The accumulation of antibiotics in wastewater has led to the development and spreading of antibiotic resistance in the environment. Amoxicillin (Amox), a beta-lactamic antibiotic, is one of the most frequently consumed antibiotics in the world. We have applied two metal-organic frameworks (MOFs) containing zinc(II) as platforms to degrade Amox. We have predicted the adsorption of this antibiotic via molecular docking calculations which have been further corroborated by means of Fourier transform infrared and UV-Vis spectroscopies, thermogravimetric analysis, X-ray diffraction and scanning microscopy measurements. We have subsequently performed mass spectrometry analysis of Amox@zeolitic imidazolate framework-8 (ZIF-8) and Amox@Zn(1,4-benzenedicarboxylate) (ZnBDC) to demonstrate the degradation of Amox upon contact with the Zn-containing frameworks. We propose a possible pathway for the degradation of Amox involving the cleavage of the four-membered β-lactam ring. These Zn-containing frameworks provide a biocompatible platform for the degradation in solution of Amox, which should also be suitable to degrade other β-lactam antibiotics.

Este trabalho relata a síntese, a caracterização e as propriedades luminescentes dos complexos de fórmulas [Tb(DBM)3L], [Tb(DBM)2(NO3)L2)] e [Tb(DBM)(NO3)2(HMPA)2)] (DBM = dibenzoilmetanato; L: TPPO = óxido de trifenilfosfina ou HMPA = óxido de hexametilfosforamida). Os compostos foram caracterizados por análise elementar (CHN), titulação complexométrica com EDTA e espectroscopia no infravermelho com transformada de Fourier (FTIR), e as propriedades de fotoluminescência foram avaliadas. As energias dos estados tripletos do ligante DBM foram determinadas experimentalmente a partir dos espectros de fosforescência resolvidos no tempo dos compostos análogos do íon Gd3+. As energias aumentam em função do número de ânions nitratos que substituem o ligante DBM nos complexos. Ademais, os espectros de luminescência e os tempos de vida dos níveis emissores revelaram que a eficiência de transferência de energia ligante-metal segue a mesma tendência. Ao contrário dos complexos tris-DBM, o bis- e o mono-DBM apresentaram elevada intensidade de luminescência, sendo candidatos promissores para camadas emissoras de luz em dispositivos moleculares conversores de luz (LCMD).

The Tb3+-β-diketonate complexes [Tb(DBM)3L], [Tb(DBM)2(NO3)L2] and [Tb(DBM)(NO3)2(HMPA)2] (DBM = dibenzoylmethanate; L: TPPO = triphenylphosphine oxide or HMPA = hexamethylphosphine oxide) were prepared and characterized by elemental analysis (CHN), complexometric titration with EDTA and Fourier transform infrared (FTIR) spectroscopy, and the photoluminescence properties evaluated. The triplet state energies of the coordinated DBM ligands were determined using time-resolved phosphorescence spectra of analogous Gd3+ complexes. The results show that the energies increase along with the number of coordinated nitrate anions replacing the DBM ligand in the complexes. The luminescence spectra and emission lifetime measurements revealed that the ligand-to-metal energy transfer efficiency follows the same tendency. Unlike the tris-DBM complexes, bis- and mono-DBM presented high luminescence, and may act as promising candidates for preparation of the emitting layer of light converting molecular devices (LCMDs).

Neste trabalho, ferramentas teóricas foram utilizadas no estudo de propriedades espectroscópicas do conjugado microcistina-LR-criptato de európio. O modelo Sparkle/AM1 foi aplicado na previsão da geometria do sistema e o modelo INDO/S-CIS foi utilizado no cálculo das energias dos estados excitados. Os parâmetros de Intensidade foram previstos baseados na teoria Judd-Ofelt e o modelo teórico baseado na teoria das transições 4f-4f foi aplicado no cálculo das taxas de transferência e de retrotransferência de energia, taxas de decaimento radiativo e não radiativo, eficiência e rendimento quânticos. Um estudo detalhado das propriedades luminescentes do conjugado microcistina-LR-criptato de európio foi realizado. Os resultados mostram que o rendimento quântico teórico de 23% está em bom acordo com valores experimentais publicados. Este fato sugere que este protocolo teórico pode ser usado para a concepção de novos sistemas objetivando melhorar as propriedades luminescentes. Os resultados sugerem que este sistema luminescente pode ser um bom conjugado para ser usado no teste ELISA para detecção por fluorescência da microcistina-LR em água.

