Fabiano Severo Rodembusch

Federal University of Rio Grande do Sul | UFRGS · Departamento de Química Orgânica (DQO)

Nonsymmetric 2-aryl (benz)imidazole derivatives were previously synthesized via C-H/N-H annulation of imidazole derivatives from lapachol moieties with internal alkynes as an efficient tool to increase the π-system of lapimidazole derivatives. To investigate their photophysical properties, time-resolved and steady-state fluorescence measurements we...

Organic light-emitting diodes (OLEDs) are one of the most studied and utilized optoelectronic components in display technology. However, their application in lighting remains limited due to materials costs and a guaranteed feasible deposition technique. To address this challenge, we explored the use of easily synthesized organic molecules capable o...

2,5-Di(hetero)arylthiophenes are key structural scaffolds for several emissive applications and offer tunable fluorescent features attributed to their π-conjugated structures and versatile substituents. In this context, we assessed the photoluminescence of 2,5-di(hetero)arylthiophene derivatives synthesized from 1,3-diynes through cyclization react...

The impact of the polymeric matrix on the photophysical characteristics of monomeric dyes responsive to excited‐state intramolecular proton transfer (ESIPT) was investigated through UV–Vis absorption as well as steady‐state and time‐resolved emission spectroscopies. For this purpose, two benzoxazole monomers (M1 and M2) with acryloyl groups at diff...

Herein, we present the preparation of solid-state photoactive starches with a large Stokes shift, along with the resulting materials. In this investigation, 2-(2′-hydroxyphenyl)benzazole derivatives responsive to intramolecular proton transfer in the excited state (ESIPT) were covalently bonded to the polymeric structure of starch through a reactio...

In this study, we present a comprehensive photophysical investigation of ESIPT-reactive benzazole derivatives in both solution and the solid state. These derivatives incorporate different chalcogen atoms (O, S, and Se) into their structures, and we explore how these variations impact their electronic properties in both ground and excited states. Ch...

Lophine-benzothiazole dyads were synthesized via the amine-isocyanate reaction involving N-alkylamino lophine and 2-(5′-isothiocyanate-2-hydroxyphenyl)benzothiazole. The resultant coupling generated a thiourea linkage, connecting the two primary fluorophores with varying chain lengths (2 and 8 methylene groups). These newly formed dyads exhibit dis...

In this work, we present a series of chromophores based on dialkynyl‐N‐(het)arylpyrrole, featuring diverse combinations of donor‐acceptor moieties. The study explores the potential of fluorophores derived from (alkynyl)arylpyrroles, investigating the impact of the central core‘s nature with phenyl and pyridyl groups, along with various arylethynyl...

Invited for the cover of this issue are the groups of Holger Braunschweig at the Julius‐Maximilians‐Universität Würzburg, Germany and Eufrânio N. da Silva Júnior at the Universidade Federal de Minas Gerais, UFMG, Brazil. The image depicts the electrochemical synthesis of selenium‐containing BODIPY molecules with lightning symbolizing the electrifyi...

We report a rapid, efficient, and scope‐extensive approach for the late‐stage electrochemical diselenation of BODIPYs. Photophysical analyses reveal red‐shifted absorption – corroborated by TD‐DFT and DLPNO‐STEOM‐CCSD computations – and color‐tunable emission with large Stokes shifts in the selenium‐containing derivatives compared to their precurso...

The study reported herein describes the synthesis of benzothiadiazole(BTD)-N-heterocycle derivatives by metal-catalyzed cross-coupling reactions with relatively good yields. The photophysical characteristics of these derivatives were assessed in solution through UV–Vis...

This study presents the synthesis of novel glycoconjugates by connecting benzazole and carbohydrate units with a 1,2,3-triazole linker. A simple synthetic route employing a copper (I) catalyzed azide-alkyne 1,3-dipolar cycloaddition...

This study presents a comprehensive analysis of the synthesis and photophysical properties of thiazolidine-functionalized chiral ionic liquids (CILs) derived from L-cysteine. The synthesis involves a four-step route, encompassing N-protection, coupling reactions with bromoalco-hols, and ionic liquid formation. The optical properties of the compound...

