resulting membranes. Current challenges and opportunities for future research are discussed.

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The complexity of the central nervous system (CNS), its limited self-repairing capacity and the ineffective delivery of most CNS drugs to the brain contribute to the irreversible and progressive nature of many neurological diseases and also the severity of the outcome. Therefore, neurological disorders belong to the group of pathologies with the greatest need of new technologies for diagnostics and therapeutics. In this scenario, nanotechnology has emerged with innovative and promising biomaterials and tools. This review focuses on ischemic stroke, being one of the major causes of death and serious long-term disabilities worldwide, and the recent advances in the study of liposomes and carbon nanomaterials for therapeutic and diagnostic purposes. Ischemic stroke occurs when blood flow to the brain is insufficient to meet metabolic demand, leading to a cascade of physiopathological events in the CNS including local blood brain barrier (BBB) disruption. However, to date, the only treatment approved by the FDA for this pathology is based on the potentially toxic tissue plasminogen activator. The techniques currently available for diagnosis of stroke also lack sensitivity. Liposomes and carbon nanomaterials were selected for comparison in this review, because of their very distinct characteristics and ranges of applications. Liposomes represent a biomimetic system, with composition, structural organization and properties very similar to biological membranes. On the other hand, carbon nanomaterials, which are not naturally encountered in the human body, exhibit new modes of interaction with biological molecules and systems, resulting in unique pharmacological properties. In the last years, several neuroprotective agents have been evaluated under the encapsulated form in liposomes, in experimental models of stroke. Effective drug delivery to the brain and neuroprotection were achieved using stealth liposomes bearing targeting ligands onto their surface for brain endothelial cells and ischemic tissues receptors. Carbon nanomaterials including nanotubes, fullerenes and graphene, started to be investigated and potential applications for therapy, biosensing and imaging have been identified based on their antioxidant action, their intrinsic photoluminescence, their ability to cross the BBB, transitorily decrease the BBB paracellular tightness, carry oligonucleotides and cells and induce cell differentiation. The potential future developments in the field are finally discussed.

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As a new category of solids, crystalline materials constructed with amorphous building blocks expand the structure categorization of solids, for which designing such new structures and understanding the corresponding formation mechanisms are fundamentally important. Unlike previous reports, new amorphous carbon clusters constructed ordered carbon phases are found here by compressing C8 H8 /C60 cocrystals, in which the highly energetic cubane (C8 H8 ) exhibits unusual roles as to the structure formation and transformations under pressure. The significant role of C8 H8 is to stabilize the boundary interactions of the highly compressed or collapsed C60 clusters which preserves their long-range ordered arrangement up to 45 GPa. With increasing time at high pressure, the gradual random bonding between C8 H8 and carbon clusters, due to "energy release" of highly compressed cubane, leads to the loss of the ability of C8 H8 to stabilize the carbon cluster arrangement. Thus a transition from short-range disorder to long-range disorder (amorphization) occurs in the formed material. The spontaneous bonding reconstruction most likely results in a 3D network in the material, which can create ring cracks on diamond anvils.

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The geometry configuration of charged armchair graphene nanoribbons (AGNRs) is theoretically investigated in the framework of a two-dimensional tight-binding model that includes lattice relaxation. Our findings show that the charge distribution and, consequently, the bond length pattern is dependent on the parity of the nanoribbon width. In this sense, the lattice distortions decrease smoothly for increasingly wider GNRs. As should be expected, AGNRs belonging to a particular family present similar patterns for the bond lengths. The interplay between the electron-phonon coupling and band gap is also investigated. The results show that the electron-phonon coupling strength is fundamental to promote the transition from metallic towards semiconducting-like behavior for the band gap. Most important, such strength is crucial on defining the degree of lattice distortions in AGNRs.

