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1.
Chem Asian J ; 18(22): e202300654, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37818755

RESUMO

Two Zn(II)-based compounds, [Zn2 L1 (OAc)3 (MeOH)] (1) and [Zn2 L2 (OAc)3 ]n (2), have been reported where HL1 is (E)-4-bromo-2-methoxy-6-(((2-morpholino ethyl)imino) methyl)phenol and HL2 is (E)-4-bromo-2-methoxy-6-(((2-(piperazine-1-yle)ethyl)imino)methyl) phenol. Single-crystal X-ray diffraction (SCXRD) analysis unveils vivid change in structural arrangements and dimensionality from 1 to 2 due to change in coordinated atom from oxygen to nitrogen of the ligands. SCXRD study shows that compound 1 is dinuclear but compound 2 has a 1-dimensional polymeric structure having helical chain. Structural diversity greatly influences the catalytic activity. Compound 1 acts as excellent catalyst for conversion of 3, 5-di-tert-butyl catechol (3, 5-DTBC) to 3, 5-di-tert-butylbenzoquinone (3, 5-DTBQ) with the turnover number (kcat ) value of 34.94 sec-1 . Further, compound 1 reveals phosphatase like activity for conversion of disodium salt of (4-nitrophenyl)-phosphate hexahydrate to p-nitrophenolate with the kcat value of 24.64 sec-1 . Interestingly, compound 2 does not show any catalytic activity. To correlate this distinctly different catalytic behavior of two compounds, DFT calculation was carried out. The calculation reveals that detachment of coordinated methanol from coordination sphere of zinc in compound 1 is energetically favourable which creates room for substrate binding, resulting in high catalytic activity. By contrast, in compound 2, detachment of piperazine or Zn-O of -COOH group is energetically unfavourable, resulting in no catalytic activity.

2.
Front Plant Sci ; 14: 1239594, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37674739

RESUMO

The Internet of Things (IOT)-based smart farming promises ultrafast speeds and near real-time response. Precision farming enabled by the Internet of Things has the potential to boost efficiency and output while reducing water use. Therefore, IoT devices can aid farmers in keeping track crop health and development while also automating a variety of tasks (such as moisture level prediction, irrigation system, crop development, and nutrient levels). The IoT-based autonomous irrigation technique makes exact use of farmers' time, money, and power. High crop yields can be achieved through consistent monitoring and sensing of crops utilizing a variety of IoT sensors to inform farmers of optimal harvest times. In this paper, a smart framework for growing tomatoes is developed, with influence from IoT devices or modules. With the help of IoT modules, we can forecast soil moisture levels and fine-tune the watering schedule. To further aid farmers, a smartphone app is currently in development that will provide them with crucial data on the health of their tomato crops. Large-scale experiments validate the proposed model's ability to intelligently monitor the irrigation system, which contributes to higher tomato yields.

3.
J Proteome Res ; 22(4): 1043-1055, 2023 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-36317652

RESUMO

Post-translational modifications (PTMs) are one of the compulsive and predominant biological processes that regulate the diverse molecular mechanism, modulate the onset of disease, and are the reason behind the functional diversity of proteins. Despite the widespread research findings in neuroproteomics, one of the key drawbacks has been the lack of proteome-level knowledge of hemispheric lateralization. We have investigated the proteome level expression in different neuroanatomical regions under the Human Brain Proteome Project (HBPP) and developed the global interhemispheric brain proteome map (Brainprot) earlier. Furthermore, this study has extended to decipher the phosphoproteome map of human brain interhemispheric regions through high-resolution mass spectrometry. The phosphoproteomics examination of 12 unique interhemispheric neurological brain regions using Orbitrap fusion liquid chromatography with tandem mass spectrometry provided comprehensive coverage of 996 phosphoproteins, 2010 phosphopeptides, and 3567 phosphosites. Moreover, interhemispheric phosphoproteome profiling has been categorized according to synaptic ontologies and interhemispheric expression to understand the functionality. Finally, we have integrated the phosphosites data under the PhosphoMap section in the Inter-Hemispheric Brain Proteome Map Portal (https://www.brainprot.org/) for the advancement and support of the ongoing neuroproteomics research worldwide. Data is available via ProteomeXchange with the identifier PXD031188.