In this study, we present the synthesis of benzimidazo[1,2-a] quinoline-based heterocycles bearing organosulfur and organoselenium moieties through transition-metal-free cascade reactions involving a sequential intermolecular aromatic nucleophilic substitution (SNAr). Both sulfur and selenium derivatives presented absorption maxima located around 3...

In this work, imidazole- or imidazolium-based benzothiadiazole ligands functionalized on graphene oxide combined with cholesterol oxidase constitute efficient, robust, and easy-to-handle materials with high biosensing activity for the detection of cholesterol by colorimetric methods. The presence of lanthanum(III) supported on graphene oxide as a p...

Excited-state chemistry relies on the communication between molecules, making it a crucial aspect of the field. One important question that arises is whether intermolecular communication and its rate can be modified when a molecule is confined. To explore the interaction in such systems, we investigated the ground and excited states of 4′-N,N-dieth...

We report a photocatalytic device based on gold nanoparticles (AuNPs/TiO2) coated with an ionic liquid (IL) as a very active, stable, and versatile system for hydrogen evolution reactions (HERs) via methanol photo reforming (MPR) and photocatalytic water-splitting (WSR) reaction. The devices prepared by magnetron sputtering yield hybrid materials w...

The work presents the synthesis and characterization of zinc oxide (ZnO) nanoparticles obtained by the starch-assisted sol-gel route. To observe the influence of the botanical source on the final properties of the nanoparticles, corn, and potato starches were used. After calcination (500°C/2h), the resulting material was analyzed by X-ray Diffracti...

We report herein an efficient, fast, and sustainable method for the preparation of fluorescent indolizine derivatives under ultrasound (US) irradiation using a one-pot and multicomponent methodology. In solution, the indolizine derivatives present absorption in the UV region and fluorescence emission in the violet-to-blue region with a relatively l...

This study describes the synthesis of new pyromellitic diimide (PMDI) derivatives obtained in good yields from the reaction between pyromellitic dianhydride and aminobenzazoles reactive to proton-transfer in the excited state (ESIPT). In this investigation, a non-ESIPT PMDI was also prepared for comparison. These compounds presented absorption maxi...

Here we present simple fluorophores based on the pyridine core, obtained with straightforward synthetic methodologies. These compounds present in solution absorption maxima in the UV region and fluorescence emission of between 300 and 450 nm, depending on the solvent and chemical structure of the fluorophore. The nature of the solvent was shown to...

The Cover Feature shows an aqueous environment in which a designer surfactant forms a micelle that works as a nanoreactor, inside of which a Pd‐catalyzed Suzuki reaction takes place. Traditionally, organic reactions are carried out in laboratories worldwide in organic solvents. A natural evolution in this area would be to imitate the biosynthesis p...

A series of amino acid-derived 1,2,3-triazoles presenting the amino acid residue and the benzazole fluorophore connected by a triazole-4-carboxylate spacer was studied for enantioselective recognition using only steady-state fluorescence spectroscopy in solution. In this investigation, the optical sensing was performed with D-(-) and L-(+)-Arabinos...

Herein we report the arylation of Tröger's base via the Suzuki cross‐coupling reaction through aqueous micellar catalysis. The developed reaction conditions enabled us to prepare a variety of different derivatives with Tröger's base skeleton, using a low catalytic loading of the readily available Pd(OAc)2 catalyst and under environmentally friendly...

Heptamethine cyanine dyes were synthesized in good yields by the reaction between quaternary indoles and a pentamethinic salt, under mild reaction conditions minimizing photoox-idation. These compounds were used as precursors to prepare meso-substituted derivatives. The cyanine dye precursors presented UV-Vis absorption, related to fully allowed el...

The present work describes the synthesis of three classes of mono-silylated benzothiadiazole and their application in obtaining organic-inorganic fluorescent hybrid materials. The mono-silylated compounds were obtained through a Pd-catalyzed Sonogashira coupling reaction with silicon-functionalized alkynes (25–61% yield). One of the silylated produ...

