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1.
Micromachines (Basel) ; 15(6)2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38930648

RESUMO

MEMS devices are more and more commonly used as sensors, actuators, and microfluidic devices in different fields like electronics, opto-electronics, and biomedical engineering. Traditional fabrication technologies cannot meet the growing demand for device miniaturisation and fabrication time reduction, especially when customised devices are required. That is why additive manufacturing technologies are increasingly applied to MEMS. In this review, attention is focused on the Italian scenario in regard to 3D-printed MEMS, studying the techniques and materials used for their fabrication. To this aim, research has been conducted as follows: first, the commonly applied 3D-printing technologies for MEMS manufacturing have been illustrated, then some examples of 3D-printed MEMS have been reported. After that, the typical materials for these technologies have been presented, and finally, some examples of their application in MEMS fabrication have been described. In conclusion, the application of 3D-printing techniques, instead of traditional processes, is a growing trend in Italy, where some exciting and promising results have already been obtained, due to these new selected technologies and the new materials involved.

2.
Materials (Basel) ; 16(24)2023 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-38138817

RESUMO

Modifying material properties within a specific spatial region is a pivotal stage in the fabrication of microelectronic devices. Laser annealing emerges as a compelling technology, offering precise control over the crystalline structure of semiconductor materials and facilitating the activation of doping ions in localized regions. This obviates the necessity for annealing the entire wafer or device. The objective of this review is to comprehensively investigate laser annealing processes specifically targeting the crystallization of amorphous silicon (Si) and silicon carbide (SiC) samples. Silicon finds extensive use in diverse applications, including microelectronics and solar cells, while SiC serves as a crucial material for developing components designed to operate in challenging environments or high-power integrated devices. The review commences with an exploration of the underlying theory and fundamentals of laser annealing techniques. It then delves into an analysis of the most pertinent studies focused on the crystallization of these two semiconductor materials.

3.
Dalton Trans ; 52(45): 16974-16983, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37933188

RESUMO

New 1,2-azolylamidino complexes fac-[RuCl(DMSO)3(NHC(R)az*-κ2N,N)]OTf [R = Me (2), Ph (3); az* = pz (pyrazolyl, a), indz (indazolyl, b)] are synthesized via chloride abstraction from their corresponding precursors cis,fac-[RuCl2(DMSO)3(az*H)] (1) after subsequent base-catalyzed coupling of the appropriate nitrile with the 1,2-azole previously coordinated. All the compounds are characterized by 1H NMR, 13C NMR and IR spectroscopy. Those derived from MeCN are also characterized by X-ray diffraction. Electrochemical studies showed several reduction waves in the range of -1.5 to -3 V. The electrochemical behavior in CO2 media is consistent with CO2 electrocatalytic reduction. The catalytic activity expressed as [icat(CO2)/ip(Ar)] ranged from 1.7 to 3.7 for the 1,2-azolylamidino complexes at voltages of ca. -2.7 to -3 V vs. ferrocene/ferrocenium. Controlled potential electrolysis showed rapid decomposition of the Ru catalysts. Photocatalytic CO2 reduction experiments using compounds 1b, 2b and 3b carried out in a CO2-saturated MeCN/TEOA (4 : 1 v/v) solution containing a mixture of the catalyst and [Ru(bipy)3]2+ as the photosensitizer under continuous irradiation (light intensity of 150 mW cm-2 at 25 °C, λ > 300 nm) show that compounds 1b, 2b and 3b allowed CO2 reduction catalysis, producing CO and trace amounts of formate. The combined turnover number for the production of formate and CO is ca. 100 after 8 h and follows the order 1b < 2b ≈ 3b.

