RESUMEN
Combination of the calculation of reactivity descriptors and the cold iodine test for some coumarin derivatives was used in order to optimize the radioiodination reaction. The strongly nucleophilic predicted coumarins were subjected to the action of cold iodine. With two coumarins substituted at 3 by the 2-hydroxybenzoyl group, iodination did not occur but a product of intramolecular heterocyclization was obtained. This strategy is useful for economic and environmentally friendly radioiodination.
Asunto(s)
Costos y Análisis de Costo , Cumarinas/química , Radioisótopos de Yodo/química , Cromatografía Líquida de Alta Presión , Ciclización , Espectrofotometría UltravioletaRESUMEN
The single methyl group transfer (MGT), double MGT and single MGT assisted by proton transfer (PT) that occurs in small biological systems N-methoxy methylene formamide and N-hydroxy methylen formamide (NMMF-NHMF) have been investigated completely in the present study using density functional theory (DFT) and Möller-Plesset perturbation (MP2) methods with a 6-31G(d) basis set. The barrier height for MGT assisted by PT is significantly lower than those of the single and double MGT. Polar solvents decrease the energy barriers.
RESUMEN
The interaction between one polychlorobiphenyl (3,3',4,4',-tetrachlorobiphenyl, coded PCB77) and the four DNA nucleic acid-base is studied by means of quantum mechanics calculations in stacked conformations. It is shown that even if the intermolecular dispersion energy is the largest component of the total interaction energy, some other contributions play a non negligible role. In particular the electrostatic dipole-dipole interaction and the charge transfer from the nucleobase to the PCB are responsible for the relative orientation of the monomers in the complexes. In addition, the charge transfer tends to flatten the PCB, which could therefore intercalate more easily between DNA base pairs. From these seminal results, we predict that PCB could intercalate completely between two base pairs, preferably between Guanine:Cytosine pairs.
Asunto(s)
Adenina/química , Citosina/química , ADN/química , Contaminantes Ambientales/química , Guanina/química , Sustancias Intercalantes/química , Bifenilos Policlorados/química , Timina/química , Emparejamiento Base , Humanos , Enlace de Hidrógeno , Modelos Moleculares , Conformación de Ácido Nucleico , Teoría Cuántica , Electricidad Estática , TermodinámicaRESUMEN
Iridium(III) complexes are among the most used phosphorescent materials for the development of organic light emitting diodes (OLEDs). In this work, the photophysical properties of a family of complexes based on phenyldiazine ligands were studied. Their ground state geometric and electronic structures as well as their absorption and emission spectra were investigated by the means of density functional theory (DFT) and time-dependent DFT (TD-DFT). An extremely good agreement between the computed and experimental values is obtained, thus suggesting that the computational protocol here applied could be used for the in silico screening and design of new Ir-based emitting complexes.
