Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs
This article is engaged with the search for a confident theoretical model to study the stabilization energies and geometry of free radicals stabilized by a porphin ring and/or a p-X-substituted phenyl ring, where X is either an electron donating or withdrawing atom or group. DFT calculations at the B3LYP/6-31G(d,p) or UB3LYP/6-31G(d,p) levels of theory were applied to homolog series of saturated porhyrins 2(a-h) - 5(a-h) and porphyrinoids 3⋅(a-h), 4⋅(a-h) series, respectively. Calculated radical stabilization energy (RSE) values for the various p-X-phenyl substituents of benzyl radical 6⋅(a-h) series obtained through an isodesmic reaction model (Scheme 1) provided a quite good correlation (r = 0.989) with the radical total effect (TE) reported by Wu (Wu et al., 1996). The TE effect is generally accepted as a scale to study radical stabilization due to spin delocalization, since it is in a very good agreement with the experimental ESR hyperfine coupling constants (hfc) of benzyl radicals (Dust and Arnold, 1983). Likewise, isodesmic RSE values for porphyrinoid 3⋅(a-h) series provided a good correlation (r = 0.940) with RSE values for 6⋅. However, RSE values for porphyrinoid 4β⋅(a-h) series deviate from the expected correlation trend (r = 0.731), not to mention 4α⋅(a-h) series (r = 0.660). Relative absorption wavenumbers (Δλ, nm) at the λmax bands of porphyrin series [λ(3.) -λ(3)] and [λ(4.) -λ(4)] indicate large porphyrinoid bathochromic effects (ca. 200 - 300 nm).
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Laboratorios Mixim S.A.
2012
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oai:scielo:S0370-594320120003000062014-09-23Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugsGordillo-Román,Bárbara porphyrin theoretical calculations free radicals bathochromic effect This article is engaged with the search for a confident theoretical model to study the stabilization energies and geometry of free radicals stabilized by a porphin ring and/or a p-X-substituted phenyl ring, where X is either an electron donating or withdrawing atom or group. DFT calculations at the B3LYP/6-31G(d,p) or UB3LYP/6-31G(d,p) levels of theory were applied to homolog series of saturated porhyrins 2(a-h) - 5(a-h) and porphyrinoids 3⋅(a-h), 4⋅(a-h) series, respectively. Calculated radical stabilization energy (RSE) values for the various p-X-phenyl substituents of benzyl radical 6⋅(a-h) series obtained through an isodesmic reaction model (Scheme 1) provided a quite good correlation (r = 0.989) with the radical total effect (TE) reported by Wu (Wu et al., 1996). The TE effect is generally accepted as a scale to study radical stabilization due to spin delocalization, since it is in a very good agreement with the experimental ESR hyperfine coupling constants (hfc) of benzyl radicals (Dust and Arnold, 1983). Likewise, isodesmic RSE values for porphyrinoid 3⋅(a-h) series provided a good correlation (r = 0.940) with RSE values for 6⋅. However, RSE values for porphyrinoid 4β⋅(a-h) series deviate from the expected correlation trend (r = 0.731), not to mention 4α⋅(a-h) series (r = 0.660). Relative absorption wavenumbers (Δλ, nm) at the λmax bands of porphyrin series [λ(3.) -λ(3)] and [λ(4.) -λ(4)] indicate large porphyrinoid bathochromic effects (ca. 200 - 300 nm).info:eu-repo/semantics/openAccessLaboratorios Mixim S.A.Revista latinoamericana de química v.40 n.3 20122012-01-01info:eu-repo/semantics/articletext/htmlhttp://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0370-59432012000300006en |
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Gordillo-Román,Bárbara Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs |
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Gordillo-Román,Bárbara |
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Gordillo-Román,Bárbara |
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Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs |
title_short |
Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs |
title_full |
Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs |
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Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs |
title_full_unstemmed |
Radical stabilization of meso porphyrinoids: Gleaning theoretical data for the rational design of porphyrinyl prodrugs |
title_sort |
radical stabilization of meso porphyrinoids: gleaning theoretical data for the rational design of porphyrinyl prodrugs |
description |
This article is engaged with the search for a confident theoretical model to study the stabilization energies and geometry of free radicals stabilized by a porphin ring and/or a p-X-substituted phenyl ring, where X is either an electron donating or withdrawing atom or group. DFT calculations at the B3LYP/6-31G(d,p) or UB3LYP/6-31G(d,p) levels of theory were applied to homolog series of saturated porhyrins 2(a-h) - 5(a-h) and porphyrinoids 3⋅(a-h), 4⋅(a-h) series, respectively. Calculated radical stabilization energy (RSE) values for the various p-X-phenyl substituents of benzyl radical 6⋅(a-h) series obtained through an isodesmic reaction model (Scheme 1) provided a quite good correlation (r = 0.989) with the radical total effect (TE) reported by Wu (Wu et al., 1996). The TE effect is generally accepted as a scale to study radical stabilization due to spin delocalization, since it is in a very good agreement with the experimental ESR hyperfine coupling constants (hfc) of benzyl radicals (Dust and Arnold, 1983). Likewise, isodesmic RSE values for porphyrinoid 3⋅(a-h) series provided a good correlation (r = 0.940) with RSE values for 6⋅. However, RSE values for porphyrinoid 4β⋅(a-h) series deviate from the expected correlation trend (r = 0.731), not to mention 4α⋅(a-h) series (r = 0.660). Relative absorption wavenumbers (Δλ, nm) at the λmax bands of porphyrin series [λ(3.) -λ(3)] and [λ(4.) -λ(4)] indicate large porphyrinoid bathochromic effects (ca. 200 - 300 nm). |
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Laboratorios Mixim S.A. |
publishDate |
2012 |
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http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0370-59432012000300006 |
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AT gordilloromanbarbara radicalstabilizationofmesoporphyrinoidsgleaningtheoreticaldatafortherationaldesignofporphyrinylprodrugs |
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