Complexes between 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH) and cucurbit[ n ]uril hosts modulate the yield and fate of photolytically-generated AAPH radicals.

Autor:	Forero-Girón AC; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Oyarzún M; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Droguett K; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Fuentealba D; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Gutiérrez-Oliva S; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Herrera B; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Toro-Labbé A; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Fuentes-Lemus E; Department of Biomedical Sciences, Panum Institute, University of Copenhagen Denmark., Davies MJ; Department of Biomedical Sciences, Panum Institute, University of Copenhagen Denmark., López-Alarcón C; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl., Aliaga ME; Departmento de Química Física, Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile Chile mealiaga@uc.cl clopezr@uc.cl.
Jazyk:	angličtina
Zdroj:	RSC advances [RSC Adv] 2024 Nov 11; Vol. 14 (48), pp. 35980-35991. Date of Electronic Publication: 2024 Nov 11 (Print Publication: 2024).
DOI:	10.1039/d4ra07150f
Abstrakt:	Using theoretical and experimental tools we investigated the recognition of AAPH (2,2'-azobis(2-methylpropionamidine) dihydrochloride), a well-known water-soluble azo-compound employed as a source of peroxyl radicals, by cucurbit[6]uril (CB[6]), and cucurbit[8]uril (CB[8]). Density functional theory calculations and isothermal titration calorimetry experiments demonstrated that AAPH was not included in the cavity of CB[6], however, an exclusion complex was generated. Inclusion of AAPH in the CB[8] cavity was favored, forming stable inclusion complexes at 1 : 1 and 2 : 1 stoichiometries; AAPH@CB[8] and 2AAPH@CB[8], respectively. Radical formation upon photolytic cleavage of AAPH was examined theoretically, and by spin trapping with electron paramagnetic resonance. The radical yields detected with uncomplexed (free) AAPH and the AAPH-CB[6] (exclusion) complex were identical, whereas a marked decrease was shown for AAPH@CB[8]. Lower decreases were seen with a bimolecular (2 : 1) AAPH-CB[8] inclusion complex (2AAPH@CB[8]). This modulation was corroborated by the consumption of pyrogallol red (PGR), an oxidizable dye that does not associate with CB[6] or CB[8]. AAPH-CB[6] and 2AAPH@CB[8] did not significantly modify the initial consumption rate (Ri) of PGR, whereas AAPH@CB[8] decreased this. The oxidative consumption of free Trp, Gly-Trp and Trp-Gly by radicals derived from AAPH in the presence of CB[8] showed a dependence on the association of the targets with CB[8]. Competing Interests: There are no conflicts to declare. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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