Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

Metformin hydrochloride (MET) (N,N-dimethylbiguanide) is an antidiabetic drug and widely used for treating worldwide disease, Type 2 diabetes. MET shows significant benefits for human health such as reducing high blood sugar and cholesterol/triglyceride levels, treating for polycystic ovary syndrome and having anticancer and antiaging effects. In this study, a facile colorimetric determination of metformin in drug preparations was carried out by environmentally friendly gamma-cyclodextrin (γ-CD) stabilized silver nanoparticles (CD-AgNPs). Gamma-cyclodextrin was used for the formation of AgNPs as both the metal salt − reducing and nanoparticle − stabilizing agent. As a visual optical probe, well-dispersed spherical yellow-colored CD-AgNPs (at an average particle size of 10 ± 2 nm) showing maximal surface plasmon resonance absorption at 405 nm was synthesized by one-step method. In the presence of metformin, dispersed AgNPs get aggregated, and a controlled destabilization of CD-AgNPs and core-centered growth of Ag(0) atoms (20 ± 2 nm) were observed a result of host-guest interaction between CD-AgNPs and metformin. Non-covalent hydrogen bonding between the hydroxyl groups of CD-AgNPs (in the outer cavity) and the guanidine groups of MET enables the CDs to form a host-guest inclusion complexation followed by aggregation leading to color change from yellow to orange and an increase of the absorbance at 550 nm. Inclusion complex formation was characterized by using FTIR, UV-Vis spectroscopy, DSC and STEM techniques. Under optimized conditions, the absorbance ratio at A_{550 nm}/A_{405 nm} was linearly correlated to the concentration of metformin in the range of 0.2–1.25 µM. The proposed assay showed high sensitivity with 42 nM detection limit. The method was selective toward possible interferents (potassium, carbonate, sulfate, chloride and sodium ions, urea, glucose) and also successfully applied to conventional drug samples including MET. The results obtained by proposed, reference and HPLC assays were analyzed statistically using the two-way ANOVA test to demonstrate their agreement with each other at 95% confidence level (P = 0.05, F_exp = 0.068, F_crit(table) = 6.943, F_exp < F_crit(table)). MET contents (mg) of drug samples in tablet form were determined with high accuracy (REC% 97.3-100.7) and reproducibility (RSD% 1.49–2.78). It is noteworthy that the developed CD-AgNP − based colorimetric method seems to be of higher or comparable sensitivity compared to other nanoparticle − based optical assays.

In the field of wearable electronics, MXenes have emerged as promising two-dimensional (2D) materials, exhibiting exceptional properties such as metallic conductivity, water dispersibility, thermal stability, mechanical stability, and high optical transmittance. In this study, we present a unique flexible transparent conductive electrode (FTCE) composed of MXene, Ag nanowire (AgNW), ultraviolet resin (UV-resin), and polycarbonate (PC). Our fabrication process involves a roll-to-roll process and entirely solution-based methods including UV-resin dispensing, AgNW solution coating, and FTCE dipping in an MXene solution, providing a cost-effective manufacturing approach. Notably, compared to the pure AgNW-based FTCE, the proposed FTCE incorporating an MXene concentration of 5 mg/mL showed a significant enhancement of 40% in electrical conductivity, while the FTCE with a concentration of 2 mg/mL exhibited an improved figure of merit. Furthermore, we successfully demonstrate an embedded system integrating the FTCE-based capacitive touch and proximity sensor. These achievements in optoelectronic performance signify a tremendous potential for the development of high-performance flexible devices.

This short note shows that the Scott test, which is widely used for the detection of cocaine by authorities, produces false-positives for the entire series of cucurbit[n]uril-type uril macrocycles and also for hemi-cucurbit[n]uril. For analogous macrocycles such as bambus[6]uril and biotin[6]uril this does not happen. This is a wake-up call to the scientific community and international authorities.

Today, the modification of the organic molecules using the copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) is of great interest, as evidenced by the Nobel Prize in Chemistry awarded in 2022 to the founder of “click” chemistry. Supramolecular chemistry, in turn, is one of the actively developing branches of modern science. Using the CuAAC approach is a very convenient method to obtain new macrocyclic structures of interest. This review focuses on the use of the modular “click”-chemistry approach for the synthesis of various triazole derivatives of thiacalix[4]arenes and calix[4]arenes as well as general routes for the synthesis of their precursors (azides and alkynes). Examples of some functional systems based on triazole-containing macrocycles, such as chemosensors, multicalixarenes, amphiphilic calixarenes as well as examples of the use of triazole calixarenes for bioapplications are described.

