Quinolin-, pyridin- and thiophene-nitrobenzene compounds were synthesized via Suzuki–Miyaura cross-coupling reaction, which can be assigned as non-symmetric and symmetric species. All compounds were fully characterized via 1D and 2D NMR spectroscopy, which provided detailed insights into electronic environment and connectivity between aromatic rings, in good agreement with theoretical calculations. Particularly, a significant shielding effect by phenyl ring (from benzoimidazole fragment) on pyridin proton, compared to analogous nitro-derivatives. Electrochemical studies were carried out under cyclic voltammetry technique, using HB2 pencil graphite as working electrode, in an acetonitrile/sulfuric acid medium under atmospheric conditions. Fruitfully, all nitro-benzene compounds present redox activity, which are assigned to reduction potentials on nitro-fragment. Additionally, this redox activity can be influenced through electronic nature and positional substitution of the heterocyclic rings, with lower reduction potentials observed for symmetrical thiophene derivative, compared with unsubstituted nitro-benzene. Finally, in selected cases, a chemical reduction and redox behavior analysis was carried out in successfully way, transforming the nitro- to amine- species, with fluorescence turn-on observed.

An ecofriendly epoxidation reaction of styrene, cyclooctene (COE), cyclooctadiene (COD) and dicyclopentadiene (Cp2) by manganese complexes containing N,N,N,O-donor Schiff Base ligands, using water/ethanol as solvent reaction mixture and H2O2 as oxygen source, with tetra-methyl-ammonium hydroxide (TBAH) as phase transfer agent, is reported. All new half-unit N,N,O- and N,N,N,O-donor Schiff Base ligands were characterized by comparative 1D and 2D NMR spectra analysis. Additionally, Mn-complexes characterization is based on e.a., IR-FT and UV/Vis experimental data. Styrene oxidation was analyzed to find our best conditions, reaching isolation of 1-phenyl-1,2-ethanediol as main product. Excellent results were obtained for COE, COD and Cp2 epoxidation, respectively.

Ketones are versatile organic compounds involved in various natural and industrial processes. Therefore, developing practical methods for their detection is essential for applications in industrial safety, food quality control, and environmental monitoring. This work reports a novel and fundamental method for the photoluminescent sensing of ketones with terpyridine derivatives. Firstly, 4 '-(4-N-aminoethylenephenyl)-2,2 ':6 ',2 '' terpyridine (TpyPhEDA) was synthesized, and a comprehensive study of its structural and photoluminescent properties was conducted, emphasizing its application as a sensor. The luminescent response was evaluated in various organic solvents and ketones of different chemical nature, revealing a highly selective reaction with acetylacetone (AcAc). The analytical response was characterized by rapid reaction kinetics, enhanced emission intensity, band broadening, emission lifetime shortening, and a shift in the emission wavelengths as AcAc concentration increased. The underlying sensing mechanism involves a Schiff base formation between TpyPhEDA and AcAc, governed by a keto-enamine tautomeric form. The resulting Schiff base is stabilized in its ketoenamine form, enabling molecular polarization, as demonstrated by molecular electrostatic potential surface (MEPS) diagrams. This polarization triggers intramolecular charge transfer (ICT) processes, leading to turn-on luminescence and wavelength-shifting dual-mode detection of AcAc. Those results demonstrate that keto-enol tautomerism plays a crucial role in modulating the sensor's photoluminescent response, explaining variations in reaction kinetics and providing the basis for selective sensing of ketones.

Reliable determination of long and very long chain fatty acids, which are abundant in marine foods, remains a challenge. In this work, 1-(2-aminoethyl)pyridin-1-ium bromide hydrobromide (AEPy) is proposed for isotope-coded derivatization of fatty acids released from oils through saponification and extraction (esterified and free FAs). Pyridine deuteration was accomplished, and three AEPy isotopologues were synthesized (AEPy-dn, n = 0,3,5). The introduction of permanent positive charge during derivatization facilitated electrospray ionization process in positive mode. Once the molecular structures were confirmed by high-resolution mass spectrometry and NMR, the main emphasis was placed on setting a liquid chromatography-ion trap mass spectrometry procedure allowing the detection/annotation and quantification of fatty acids (FAs) in real-world samples, although without distinguishing their positional isomers. In an untargeted approach, isotope cluster analysis of data obtained for a mixture of two differentially labeled sample portions allowed annotation of fatty acids, revealing unexpected presence of C24:1 in cod liver oil and C28:8 in menhaden oil. In quantitative analysis based on selected ion monitoring, light AEPy was used to derivatize the calibrator (cod liver oil CRM) and real-world samples, while heavy AEPy derivatives served as internal standards in external calibration and were applied for bracketing isotope dilution. For FAs certified in cod liver oil, the method LOQs were in the range 0.03–0.33 mg g−1. Three oil dietary supplements were analyzed, confirming high relative abundance of C20:5, C22:6, C18:1, C16:0 in krill; C18:2, C18:1, C20:5, C22:6 in salmon and C20:5, C22:6, C22:5 in anchovy/sardine products. The two quantification methods provided consistent results; however, bracketing isotope dilution offers better protection against matrix interferences.

