1
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de Souza HKS, Guimarães M, Mateus N, de Freitas V, Cruz L. Chitosan/Polyvinyl Alcohol-Based Biofilms Using Ternary Deep Eutectic Solvents towards Innovative Color-Stabilizing Systems for Anthocyanins. Int J Mol Sci 2024; 25:6154. [PMID: 38892341 PMCID: PMC11173141 DOI: 10.3390/ijms25116154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 05/29/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
Anthocyanins are amazing plant-derived colorants with highly valuable properties; however, their chemical and color instability issues limit their wide application in different food industry-related products such as active and intelligent packaging. In a previous study, it was demonstrated that anthocyanins could be stabilized into green plasticizers namely deep eutectic solvents (DESs). In this work, the fabrication of edible films by integrating anthocyanins along with DESs into biocompatible chitosan (CHT)-based formulations enriched with polyvinyl alcohol (PVA) and PVA nanoparticles was investigated. CHT/PVA-DES films' physical properties were characterized by scanning electron microscopy, water vapor permeability, swelling index, moisture sorption isotherm, and thermogravimetry analysis. Innovative red-to-blue formulation films were achieved for CHT/PVA nanoparticles (for 5 min of sonication) at a molar ratio 1:1, and with 10% of ternary DES (TDES)-containing malvidin-3-glucoside (0.1%) where the physical properties of films were enhanced. After immersion in solutions at different pH values, films submitted to pHs 5-8 were revealed to be more color stable and resistant with time than at acidic pH values.
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Affiliation(s)
- Hiléia K. S. de Souza
- REQUIMTE/LAQV, Chemistry and Biochemistry Department, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (H.K.S.d.S.); (M.G.); (N.M.); (V.d.F.)
- PIEP—Pólo de Inovação em Engenharia de Polímeros, Universidade do Minho, Campus de Azurém, Edifício 15, 4800-058 Guimarães, Portugal
| | - Marta Guimarães
- REQUIMTE/LAQV, Chemistry and Biochemistry Department, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (H.K.S.d.S.); (M.G.); (N.M.); (V.d.F.)
| | - Nuno Mateus
- REQUIMTE/LAQV, Chemistry and Biochemistry Department, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (H.K.S.d.S.); (M.G.); (N.M.); (V.d.F.)
| | - Victor de Freitas
- REQUIMTE/LAQV, Chemistry and Biochemistry Department, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (H.K.S.d.S.); (M.G.); (N.M.); (V.d.F.)
| | - Luís Cruz
- REQUIMTE/LAQV, Chemistry and Biochemistry Department, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (H.K.S.d.S.); (M.G.); (N.M.); (V.d.F.)
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2
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Cruz L, Basílio N, Mateus N, de Freitas V, Pina F. Natural and Synthetic Flavylium-Based Dyes: The Chemistry Behind the Color. Chem Rev 2021; 122:1416-1481. [PMID: 34843220 DOI: 10.1021/acs.chemrev.1c00399] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Flavylium compounds are a well-known family of pigments because they are prevalent in the plant kingdom, contributing to colors over a wide range from shades of yellow-red to blue in fruits, flowers, leaves, and other plant parts. Flavylium compounds include a large variety of natural compound classes, namely, anthocyanins, 3-deoxyanthocyanidins, auronidins, and their respective aglycones as well as anthocyanin-derived pigments (e.g., pyranoanthocyanins, anthocyanin-flavan-3-ol dimers). During the past few decades, there has been increasing interest among chemists in synthesizing different flavylium compounds that mimic natural structures but with different substitution patterns that present a variety of spectroscopic characteristics in view of their applications in different industrial fields. This Review provides an overview of the chemistry of flavylium-based compounds, in particular, the synthetic and enzymatic approaches and mechanisms reported in the literature for obtaining different classes of pigments, their physical-chemical properties in relation to their pH-dependent equilibria network, and their chemical and enzymatic degradation. The development of flavylium-based systems is also described throughout this Review for emergent applications to explore some of the physical-chemical properties of the multistate of species generated by these compounds.
