p-Sulfonatocalix[8]arene and vitamin C complexation: assessment of photophysical, pKa and antioxidant property

Anthocyanin Color Stabilization by Host-Guest Complexation with p-Sulfonatocalix[n]arenes

“…Notwithstanding the moderate selectivity observed for the different SCn homologues, it is interesting to note that, in the case of DHF, the higher association constant was obtained for the complex with SC4 (1.1 × 10 4 M −1 ). This particular result is in good agreement with the association constants previously reported for similar guests [36]. The small cavity and the proximity of the sulfonate groups in the host as well as the small size of the guest can be responsible for the higher binding constant.…”

“…1 H NMR spectroscopy is a powerful tool to identify the binding sites in the structure of the SCn and phenolic compounds complexes, analyzing the complexation-induced changes in the chemical shifts (∆δ) of the guest protons [35,36,39]. The protons with the largest ∆δ are mostly affected by the ring current effect of the aromatic nuclei in the SCn macrocycles.…”

“…SCn macrocycles are provided with an aromatic binding pocket decorated with SO 3 − groups in the upper rim, being particularly suitable for the binding of positively charged guests that can be stabilized by different interactions such as ion-pairing, cation-π, πstacking, CH-π, and hydrophobic effects [34,35]. In a previous work, we demonstrated the formation of the photo-responsive host-guest complexes between flavylium-based photo switches and SC4 [36]. On account of the high binding constants observed for selective complexation of synthetic flavylium compounds, in this work we report the results of our studies on the complexation and color stabilization of a synthetic flavylium cation and a natural anthocyanin with SC4, SC6, and SC8 (Scheme 1).…”

pH Dependent Self‐Assembly of Single‐Pyrene‐Armed Calix[4]arene: Modulation and Complexation with p‐Sulfonatocalix[6]arene

“…On the other hand, homologues of p ‐sulfonatocalixarene have been utilized broadly as macrocyclic cavitands for several guest molecules, and have been reported to modify the physicochemical properties of these guest molecules via noncovalent interaction . Since last two decades, it has been receiving increased attention, particularly, in the area of controlled drug delivery applications, solubility enhancement of insoluble drug, such as, niclosamide, furosemide and nifedipine, receptor for cations, anions, neutral molecules, vitamins and molecular sensors…”

“…On the other hand, homologues of p-sulfonatocalixarene have been utilized broadly as macrocyclic cavitands for several guest molecules, and have been reported to modify the physicochemical properties of these guest molecules via noncovalent interaction. [24] Since last two decades, it has been receiving increased attention, particularly, in the area of controlled drug delivery applications, [25] solubility enhancement of insoluble drug, such as, niclosamide, furosemide and nifedipine, [26] receptor for cations, [27] anions, [28] neutral molecules, [29] vitamins [30] and molecular sensors. [31] In the present contribution, we have also investigated the effect of addition of p-sulfonatocalix [6]arene on the pH induced aggregate assembly of single pyrene substituted calixarene derivative (MPCX4) using various experimental techniques viz steady-state emission, time-resolved emission measurements, 1 H-NMR, FT-IR, and HR-MS. Figure 1 represents the structure of host and guest molecules.…”