Assuntos
Proteoma , Espectrometria de Massas em Tandem , Humanos , Proteoma/genética , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida/métodos , Processamento de Proteína Pós-Traducional , Encéfalo/metabolismo , Fosfoproteínas/metabolismo , Fosfopeptídeos/análise
4.
ACS Appl Mater Interfaces ; 15(21): 25173-25183, 2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-36449661

RESUMO

There has been a widespread interest in developing self-assembled porphyrin nanostructures to mimic nature's light-harvesting processes. Herein, porphyrin-based coordination polymer gel (CPG) has been developed as a "soft" photocatalyst material for hydrogen (H2) production from water under visible light. The CPG offers a hierarchical nanofibrous network structure obtained through self-assembly of a terpyridine alkyl-amide appended porphyrin (TPY-POR)-based low molecular weight gelator with ruthenium ions (RuII) and produces H2 with a rate of 5.7 mmol g-1 h-1 in the presence of triethylamine (TEA) as a sacrificial electron donor. Further, the [Fe2(bdt)(CO)6] (dbt = 1,2-benzenedithiol) cocatalyst, which can mimic the activity of iron hydrogenase, is coassembled in the CPG and shows remarkable improvement in H2 evolution (catalytic activity; rate ∼10.6 mmol g-1 h-1 and turnover number ∼1287). The significant enhancement in catalytic activity was supported by several controlled experiments, including femtosecond transient absorption (TA) spectroscopy and also DFT calculation. The TA study supported the cascade electron transfer process from porphyrin core to [Ru(TPY)2]2+ center, and subsequently, the electron transfers to the cocatalyst [Fe2(bdt)(CO)6] for H2 production.

5.
J Healthc Eng ; 2022: 7351061, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35265303

RESUMO

At present, a multifaceted clinical disease known as heart failure disease can affect a greater number of people in the world. In the early stages, to evaluate and diagnose the disease of heart failure, cardiac centers and hospitals are heavily based on ECG. The ECG can be considered as a regular tool. Heart disease early detection is a critical concern in healthcare services (HCS). This paper presents the different machine learning technologies based on heart disease detection brief analysis. Firstly, Naïve Bayes with a weighted approach is used for predicting heart disease. The second one, according to the features of frequency domain, time domain, and information theory, is automatic and analyze ischemic heart disease localization/detection. Two classifiers such as support vector machine (SVM) with XGBoost with the best performance are selected for the classification in this method. The third one is the heart failure automatic identification method by using an improved SVM based on the duality optimization scheme also analyzed. Finally, for a clinical decision support system (CDSS), an effective heart disease prediction model (HDPM) is used, which includes density-based spatial clustering of applications with noise (DBSCAN) for outlier detection and elimination, a hybrid synthetic minority over-sampling technique-edited nearest neighbor (SMOTE-ENN) for balancing the training data distribution, and XGBoost for heart disease prediction. Machine learning can be applied in the medical industry for disease diagnosis, detection, and prediction. The major purpose of this paper is to give clinicians a tool to help them diagnose heart problems early on. As a result, it will be easier to treat patients effectively and avoid serious repercussions. This study uses XGBoost to test alternative decision tree classification algorithms in the hopes of improving the accuracy of heart disease diagnosis. In terms of precision, accuracy, f1-measure, and recall as performance parameters above mentioned, four types of machine learning (ML) models are compared.


Assuntos
Insuficiência Cardíaca , Isquemia Miocárdica , Algoritmos , Teorema de Bayes , Insuficiência Cardíaca/diagnóstico , Humanos , Aprendizado de Máquina , Máquina de Vetores de Suporte , Tecnologia
6.
Math Biosci Eng ; 19(4): 3701-3719, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35341270

RESUMO

Source code is the heart of the software systems; it holds a wealth of knowledge that can be tapped for intelligent software systems and leverage the possibilities of reuse of the software. In this work, exploration revolves around making use of the pattern hidden in various software development processes and artifacts. This module is part of the smart requirements management system that is intended to be built. This system will have multiple modules to make the software requirements management phase more secure from vulnerabilities. Some of the critical challenges bothering the software development community are discussed. The background of Machine Learning approaches and their application in software development practices are explored. Some of the work done around modeling the source code and approaches used for vulnerabilities understanding in software systems are reviewed. Program representation is explored to understand some of the principles that would help in understanding the subject well. Further deeper dive into source code modeling possibilities are explored. Machine learning best practices are explored inline with the software source code modeling.


