Journal of Inclusion Phenomena and Macrocyclic Chemistry最新文献

Facing the dual pressure of increasing global energy demand and heavy task in carbon emission reduction on schedule, nuclear renaissance is being seriously discussed as transitive choice before full renewable energy supply, yet there is a crucial concern about radioactive safety. The treatment of radioactive iodine is particularly important and challenging because of its high ratio in fission product, extremely long radioactive periods up to several millions of years, as well as easy diffusion in the whole ecosystem. Given that several challenge including easy sublimation, high water solubility, diverse existing species of I₂, I⁻, I_2n+1⁻ and organic iodine, biocompatibility and strong aggregation in thyroid, rapid capture and permanent storage of iodine is requested. Comparing to inorganic adsorbents of zeolite and inorganic–organic hybrid MOFs, pure organic porous solid are emerging as new and promising iodine capture material. Their high iodine affinity and adsorption capacity, good stability in various environments, facile modification and functionalization, intrinsic structural flexibility guaranteed the outstanding performance in iodine capture. Four main categories of organic cages, supramolecular framework connected by weak interaction, covalent organic frameworks and polymers with intrinsic microporosity were summarized and discussed, from the viewpoints of design principles, iodine capture performance, and adsorbent-iodine interactions. As the main prospect, we hope this work will attracting more researchers to study porous organic materials and address the challenge of effective capture of radioactive iodine.

A new acyclic cucurbit[n]uril (CB[n]) dimer is synthesized by copper-catalyzed azide-alkyne cycloaddition or “click” reaction. The acyclic CB[n] dimer possesses two cavities, and is able to encapsulate two guest molecules simultaneously. This dimer is discovered to be high affinity host molecule for a wide variety of dyes, pharmaceutical drugs and guest molecules.

The directed synthesis of asymmetrically substituted porphyrins—tetraphenylporphyrine derivatives containing amino acid residues as a functional group, which can be used as “anchor” groups, for incorporation into the structure of a protein molecule, was carried out. The obtained compounds were characterized by a number of spectral methods confirming their structure and purity. Their base and acid ionization constants in the AN–HClO₄ and DMSO–potassium cryptate (KOH[222])—systems were measured by spectrophotometric titration. It was found that the asymmetric substitution architecture contributed to the stabilization of the protonated forms of porphyrins. This allowed, for the first time, to extract and spectrally characterize the mono- and doubly-protonated forms (H₃P⁺ and H₄P²⁺) of each ligands in the AN–HClO₄ system. The analysis of the spectral changes of the monoamino derivative led to identify three stages of the protonation, which first involves the nitrogen atom of the periphery substituent (pK_b = 13.26) and then the central nitrogen atoms of the macrocycle (pK_b1 = 11.50; pK_b2 = 9.65; pK_b1,2 = 21.15). The relative stability of the first intermediate is assumed to be caused by charge delocalization. The electron-donor nature of the solvent in the DMSO–KOH [222] system led to the leveling of the ionization constants for the first and second stages, which allowed us to determine only the total values for the porphyrins studied. The successive stages of acid–base interactions were analyzed in the article.

Graphical abstract

Hydroxypyridinones (HOPOs) are excellent class of chelators that have been gaining attention in the field of pharmaceutical drugs by their high chelating efficacy and specificity with different metal ions. Among all the metal ions, they exhibit a high binding affinity towards iron (III) and are clinically used as iron chelators nowadays. The HOPO family has different isomers, out of which 3,4-HOPO possesses applicability for designing drugs. The effect of methyl substitution on different positions of pyridinone ring also plays an essential role in deciding the pM values, thus describing the metal affinity. Several metal ions like Fe, Al, Cu, Zn, and some actinides are found to exhibit good chelation efficacy with HOPOs. In terms of denticity, there are various forms of HOPO. Among these, discussion on bidentate, tetradentate, hexadentate, octadentate, and dendrimers will be done here. This review systematically summarizes the various literature reports on the design and pharmacological activities of the newly developed HOPOs and their derivatives, including antibiotics, anticancer, and antineurodegeneratives.

The paramagnetic lanthanide complexes with polyaminopolycarboxylate (PAPC) ligands attract considerable attention from the standpoint of potential applications thereof as relaxation agents used in medical magnetic resonance imaging (MRI) and in luminescent materials, as well as owing to promising use thereof as paramagnetic labels for studying the properties of biopolymers since they exhibit thermodynamic stability, good solubility in aqueous media and moderate toxicity. For the last decades, the NMR methods have been used to determine the physical and chemical properties of paramagnetic Ln compounds. The studies concerning paramagnetic NMR lanthanide-induced shifts (LISs) in dissolved Ln complexes, as well as the analysis of band shape as a function of temperature make it possible to obtain valuable information on the structure, intra- and intermolecular dynamics and paramagnetic properties thereof. This review is devoted solely to the following features: firstly, the processes of intramolecular dynamics of lanthanide complexes with polyamino-polycarboxylate ligands such as DOTA, EDTA and DTPA and their derivatives studied by NMR; secondly, the LISs of lanthanide complexes with EDTA, DOTA, DTPA and some of their derivatives depending on temperature and pH. Moreover, in this review, for the first time, the dependence of the activation energy of molecular dynamics in complexes with polydentate ligands on the atomic number of the lanthanide cation is analyzed and a monotonic change in energy is detected, which is due to the effect of lanthanide contraction. It should be noted that this phenomenon is quite general and may also appear in the future in many other series of lanthanide complexes with both other multidentate ligands and with bidentate and monodentate ligands. In the future, it is possible to predict the dependence of the properties of certain lanthanide complexes on the ionic radius of the lanthanide cation based on the approaches presented in the review. In this review, we have also presented the dynamic NMR as the main research method widely used to analyze the processes of molecular dynamics, and the structural studies based on the NMR relaxation spectroscopy and LIS analysis.

