Mario N Berberan Santos

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Verified

Mario N verified their affiliation via an institutional email.

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• Ph D
• Professor (Full) at University of Lisbon

A complete set of criteria for the classification, design and selection of optimal Thermally Activated Delayed Fluorescence (TADF) emitters, for both photoluminescence and electroluminescence applications, is presently unavailable. In this work, and as a contribution towards this aim, a detailed characterization of TADF photophysical kinetics is pr...

Phasor plots of the fluorescence intensity decay (plots of the Fourier sine transform vs. the Fourier cosine transform, for one or several angular frequencies) are being increasingly used in studies of homogeneous and heterogeneous systems. In this work, the phasor approach is applied to monomer-excimer kinetics. The results obtained allow a clear...

Luminescence decay functions describe the time dependence of the intensity of radiation emitted by electronically excited species. Decay phasor plots (plots of the Fourier sine transform vs. the Fourier cosine transform, for one or several angular frequencies) are being increasingly used in fluorescence, namely in lifetime imaging microscopy (FLIM)...

Fluorescence and phosphorescence are two forms of photoluminescence used in modern research and in practical applications. The early observations of these phenomena, before the emergence of quantum theory, highlight the investigation into the mechanism of light emission. In contrast to incandescence, photoluminescence does not require high temperat...

Light-based detectors have been widely used in fundamental research and industry since their inception in the 1930s. The energy particles deposit in these detectors is converted to optical signals via the Cherenkov and scintillation mechanisms that are then propagated through transparent media to photosensors placed typically on the detector's peri...

Organic Thermally Activated Delayed Fluorescence (TADF) molecules are luminescent compounds capable of harvesting energy from triplet states without using heavy metals. This process results in oxygen‐sensitive, long‐lived delayed emission, suitable for developing optical probes for time‐gated cell imaging, oxygen sensors, and singlet oxygen photose...

Due to their structural features, macrocyclic compounds such as calixarenes, conjugated with a variety of fluorophores have led to the development of fluorescent probes for numerous applications. This review covers the recent advances (from 2009 to date) made in calixarene-based fluorescent sensors and their biological applications. In addition to...

A comparative study of the photophysical properties of pristine C70 and two C70 derivatives, including their thermally activated delayed fluorescence (TADF) is reported. It is observed that the addition of a substituent group to the C70 cage-like structure changes both the radiative and the nonradiative rate constants, the change being more pron...

In the original publication [...]

A simple method for obtaining triplet-triplet absorption (TTA) spectra and triplet state (T1) lifetimes of long-lived triplets is presented and demonstrated with the polycyclic aromatic hydrocarbon coronene (both normal and perdeuterated forms) in a polymer matrix at room temperature. The TTA spectra obtained with a camera flash and a spectropho...

“A fundamental… issue is the relationship between [carbon dots’] morphological characteristics in the solid state and their photoluminescence both in the solid state and in solution.” This and more about the story behind the front cover can be found in the article at 10.1002/chem.202302955). image

A model for the morphology (size, shape, and crystallinity) of carbon dots (CDs) in the solid state consistent with the observed photoluminescence in solution is proposed herein. Overwhelming evidence has been collected that links the data coming from solid‐state analysis (high‐resolution transmission electron microscopy (HRTEM), atomic force micro...

This review covers recent advances (from 2006 to date) in supramolecular systems based on fluorescent homooxacalixarenes, namely hexahomotrioxacalix[3]arenes, dihomooxacalix[4]arenes and tetrahomodioxacalix[4]arenes, focusing on fluorescence sensing using their intrinsic fluorescence (built-in mesitol-like groups) or the extrinsic fluorescence of o...

Phobos, a satellite of Mars, was successfully studied by flyby, orbiter, and landing missions to the Red Planet, but several questions remain about its origin, composition, and relationship to Mars. It is suggested that Phobos is either a captured body from the asteroid belt or the outer Solar System (capture scenario), or a consequence of re-accre...

The binding behaviour of two ureido-hexahomotrioxacalix[3]arene derivatives bearing naphthyl (1) and pyrenyl (2) fluorogenic units at the lower rim towards selected nitroaromatic compounds (NACs) was evaluated. Their affinity, or lack of it, was determined by UV-Vis absorption, fluorescence and NMR spectroscopy. Different computational methods were...

