RT Journal Article
T1 Dendrimers as Color-Stabilizers of Pyranoanthocyanins: the Dye Concentration Governs the Host-Guest Interaction Mechanisms
A1 Cruz, Luis
A1 Correa Chinea, Juan Francisco
A1 Mateus, Nuno
A1 Freitas, Víctor de
A1 Tawara, Maun H.
A1 Fernández Megía, Eduardo
K1 NMR
K1 UV-vis
K1 Pyranoanthocyanins
K1 Dendrimers
K1 Encapsulation
K1 PHsensors
K1 Host−guest interaction
AB Anionic dendrimers have recently emerged as hosts (H) for the color stabilization of the flavylium cation of anthocyanin guests (G). The interaction with a promising, more hydrophobic pyranoanthocyanin illustrates how the structure and concentration of the dye modulate the host–guest interaction mechanisms. NMR and UV–vis titrations (host over guest, from G/H ratio 2089 to 45) showed that at relatively low dendrimer-to-dye concentrations, ion pairs at the dendrimer periphery prevail over dye encapsulation. This promotes the deaggregation of the dye, not previously observed with anthocyanins, and related to the more hydrophobic nature of this dye (deshielding of the dye 1H signals, higher T2 relaxation times, constant diffusion coefficient). As the dendrimer concentration increases, the dye encapsulation, earlier unseen with structurally simpler flavylium dyes, becomes dominant (shielding and broadening of the dye 1H signals and lower T2 and diffusion coefficient). The interaction parameters of the encapsulation process (K ∼ 4.51 × 104 M–1, n ∼ 150) indicate the binding of ca. one pyranoanthocyanin molecule by each sulfate terminal group. Our results provide insights into the ability of dendrimers to host structurally diverse pyranoflavylium-based dyes and how the structure of the latter modulates the range of interactions involved. The encapsulation ability of this dendrimer to such pH-sensitive dyes is envisioned for the host–guest sensing applications such as pH-responsive systems used for example in food smart packaging
PB ACS
SN 1457−1464
YR 2021
FD 2021
LK http://hdl.handle.net/10347/27028
UL http://hdl.handle.net/10347/27028
LA eng
NO ACS Appl. Polym. Mater. 2021, 3, 1457−1464
NO This research was supported by a research project grant (PTDC/OCE-ETA/31250/2017) with financial support from FCT/MCTES through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 (UID/QUI/50006/2020, ). This research was conducted under the project AgriFood XXI–NORTE-01–0145-FEDER-000041, financed by European Regional Development Fund (FEDER) through North Portugal Regional Operational Programme (Norte 2020). Financial support was also obtained from the Spanish Ministry of Science and Innovation (RTI2018-102212-B-I00), Xunta de Galicia (ED431C 2018/30 and Centro singular de investigación de Galicia accreditation 2019–2022, ED431G 2019/03), Axencia Galega de Innovación (IN845D 2020/09), and the European Union (European Regional Development Fund-ERDF)
DS Minerva
RD 28 abr 2026