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Affiliation(s)
- Luis Cruz
- LAQV-REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Nuno Basílio
- LAQV-REQUIMTE, Department of Chemistry, Faculty of Sciences and Technology, New University of Lisbon, 2829-516 Caparica, Portugal
| | - Nuno Mateus
- LAQV-REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Victor de Freitas
- LAQV-REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Fernando Pina
- LAQV-REQUIMTE, Department of Chemistry, Faculty of Sciences and Technology, New University of Lisbon, 2829-516 Caparica, Portugal
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3
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Mendoza J, Cruz L, de Freitas V, Pina F, Basílio N. Anthocyanin Color Stabilization by Host-Guest Complexation with p-Sulfonatocalix[n]arenes. Molecules 2021; 26:molecules26175389. [PMID: 34500822 PMCID: PMC8434021 DOI: 10.3390/molecules26175389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/16/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022] Open
Abstract
Flavylium-based compounds in their acidic and cationic form bring color to aqueous solutions, while under slightly acidic or neutral conditions they commonly bring discoloration. Selective host-guest complexation between water-soluble p-sulfonatocalix[n]arenes (SCn) macrocycles and the flavylium cationic species can increase the stability of the colored form, expanding its domain over the pH scale. The association constants between SCn and the cationic (acid) and neutral basic forms of flavylium-based compounds were determined through UV-Vis host-guest titrations at different pH values. The affinity of the hosts for synthetic chromophore was found to be higher than for a natural anthocyanin (Oenin). The higher affinity of SC4 for the synthetic flavylium was confirmed by 1H NMR showing a preferential interaction of the flavylium phenyl ring with the host cavity. In contrast with its synthetic counterpart, the flavylium substitution pattern in the anthocyanin seems to limit the inclusion of the guest in the host’s binding pocket. In this case, the higher affinity was observed for the octamer (SC8) likely due to its larger cavity and higher number of negatively charged sulfonate groups.
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Affiliation(s)
- Johan Mendoza
- LAQV—REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
- Correspondence: (J.M.); (N.B.)
| | - Luis Cruz
- LAQV—REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (L.C.); (V.d.F.)
| | - Victor de Freitas
- LAQV—REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal; (L.C.); (V.d.F.)
| | - Fernando Pina
- LAQV—REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
| | - Nuno Basílio
- LAQV—REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal;
- Correspondence: (J.M.); (N.B.)
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4
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Ujihara T, Hayashi N. Mechanism of Copigmentation of Monoglucosylrutin with Caffeine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:323-331. [PMID: 31880932 DOI: 10.1021/acs.jafc.9b06235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
4G-α-Glucopyranosylrutin (monoglucosylrutin, MGR) is a flavonol glycoside with quercetin as an aglycone, is pale yellow in color, and engages in both copigmentation and anticopigmentation. In this study, we elucidated the mechanism underlying the copigmentation of MGR upon complexation with caffeine. Three approaches were used: binding analyses based on changes in the absorbance spectrum, NOESY experiments, and DFT and TDDFT calculations using an explicit solvation model. Our findings show that copigmentation mainly results from a bathochromic shift in the absorbance spectrum and not a from hyperchromic effect. MGR and caffeine form a complex in both 1:1 and 1:2 stoichiometric ratios. The calculated optimized 1:1 and 1:2 complex structures were supported by the NOESY spectrum and form a cluster with 13 and 11 water molecules, respectively, through hydrogen bonds. Although HOMO and LUMO contribute most to the excitation of both the MGR monomer and the complexes, these frontier molecular orbitals in the complexes are distributed more widely than those in the MGR monomer. In particular, LUMO in the complexes spreads into the copigment caffeine and the solvent water molecules. This increase in electron delocalization reduces the energy gap between the frontier molecular orbitals, resulting in copigmentation with a bathochromic shift.
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Affiliation(s)
- Tomomi Ujihara
- Food Research Institute , National Agriculture and Food Research Organization (NARO) , 2-1-12 Kannondai , Tsukuba , Ibaraki 305-8642 , Japan
| | - Nobuyuki Hayashi
- Food Research Institute , National Agriculture and Food Research Organization (NARO) , 2-1-12 Kannondai , Tsukuba , Ibaraki 305-8642 , Japan
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Araújo P, Basílio N, Fernandes A, Mateus N, de Freitas V, Pina F, Oliveira J. Impact of Lignosulfonates on the Thermodynamic and Kinetic Parameters of Malvidin-3- O-glucoside in Aqueous Solutions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:6382-6387. [PMID: 29870233 DOI: 10.1021/acs.jafc.8b02273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The interaction of malvidin-3- O-glucoside (1) and a lignosulfonate was studied by UV-visible spectroscopy, and the results obtained showed the formation of a complex between the negatively charged lignosulfonate and the flavylium cation form (AH+) of this anthocyanin at pH 1. The thermodynamic and kinetic parameters of 1 in the presence of a lignosulfonate were determined by UV-visible spectroscopy and stopped-flow techniques. The main differences were observed in the flavylium cation (AH+)/quinoidal base (A) equilibrium, the AH+ form being more stabilized than A (p Ka1 = 4.4 ± 0.1) compared with 1 in the absence of the lignosulfonate (p Ka1 = 3.9 ± 0.1). Furthermore, comparing the hydration ( kh = 0.028 s-1) and dehydration ( k-h = 40 M-1 s-1) processes of 1 in the presence of the lignosulfonate with the processes of 1 ( kh = 0.12 s-1 and k-h = 35 M-1 s-1) show that the hydration process is slower while the dehydration process is practically unaffected in the presence of the lignosulfonate.