4.
Av. psicol. latinoam ; 41(2): [1-14], may-ago. 2023.
Artigo em Inglês | LILACS | ID: biblio-1510502

RESUMO

El TDAH es el trastorno del neurodesarrollo más diagnosticado en escolares. La evidencia indica que las funciones ejecutivas, como es el caso de la velocidad de procesamiento y la memoria de trabajo, están afectadas en estudiantes con TDAH, aunque no existe un acuerdo definitivo sobre su presencia sistemática en este trastorno. Esta investigación pretende determinar si la velocidad de procesamiento y la memoria de trabajo corresponden a variables cognitivas en el TDAH. Participaron 138 estudiantes de 10 a 17 años. Se determinó TDAH con la escala VADTRS; se evaluó velocidad de procesamiento con una tarea de rapidez grafomotora y memoria de trabajo con una tarea de dígitos. Se utilizó un diseño transversal, univariante e intersujeto para el análisis de los datos. El VADTRS detectó un grupo con TDAH (N = 97) y otro sin TDAH (N = 41). A ambos grupos se aplicaron tareas de velocidad de procesamiento y memoria de trabajo; los análisis permitieron detectar diferencias significativas en estas variables entre los grupos con y sin TDAH. El grupo con TDAH fue dividido según su presentación; no se detectaron diferencias significativas en velocidad de procesamiento; la memoria de trabajo mostró un rendimiento significativa- mente menor en las presentaciones de TDAH inatenta y combinada. La velocidad de procesamiento y la memoria de trabajo parecen distinguir entre sujetos con y sin TDAH, la velocidad de procesamiento no parece distinguir entre presentaciones y la memoria de trabajo aparece alterada en aquellas presentaciones en que el componente atencional es definitorio


ADHD is the most commonly diagnosed neurodevelopmental disorder in schoolchildren. Evidence indicates that executive functions, such as processing speed and working memory, are affected in students with ADHD, although there is no definitive agreement on their sys- tematic presence in this disorder. This research aims to determine whether processing speed and working memory correspond to cognitive variables in ADHD. A total of 138 students aged 10 to 17 years participated. ADHD was determined with the VADTRS scale; processing speed was assessed with a graphomotor speed task and working memory with a digit task. A cross-sectional, univariate, intersubject design was used for data analy- sis. The VADTRS detected one group with ADHD (N = 97) and one without ADHD (N = 41). Processing speed and working memory tasks were applied to both groups; analyses detected significant differences in these variables between the ADHD and non- ADHD groups. The ADHD group was divided according to presentation; no significant differences were detected in processing speed; working memory showed significantly lower performance in the inattentive and combined ADHD presentations. Processing speed and working memory appear to distinguish between subjects with and without ADHD, processing speed does not appear to distinguish between presentations, and working memory appears impaired in those presentations in which the attentional component is defining.


O TDAH é o distúrbio de desenvolvimento neurológico mais frequentemente diagnosticado em crianças em idade escolar. As provas indicam que as funções executivas, tais como a velocidade de processamento e a memória de trabalho, são afectadas nos estudantes com TDAH, embora não haja um acordo definitivo sobre a sua presença sistemática nesta doença. Esta investiga- ção visa determinar se a velocidade de processamento e a memória de trabalho correspondem a variáveis cognitivas na TDAH. Um total de 138 estudantes com idades compreendidas entre os 10 e os 17 anos participaram. A TDAH foi determinada com a escala VADTRS; a velocidade de processamento foi avaliada com uma tarefa de velocidade grafomotora e a memória de trabalho com uma tarefa de dígitos. Foi utilizado um desenho transversal, univariado e intersubjecto para análise de dados. O VADTRS detectou um grupo com ADHD (N = 97) e um grupo sem ADHD (N = 41). Ambos os grupos foram administrados com velocidade de processamento e tarefas de memória de trabalho; as análises detectaram diferenças significativas nestas variáveis entre os grupos com ADHD e sem ADHD. O grupo TDAH foi dividido de acordo com a apresentação; não foram detectadas diferenças significativas na velocidade de processamento; a memória de trabalho mostrou um desempenho significativamente inferior nas apresentações de TDAH desatenta e combinada. A velocidade de processamento e a memória de trabalho parecem distinguir entre assuntos com e sem TDAH; a velocidade de processamento não parece distinguir entre apresentações e memória de trabalho parece prejudicada nas apresentações em que a componente atencional está a definir


Assuntos
Humanos
5.
Int J Mol Sci ; 24(3)2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36769053

RESUMO

By employing a variation of the polyamidation method using in situ silylated diamines and acid chlorides, it was possible to obtain a rod-type polyamide: poly(p-phenylene terephthalamide) (PPTA, a polymer used in the high-value-added material Kevlar), with a molecular weight much higher than that obtained with the classical and industrial polyamidation method. The optimization of the method has consisted of using, together with the silylating agent, a mixture of pyridine and a high-pKa tertiary amine. The research was complemented by a combination of nuclear magnetic resonance and molecular simulation studies, which determined that the improvements in molecular weight derive mainly from the formation of silylamide groups in the growing polymer.