Assuntos
Aprendizado de Máquina , Software
7.
Angew Chem Int Ed Engl ; 61(16): e202116094, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35129254

RESUMO

The self-assembly of a well-defined and astutely designed, low-molecular weight gelator (LMWG) based linker with a suitable metal ion is a promising method for preparing photocatalytically active coordination polymer gels. Here, we report the design, synthesis, and gelation behaviour of a tetrapodal LMWG based on a porphyrin core connected to four terpyridine units (TPY-POR) through amide linkages. The self-assembly of TPY-POR LMWG with RuII ions results in a Ru-TPY-POR coordination polymer gel (CPG), with a nanoscroll morphology. Ru-TPY-POR CPG exhibits efficient CO2 photoreduction to CO (3.5 mmol g-1 h-1 ) with >99 % selectivity in the presence of triethylamine (TEA) as a sacrificial electron donor. Interestingly, in the presence of 1-benzyl-1,4-dihydronicotinamide (BNAH) with TEA as the sacrificial electron donor, the 8e- /8H+ photoreduction of CO2 to CH4 is realized with >95 % selectivity (6.7 mmol g-1 h-1 ). In CPG, porphyrin acts as a photosensitizer and covalently attached [Ru(TPY)2 ]2+ acts as a catalytic center as demonstrated by femtosecond transient absorption (TA) spectroscopy. Further, combining information from the in situ DRIFT spectroscopy and DFT calculation, a possible reaction mechanism for CO2 reduction to CO and CH4 was outlined.

8.
J Healthc Eng ; 2021: 9806011, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34858565

RESUMO

One of the most important and difficult research fields is newborn jaundice grading. The mitotic count is an important component in determining the severity of newborn jaundice. The use of principal component analysis (PCA) feature selection and an optimal tree strategy classifier to produce automatic mitotic detection in histopathology images and grading is given. This study makes use of real-time and benchmark datasets, as well as specific approaches for detecting jaundice in newborn newborns. According to research, the quality of the feature may have a negative impact on categorization performance. Additionally, compressing the classification method for exclusive main properties can result in a classification performance bottleneck. As a result, identifying appropriate characteristics for training the classifier is required. By combining a feature selection method with a classification model, this is possible. The major outcomes of this study revealed that image processing techniques are critical for predicting neonatal hyperbilirubinemia. Image processing is a method of translating analogue images to digital formats and manipulating them. The primary goal of medical image processing is to collect information useful for disease detection, diagnosis, monitoring, and therapy. Image datasets can be used to validate the performance of newborn jaundice detection. When compared to conventional approaches, it offers results that are accurate, quick, and time efficient. Accuracy, sensitivity, and specificity, which are common performance indicators, were also predictive.


Assuntos
Processamento de Imagem Assistida por Computador , Icterícia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Lactente , Recém-Nascido , Análise de Componente Principal
9.
Dalton Trans ; 50(38): 13374-13386, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34473159

RESUMO

A new "end-off" compartmental Mannich ligand (HL1) namely 3-((bis(2-methoxyethyl)amino)methyl)-5-bromo-2-hydroxybenzaldehyde containing two methoxyethyl pendant arms and one-CHO functionality has been synthesized through conventional C-C and C-N coupling reactions. On treatment with Cu(ClO4)2, HL1 yields a dinuclear µ-phenolatocopper(II) complex having the molecular formula [Cu2(L1)2](ClO4)2(H2O)1.5 (1). Surprisingly, the ligand HL1 is radically transformed into a new asymmetric Schiff-Mannich base ligand (HLF) in the presence of NaN3 and Cu(ClO4)2 forming a unique dinuclear centro-symmetric Cu(II) complex [Cu(LF)]2 (2) as evident from single-crystal X-ray diffraction (SCXRD) analysis. A probable mechanistic rationalization has been proposed on the basis of theoretical calculations, which suggests systematic fragmentation of HL1 in the presence of azide residue and re-condensation of the fragmented units to yield the final Cu-HLF complex (2). SCXRD analysis portrays a large inter-metallic distance in complex 2 in comparison with complex 1 (5.493 vs. 2.989 Å, respectively) along with other distinct structural features. After physicochemical characterization both the complexes have been exploited to evaluate their possible anticancer proficiency on lung adenocarcinoma cell line (A549). Complex 1 distinctly impeded the proliferation of lung adenocarcinoma cells in a dose-dependent manner more efficiently than complex 2. Due to the behavior of complex 1 as potential therapeutics, cellular transformations of A549 cells have been systematically investigated. As evidenced from various in vitro experiments, the cell death mechanism triggered by complex 1 turned out to be apoptosis, as indicated by the DNA fragmentation, chromatin condensation, membrane blebbing and imbalanced cell cycle distribution as well as retard migration in A549 cells.