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Affiliation(s)
- Paula Araújo
- ICETA/REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências , Universidade do Porto , Rua do Campo Alegre, 687 , 4169-007 Porto , Portugal
| | - Nuno Basílio
- REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química, Faculdade de Ciências e Tecnologia , Universidade NOVA de Lisboa , 2829-516 Monte de Caparica , Portugal
| | - Ana Fernandes
- ICETA/REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências , Universidade do Porto , Rua do Campo Alegre, 687 , 4169-007 Porto , Portugal
| | - Nuno Mateus
- ICETA/REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências , Universidade do Porto , Rua do Campo Alegre, 687 , 4169-007 Porto , Portugal
| | - Victor de Freitas
- ICETA/REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências , Universidade do Porto , Rua do Campo Alegre, 687 , 4169-007 Porto , Portugal
| | - Fernando Pina
- REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química, Faculdade de Ciências e Tecnologia , Universidade NOVA de Lisboa , 2829-516 Monte de Caparica , Portugal
| | - Joana Oliveira
- ICETA/REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências , Universidade do Porto , Rua do Campo Alegre, 687 , 4169-007 Porto , Portugal
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6
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Macartney DH. Cucurbit[n]uril Host-Guest Complexes of Acids, Photoacids, and Super Photoacids. Isr J Chem 2017. [DOI: 10.1002/ijch.201700096] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Donal H. Macartney
- Department of Chemistry; Queen's University; 90 Bader Lane, Kingston ON Canada K7L3N6
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7
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Basílio N, Lima JC, Cruz L, de Freitas V, Pina F, Ando H, Kimura Y, Oyama KI, Yoshida K. Unveiling the 6,8-Rearrangement in 8-Phenyl-5,7-dihydroxyflavylium and 8-Methyl-5,7-dihydroxyflavylium through Host-Guest Complexation. European J Org Chem 2017. [DOI: 10.1002/ejoc.201701009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Nuno Basílio
- LAQV; REQUIMTE; Departamento de Química; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; 2829-516 Caparica Portugal
| | - João Carlos Lima
- LAQV; REQUIMTE; Departamento de Química; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; 2829-516 Caparica Portugal
| | - Luís Cruz
- REQUIMTE/LAQV; Departamento de Química e Bioquímica; Faculdade de Ciências e Tecnologia; Universidade do Porto; Rua do Campo Alegre 687 4169-007 Porto Portugal
| | - Victor de Freitas
- REQUIMTE/LAQV; Departamento de Química e Bioquímica; Faculdade de Ciências e Tecnologia; Universidade do Porto; Rua do Campo Alegre 687 4169-007 Porto Portugal
| | - Fernando Pina
- LAQV; REQUIMTE; Departamento de Química; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; 2829-516 Caparica Portugal
| | - Hiroki Ando
- Graduate School of Information Sciences; Nagoya University; 464-8601 Chikusa, Nagoya Japan
| | - Yuki Kimura
- Graduate School of Information Sciences; Nagoya University; 464-8601 Chikusa, Nagoya Japan
| | - Kin-Ichi Oyama
- Chemical Instrumentation Facility; Research Center for Materials Science; Nagoya University; 464-8602 Chikusa, Nagoya Japan
| | - Kumi Yoshida
- Graduate School of Informatics; Nagoya University; 464-8601 Chikusa Japan
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8
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Basílio N, Gago S, Parola AJ, Pina F. Contrasting p K a Shifts in Cucurbit[7]uril Host-Guest Complexes Governed by an Interplay of Hydrophobic Effects and Electrostatic Interactions. ACS OMEGA 2017; 2:70-75. [PMID: 31457209 PMCID: PMC6640924 DOI: 10.1021/acsomega.6b00427] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 12/29/2016] [Indexed: 05/22/2023]
Abstract
Cucurbit[7]uril inclusion complexes with guests bearing dimethylamino groups show the expected upward pK a shifts, whereas their diethylamino counterparts display a decrease in pK a due to the preferential stabilization of the unprotonated form. These results identify the diethylamino group as the substituent of choice to avoid receptor-assisted protonation of guest molecules and present new evidence for the role of the hydrophobic effect as a driving force in cucurbituril complexation.