Fluorescent and colorimetric sensors are important tools for investigating the chemical compositions of different matrices, including foods, environmental samples, and water. The high sensitivity, low interference, and low detection limits of these sensors have inspired scientists to investigate this class of sensing molecules for ion and molecule...

Herein, we report the synthesis of bis-silylated 2,1,3-benzothiadiazole derivatives and their use in the preparation of photoactive organic-inorganic hybrid materials with extremely low fluorophore/tetraethylorthosilicate molar ratios. The organic compounds were synthesized in good to excellent yields (55%-94%) using Pd-catalyzed Sonogashira cross-...

This study describes the synthesis, photophysical characterization, and TD-DFT calculation of a series of benzothiazole-based styryl fluorophores (F1-F5) harboring a D-π-A structure. The compounds were obtained through a simple and efficient synthetic route using low-cost starting materials. The investigation and analysis of their photophysical pro...

This study describes the synthesis and characterization of novel π-conjugated compounds based on 1,3-diynes containing an alkylated tetrazole moiety. Optical properties were characterized by UV–Vis absorption and fluorescence emission spectrophotometry, showing absorption in the ultraviolet region with a molar absorption coefficient of approximatel...

This review summarizes diverse synthetic methodologies to prepare a wide range of heptamethine cyanine dyes, including symmetrical, unsymmetrical, and meso‐substituted derivatives, and their photophysical properties and use. Their sensing applications are also discussed, considering the nature of their electronic structures and photophysical proper...

This review summarizes diverse synthetic methodologies to prepare a wide range of heptamethine cyanine dyes, including symmetrical, unsymmetrical, and meso‐substituted derivatives, and their photophysical properties and uses. Their sensing applications are also discussed, considering the nature of their electronic structures and photophysical prope...

In this article, the binding affinity of 1,4-dihydropyridine-based hexahydroquinoline-3-carboxylates with bovine serum albumin (BSA) was studied by electronic spectroscopies, quantum calculations, and molecular docking. These compounds were obtained by the one-pot microwave-assisted method via a modified Hantzsch reaction. The photophysical charact...

We presented a lamellar K4Nb6O17.xH2O hexaniobate (KNbO) decorated with sputtered Cu, Ag, and Au nanoparticles (MNPs) for photocatalytic hydrogen production from water/methanol solutions and describe the effect of embedded 1-butyl-3-methyl-imidazolium bis((trifluoromethyl)sulfonyl) amide ionic liquid (IL) over catalyst performance. At chosen sputte...

Herein, we report a photocatalytic device based on gold nanoparticles (AuNPs)/titanium dioxide (TiO2) nanomaterial coated with an ionic liquid (IL) as a very active, stable, and versatile system for hydrogen evolution reactions (HERs) via aqueous methanol photo reforming (MPR) and water splitting (WSR). The devices prepared by magnetron sputtering...

In this study, the interactions of ESIPT fluorescent lipophile-based benzazoles with bovine serum albumin (BSA) were studied and their binding affinity was evaluated. In phosphate-buffered saline (PBS) solution these compounds produce absorption maxima in the UV region and a main fluorescence emission with a large Stokes shift in the blue–green reg...

This work reports the synthesis of four homomolecular bis(n)-Lophines dyads achieved by a one-pot four component reaction. The dyads show absorption maxima below 300 nm and present intense fluorescence emission, with large Stokes shift, around 380 nm. Intercalation phenomenon and hydrophobic forces can be predicted for dyads, according to the resul...

This review summarizes several aspects of type II photoactive organic-inorganic hybrid materials prepared from silylated fluorophores, including their photophysical properties and uses. In this sense, several examples are presented and discussed taking the nature of the silyl derivative into account. Applications as latent fingerprints detection, c...

Diverse structural frameworks are found in natural compounds and are well known for their chemical and biological properties; such compounds include the imidazoles and oxazoles. Researchers worldwide are continually working on the development of methods for synthesizing new molecules bearing these basic moiety and evaluating their properties and ap...