The urgent demand for advanced energy storage systems (ESSs) has intensified the exploration of conductive polymers (CPs) due to their lightweight nature, design flexibility, and dual p-/n-doping capabilities. However, achieving stable n-type doping in pi-conjugated systems remains a major challenge, and a rational molecular design is necessary. In this work, we report the synthesis of an electrochemical copolymer based on bithiophene (BT) and 1-(perfluorophenyl)-2-(thiophen-3-ylmethylene)hydrazine (FTh1) monomer, containing a strong electron-withdrawing fluorinated substituent. While FTh1 monomer electropolymerization fails under our experimental conditions, its copolymerization with BT enables the formation of stable, adherent films on glassy carbon electrodes. These films reveal a reversible and stable n-doping response attributed to copolymer species, which is absent in pristine polybithiophene, showing a successful stabilization of carbanionic species. Additionally, incorporation of FTh1 monomer induces significant shifts in p-doping profile and enables charge trapping during redox cycling. Furthermore, scan rate-dependent analyses demonstrate diffusion-controlled ion transport for both anodic and cathodic processes. These findings highlight the potential of strategic monomer design to modulate the redox behavior of CPs, paving the way for their application in next-generation symmetric pseudocapacitors. The FTh1compound was synthesized with 98% purity via an aromatic aldehyde-hydrazine condensation reaction.Electrochemical co-polymerization and subsequent characterization of the FTh1:BT composite were performed in acetonitrile (ACN) within an argon-filled glovebox.Incorporation of the bithiophene moiety into the polymer backbone promotes internal chain ordering, facilitating n-type doping.FTh1:BT system undergoes a reversible reduction process starting at -1.6 V vs reference, demonstrating stable charge/discharge cycling.

A small family of N,N,C-donor pincer-palladacycles complexes supported by (benzo-oxazole, imidazole, and thiazole)-pyridin-thiophene type ligands is obtained via C-H bond activation at room temperature under atmospheric conditions. All compounds are isolated in good yield as orange to yellow-orange solids. Molecular structures are proposed based on nuclear magnetic resonance (NMR) experiments, showing significant chemical shift values on pyridin and thiophene fragments after cyclopalladation reaction, compared with the free ligand's signals. For a selected case of (benzo-oxazole)-pyridin-thiophene pincer-palladacycle, the structure is corroborated via X-ray diffraction analysis. Electrospray ionization-high resolution mass spectrometry analysis (ESI-MS) performed in fresh methanol or acetonitrile solution supports the identity of pincer-palladacycles by detecting ionic palladium-bimetallic species and dinitrogen-adducts. When MS/MS experiments are carried out for palladium-bimetallic species, spectral data point to the formation of dinitrogen-palladium. Although palladium-bimetallic species and dinitrogen-adduct ions are formed in the ESI source and in the collision-induced dissociation cell, to the best of our knowledge, this is the first report for the detection of organometallic dinitrogen-palladium species. N,N,C-donor pincer-palladacycles are found as feasible catalytic precursors on Suzuki-Miyaura reaction, showing excellent conversion, yields, and functional group tolerance.

En el presente Verano de la Ciencia UG se logró realizar la electro-síntesis de tres nuevos composites a base de polianilina (PANI) conteniendo paladio, sobre grafito HB2, bajo condiciones atmosféricas. Los composites resultaron ser una estrategia efectiva para obtener catalizadores heterogéneos frente a la reacción de acoplamiento cruzado Suzuki-Miyaura. Además, se mostró una tolerancia a la naturaleza de los grupos funcionales p.e. nitratos, aldehídos, anilina, entre otros, obteniendo de buenos a moderados rendimientos en la mayoría de las pruebas, aunado a la estabilidad y la opción viable de reciclado mediante filtración o centrifugado. Finalmente, el análisis de los voltamperogramas permite observar cambios significativos en la respuesta de los procesos redox derivados de la electrosíntesis, confirmando que los derivados de paladio se incorporaron adecuadamente en la matriz de polianilina.