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Affiliation(s)
- Nuno Basílio
- Laboratório Associado
para a Química Verde (LAQV), Rede de Química e Tecnologia
(REQUIMTE), Departmento de Química, Faculdade de Ciências
e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Sandra Gago
- Laboratório Associado
para a Química Verde (LAQV), Rede de Química e Tecnologia
(REQUIMTE), Departmento de Química, Faculdade de Ciências
e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - A. Jorge Parola
- Laboratório Associado
para a Química Verde (LAQV), Rede de Química e Tecnologia
(REQUIMTE), Departmento de Química, Faculdade de Ciências
e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Fernando Pina
- Laboratório Associado
para a Química Verde (LAQV), Rede de Química e Tecnologia
(REQUIMTE), Departmento de Química, Faculdade de Ciências
e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
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9
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Basílio N, Pina F. Chemistry and Photochemistry of Anthocyanins and Related Compounds: A Thermodynamic and Kinetic Approach. Molecules 2016; 21:E1502. [PMID: 27834931 PMCID: PMC6273059 DOI: 10.3390/molecules21111502] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/02/2016] [Accepted: 11/03/2016] [Indexed: 11/25/2022] Open
Abstract
Anthocyanins are identified by the respective flavylium cation, which is only one species of a multistate of different molecules reversibly interconverted by external inputs such as pH, light and temperature. The flavylium cation (acidic form) is involved in an apparent acid-base reaction, where the basic species is the sum of quinoidal base, hemiketal and cis- and trans-chalcones, their relative fraction depending on the substitution pattern of the flavylium cation. The full comprehension of this complex system requires a thermodynamic and kinetic approach. The first consists in drawing an energy level diagram where the relative positions of the different species are represented as a function of pH. On the other hand, the kinetic approach allows measuring the rates of the reactions that interconnect reversibly the multistate species. The kinetics is greatly dependent on the existence or not of a high cis-trans isomerization barrier. In this work, the procedure to obtain the energy level diagram and the rates of inter-conversion in the multistate in both cases (low or high isomerization barrier) are described. Practical examples of this approach are presented to illustrate the theory, and recently reported applications based on host-guest complexes are reviewed.
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Affiliation(s)
- Nuno Basílio
- LAQV, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
| | - Fernando Pina
- LAQV, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
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10
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Basílio N, Pischel U. Drug Delivery by Controlling a Supramolecular Host-Guest Assembly with a Reversible Photoswitch. Chemistry 2016; 22:15208-15211. [DOI: 10.1002/chem.201603331] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Nuno Basílio
- Laboratório Associado para a Química Verde (LAQV); Rede de Química e Tecnologia (REQUIMTE); Departmento de Química; Faculdade de Ciências e Tecnologia; Universidade NOVA de Lisboa; 2829-516 Caparica Portugal
| | - Uwe Pischel
- CIQSO - Center for Research in Sustainable Chemistry and; Department of Chemistry; University of Huelva, Campus de El Carmen s/n; 21071 Huelva Spain
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11
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Basílio N, Cruz L, de Freitas V, Pina F. A Multistate Molecular Switch Based on the 6,8-Rearrangement in Bromo-apigeninidin Operated with pH and Host–Guest Inputs. J Phys Chem B 2016; 120:7053-61. [DOI: 10.1021/acs.jpcb.6b03694] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nuno Basílio
- LAQV,
REQUIMTE, Departamento de Química, Faculdade de Ciências
e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Luís Cruz
- LAQV,
REQUIMTE, Departamento de Química e Bioquímica, Faculdade
de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Victor de Freitas
- LAQV,
REQUIMTE, Departamento de Química e Bioquímica, Faculdade
de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Fernando Pina
- LAQV,
REQUIMTE, Departamento de Química, Faculdade de Ciências
e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
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12
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Silva VO, Freitas AA, Maçanita AL, Quina FH. Chemistry and photochemistry of natural plant pigments: the anthocyanins. J PHYS ORG CHEM 2016. [DOI: 10.1002/poc.3534] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Volnir O. Silva
- Instituto de Química; Universidade de São Paulo; São Paulo CP 26077, 05513-970 Brazil
| | - Adilson A. Freitas
- Centro de Química Estrutural, Instituto Superior Técnico; Universidade de Lisboa; Lisbon Portugal
| | - António L. Maçanita
- Centro de Química Estrutural, Instituto Superior Técnico; Universidade de Lisboa; Lisbon Portugal
| | - Frank H. Quina
- Instituto de Química; Universidade de São Paulo; São Paulo CP 26077, 05513-970 Brazil
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13
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Held B, Tang H, Natarajan P, da Silva CP, de Oliveira Silva V, Bohne C, Quina FH. Cucurbit[7]uril inclusion complexation as a supramolecular strategy for color stabilization of anthocyanin model compounds. Photochem Photobiol Sci 2016; 15:752-7. [DOI: 10.1039/c6pp00060f] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Complete stabilization of the color of a flavylium cation by the formation of a higher order (1 : 2) complex with cucurbit[7]uril.