Azo dyes are widely spread in our day life, being heavily used in cosmetics, healthcare products, textile industries, and as artificial food colorants. This intense industrial activity, which inherently includes their own production, inexorably leads to uncontrolled release of dyes into the environment. As emerging pollutants, their detection, part...

Carbon nanomaterials endowed with significant luminescence have been synthesized for the first time from an abundant, highly localized waste, the wet pomace (WP), a semi-solid by-product of industrial olive oil production. Synthetic efforts were undertaken to outshine the photoluminescence (PL) of carbon nanoparticles through a systematic search of...

In this work, the oxygen transport and hydrodynamic flow of the PBS Vertical-Wheel MINI™ 0.1 bioreactor were characterized using experimental data and computational fluid dynamics simulations. Data acquired from spectroscopy-based oxygenation measurements was compared with data obtained from 3D simulations with a rigid-lid approximation and LES-WAL...

Fluorescent receptors (4a–4c) based on (thio)ureido-functionalized hexahomotrioxacalix[3]arenes were synthesised and obtained in the partial cone conformation in solution. Naphthyl or pyrenyl fluorogenic units were introduced at the lower rim of the calixarene skeleton via a butyl spacer. The binding of biologically and environmentally relevant ani...

The photoluminescence (PL) of powders consisting of N,N′-(N,N′-dimethylethyleneamine-N″-allyl) – 1,4,5,8-naphthaldiimide (ANDI) and polystyrene (PS) was studied as they are simply ground together and as repetitive units of copolymers. Reflectance absorption spectra showed typical solid-state ANDI CT-band from 430 nm until 600 nm by both the mixture...

Direct O-alkylation of p-tert-butyldihomooxacalix[4]arene (1) with N-(bromopropyl)- or N-(bromoethyl)phthalimides and K2CO3 in acetonitrile was conducted under conventional heating (reflux) and using microwave irradiation and ball milling methodologies. The reactions afforded mono- and mainly distal di-substituted derivatives in the cone conformati...

Fluorescent dihomooxacalix[4]arene-based receptors 5a–5c, bearing two naphthyl(thio)ureido groups at the lower rim via a butyl spacer, were synthesised and obtained in the cone conformation in solution. The X-ray crystal structures of 1,3- (5a) and 3,4-dinaphthylurea (5b) derivatives are reported. Their binding properties towards several anions of...

In this work, some new exact and approximate analytical solutions are obtained for the SIR epidemic model, which is formulated in terms of dimensionless variables and parameters. The susceptibles population (S) is in this way explicitly related to the infectives population (I) using the Lambert W function (both the principal and the secondary branc...

Tanto a Cinética Química como a Dinâmica Epidemiológica descrevem e interpretam a evolução de populações, tendo, por essa razão, muitos aspetos em comum. Neste artigo, estabelece-se o paralelo entre o modelo epidemiológico SIR (modelo de Kermack-McKendrick) e a autocatálise com inibição. A autocatálise sem inibição, que possui solução analítica (a...

Valorisation of industrial low-value waste residues was preconized. Hence, carbon dots (C-dots) were synthesized from wastewaters of the cork industry—an abundant and affordable, but environmentally-problematic industrial effluent. The carbon nanomaterials were structurally and morphologically characterised, and their photophysical properties were...

Thermally activated delayed fluorescence (TADF) molecules offer nowadays a powerful tool in the development of novel organic light emitting diodes due to their capability of harvesting energy from non-emissive triplet states without using heavy-metal complexes. TADF emitters have very small energy difference between the singlet and triplet excited...

Thermally activated delayed fluorescence (TADF) has revolutionized the field of organic light emitting diodes owing to the possibility of harvesting non-emissive triplet states and converting them in emissive singlet states. This mechanism generates a long-lived delayed fluorescence component which can also be used in sensing oxygen concentration,...

Four novel TADF emitters, containing phenothiazine and phenoxazine as electron-donors and benzonitrile derivatives as electron-acceptors were synthesized and fully characterized. Their photophysical (absorption and emission spectra, molar extinction coefficients, fluorescence quantum yields and lifetimes) and electrochemical properties (HOMO and LU...

Two bidentate dihomooxacalix[4]arene receptors bearing phenylurea moieties substituted with electron-withdrawing groups at the lower rim via a butyl spacer (CF3-Phurea 5b and NO2 Phurea 5c) were obtained in the cone conformation in solution, as shown by NMR. The X-ray crystal structure of 5b is reported. The binding affinity of these receptors towa...

