1H NMR and calorimetric study on binding ability of cyclodextrins to isomeric pyridinecarboxylic acids in aqueous solution

Aqueous Zirconium‐MOF Synthesis Assisted by α‐Cyclodextrin: Towards Deeper Understanding of the Beneficial Role of Cyclodextrin

“…These hystereses, which appear more prominently with the UiO‐66−F 4 , UiO‐66−(COOH) 2 and UiO‐66−PDC structures, could be a sign of higher disturbance in the nucleation, growth and agglomeration of the corresponding MOF particles. In the former two cases, this can be indicative of additional steric hindrance generated on the pyromellitic acid and tetrafluoroterephthalic acid, which can lead to the creation of more defects, such as pending linkers, missing‐linker defects or cluster‐missing defects [18,19] For UiO‐66−PDC, the hysteresis may originate from the occurrence of preferential interactions between α‐CD and the PDC linker (pyridine‐2,5‐dicarboxylic acid) in the form of inclusion and external complexes [20] . These interactions may disturb the growth process as a result of secondary or incomplete reactions that ultimately induce more defects within the framework.…”

Selective Na+/K+ Effects on the Formation of α-Cyclodextrin Complexes with Aromatic Carboxylic Acids: Competition for the Guest

“…In the previous publications, the possibility of nicotinic acid encapsulation by native and modified α-CD and β-CD has been investigated by several experimental techniques at different pH levels. ,− It has been shown that more stable inclusion complexes of 1:1 stoichiometric ratio are formed between α-CD and nicotinic acid zwitterions. According to literature data, benzoate forms 1:1 inclusion complexes with α-CD in aqueous solution.…”

“…Stability constants of the complexes (K) were evaluated from the concentration dependences of ∆δ by the nonlinear curve fitting procedure reported early. 30 Values of K are presented in Table 1.…”

“…The absence of change in the chemical shift for H6 proton additionally proves this binding mode. The 1 H NMR spectra of nicotinic acid have been early considered, 30,49 and it has been shown that the signals of the protons located near -COOgroup are significantly shifted upon complex formation with R-CD, while the changes for another proton of its aromatic ring have not been observed. These results were interpreted in terms of preferential inclusion of carboxylate group into R-CD cavity in comparison with the pyridine ring carrying the positively charged NH + group.…”

Molecular recognition of aromatic carboxylic acids by hydroxypropyl-γ-cyclodextrin: experimental and theoretical evidence

“…In particular, binding of a-CD and b-CD as well as their hydroxypropylated derivatives (HP-a-CD and HP-b-CD) with nicotinic acid (vitamin B 3 , component of the coenzymes and antihyperlipidemic medicine), benzoic acid (preservative, analgesic and antiseptic), p-aminobenzoic acid (vitamin B 10 , sunscreen cosmetics) and maminobenzoic acid (p-aminobenzoic acid isomer displaying no bioactivity) has been investigated by different experimental methods. [5][6][7] Moreover, these systems are well studied in the literature. [8][9][10][11] It has been demonstrated that insertion of the acids into cavity of a-CD and HP-a-CD is partial, while the deep penetration of the acids into cavity of b-CD and HP-b-CD was observed.…”