Assuntos
Antineoplásicos/química , Azidas/química , Complexos de Coordenação/química , Cobre/química , Bases de Mannich/química , Bases de Schiff/química , Células A549 , Antineoplásicos/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , Humanos , Ligantes , Conformação Molecular
10.
Nanomedicine (Lond) ; 16(12): 1035-1047, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33970689

RESUMO

Aim: Further to our reports on chip-integrable uncooled terahertz microbolometer arrays, compatible with medium-scale semiconductor device fabrication processes, the possibility of the development of chip-integrable medical device is proposed here. Methods: The concept of graphene-based nanopatch antennas with design optimization by the finite element method (FEM) is explored. The high-frequency structure simulator (HFSS) utilized fine FEM solver for analyzing empirical mode decomposition preprocessing and for modeling and simulating graphene antennas. Results: Graphene nanopatch antennas exhibited tunable features with varying patch dimensions and dependence on substrate material permittivity. Conclusion: This work implements reconfigurable graphene nanopatch antenna compatible with terahertz microbolometer arrays. This design concept further develops on-chip medical devices for possible screening of cancer cell with terahertz image processing.


Assuntos
Grafite , Neoplasias , Diagnóstico por Imagem , Neoplasias/diagnóstico por imagem
11.
Comput Intell Neurosci ; 2021: 8522839, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34987569

RESUMO

Security of the software system is a prime focus area for software development teams. This paper explores some data science methods to build a knowledge management system that can assist the software development team to ensure a secure software system is being developed. Various approaches in this context are explored using data of insurance domain-based software development. These approaches will facilitate an easy understanding of the practical challenges associated with actual-world implementation. This paper also discusses the capabilities of language modeling and its role in the knowledge system. The source code is modeled to build a deep software security analysis model. The proposed model can help software engineers build secure software by assessing the software security during software development time. Extensive experiments show that the proposed models can efficiently explore the software language modeling capabilities to classify software systems' security vulnerabilities.


Assuntos
Idioma , Software , Segurança Computacional
12.
Dalton Trans ; 49(43): 15461-15472, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33141130

RESUMO

Three copper(ii) complexes, [Cu(L1)(NCS)]n (1), [Cu(L1)(N3)]n (2) and [Cu(L2)(N3)] (3) were synthesized from one Schiff base ligand and one reduced Schiff base ligand, (E)-4-chloro-2-[(2-propylaminoethylimino)methyl]phenol (HL1) and 4-chloro-2-[(2-(propylaminoethylamino) methyl]phenol (HL2), respectively. All complexes were characterized by various physicochemical studies, such as FT-IR, UV-Vis, ESI-MS, EPR and single crystal X-ray diffraction. Complexes 1 and 2 have 1D polymeric chain-like structures bridging through thiocyanate and azide anions, whereas complex 3 has a mononuclear structure in the solid state. All the complexes are active towards mimicking two well-known proteins, phosphatase and phenoxazinone synthase, using the disodium salt of 4-nitrophenylphosphate (4-NPP) and 2-aminophenol (OAP) as the substrate in DMF medium. Complexes 2 and 3 show the highest activity towards phosphatase and phenoxazinone synthase activity with kcat values of 22.6 s-1 and 134.4 h-1, respectively. EPR studies confirmed that for complex 1, the OAP oxidation goes through the generation of an organic radical at g = 1.99, which is due to an imine radical formation, whereas the metal center redox pathway is followed for complex 3. Extensive DFT calculations have been performed for both catalytic studies to put forward the most probable mechanistic pathways.


Assuntos
Materiais Biomiméticos/química , Materiais Biomiméticos/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Cobre/química , Teoria da Densidade Funcional , Catálise , Técnicas de Química Sintética , Modelos Moleculares , Conformação Molecular , Bases de Schiff/química
13.
Angew Chem Int Ed Engl ; 59(42): 18479-18484, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-32652809

RESUMO

We demonstrate a redox-active, crystalline donor-acceptor (D-A) assembly in which the electron transfer (ET) process can be reversibly switched. This ET process, induced by a guest-responsive structural transformation at room temperature, is realized in a porous, metal-organic framework (MOF), having anthracene (D)-naphthalenediimide (A) as struts. A control MOF structure obtained by a solvent-assisted linker exchange (SALE) method, replacing an acceptor strut with a neutral one, supported the switchable electronic states in the D-A MOF. Combined investigations with X-ray diffraction, spectroscopy, and theoretical analyses revealed the dynamic metal paddle-wheel node as a critical unit for controlling structural flexibility and the corresponding unprecedented ET process.

