A multifunctional smart supramolecular platform based on a lanthanide-organic hydrogel is presented. This platform, which provides unique biocompatibility and tunable optical properties, is synthesized by a simple, fast, and reproducible eco-friendly microwave-assisted route. Photoluminescent properties enable the production of coated light-emitting diodes (LED), unique luminescent barcodes dependent on the excitation wavelength and thin-films for use in tamper seals. Moreover, piroxicam entrapped in hydrogel acts as a transdermal drug release device efficient in inhibiting edemas as compared to a commercial reference.
The metal–organic framework
(MOF) [Eu(DPA)(HDPA)] (where
DPA is dipicolinic acid) has been previously reported as an efficient
marker for gunshot residues (GSRs). Since this marker will be in contact
with various shooters, industrial workers, and the environment, however,
it is important to identify its toxicity. In this work, the oral and
the inhalation acute toxicities of the MOF [Eu(DPA)(HDPA)] (also called
R-Marker) were evaluated in young Wistar rats using Guidelines 423
(oral) and 436 (inhalation) from the Organisation for Economic Co-operation
and Development (OECD). Animal behavior; body weight, water, and food
intake; and organ weight, as well as biochemical parameters were evaluated
in both evaluations. For the inhalation test, a concentration of 1
mg·Lair
–1·(4 h–1) was reached in a whole-body inhalation chamber. When the respiratory
tract was analyzed, it was observed that part of the marker had been
swallowed instead of inhaled by the animal. For the oral test, the
highest administrated dose was 2000 mg/kg with no sign of toxicity.
This marker has been classified in the least toxic category of the
Globally Harmonized System (GHS; category 5), with an oral median
lethal dose (LD50) of 5000 mg/kg. After the oral administration,
the feces of the animals were collected using a metabolic cage. Luminescent
feces were present up to 24 h after administration, indicating that
the marker had been excreted by the organism without causing intoxication.
This study has opened perspectives for drug delivery and toxicity
studies, since it enables visual detection of the marker.
Ozone chambers have emerged as an alternative method to decontaminate firefighters’ Personal Protective Equipment (PPE) from toxic fire residues. This work evaluated the efficiency of using an ozone chamber to clean firefighters’ PPE. This was achieved by studying the degradation of pyrene and 9-methylanthracene polycyclic aromatic hydrocarbons (PAHs). The following experiments were performed: (i) insufflating ozone into PAH solutions (homogeneous setup), and (ii) exposing pieces of PPE impregnated with the PAHs to an ozone atmosphere for up to one hour (heterogeneous setup). The ozonolysis products were assessed by Fourier Transform Infrared Spectroscopy (FTIR), Thin-Layer Chromatography (TLC), and Mass Spectrometry (MS) analysis. In the homogeneous experiments, compounds of a higher molecular weight were produced due to the incorporation of oxygen into the PAH structures. Some of these new compounds included 4-oxapyren-5-one (m/z 220) and phenanthrene-4,5-dicarboxaldehyde (m/z 234) from pyrene; or 9-anthracenecarboxaldehyde (m/z 207) and hydroxy-9,10-anthracenedione (m/z 225) from 9-methylanthracene. In the heterogeneous experiments, a lower oxidation was revealed, since no byproducts were detected using FTIR and TLC, but only using MS. However, in both experiments, significant amounts of the original PAHs were still present even after one hour of ozone treatment. Thus, although some partial chemical degradation was observed, the remaining PAH and the new oxygenated-PAH compounds (equally or more toxic than the initial molecules) alerted us of the risks to firefighters’ health when using an ozone chamber as a unique decontamination method. These results do not prove the ozone-advertised efficiency of the ozone chambers for decontaminating (degrading the toxic combustion residues into innocuous compounds) firefighters’ PPE.
In this work, we describe the synthetic approach of pyrimidine-substituted derivatives, photoluminescence properties and theoretical calculations of the geometry optimization and electron density distribution on the molecules in the ground and excited states. According to calculations, the location of HOMO electron density is mainly located over the molecular region with highest electron-donor character (or lower electron-acceptor). On the other hand, the electronic transition from HOMO to LUMO promotes a change in the electron density distribution on the molecule. The simulations also reveal that plane of all aryl substituent's located at positions 2 and 6, are out of the pyrimidine ring plane and the absolute dihedral angles values between n-(p-phenyl) and pyrimidine ring planes are intrinsically dependent on the spatial HOMO distribution on the phenyl ring and p-substituent group. The higher donor character of the substituent leads to substantial changes in the absorption spectra. We also notice that the absorption changes are intrinsically related to the portion of ICT in the molecules, which are strongly dependent on polar interaction. All compounds present large Stokes shifts, higher than 3.370 cm-1 , and the emission spectra in solution present broad bands in the ultraviolet-visible region. On the other hand, the solid-state luminescence of 3a and 3c compounds shows emission band in the near-yellow color region 0.423, 0.475 (x, y) and 0.485, 0.542, respectively, in which the 5a and 5c compounds exhibit emission bands corresponding to the near-red color region 0.569, 0.415 and 0.608, 0.389, respectively.
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