Assuntos
Nylons , Polímeros , Peso Molecular , Espectroscopia de Ressonância Magnética , Diaminas
6.
Chem Commun (Camb) ; 57(84): 11013-11016, 2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34570131

RESUMO

Herein, we report molecular tweezers for fullerene recognition based on 2,2'-bipyridine-bearing corannulene motifs. The syn or anti confirmation can be selected simply by Cu(I) coordination/decoordination, thus controlling the fullerene recognition capability of the system on demand and leading to the formation of effective metal-triggered ON/OFF molecular tweezers.

7.
rev. psicogente ; 23(44): 93-112, jul.-dic. 2020. tab
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1361211

RESUMO

Resumen Objetivo: El Trastorno por Déficit de Atención con Hiperactividad/impulsividad (TDAH) es una de las dificultades de aprendizaje más comunes en las escuelas chilenas. Se caracteriza por un patrón de funcionamiento atípico en atención e inhibición, con fuerte compromiso de otras funciones ejecutivas. Uno de los desafíos que plantea este trastorno está referido al proceso de diagnosis, el cual no suele ser suficientemente preciso. Se pretende explorar las diferencias en la distribución de dos muestras de estudiantes con y sin TDAH diagnosticadas con una escala de observación conductual a través de la evaluación de las funciones ejecutivas de atención, inhibición y flexibilidad cognitiva. Método: En este estudio se evaluó a 132 escolares, 66 con TDAH y 66 sin TDAH, en las variables de atención, inhibición y flexibilidad cognitiva de un colegio de la ciudad de Concepción en Chile. Se contrastó el rendimiento cognitivo con los diagnósticos y se reagrupó a los estudiantes en los subtipos conocidos del trastorno. Resultados: La evaluación neuropsicológica mostró que en el grupo con TDAH había alumnos que no cumplían los criterios diagnósticos para estar incluidos en él. En el grupo sin TDAH se observó un fenómeno semejante. En ambos grupos la evaluación neuropsicológica de la atención y la inhibición resultaron útiles para diagnosticar con mayor certeza y para determinar el subtipo al que pertenecía cada estudiante con TDAH detectado. La flexibilidad cognitiva solo permitió diferenciar a los sujetos con y sin TDAH. Conclusiones: En ambos grupos estudiados fue posible encontrar sujetos mal diagnosticados; el sobrediagnóstico fue de 43,93 % en el grupo con TDAH, mientras que el infradiagnóstico fue de 42,42 % en el grupo sin TDAH.


Abstract Objective: Attention Deficit Hyperactivity/Impulsivity Disorder (ADHD) is one of the most common learning difficulties in Chilean schools. It is characterized by an atypical functioning pattern in attention and inhibition, strongly compromising other executive functions. One of the challenges posed by this disorder is the diagnosis process, which is often not sufficiently accurate. The intention is to study the distribution of two students samples, with and without ADHD, diagnosed by a behavioral observation scale through the evaluation of attention, inhibition, and cognitive flexibility executive functions. Method: This study evaluated 132 students, 66 with ADHD and 66 without ADHD, considering the attention, inhibition, and cognitive flexibility variables of a school in the city of Concepción in Chile. Cognitive performance was contrasted with the diagnoses, and students were regrouped in the disorder known subtypes. Results: The neuropsychological evaluation showed that in the ADHD group, there were students who did not meet the diagnostic criteria to be included in the group. A similar phenomenon was observed in the group without ADHD. In both the groups, the neuropsychological evaluation of attention and inhibition was useful in providing a more certain dignosis and in determining the subtype to which each student detected with ADHD belonged. Cognitive flexibility was only useful in differentiating betwen the subjects with and without ADHD. Conclusions: In both the groups studied, it was possible to find misdiagnosed subjects; the overdiagnosis was 43,93 % in the ADHD group, while the under-diagnosis was 42,42 % in the group without ADHD.

8.
Sci Rep ; 10(1): 13335, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770035

RESUMO

Rapid Prototyping (RP) promises to induce a revolutionary impact on how the objects can be produced and used in industrial manufacturing as well as in everyday life. Over the time a standard technique as the 3D Stereolithography (SL) has become a fundamental technology for RP and Additive Manufacturing (AM), since it enables the fabrication of the 3D objects from a cost-effective photocurable resin. Efforts to obtain devices more complex than just a mere aesthetic simulacre, have been spent with uncertain results. The multidisciplinary nature of such manufacturing technique furtherly hinders the route to the fabrication of complex devices. A good knowledge of the bases of material science and engineering is required to deal with SL technological, characterization and testing aspects. In this framework, our study aims to reveal a new approach to obtain RP of complex devices, namely Organic Electro-Chemical Transistors (OECTs), by SL technique exploiting a resin composite based on the conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and the photo curable Poly(ethylene glycol) diacrylate (PEGDA). A comprehensive study is presented, starting from the optimization of composite resin and characterization of its electrochemical properties, up to the 3D OECTs printing and testing. Relevant performances in biosensing for dopamine (DA) detection using the 3D OECTs are reported and discussed too.