A new family of eight benz(imida, oxa and thiazole)-pyridin-thiophene derivatives was synthesized via the Suzuki-Miyaura reaction conditions. Once the structures of all compounds were confirmed by 1D and 2D Nuclear Magnetic Resonance (NMR) analyses, electrochemical studies using Cyclic Voltammetry (CV) revealed enhanced redox activity. Under our experimental conditions, a solvent mixture of acetonitrile and sulfuric acid played a key role in boosting the electrochemical response, yielding anodic current values of up to 0.86 mA. For direct comparison, we also synthesized the parent pyridin-thiophene compounds, which exhibited anodic current values of up to 0.72 mA. Those values are significantly higher than the 0.002 mA observed for analogous materials synthesized in dry acetonitrile and ammonium salt mixture under nitrogen atmosphere. The electrochemical response of the synthesized compounds is comparable to that of commercially available monomers 3,4-ethylenedioxythiophene (EDOT) and bithiophene (BiThio), which could be exploited in the production of conductive organic films with diverse optoelectronic applications.

Herein, we report the synthesis and characterization of a small family of Ir(I) and Ir(III) complexes supported by beta-thioketoiminates (SacNac) ligands. All complexes were fully characterized by IR, 1D and 2D NMR, and Elemental Analysis (e.a.) experiments. X-ray diffraction studies were carried out to corroborate the structure of compounds [Ir(cod)(SacNac)] (1) (cod=1,5-cyclooctadiene), [Ir(dmb)(SacNac)] (2) (dmb=2,3-dimethyl-1,3-butadiene) and [IrCp*(SacNac-H)(Cl)2] (8) (Cp*=pentamethyl-cyclopentadienyl). Complexes 1 and 2 are Ir(I) species and have square-planar geometry in solid state, with bond angles and distances that suggest semi-aromaticity in the six-membered ring. To the best of our knowledge, we report the first mono-coordination mode of a SacNac ligand via sulfur atom in complex 8. Also, we report the first application of iridium-SacNac complexes as catalytic precursors in hydroboration reactions, where Ir(III) species give the best results.

This research aimed to assess the potential of Cu50PANI@UG composite for sunlight drive photocatalytic dye degradation, targeting specifically Thymol Blue (TB) and Black NT (BNT) dyes and their mixture (DM). The Cu50PANI@UG composite was successfully synthesized via electropolymerization in acetonitrile/sulfuric acid mixture under atmospheric conditions. Photocatalytic experiments were conducted by exposing aqueous dye solutions to sunlight. N,N-dimethyl-p-nitrosoaniline (RNO) served as a molecular probe for detecting hydroxyl radicals (•OH). Additionally, experiments capturing free radicals were performed to identify active components, with a concomitant proposal of plausible degradation reaction mechanism for the Photo-Fenton-Like degradation into the Cu50PANI@UG composite + H2O2 + hv reaction system. Various operating parameters affecting dye degradation were evaluated, including catalyst dosage (from 0.27 to 0.67 g L-1), H2O2 concentration (from 16 to 64 mM), pH (from 3.0 to 9.0), and dye concentration (from 25 to 100 mg L-1). Optimization of key parameters such as pH, catalyst dosage, and H2O2 concentration was conducted. The highest degradation efficiency, ca. 100% of DM dye, was achieved within 35 min under optimized conditions, using Cu50PANI@UG composite as a catalytic precursor. These conditions were determined as follows: Catalyst dosage = 0.67 g L-1, pH = 3.0-6.0, H2O2 = 32-64 mM, and irradiation time of 35 min. The degradation percentage under the Response Surface Methodology (RSM) was utilized as a statistical tool to correlate influential parameters. Four consecutive reusability trials were performed to assess catalyst stability.

In this contribution, we report a straightforwardly and easily one-step synthesis of a small family of composites based in polyaniline grafted on HB2 graphite (PANI@UG) and their copper-doped derivatives (Cu50PANI@UG5-6). The PANI@UG composites were synthesized through electrochemical polymerization using cyclic voltammetry (CV) in three different acidic media: i) acetic acid (AcOH) at high and low concentration (12 and 1 M, using KCl as electrolytic support); ii) a mixture of AcOH and sulfuric acid (H2SO4, which have two roles: as electrolytic support and proton source) and iii) a mixture of acetonitrile (NCCH3) and H2SO4, under atmospheric conditions. Once the best conditions were achieved, our next step was focused on obtaining the Cu50PANI@UG5-6 composites using a solution of aniline and CuSO4 (50 mM) in AcOH:H2SO4 and NCCH3:H2SO4 solutions, respectively. All composites were characterized by CV, FT-IR, SEM and MALDI-TOF experiments. So, the current value was enhanced for the Cu50PANI@UG6 composite, which have three potential catalytical applications in: i) HClO4 acid sensing, ii) click chemistry and iii) sunlight drive photo-activation of H2O2.