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Affiliation(s)
- Barbara Held
- Instituto de Química
- Universidade de São Paulo
- São Paulo 05513-970
- Brasil
| | - Hao Tang
- Department of Chemistry
- University of Victoria
- Victoria
- Canada V8W 3V6
| | - Palani Natarajan
- Department of Chemistry
- University of Victoria
- Victoria
- Canada V8W 3V6
| | | | | | - Cornelia Bohne
- Department of Chemistry
- University of Victoria
- Victoria
- Canada V8W 3V6
| | - Frank H. Quina
- Department of Chemistry
- University of Victoria
- Victoria
- Canada V8W 3V6
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14
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Diniz AM, Basílio N, Cruz H, Pina F, Parola AJ. Spatiotemporal control over the co-conformational switching in pH-responsive flavylium-based multistate pseudorotaxanes. Faraday Discuss 2015; 185:361-79. [PMID: 26395804 DOI: 10.1039/c5fd00078e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A multistate molecular dyad containing flavylium and viologen units was synthesized and the pH dependent thermodynamics of the network completely characterized by a variety of spectroscopic techniques such as NMR, UV-vis and stopped-flow. The flavylium cation is only stable at acidic pH values. Above pH ≈ 5 the hydration of the flavylium leads to the formation of the hemiketal followed by ring-opening tautomerization to give the cis-chalcone. Finally, this last species isomerizes to give the trans-chalcone. For the present system only the flavylium cation and the trans-chalcone species could be detected as being thermodynamically stable. The hemiketal and the cis-chalcone are kinetic intermediates with negligible concentrations at the equilibrium. All stable species of the network were found to form 1 : 1 and 2 : 1 host : guest complexes with cucurbit[7]uril (CB7) with association constants in the ranges 10(5)-10(8) M(-1) and 10(3)-10(4) M(-1), respectively. The 1 : 1 complexes were particularly interesting to devise pH responsive bistable pseudorotaxanes: at basic pH values (≈12) the flavylium cation interconverts into the deprotonated trans-chalcone in a few minutes and under these conditions the CB7 wheel was found to be located around the viologen unit. A decrease in pH to values around 1 regenerates the flavylium cation in seconds and the macrocycle is translocated to the middle of the axle. On the other hand, if the pH is decreased to 6, the deprotonated trans-chalcone is neutralized to give a metastable species that evolves to the thermodynamically stable flavylium cation in ca. 20 hours. By taking advantage of the pH-dependent kinetics of the trans-chalcone/flavylium interconversion, spatiotemporal control of the molecular organization in pseudorotaxane systems can be achieved.
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Affiliation(s)
- Ana Marta Diniz
- Laboratório Associado para a Química Verde (LAQV), REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica, Portugal. and Departamento de Química, Escola Superior de Tecnologia da Saúde de Lisboa - Instituto Politécnico de Lisboa, Lisboa, Portugal
| | - Nuno Basílio
- Laboratório Associado para a Química Verde (LAQV), REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica, Portugal.
| | - Hugo Cruz
- Laboratório Associado para a Química Verde (LAQV), REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica, Portugal.
| | - Fernando Pina
- Laboratório Associado para a Química Verde (LAQV), REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica, Portugal.
| | - A Jorge Parola
- Laboratório Associado para a Química Verde (LAQV), REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica, Portugal.
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