In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water.

Neste trabalho relatamos o uso de nitratos de lantanídeos [Ln(NO3)3] atuando como catalisador na síntese de uma única etapa de derivados de 3-benzoíla- e 3-acetila-1,2,4-oxadiazóis a partir de cetonas, nitrilas e ácido nítrico. Este é o primeiro exemplo da síntese em única etapa de preparação de derivados benzoíla e acetila-1,2,4-oxadiazóis, usando acetofenonas com grupos doadores de elétrons.

In this work we report the use of lanthanide nitrates [Ln(NO3)3] acting as catalyst in direct one-pot synthesis of 3-benzoyl- and 3-acetyl-1,2,4-oxadiazoles derivatives from ketones, nitriles and nitric acid. This is the first example of one-pot synthesis of benzoyl- and acetyl 1,2,4-oxadiazoles derivatives preparation using acetophenones derivates with electron-donator groups.

Uma nova classe de complexos ditiocarbamato de lantanídeo foi usada para promover a cianosililação de aldeídos com elevados rendimentos à temperatura ambiente. Esta é a primeira aplicação de ditiocarbamato de lantanídeo atuando como ácido de Lewis.

A new class of lanthanide dithiocarbamate complexes was used to promote the cyanosilylation of aldehydes at high yields at room temperature. This represents the first application of lanthanide dithiocarbamate acting as Lewis acid.

This work reports on the synthesis, characterization (infrared and hidrogen nmr spectra) and photophysical properties (luminescence spectra and emission quantum yield) of the lanthanide cryptates [Ln<FONT FACE=Symbol>Ì</FONT>(bipy)2py(CO2Et) 2]3+ with Ln = Eu3+, Tb3+ or Gd3+, which can be applied as efficient Light-Conversion-Molecular-Devices. From emission spectra of [Eu<FONT FACE=Symbol>Ì</FONT>(bipy)2py(CO2Et) 2]3+ it was possible to assign C3 symmetry to the metal ion. The spectroscopic studies show a higher emission quantum yield (q=25%) for [Tb<FONT FACE=Symbol>Ì</FONT>(bipy)2py(CO2Et) 2]3+ in aqueous solution, whereas the europium cryptate presents q=14%. This is justified by a more efficient energy transfer between triplet and emission levels of terbium (T->5D4).

We are working in a new multi-doped glassy material to generate simultaneously the three primary light color (by addition) of the visible spectrum, with the control of the intensity of each one, allowing the simulation of any color: a full-color generator device. Tm+3, Tb+3 and Eu+3 ions were used (0.01 to 5,0 mol%) as blue, green and red narrow line emitters. A wide color gamut was obtained under ultraviolet excitation by varying the material composition. The chromaticity diagram is covered, including the white simulation.

Recentlly, we have proposed the representation of lanthanides within AM1 as sparkles for the purpose of obtaing ground state geometries of their complexes. We tested our quantum chemical sparkle model (SMLC/AM1) for the prediction of the crystallographic structure of complexes with coordination number nine, eight and seven. A technique is introduced for the theoretical prediction of eletronic spectra of the organic part of lanthanide complexes by replacing the metal ion by a point charge with the ligands held in their positions as determined by the SMLC/AM1, and by computing the theoretical spectra via the intermediate neglect of differential overlap/spectroscopic-configuration interaction (INDO/S-CI).