9.
J Sci Food Agric ; 100(10): 3971-3978, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32333388

RESUMO

BACKGROUND: Nowadays, low alcohol and non-alcohol beer intake has increased due to expanding concerns about healthy diets. However, there are still appreciable differences between non-alcoholic beer and conventional beer, particularly regarding flavor. Vacuum distillation is commonly used to remove ethanol from the beer in industrial processes and it is used here. RESULTS: The presence of n-propanol, isobutanol, 3-methylbutanol, 2-methylbutanol, 2-phenylethanol, ethyl acetate, isoamyl acetate, and acetaldehyde, which are key compounds responsible for aroma and flavor of beer, have been analyzed using nuclear magnetic resonance (NMR) spectroscopy in commercial beers and also in the corresponding distillates and residual phases after dealcoholization. CONCLUSION: The compounds present in each phase were identified by monodimensional and bidimensional NMR spectra. The compounds that are completely removed or that remain in the residue of the conventional beers studied are described in detail. The presence of these compounds in dealcoholized beer would be beneficial in keeping the aroma and flavor in dealcoholized beer. © 2020 Society of Chemical Industry.


Assuntos
Cerveja/análise , Aromatizantes/análise , Espectroscopia de Ressonância Magnética/métodos , Destilação/instrumentação , Destilação/métodos , Etanol/análise , Humanos , Odorantes/análise , Paladar , Vácuo
10.
J Org Chem ; 85(7): 4918-4926, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32153183

RESUMO

An octapodal corannulene-based supramolecular system has been prepared by introducing eight corannulene moieties in a porphyrin scaffold. Despite the potential of this double picket fence porphyrin for double-tweezer behavior, NMR titrations show exclusive formation of 1:1 adducts. The system exhibits very strong affinity for C60 and C70 (K1 = (2.71 ± 0.08) × 104 and (2.13 ± 0.1) × 105 M-1, respectively), presenting selectivity for the latter. Density functional theory (DFT) calculations indicate that, in addition to the four corannulene units, the relatively flexible porphyrin tether actively participates in the recognition process, resulting in a strong synergistic effect. This leads to a very strong interaction with C60, which in turn also induces a large structural change on the other face (second potential binding site), leading to a negative allosteric effect. We also introduced Zn2+ in the porphyrin core in an attempt to modulate its flexibility. The resulting metalloporphyrin also displayed single-tweezer behavior, albeit with slightly smaller binding constants for C60 and C70, suggesting that the effect of the coordination of fullerene to one face of our supramolecular platform was still transmitted to the other face, leading to the deactivation of the second potential binding site.

11.
RSC Adv ; 10(59): 36164-36173, 2020 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-35517082

RESUMO

In this work, we report a two-step synthesis that allows the introduction of four pyrene or corannulene fragments at the para position of meso-tetraarylporphyrins using a microwave-assisted quadruple Suzuki-Miyaura reaction. Placing the PAHs at this position, further from the porphyrin core, avoids the participation of the porphyrin core in binding with fullerenes. The fullerene hosting ability of the four new molecular receptors was investigated by NMR titrations and DFT studies. Despite having two potential binding sites, the pyrene derivatives did not associate with C60 or C70. In contrast, the tetracorannulene derivatives bound C60 and C70, although with modest binding constants. In these novel para-substituted systems, the porphyrin core acts as a simple linker that does not participate in the binding process, which allows the system to be considered as two independent molecular tweezers; i.e., the first binding event is not transmitted to the second binding site. This behavior can be considered a direct consequence of the decoupling of the porphyrin core from the binding event.

12.
Org Lett ; 21(15): 5803-5807, 2019 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-31241968

RESUMO

We report the use of a tetraborylated perylenediimide as starting material for the preparation of a tetracorannulene-perylenediimide that is able to bind up to two fullerene-C60 molecules by host-guest molecular recognition with preference over C70. Titration with fullerene-C60 is followed by a dramatic shift of the aromatic signals in 1H NMR and an initial increase in the fluorescence of the system. By this simple mechanism, fluorogenic sensing of fullerene-C60 is easily accomplished by an unprecedented fluorescent turn-on mechanism.