14.
Inorg Chem ; 59(13): 9014-9028, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32573221

RESUMO

The present work discloses the application of two fluorescent zinc and cadmium complexes (1 and 2) for sensing of Hg(II) ions through a chemodosimetric approach. The ligand under consideration in this work is a N2O donor Schiff base ligand (E)-4-bromo-2-(((2-morpholinoethyl)imino)methyl)phenol (HL), which has been harnessed to generate complexes [Zn3L2(OAc)4] (1) and [Cd3L2(OAc)4] (2). X-ray single crystal diffraction studies unveil the trinuclear skeleton of complexes 1 and 2. Both complexes have been found to be highly fluorescent in nature. However, the quantum efficiency of Zn(II) complex (1) dominates over the Cd(II) analogue (2). The absorption and emission spectroscopic properties of the complexes have been investigated by density functional theory. Complexes 1 and 2 can detect Hg2+ ions selectively by fluorescence quenching, and it is noteworthy to mention that the mechanism of sensing is unique as well as interesting. In the presence of Hg2+ ions, complexes 1 and 2 are transformed to mononuclear mercuric intermediate complex (3) and finally to a trinuclear mercuric complex (4) by hydrolysis. We have successfully trapped the intermediate complex 3, and we characterized it with the aid of X-ray crystallography. Transformation of complexes 1 and 2 to intermediate complex 3 and finally to 4 has been established by UV-vis spectroscopy, fluorescence spectroscopy, ESI-MS spectroscopy, 1H NMR spectroscopy, and X-ray crystallography. The spontaneity of the above conversion is well supported by thermodynamic aspects as reflected from density functional theoretical calculations.

15.
ACS Appl Mater Interfaces ; 12(18): 20991-20997, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32283917

RESUMO

Design and synthesis of solid-state photochromic materials remain a challenge because of high structural constrain. However, this can be mitigated in attaining structural flexibility by introducing permanent porosity into the system. Here, we report for the first time the design and synthesis of a photochromic conjugated microporous polymer (pcCMP) by assembling photochromic dithienylethene aldehyde and benzene-1,3,5-tricarbohydrazide. The yellow photo-isomer pcCMP-O gets converted to a deep-green photo-isomer pcCMP-C by UV-light irradiation, which can be reverted to pcCMP-O by visible light or thermal treatment. Owing to the thermo-irreversible nature, the pcCMP is found to be suitable for designing an INH functioning logic gate. pcCMP-C shows highly enhanced conductivity (92 times) because of enhanced conjugation compared to pcCMP-O. Furthermore, we demonstrate the bio-inspired photo-switchable pcFRET process by encapsulation of a red-emissive green fluorescent protein (gfp) chromophore analogue into the pcCMP. This material shows high processibility and has been exploited further for secret writing.


Assuntos
Proteínas de Fluorescência Verde/química , Lógica , Polímeros/química , Animais , Condutividade Elétrica , Transferência Ressonante de Energia de Fluorescência , Hidrozoários/química , Tinta , Isomerismo , Polímeros/síntese química , Polímeros/efeitos da radiação , Porosidade , Raios Ultravioleta
16.
Dalton Trans ; 49(18): 5999-6011, 2020 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-32314779

RESUMO

Three mononuclear and one hexanuclear manganese(iii) complexes, [Mn(L)(H2O)2]·Cl (1), [Mn(L)(H2O)2]·Br (2), [Mn(L)(H2O)2]·NO3 (3), and [Mn6(L)6(NCS)6] (4), have been synthesized using a Schiff-base ligand, namely (E)-2-((3-(2-hydroxyethylamino)propylimino)methyl)phenol (H2L), and structurally characterized by the usual physicochemical techniques such as UV-Vis, FT-IR, ESI-MS, EPR and single crystal XRD. The structure of complex 4 is unique among all four complexes as the sixth coordination position of manganese is fulfilled by the oxygen atom of a neighbouring unit by covalent interaction. The phenoxazinone synthase like activity of all four complexes has been thoroughly investigated using three different substrates, o-aminophenol (OAP), 2-amino-4-methylphenol (MAP) and 3-amino-4-hydroxybenzoic acid (CAP). All complexes were found to be active towards catalysis and complex 4 showed the highest activity. The EPR study reveals that the oxidative dimerization of the substrates occurred through metal centered redox participation rather than a radical formation pathway. The experimental observations have been supported by DFT calculations to put forward the most probable mechanistic pathways operating in the catalytic cycle. Moreover, Mn3O4 nanoparticles (NPs) having two different morphologies have been synthesized using complexes 1 and complex 4 simply by calcination, respectively, with the aim to prepare nanozymes. These two synthesized NPs were also able to show phenoxazinone synthase like activity and thus complexes 1 and 4 can be claimed as precursors of nanozymes.