«The best fruit in the world»: the durian paradox The durian, a fruit from Southeast Asia, has unique organoleptic characteristics: excellent taste and consistency, but a very unpleasant odour (for the uninitiated), which has limited its diffusion. Besides the description of the fruit and its properties, including the main compounds responsible for...

Conjugated polymers (CPs) have arisen as promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily measured high sensitivity optical output. The best CP in our studies was found to be poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). It is photostable, ha...

The chemiluminescence of several naphthalene-based luminol analogues is characterized and compared with that of luminol. The compounds produce a strong greenish or green-yellow chemiluminescence in alkaline aqueous and nonaqueous solutions by reaction with hydrogen peroxide in the presence of hexacyanoferrate (III). The results point to the possibi...

Potassium channels selectivity filter (SF) conformation is modulated by several factors, including ion-protein and protein-protein interactions. Here, we investigate the SF dynamics of a single Trp mutant of the potassium channel KcsA (W67) using polarized time-resolved fluorescence measurements. For the first time, an analytical framework is repor...

Aeronautical industry deals with extremely complex and sensitive issues, the most critical of which being arguably aircraft safety during flight. For a variety of reasons and through different pathways, the integrity of an airplane might be compromised in such a way that passengers and crew might be at risk. In the case of military aircraft, this r...

The purpose of this chapter is to summarize the state of art of fluorescence-based explosive sensors in a simple way, focusing especially on the research progress. Importantly, the advances in this field are organized in the different strategies and improvements in the exploitation of fluorescence explosives detection. Mechanisms of fluorescence ex...

The Moon seen from the Earth-The Moon, an old and assiduous presence in our sky, continues to have novelty and attractiveness. In 2019, we will commemorate the 50th anniversary of the first human on the Moon, the first landing on the far side being also expected for this year. The colonization of the Moon is a matter of time. Today, still deserted...

Material suplementar do artigo A Lua vista da terra

The study of thermally activated delayed fluorescence (TADF) started almost a century ago, when the fluorescence and phosphorescence mechanisms were still unclear. Third‐generation organic light‐emitting diodes (OLEDs) relying on TADF were proposed and are under active development, with an already vast and rapidly growing literature. In both TADF k...

Conjugated polymers (CPs) have arisen as promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily measured high sensitivity optical output. The best CP in our studies was found to be poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). It is photostable, ha...

A series of novel donor-acceptor-donor (D-AD) compounds featuring dibenzothiophene (DBT) and phenothiazine (PTZ) units are presented. A different degree of steric hindrance between the donor and acceptor fragments is achieved by the systematic changes of donor substituents (methyl, iso-propyl, tert-butyl groups). This leads to the tuning of photoph...

The recent rise in global terrorism has stimulated the necessity of developing a portable, miniaturized and sensitive monitoring device for in-field and real-time detections of explosives. One particularly attractive and promising approach involves the use of optical methods, which offer many benefits over other common detection techniques. Our mai...

Thermally activated delayed fluorescence (TADF) of ¹²C70 and ¹³C70 was observed up to 140 °C in a p-tert-butyldihomooxacalix[4]arene solid matrix, a temperature range significantly higher than that of previous TADF quantitative studies. An effective singlet–triplet energy gap of 29 kJ/mol and triplet formation quantum yields of 0.97 and 0.99 were m...

Thermally Activated Delayed Fluorescence (TADF), also known as E-type delayed fluorescence, is currently a topic of great interest in molecular photophysics. Numerous TADF emitters have been designed in recent years. Mainly due to their ability to harvest triplet states using metal-free organic molecules, which offer the opportunity to enhance the...

Conjugated polymers (CPs) have proved to be promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily-measured high-sensitivity optical output. The nitroaromatic analytes are strongly electron-deficient, whereas the conjugated polymer sensing materials are electron-...

Phasor plots (plots of the Fourier sine transform vs. the Fourier cosine transform, for one or several angular frequencies) of the fluorescence intensity decay are being increasingly used in studies of homogeneous and heterogeneous systems. In this work, the phasor approach is applied to monomer-excimer systems with a focus on mixed decays, i.e. de...

Intense, simultaneous, room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) is observed in a series of donor-acceptor-donor (D-A-D) molecules. This dual-luminescence is stronger in the "angular" isomers, compared to their "linear" regioisomers, which is consistent with an enhanced intersystem crossing (ISC) in...