13.
Polymers (Basel) ; 11(2)2019 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-30960275

RESUMO

Stereolithography 3D printing is today recognized as an effective rapid prototyping technique in the field of polymeric materials, which represents both the strengths and the weaknesses of this technique. The strengths relate to their easy handling and the low energy required for processing, which allow for the production of structures down to the sub-micrometric scale. The weaknesses are a result of the relatively poor mechanical properties. Unfortunately, the choice of the right material is not sufficient, as the printing parameters also play a crucial role. For this reason, it is important to deepen and clarify the effect of different printing conditions on final product characteristics. In this paper, the behavior of commercial Standard Blend (ST Blend) acrylic resin printed with stereolithography (SL) apparatus is reported, investigating the influence of printing parameters on both the tensile properties of the printed parts and the build accuracy. Twenty-four samples were printed under different printing conditions, then dimensional analyses and tensile tests were performed. It was possible to find out the optimum printing setup to obtain the best result in terms of mechanical resistance and printing accuracy for this kind of resin. Finally, a micrometric spring was printed under the optimal conditions to demonstrate the possibility of printing accurate and tiny parts with the commercial and inexpensive STBlend resin.

14.
J Org Chem ; 84(10): 6183-6190, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-30993988

RESUMO

The incorporation of eight pyrene units in a single porphyrin core exhibits a great synergistic effect, resulting in high affinity toward C60 and C70. This octapyrene porphyrin is easily accessible by a straightforward two-step synthetic approach that involves an octuple Suzuki reaction. The new supramolecular platform can present single- or double-tweezer fullerene hosting behavior. The switch from double- to single-tweezer behavior is triggered by the simple coordination of Zn2+ to the porphyrin. Both the octapyrene porphyrin 2HPOP and its zinc metalloporphyrin analogue ZnPOP show very high affinity for C60 and C70, while simultaneously allowing the discrimination of C70 over C60 in a C60/C70 mixture. The use of 2HPOP and ZnPOP for the enrichment of real fullerene mixtures is also demonstrated.

15.
Rev. chil. neuropsicol. (En línea) ; 13(2): 58-62, dic. 2018. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1100358

RESUMO

El trastorno de Tourette (TT) es un trastorno del neurodesarrollo que aparece en la primera infancia caracterizado por la presencia de tics fónicos y motores que dificultan la socialización y el proceso de aprendizaje escolar. El TT posee una variada comorbilidad que incluye el trastorno por déficit de atención con hiperactividad (TDAH), el trastorno obsesivo compulsivo (TOC), y dificultades de aprendizaje y del comportamiento. Presentamos el caso de un adolescente de 13 años diagnosticado con TT y con TDAH a los 6 y 10 años respectivamente. El paciente ha tenido una escolarización dificultosa y se encuentra con tratamiento médico de clozapina, aripiprazol, haloperidol y litio. Se aplica una batería neuropsicológica para evaluar la atención e inhibición, organización visuoespacial, memoria de trabajo, flexibilidad cognitiva, memoria verbal y memoria no-verbal, con el propósito de describir su perfil cognitivo de funciones ejecutivas y memoria. El estudio reveló que la atención está deteriorada pero que la inhibición se encuentra preservada; esto confirma el diagnóstico de TDAH y establece el subtipo de inatento para el caso en estudio. Las demás funciones ejecutivas evaluadas se encuentran severamente descendidas, situación que es coincidente con el perfil desarrollado por otros autores para el TT con comorbilidad TDAH. Sin embargo, no es claro si la disfuncionalidad ejecutiva se debe al TDAH que presenta, o a factores sociales y culturales derivados de las dificultades de escolarización causadas por el TT.


Tourette's disorder (TD) is a neurodevelopmental disorder that appears in early childhood characterized by the presence of phonic and motor tics that hinder socialization and the school learning process. TD has a varied comorbidity that includes attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), learning and behavioral difficulties. We present the case of a 13-year-old adolescent diagnosed with TD and with ADHD at 6 and 10 years old respectively. The patient has had a difficult schooling and is under medical treatment of clozapine, aripiprazole, haloperidol and lithium. A neuropsychological battery is applied to evaluate the attention and inhibition, visuospatial organization, working memory, cognitive flexibility, verbal memory and non-verbal memory, with the purpose of describing its cognitive profile of executive functions and memory. The study revealed that the attention is impaired but that the inhibition is preserved; This confirms the diagnosis of ADHD and establishes the inattentive subtype for the case under study. The other executive functions evaluated are severely descended, a situation that coincides with the profile developed by other authors for TD with comorbid ADHD. However, it is not clear if the executive dysfunctionality is due to the ADHD it presents, or to social and cultural factors derived from the difficulties of schooling caused by the TD.