The development of biodegradable curative systems containing antibacterial drug are fundamental for the promotion of therapeutic actions, reducing the infections caused by microorganisms and being able to substitute conventional dressings which are not biodegradable polymers in their composition. Meeting those needs, poly (butylene adipate‐co‐terep...

In this work, the role of deoxycholic acid (DCA) as a coadsorbent was investigated in the sensitization of mesoporous TiO2 layers (host) with symmetrical carboxy heptamethine cyanine dyes (guest). Different approaches have been tested, aimed at reducing the H-aggregation and minimizing the competition between cyanine molecules and DCA for active si...

ZnO nanoparticles were successfully synthesized using cassava starch (tapioca) as a chelating agent. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses revealed that the synthesized nanoparticles were in the form of ZnO with no impurities present. The estimated average crystallite size, determined from Rietveld refined XRD patte...

Benzothiazole derivatives were used as models to study the excited-state intramolecular proton transfer (ESIPT) in an experimental and theoretical point of view. The experimental electronic and vibrational results were compared with a comprehensive selection of state-of-the-art computational methods in a workflow approach. These latter were perform...

Zn(II) coordination compounds with asymmetric salicylidene ligands in PFO composites were used for all-solution-processable white organic light-emitting diodes (WOLEDs) purposes. These Zn(II) complexes were strategically synthesized to optimize their electronic structures, starting from the widespread known salophen core. Vertical excitation energi...

Multivariate Curve Resolution with Alternating Least Squares (MCR-ALS) was for the first time successfully used to evaluate an intricate photophysical behavior, where deprotonation on the electronic ground state (S0), intra and intermolecular proton transfer processes (ESPT and ESIPT) on the electronic excited state (S1) can simultaneously be prese...

Here we report the effect of ionic liquids over sputtered Au nanoparticles on TiO2 for hydrogen production in aqueous methanol and using monochromatic UV-A-LED light strips to activate the surface. Different sputtering conditions afforded to AuTi1-7 catalytic systems that were subsequently embedded with ionic liquids [BMIm.OAc](IL1); [BMIm.NTf2](IL...

Herein, we describe the syntheses of symmetric and asymmetric benzothiadiazole (BTD)-based fluorophores via the Sonogashira coupling reaction, using 4,7-dibromobenzothiadiazole as the central core and propargyl carbazole and/or propargyl diphenylamine as the side groups. The synthesized fluorophores exhibited absorption bands in the ultraviolet reg...

This work describes the synthesis of new fluorophores based on non-symmetric 4,7-dibromobenzo[c][1,2,5]thiadiazole derivatives with benzene ethynyl tetrazole and propargyl carbazole as terminal groups. The new compounds were obtained using the Sonogashira cross-coupling reaction and produced good yields. The benzothiadiazole derivatives presented a...

A series of new hybrid fluorescent Biginelli compounds, including a Monastrol derivative were designed and synthesized with good yields. The photophysical studies revealed dual fluorescence emission, attributed to excited enol forms (E*) and tautomeric (K*) species, respectively, due to the ESIPT mechanism. The cytotoxic activity of all compounds w...

This study presents a low-cost method for obtaining nanometric zinc oxide (ZnO) using a cassava starch (Tapioca)-assisted by sol-gel route. In this procedure, ZnO nanopowders (~20 nm and 59 nm according to XRD) were obtained after 2 h of calcination at 500oC. The cassava starch played a fundamental role during the sol-gel synthesis allowing the obt...

This study presents the synthesis in good overall yields of oxazolidine-based ionic compounds obtained from protected l-serine followed by an esterification reaction with bromoalcohols and a reaction with 1-methylimidazole in acetonitrile under reflux. These compounds present in ethanol solution an absorption maxima located around 210 nm, resulting...