Modification of the upper rim of the lipophilic cone-shaped tetrapropoxycalix [4]arene with hydrophilic phosphine oxide groups or phosphinic acid groups yielded nano-sized water-soluble calixarenes that form supramolecular complexes with uracils, including active pharmaceutical ingredients of 5-Fluorouracil and 5-Methyluracil drugs. Stability constants of the formed complexes in an aqueous-organic medium were determined by the HPLC method. The most favored structures of the calixarenes and their uracil complexes were optimized at the DFT level of approximation. In the most favored structures of all adducts, the uracil molecules coordinate via hydrogen bonding with the phosphorus-containing groups on the upper rim of the calixarene ligands.

Anionic complex of antamanide with the nitrate anion has been proven by electrospray ionization mass spectrometry (ESI-MS) method. Further, applying quantum chemical DFT calculations, the most probable structure of this complex was derived. The nitrate anion is embedded in the molecule of antamanide and its oxygens atoms are bonded by seven bonds to the hydrogen atoms of the ligand. Finally, the interaction energy, E(int), of the antamanide-NO₃⁻ complex was calculated as E(int) = -175.9 kJ/mol.

The present manuscript describes the synthesis, spectral characterisation, DFT studies and biological activity of a series of 3d transition metal complexes of (E)-2-((2-(benzo[d]thiazole-2-yl)hydrazono)methyl)-5-(diethylamino)phenol (L1) in (1:1) and (1:2) ratio. Various spectral analysis revealed the presence of ONN binding domain in L1. The elemental composition was confirmed using mass spectrometry technique. The stability of the geometry was also confirmed with DFT based method using B3LYP/LanL2Dz level of theory. Absence of any imaginary frequency revealed the presence of geometry on global minima of potential energy surface. Job’s plot confirm the stoichiometric ratio of metal complexes. Electrochemical behaviour (cyclic voltammetry), magnetic moment and Conductance measurements were also investigated for the metal-complexes. Kinetic parameters for different stages of thermal decomposition of metal complexes were calculated by using Coats–Redfern and Broido method. Positive free-energy of decomposition describes the non-spontaneous nature of thermal decomposition. The negative ΔS value observed for metal complexes under consideration reveals the ordered arrangement of metal complexes than their reactants. The octahedral environment of Co²⁺, Ni²⁺, Cu²⁺ and Cd²⁺ complexes was elucidated with the help of spectroscopic data. The ligand (L1) and its metal complexes (M1–M8) exhibited excellent α-amylase and moderate anti-oxidant activities. Maximum α-amylase inhibition was exhibited by M7 with a percentage inhibition of 96.65% (IC₅₀ = 0.070 µM) and the lowest by M1 (87.00%, IC₅₀ = 0.086 µM).

A new theoretical approach was recently addressed to predict cyclodextrin host–guest binding constants with the GFN2-xTB semiempirical quantum method. Within such a strategy, a set of starting supramolecular arrangements is automatically obtained through the UD-APARM software, and many optimized host–guest systems are used to obtain each binding constant. In the present work, within the scope of the multi-equilibrium treatment, we carried out a theoretical study concerning the host–guest systems formed with paraoxon (PRX), methyl-parathion (MPTN), and parathion (PTN) into α-cyclodextrin (α-CD), for which experimental data were addressed. Those guests correspond to pesticides in use, and their inclusion plays a role in remediation technology. The procedure for estimating binding constants for the host–guest system is discussed in terms of the ranges for the supramolecular parameters employed in exploring the GFN2-xTB Potential Energy Surface (PES). As a result, by investigating an unprecedented number of starting systems (3,076), we identified that proper exploration of the GFN2-xTB PES gives a reliable prediction of the binding constant in solution. Furthermore, with the study of different starting associations, for PTN/α-CD, we found an excellent linear correlation (R² = 0.987) between GFN2-xTB data and experimental information, which, as in our previous study, supports the discussed methodology for application in predicting binding constants for CD-based host–guest systems.

Graphical abstract

A new indole-containing 2,6-pyridinedicarbohydrazide P3 was synthesized and well characterized employing NMR, ESI⁺-MS, FT-IR, and elemental analyses. The synthesized compound was examined as an efficient fluorescent turn-off and colorimetric cation receptor. The P3 receptor exhibited a remarkable rapid color change from colorless to brown in the presence of Cu²⁺ cations. P3 displayed selective fluorescence quenching and a UV-vis redshift only in the presence of Cu²⁺ ions. Job’s plot, NMR titration, and ESI⁺-MS data were used to determine the complex’s 1:2 stoichiometry between P3 and Cu²⁺. Fluorescence titration was used to calculate the association constant (K_a) as 2.9–3.5 × 10¹¹ M^− 2 and the limit of detection (LOD) as 4.2 × 10^− 9 M. P3-based test strips were developed, which might be used as a simple and effective Cu²⁺ test kit. DFT calculations were also performed to optimize the structures of the P3 and P3 + Cu²⁺ complex. This design will likely provide another avenue to develop chemosensors incorporating a functional group on the upper rim of the 2,6-pyridinedicarbohydrazide platform.