A 14-membered hexamethyl-tetraazamacrocycle, viz. Me₆[14]diene.2HClO₄ (L.2HClO₄), afforded a mixture of isomeric ligands, Me₆[14]anes, upon reduction with NaBH₄ and extraction by CHCl₃ at pH > 12. These ligands were separated by fractional crystallization from xylene and were designated as ‘tet-a’ and ‘tet-b.’ The interaction of ‘tet-b’ with excess acrylonitrile was fairly stereoselective and formed an N-pendent derivative, ‘tet-bx’, in which two cyano-ethyl groups were attached to trans N-atoms that are sterically less crowded. Aeration of ‘tet-bx’ and cobalt(II) acetate salt in methanol, followed by its treatment with HCl, yielded a bluish-green product, viz. trans-[Co(‘tet-bx’)Cl₂]Cl. trans-[Co(‘tet-bx’)Cl₂]Cl underwent axial substitution reactions with KSCN and KNO₃ and subsequent axial substitution and anion exchange reactions with NaNO₂, KBr, and KI to produce six-coordinated octahedral complexes, viz. bluish-green trans-[Co(‘tet-bx’)(NCS)₂]Cl, light-blue trans-[Co(‘tet-bx’)(NO₃)₂]Cl, yellow trans-[Co(‘tet-bx’)(NO₂)₂]NO₂, green trans-[Co(‘tet-bx’)Br₂]Br, and red trans-[Co(‘tet-bx’)I₂]I. These complexes were characterized using different modern analytical and spectroscopic techniques. The antibacterial activities of the N-pendent ligand and its cobalt(III) complexes on four types of selected bacteria were investigated.

Roof-shaped host compounds trans-α,α,α′,α′-tetraphenyl-9,10-dihydro-9,10-ethanoanthracene-11,12-dimethanol H3 and trans-α,α,α′,α′-tetra(p-chlorophenyl)-9,10-dihydro-9,10-ethanoanthracene-11,12-dimethanol H6 were assessed for their host potential and selectivity behaviour when presented with single or mixed guest solvents comprising o-xylene, m-xylene, p-xylene and ethylbenzene (o-Xy, m-Xy, p-Xy and EB). H3 included each solvent with 3:1 host:guest ratios, while the ratios preferred by H6 were more varied (4:3, 1:1 and 3:2). More importantly, the selectivity behaviour of these two host compounds was observed to be entirely different: H3 possessed only a very modest preference for o-Xy (37.9–68.2%) when recrystallized from various equimolar binary, ternary and quaternary guest mixtures, while H6 was considerably more selective, preferring m-Xy (the least favoured guest of H3) with selectivities ranging from 57.7 to 91.4% in analogous conditions. The latter result was obtained in o-Xy/m-Xy mixtures and demonstrates that H6 may be employed as a purification tool for mixtures of these two xylenes via host–guest chemistry protocols. A single crystal diffraction experiment on 3(H3)·o-Xy (containing the preferred guest of H3) revealed that the guest was retained in the host crystal by means of a singular (host)m-Ar–H···π(guest) interaction that measured 2.73 Å (148°) as well as numerous other host···guest interactions involving only the aromatic protons of the free host phenyl groups and the guest methyl protons or aromatic carbons and protons (2.20–2.54 Å, 121–125°). Thermal analyses explained the preference of H3 for o-Xy, while these were less informative for the complexes of H6.

Beta-carotene (BC) is a vitamin A precursor and has potential anticancer benefits, but the delivery of BC is hindered by its low solubility and storage instability. To overcome these challenges, this study investigated the use of fabricated cyclodextrin-based nanosponges (CDNS) using different ratios of two cross-linkers, epiclon (EPI) and hexamethylene diisocyanate (HMDI) to form inclusion complex with BC. The ratios of crosslinkers to βCD for two most optimaly encapsulated CDNSs-BC were determined to be 2:1 for EPI and 4:1 for HMDI with loading efficiency of 61.46% and 59.61%, respectively. The charachterization tests were carefully done for two optimal CDNSs. Encapsulation significantly improved the solubility by ~ 10 folds, 30-day storage stability by 40% compared to BCs. The in vitro release of the two encapsulated products showed no burst release. The MTT assay revealed a variable increase in cytotoxic effect in both normal and cancer cells compared to free BC. Overall, the CDNSs appear to be promising carriers for the delivery of BCs.