New isomeric tetra-cationic porphyrins containing peripheral [Pd(bpy)Cl]+ units attached at pyridyl substituents were synthetized and fully characterized. The porphyrins present an intense Soret band located in the blue spectral region and additional four weaker red-shifted Q bands in the visible spectral region (about 500-700 nm). The obtained Str...

A series of 1,3-benzoselenazole derivatives were prepared with different substituents by complementary methodologies starting from aldehydes or carboxylic acids, using sodium metabisulfite and tributylphosphine, respectively, according to the substituent pattern. The photophysical behaviour in solution of the benzoselenazoles was studied using UV–V...

In this study, we synthesized a spiropyran containing an electron-withdrawing carboxyl group in good yield by condensation of an aromatic aldehyde with enamine indole. The spiropyran absorbed at the ultraviolet region with a maximum at approximately 300 nm, demonstrating slight solvatochromism (~3 nm). A fluorescent emission around 360 nm was obser...

Substituted merocyanine dyes were obtained by Knoevenagel condensation between formylated arylbenzothiazole and quaternary 2-alkylbenzothiazoles. The condensations were performed in the presence of sodium methoxide and the products were obtained with excellent yields after simple purification. The merocyanines presented absorption maxima in the ran...

A novel selective fluorescent sensor for Cu²⁺ in solution has been developed by means of chelation enhancement quenching effect (CHEQ). The compound N,N′-bis(salycilidene)-(2-(3′,4′-diaminophenyl)benzothiazole (BTS) is reactive to intramolecular proton transfer on the electronic excited state (ESIPT) presenting fluorescence emission in the blue reg...

Lipophilic 2,1,3-benzothiadiazoles were obtained in a short synthesis with excellent yields by a Sonogashira coupling reaction followed by a 1,3-dipolar cycloaddition reaction with alkyl azides. The obtained compounds presented high solubility in a wide range of solvents with different polarities. The benzothiadiazoles present absorption in the vio...

Herein we report the synthesis of a series of amino acid-derived triazoles by an organocatalytic cycloaddition reaction between azides and carbonyl compounds, catalyzed by a simple amine. These compounds present absorption maxima located in the UV-B ascribed to fully spin and symmetry allowed electronic transitions and a main fluorescence emission...

A series of luminescent aryloxy-benzothiadiazole derivatives with architectures ArO-BTD-Ar’ and ArO-BTD-NAr’ were synthetized. The aim was to achieve a molecular design based on restriction of intramolecular rotation of the ArO- group associated to the presence of bulky aryl or N-aryl groups, which can avoid detrimental π-π stacking and favor radia...

This work presents the synthesis, photophysical characterization, and application of ATRP polymerization initiators to produce photoactive solid-state fluorescent polystyrene-based polymers. These compounds present absorption in the UV region (∼340 nm) and emission in the blue-green regions with large Stokes shift (∼10 000 cm−1) due to a proton tra...

The changes in the ability of three fluorescent derivatives of 2-(2’-hydroxyphenyl)benzothiazole to undergo excited-state intramolecular proton transfer (ESIPT) processes have been correlated with the rheological properties of four amino-polydimethylsiloxanes with different molar masses and containing different amounts of monomer units with amino p...

This work describes the synthesis and photophysical investigation of amino and azido benzazoles. The amino derivatives were obtained by condensation reaction between ortho-substituted anilines and p-aminobenzoic in polyphosphoric acid. The respective azides were synthesized by reaction of diazonium salts from the previously prepared amines with sod...

The effects of the polymeric matrix on the photophysical properties of monomeric dyes reactive to Excited State Intramolecular Proton Transfer (ESIPT) were evaluated by UV–Vis absorption and steady-state and time-resolved emission spectroscopies. A radical polymerization reaction was used to produce new photoactive styrene-based polymeric matrices....

The impact of cerium (Ce) and neodymium (Nd) rare-earth metal doping of TiO2 prepared by the hydrothermal method was investigated to tailor effective photocatalytic degradation of coloured wastewater under UV or visible illumination. The hydrothermal treatment of TiO2 decreased the pHpzc from 6.3 to 3.1–3.8 favouring the affinity for cationic water...