RT journal article
T1 Stability and pKa Modulation of Aminophenoxazinones and Their Disulfide Mimics by Host-Guest Interaction with Cucurbit[7]uril. Direct Applications in Agrochemical Wheat Models
A1 Rodríguez Mejías, Francisco Javier
A1 He, Suhang
A1 Varela Montoya, Rosa María
A1 González Molinillo, José María
A1 Barba-Bon, Andrea
A1 Nau, Werner M.
A1 Macías Domínguez, Francisco Antonio
A2 Química Orgánica
K1 aminophenoxazinones
K1 cucurbiturils
K1 pKa shift
K1 disulfide
K1 agrochemicals
K1 host−guest interactions
AB Aqueous solubility and stability often limit the application of aminophenoxazinones and their sulfur mimics as promising agrochemicals in a sustainable agriculture inspired by allelopathy. This paper presents a solution to the problem using host-guest complexation with cucurbiturils (CBn). Computational studies show that CB7 is the most suitably sized homologue due to its strong affinity for guest molecules and its high water solubility. Complex formation has been studied by direct titrations monitored using UV-vis spectroscopy, finding a preferential interaction with protonated aminophenoxazinone species with high binding affinities (CB7 center dot APOH+ , Ka = (1.85 +/- 0.37) x 106 M-1; CB7 center dot DiS-NH3+ , Ka = (3.91 +/- 0.53) x 104 M-1; and DiS-(NH3+)2 , Ka= (1.27 +/- 0.42) x 105M-1). NMR characterization and stability analysis were also performed and revealed an interesting pKa modulation and stabilization by cucurbiturils (2-amino-3H-phenoxazin-3-one (APO), pKa = 2.94 +/- 0.30, and CB7 center dot APO, pKa = 4.12 +/- 0.15; 2,2 '-disulfanediyldianiline (DiS-NH2), pKa = 2.14 +/- 0.09, and CB7 center dot DiS-NH2 , pKa = 3.26 +/- 0.09), thus favoring applications in different kinds of crop soils. Kinetic studies have demonstrated the stability of the CB7 center dot APO complex at different pH media for more than 90 min. An in vitro bioassay with etiolated wheat coleoptiles showed that the bioactivity of APO and DiS-NH2 is enhanced upon complexation.
PB ACS
SN 1520-5118
YR 2022
FD 2022-12
LK http://hdl.handle.net/10498/27846
UL http://hdl.handle.net/10498/27846
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 12-nov-2026