AcAc (beta-acetylacetonate) are among the first ligands ever to be studied. They form stable complexes with most metals. During the 1960s, their sulfur derivatives were introduced, including AcSac (beta-thioketonate), SacSac (beta-dithioketonate) and SacNac (beta-thioketoiminate). These derivatives exhibit contrasting reactivity, stereochemical, magnetic and spectral properties to their formed complexes. Sulfur ligand-based complexes were at their pinnacle in the early 1970s, but their fell into disuse, due to the lack of methodologies for obtaining them and the absence of synthetic tools for their structural modification. As an effort to promote the study and application of these sulfur-ligands; this review will address their history, the properties they bring to the metal centers and their potential applications.

A new type of trans‐ dichloro‐Ir(III) complexes derived from non‐symmetrical NacNac‐type ligands was unexpectedly obtained as the main reaction product from the former ligands and the dimeric species [Ir(COD)Cl 2 ]. One equivalent of LH was reacted with an excess of [Ir(COD)Cl] 2 in dichloromethane or toluene as solvent and at room temperature. The general formula of the product is [IrCl 2 (COD)L] and was isolated as a sole product instead of the expected Ir(I) compound [Ir(COD)L]; all the new Ir(III) were prepared in high yields as microcrystalline solids. They were all stable under laboratory atmosphere, lasting for weeks in solution and for months in solid state. The structure of each compound was examined by 1D and 2D nuclear magnetic resonance (NMR) and high‐resolution mass spectrometry (HRMS). Complex 1k was selected for an X‐ray diffraction study. Finally, an evaluation was made of the catalytic activity of all complexes in the transfer hydrogenation reaction of ketones and imines.

Novel amino-pyridyl-benzothiazole-derivatives (PBT) were synthesized through cycloaddition/nucleophilic aromatic substitution reactions for the development of a turn-on fluorescence chemosensor that accurately determines Zn2+ in polar media. The selectivity, water-solubility, and overall analytical response were systematically optimized through incorporation of different aliphatic amines as substituents: pyrrolidine (PBT-Pyn), ethylenediamine (PBT-Et) or 1,3-propylenediamine (PBT-Pr). Those ligands presented intense dual radiative emissions in the blue/green region upon activation with a 395 nm LED, which were attributed to the local excitation and internal energy transfer states. Although no variations were observed upon the interaction of Zn2+ with PBT-Pyn, both turn-off and turn-on responses were observed upon its interaction with PBT-Et. These responses depended on the ligand concentration and the associated inner filter effects. Thereby, PBT-Pr was selected for a deeper evaluation towards photoluminescence determination of Zn2+ due to its exclusive turn-on response and major sensibility obtained at pH 7.0, making it very convenient for analysis in physiological media. Under those conditions, the detection limits were 1.9 µM and 4.7 µM for measurements in aqueous or ethanolic solutions, respectively, with linear ranges up to 40 and 80 μM. The selectivity and good biocompatibility of the chemosensor were demonstrated through cell-viability assays with MCF-7, 3T3-L1 and HT-29 cell lines. The probe was then applied for the real-time epifluorescence imaging of Zn2+, observing emission intensities and distribution profiles that correlated with the concentration and location of the target within living cells.

Rollover iridacycle were easily obtained via a C–H bond activation on the remote position of the 2-(6-bromopyridin-2-yl)imidazo[1,2-a]pyridine ligand. DFT calculations suggest that C–H bond activation occurs during the complexation of the second ligand.

The first goal of this work was to explore the feasibility of diaryl-mercury species as the synthetic precursors of triaryl-gallium species GaAr*3 (where Ar*= pH, 4; Ar*= 3,5-difluorophenyl, 5; and Ar*= 3,5-trifluoromethylphenyl, 6). Expecting that 4–6 behave as Lewis acids of different strength, the second purpose was to use them for the synthesis of either rollover or classic cyclometallated Ga compounds. Three analogous diaryl-mercury HgAr*2 species, 1–3, were successfully synthesized. The structures of compounds 2 and 3 were confirmed by gas chromatography - mass spectrometry experiments. Additionally, compound 3 was analyzed through X-ray diffraction; in the crystal structure obtained, π-stacking interactions were observed. The only Ga compound synthesized was GaPh3, 4, because the presence of fluorine-containing groups in meta-position caused sublimation of the respective mercury diaryl compounds, impeding their reaction with gallium. The attempts toward the synthesis of the rollover or classic cyclometallated compounds in the reaction of 4 with bipyridine-, pyrazole- or benzo-imidazole- type ligands have failed. On the other hand, under the experimental conditions applied, water traces favored formation of the solid aryl-Ga cluster containing twelve Ga atoms [Ga12], whereas the above-mentioned ligands were quantitatively recovered in the solution. The identity of aryl-gallium cluster was confirmed by electrospray ionization - high resolution mass spectrometry. Although Ga cluster was not expected, it is considered an important finding of this work, owing to the variety of possible applications and still limited data available on the synthesis and structural characterization of such compounds.