17.
Dalton Trans ; 49(16): 5024-5028, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32215426

RESUMO

Ammonia borane with both hydridic and protic hydrogens in its structure acted as an efficient transfer hydrogenation agent for selective transformation of alkynes into alkenes in non-protic solvents. Catalytic synergy between the µ3-OH groups of the UiO-66(Hf) MOF and Pd active sites in Pd/UiO-66(Hf) furnished an elusive >98% styrene selectivity and full phenylacetylene conversion at room temperature. Such performance is not achievable by a Pd + UiO-66(Hf) physical mixture or by a commercial Pd/C catalyst.

18.
Chemistry ; 26(17): 3810-3817, 2020 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-31868270

RESUMO

The designing and development of heterogeneous catalysts for conversion of renewable energy to chemical energies by electrochemical as well as photochemical processes is at the forefront of energy research. In this work, two new donor-acceptor-based redox-active conjugated microporous polymers (CMPs) (TAPA-OPE-mix and TAPA-OPE-gly) are synthesized through Schiff base condensation reaction using a microwave synthesizer. Notably, the asymmetric and symmetric bola-amphiphilic nature of the OPE struts results in distinct nanostructuring and morphologies in the CMPs. Interestingly, both CMPs show impressive heterogeneous catalytic activity toward electrochemical O2 reduction and photocatalytic H2 evolution reactions, and therefore, act as bimodal electro- and photocatalytic porous organic materials. Furthermore, the redox-active property of the CMPs is exploited for in situ generation and stabilization of platinum nanoparticles (Pt), and these Pt@CMPs exhibit significantly enhanced photocatalytic activity.

19.
Dalton Trans ; 48(37): 14164-14177, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31506669

RESUMO

A series of tri-nuclear complexes of general formula [M3L2(OAc)4], where M = Mn (1), Co (2) and Ni (3), (HL = (E)-4-bromo-2-(((2-morpholinoethyl)imino)methyl)phenol), have been synthesized. Single crystal X-ray crystallography reveals that each molecule contains three metal ions which are bridged by four acetate moieties. In the solution phase, the complexes are present as mononuclear species. Amongst them, the manganese atom of complex 1 switches its oxidation state from +ii to +iii with time, as confirmed by time dependent UV-Vis and EPR spectroscopic techniques. Furthermore, complex 1 with Mn in both oxidation states can oxidise 3,5-DTBC to 3,5-DTBQ through the ligand centred radical formation pathway. It is remarkable that complex 1 in the MnII oxidation state shows an abnormally high rate constant value in the oxidation of 3,5-DTBC to 3,5-DTBQ. This difference in rate constant values for catechol oxidation reaction by complex 1 can be explained by considering the binding constant value of catechol with MnII and MnIII respectively from experimental and theoretical aspects. Similar to complex 1, complexes 2 and 3 also catalyse catechol oxidation following ligand centred imine radical formation pathways. Furthermore, magnetic properties of all the complexes were explored. DC magnetic susceptibility studies of complexes 1 and 2 revealed that in both the complexes the metal centres are antiferromagnetically coupled with adjacent metal centres, whereas in the case of complex 3, weak ferromagnetic interaction occurs between the neighbouring NiII centres at low temperature.

20.
J Org Chem ; 84(17): 10946-10952, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31401829

RESUMO

A novel π-chromophoric 1,4-bis(anthracenylethynyl)benzene (BAB)-based highly emissive J-aggregated organogel has been synthesized and characterized. Single-crystal structure determination of asymmetric π-chromophoric bola-amphiphilic BAB1 (dodecyl and triethyleneglycolmonomethylether containing side chains of bis(anthracenylethynyl)benzene) supports J-aggregation. Further, a photochromic acceptor chromophore, 4,4'-(perfluorocyclopent-1-ene-1,2-diyl)bis(5-methylthiophene-2-carbaldehyde), is noncovalently encapsulated in the gel and photoswitching studies have been performed based on photochromic Förster resonance energy transfer. The modulated emission of the processable soft material is further exploited for rewritable display. However, BAB2 (dodecyl side chain on both sides) does not show gelation property due to its low solubility.

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