Optical and morphological changes in the solid state of chiral imines bearing halogen substituents (F, Cl, and Br)

Experimental and DFT Study of the Photoluminescent Green Emission Band of Halogenated (−F, −Cl, and −Br) Imines

“…These effects are associated with the intensity of emission (green, red, and blue) bands caused by distortion in the crystal packing, i.e., the chiral carbon atoms in these crystals produce molecular dissymmetry, which leads to distortion in the packing as can be seen in PL spectra [67]. Worthy mentioning is that protonation of the molecule is a parameter affecting the intensity of emission bands in PL, as reported earlier, but this was not the case in our study [15,25]. The I − Br crystal has stronger intermolecular interactions, which could lead to its emission’s red shift [68].…”

“…On the other hand, prediction is a fundamental aim of the calculations based on the quantum chemistry methods, and several physicochemical properties depend largely on the more stable conformation of the molecular system in its fundamental state. Thus, the optimized molecular structure of I and I − X crystals can be compared in order to analyze the changes in the properties, as the − X atoms were substituted in the para-position of the phenyl group [25]. Molecular structures and schematic representation of the (a) I , (b) I − F , (c) I − Cl , and (d) I − Br crystals are showed in Figure 1.…”

“…An important aspect is the study of the relationship between the chemical structure and the photophysical properties of these optical materials. The experimental model applied in this paper has been reported in previous reports [25,43]. The correlation of the morphological properties associated with the optical response has motivated careful analysis of optical materials [44].…”

“…The PL spectra at room temperature for I and I − X crystals is shown in Figure 10, displaying emission bands for I located at ~599 nm (~2.13 eV), I − F : ~568 nm (~2.18 eV), I − Cl : ~553 nm (~2.24 eV), and I − Br : ~599 nm (~2.07 eV), respectively. Generally, in inorganic materials, this range corresponds to green, yellow, and red emission bands [15,25]. In order to obtain more information about the PL spectra, it is possible to perform the deconvolution of the Gaussians, which in this case are asymmetric, usually involving two overlapping bands.…”

Oximetría de pulso en enfermedades respiratorias

“…El oxímetro de pulso o pulsioxímetro es una herramienta de importancia clínica (1) al ser indicado en protocolos estándar de pacientes sometidos a procedimientos anestésicos y hospitalizaciones (2)(3)(4)(5)(6). Se usa principalmente para el monitoreo de saturación de oxígeno con el fin de prevenir niveles subóptimos de oxígeno arterial y complicaciones en pacientes con riesgo de hipoxia (7,8).…”