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The possibility of existence of exohedral organometallic complexes of fullerenes larger than C60 in which their coordination can have η6 hapticity was studied from a theoretical point of view. Complexes containing C70, C74 or C60 cages, as well as cyclopentadienyl (Cp), pentamethyl-cyclopentadienyl (Me5Cp), benzene rings and hexamethyl-phenyl (Me6Ph) fragments as ligands, were designed and studied. The results show that many of these molecules can be thermodynamically stable and can have electronic interesting behavior.

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In the present work, a new analytical approach is proposed for the analysis of seven fullerenes (C60, C70, N-methylfulleropyrrolidine, [6,6]-phenyl C61 butyric acid methyl ester, [6,6]-thienyl C61 butyric acid methyl ester, C60 pyrrolidine tris-acid ethyl ester and [6,6]-phenyl C71 butyric acid methyl ester fullerenes) in soils and sediments. This procedure combines an ultrasound-assisted solvent extraction (UAE) with toluene followed by liquid chromatography (LC), using a pyrenylpropyl group bonded silica based column, coupled to a high-resolution mass spectrometer (HRMS) using atmospheric pressure photoionisation (APPI) in negative ion mode. The analytical performance for fullerene separation of the pyrenylpropyl group bonded silica column was compared to the C18 column. For the ultra-trace analysis of fullerenes in complex environmental samples, the use of the APPI source and the use of the electrospray ionisation (ESI) source were compared. Using this approach for the analysis of fullerenes in complex matrices, a series of advantages, in terms of sensitivity and specificity, have been demonstrated. The method limits of detection (MLOD) and the method limits of quantification (MLOQ) in soils and sediments ranged from 0.022 to 0.39 pg/g and from 0.072 to 1.3 pg/g, respectively. Recoveries were between 68 and 106%. The analytical method was applied in order to assess the occurrence of selected fullerenes in 45 soils of Sul Catarinense (Santa Catalina State, Brazil) and 15 sediments from the Tubarão River, presenting different pressures of contamination: a coal-combustion power plant, car exhaust, coal mining industry and wastewater effluents. C60 and C70 fullerenes have been detected at concentrations ranging from the MLOD to 0.150 ng/g. None of the functionalised fullerenes were detected in any of the samples. Combustion processes, in particular car exhaust, were identified as the main source of fullerenes. However, the potential degradation of residual concentrations of engineered fullerenes to more stable forms, such as C60 and C70, should also be considered.

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The displacement per carbon atom cross-sections behaviors with the secondary electron and positron kinetic energy for spherical fullerene C60 molecules are calculated. To accomplish this, the McKinley-Feshbach approach and the Kinchin-Pease approximation were taking into account, using two different displacement threshold energies. The total displacements per atom number generated indirectly by the photons in bulk samples composed of C60 fullerenes is also calculated. Besides, the behaviors of secondary particles contributions with the used displacement threshold energies and incident photon energies are determined. The in-depth distribution of electron and positron contributions and their relationship with the total displacements number are presented and debated. It was found that the positrons contribution to the total atom displacements number is very significant in processes involving the interaction of gamma quanta with energy up to 100 MeV in C60 fullerenes bulk samples.

Teniendo en cuenta las aproximaciones de McKinley-Feshbach y Kinchin-Pease se calcularon los comportamientos de las secciones eficaces de desplazamientos de los átomos de carbono en moléculas esféricas de fullereno C60, en función de la energía cinética de los electrones y positrones secundarios para dos valores de energía umbral de desplazamiento. También se calcularon el número total de desplazamientos atómicos generados de manera indirecta por los fotones en las muestras masivas de fullerenos C60 estudiadas. Además, se estudió el comportamiento de las contribuciones electrónicas y positrónicas, determinando sus dependencias con las energías de desplazamientoutilizadas y la energía de los fotones incidentes. Se presentan y debaten la distribución en profundidad de las contribuciones de los electrones y positrones, así como la relación entre ellos y el número total de desplazamientos. El aporte de la contribución de los positrones al número total de desplazamientos atómicos generados durante el proceso de interacción de los cuantos gamma de energías hasta 100 MeV con muestras masivas de fullerenos C60 se discutió lo que este resulta muy significativo.