Assuntos
Humanos , Masculino , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Síndrome de Tourette/fisiopatologia , Atenção , Transtorno do Deficit de Atenção com Hiperatividade/complicações , Síndrome de Tourette/complicações , Função Executiva/fisiologia , Inibição Psicológica , Deficiências da Aprendizagem/fisiopatologia , Memória de Curto Prazo/fisiologia
16.
Nanotechnology ; 28(17): 174002, 2017 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-28282299

RESUMO

In certain polymers the graphenization of carbon atoms can be obtained by laser writing owing to the easy absorption of long-wavelength radiation, which generates photo-thermal effects. On a polyimide surface this process allows the formation of a nanostructured and porous carbon network known as laser-induced graphene (LIG). Herein we report on the effect of the process parameters on the morphology and physical properties of LIG nanostructures. We show that the scan speed and the frequency of the incident radiation affect the gas evolution, inducing different structure rearrangements, an interesting nitrogen self-doping phenomenon and consequently different conduction properties. The materials were characterized by infrared and Raman spectroscopy, XPS elemental analysis, electron microscopy and electrical/electrochemical measurements. In particular the samples were tested as interdigitated electrodes into electrochemical supercapacitors and the optimized LIG arrangement was tested in parallel and series supercapacitor configurations to allow power exploitation.

17.
Chem Commun (Camb) ; 52(88): 12964-12967, 2016 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-27722426

RESUMO

Six azobenzene derivatives bearing polyaromatic fragments have been prepared and their reversible photoisomerization has been assessed. Corannulene-functionalized molecules have demonstrated excellent switchable hosting abilities towards fullerenes in which an interesting range of affinities has been found. The success of this design relies upon the reversible formation and destruction of tweezer-like structures.

18.
J Vis Exp ; (115)2016 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-27685440

RESUMO

The main purpose of this video is to show 6 reaction steps of a convergent synthesis and prepare a complex molecule containing up to three nonplanar polyaromatic units, which are two corannulene moieties and a racemic hexahelicene linking them. The compound described in this work is a good host for fullerenes. Several common organic reactions, such as free-radical reactions, C-C coupling or click chemistry, are employed demonstrating the versatility of functionalization that this compound can accept. All of these reactions work for planar aromatic molecules. With subtle modifications, it is possible to achieve similar results for nonplanar polyaromatic compounds.


Assuntos
Alcinos/química , Azidas/química , Hidrocarbonetos Policíclicos Aromáticos/síntese química , Compostos Policíclicos/síntese química , Catálise , Química Click , Cobre/química , Reação de Cicloadição , Hidrocarbonetos Policíclicos Aromáticos/química , Compostos Policíclicos/química
19.
J Org Chem ; 81(14): 6081-6, 2016 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-27309203

RESUMO

Symmetric meso-tetraarylporphyrins bearing phenanthrene, pyrene, and corannulene moieties in meta positions have been synthesized in a straightforward procedure under microwave irradiation by quadruple Suzuki-Miyaura reactions. Their (1)H NMR spectra showed the typical pattern of four atropisomers distributed according to their statistical ratio not properly separable due to their fast isomerization. Their ability to bind buckminsterfullerene has been tested with the whole mixture, and different behaviors have been found, α4 isomer corannulene-substituted porphyrins being the best hosts in the family.

20.
ACS Appl Mater Interfaces ; 8(16): 10459-65, 2016 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-27035410

RESUMO

Herein, we are reporting a rapid one-pot synthesis of MoS2-decorated laser-induced graphene (MoS2-LIG) by direct writing of polyimide foils. By covering the polymer surface with a layer of MoS2 dispersion before processing, it is possible to obtain an in situ decoration of a porous graphene network during laser writing. The resulting material is a three-dimensional arrangement of agglomerated and wrinkled graphene flakes decorated by MoS2 nanosheets with good electrical properties and high surface area, suitable to be employed as electrodes for supercapacitors, enabling both electric double-layer and pseudo-capacitance behaviors. A deep investigation of the material properties has been performed to understand the chemical and physical characteristics of the hybrid MoS2-graphene-like material. Symmetric supercapacitors have been assembled in planar configuration exploiting the polymeric electrolyte; the resulting performances of the here-proposed material allow the prediction of the enormous potentialities of these flexible energy-storage devices for industrial-scale production.

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