The intrinsic electronic absorption and fluorescence properties of several multifluorophoric dihomooxacalix[4]arenes are studied. The contributions of phenyl and/or benzyl groups (lower rim) and p-tert-butylphenyl ethers (upper rim) to the absorption and fluorescence are established. Fluorescence titrations were undertaken to investigate the calixa...

Treatment of trans-[PtCl2(NCR)2] 1 (R = Me (1a), Et (1b), o-ClC6H4 (1c), p-ClC6H4 (1d), p-(HC=O)C6H4 (1e), p-O2NC6H4CH2 (1f)) with 1,3-diiminoisoindoline HN=CC6H4C(NH)=NH 2 gives access to the corresponding (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) complexes [PtCl{NH=C(R)N=C(C6H4)NC=NC(R)=NH}] 3a-f, in good yields (65–70%). The reaction of...

In this work, N-N′-diaryl-perylene-3,9-diamine (PDA) derivatives featuring different alkoxyl substituents at the para position of the N-aryl rings were synthesized and employed as emitters in solution processed organic light emitting diodes. Their physical properties were studied by UV-Vis absorption, fluorescence, differential scanning calorimetry...

Supplementary

Here we report a comprehensive photophysical investigation of a new emitter molecule DPTZ-DBTO2, showing thermally activated delayed fluorescence (TADF), with near-orthogonal electron donor (D) and acceptor (A) units. We show that DPTZ-DBTO2 has minimal singlet-triplet energy splitting due to its near-rigid molecular geometry. However, the electron...

A new diethylenetriamine-derived macrocycle known as L, bearing 2-methylquinoline arms and containing m-xylyl spacers, was prepared in good yield by a one-pot [2 + 2] Schiff base condensation procedure, followed by reduction with sodium borohydride. Up to now this is the first hexaazamacrocycle with appended fluorophore units. Single-crystal X-ray...

O Ano Internacional da Luz e das Técnicas nela Baseadas (AIL), destina-se a «mostrar a todos a importância da luz e das técnicas ópticas». Neste espírito, discutem-se, numa perspectiva histórica e fotoquímica, as representações do Sol e da luz e a respectiva base sensorial, bem como a nomenclatura de alguns elementos e processos químicos relacionad...

Phasor plots of the fluorescence intensity decay (plots of the Fourier sine transform vs. the Fourier cosine transform, for one or several angular frequencies) are being increasingly used, namely in fluorescence lifetime imaging microscopy (FLIM) of cells, tissues and surfaces, but are also relevant for the characterization of homogeneous (e.g. sol...

Dual-sensing (temperature and one analyte) based on photoluminescence is presented. After reviewing the basic definitions and concepts, sensing formats and luminescence measurement methods are discussed, as well as common probes and analytes. The structure and performance of selected dual platforms is examined. Future perspectives for nanosized and...

The kinetics of the luminescence concentration depolarization of molecules in a medium is studied theoretically. It is shown that the concentration depolarization kinetics is well described by a stretched exponential function of time, r(t)/r 0 ≈ exp[−b(t/τ)β], where r(t) and r 0 are the luminescence anisotropy values at time moments t and t = 0, re...

Luminescence decay functions describe the time dependence of the intensity of radiation emitted by electronically excited species. Decay phasor plots (plots of the Fourier sine transform vs. the Fourier cosine transform, for one or several angular frequencies) are being increasingly used in fluorescence, namely in lifetime imaging microscopy (FLIM)...

Two new coumarin-[60]fullerene dyads, in which an alkyne group covalently links C60 to coumarin, are synthesized via 1,3-dipolar cycloaddition and spectroscopically characterized. Their photophysical properties in apolar (toluene) and polar (THF and benzonitrile) solvents are studied at room temperature, revealing the nature and polarity dependence...

The luminescence decay of a species in an absorbing medium whose optical thickness changes with time, as occurs with triplet-triplet absorption following excitation cut-off, is studied theoretically and experimentally. A general luminescence decay function based on a distribution of optical thicknesses is presented. A simple decay function previous...

Molecular radiative transport, consisting in consecutive emission-absorption events by atoms or molecules of the same species, is studied in the case of excited-state absorption, a situation relevant to the phosphorescence of polycyclic aromatic hydrocarbons. This type of transfer differs in a number of ways from the better studied atomic resonance...

Luminescence decay functions describe the time dependence of radiation emitted by a sample after excitation. An overview of the mathematical aspects and systematics of luminescence decays is presented. In particular, super-exponential (faster-than-exponential) decays are defined and the possibility of their observation in single species physicochem...

The phosphorescence decay under the effect of significant excited-state absorption has a distinctive signature: it is initially concave, switching to convex (pure exponential decay) after a certain time. A simple one-parameter decay function satisfactorily reproducing the experimental decays is discussed, and some of its peculiar mathematical prope...

The dependence of the luminescence quantum yield of linear polymer molecules that contain chromophores at the ends on the number of units of polymer chain is studied. Numerical calculations for the dipole-dipole energy transfer between chromophores show that an increase in the chain length by a factor of 2 leads to a several-fold increase in the lu...

Perylene dyes comprising: (i) 4-alkoxyphenylamino moiety in the 9-position as a strong donating group, (ii) cyanoacrylic acid as electron acceptor and anchoring group and (iii) a triple bond as short and rigid linker between perylene core and the acceptor group have been successfully synthesized. Their photophysical (i.e. absorption and emission sp...

The phosphorescence and thermally activated delayed fluorescence (TADF) lifetimes of ¹²C70 and ¹³C70 in two different glassy hydrocarbon polymers, one aliphatic (cyclic polyolefin) and one aromatic (polystyrene), were measured between −200 and 100 ºC. The temperature dependence of the lifetimes is equally well described by a three-state mechanism (...

Naphthalene analogues of luminol with several types of substituents were prepared. All molecules exhibit a strong green chemiluminescence in aqueous solution, which is catalysed by iron, pointing to the possibility of increasing the sensitivity of analytical methods currently based on luminol.

Functionalized polymer nanoparticles react with and store (for several weeks) molecular oxygen. The controlled release of singlet oxygen by the particles is achieved by thermolysis.

Abstract—The dependence of the luminescence quantum yield of linear polymer molecules that contain chromophores at the ends on the number of units of polymer chain is studied. Numerical calculations for the dipole–dipole energy transfer between chromophores show that an increase in the chain length by a factor of 2 leads to a several�fold increase...

Discutem-se o conteúdo e o contexto cultural das «Memórias dum Átomo», singular romance oitocentista, dando-se especial atenção aos aspectos químicos e a possíveis fontes de inspiração.

New C60 and C70 fullerene dyads formed with 4-amino-1,8-naphthalimide chromophores have been prepared by the Bingel cyclopropanation reaction. The resulting monoadducts were investigated with respect to their fluorescence properties (quantum yields and lifetimes) to unravel the role of the charge-transfer naphthalimide chromophore as a light-absorb...

The past and the present of the Portuguese Chemical Society (Sociedade Portuguesa de Química) is briefly described.

Ensemble fluorescence decays are usually analyzed with a sum of exponentials. However, broad continuous distributions of lifetimes, either unimodal or multimodal, occur in many situations. A simple and flexible fitting function for these cases that encompasses the exponential is the Becquerel function. In this work, the applicability of the Becquer...

We report on a new method for sensing trace oxygen in the gas phase. It is based on the extreme efficiency of the quenching of the thermally activated delayed fluorescence of isotopically enriched carbon-13 fullerene C70 (13C70). This fullerene was dissolved in polymer matrices of varying oxygen permeability, viz. polystyrene (PS), ethyl cellulose...

A new approach to Henri-Michaelis-Menten (HMM) enzyme kinetics is presented. In the first part, a simplified but useful description that stresses the cyclic nature of the catalytic process is summarized. In particular, the timedependence of the substrate concentration is obtained in a simple way that dispenses the quasi-steady-state approximation....

A publicação da obra Gustavo de Matos Sequeira: Retrato de um Olisipógrafo, no quadro do Acordo de Parceria celebrado entre a Câmara Municipal de Lisboa e a Imprensa Nacional-Casa da Moeda, com o apoio do Instituto Superior Técnico, é um testemunho do tributo do Município de Lisboa a um dos mais importantes olisipógrafos do século xx, Gustavo de Ma...

Understanding biological complexity requires new techniques, such as high-resolution magnetic resonance imaging (MRI), for visualizing heterogeneous materials. Fundamental to the application of techniques based on nuclear magnetic resonance (NMR) is the use of new conceptual tools from mathematics and the physical sciences (e.g., fractional calculu...