Chiral N,N'-disubstituted squaramide has been found to undergo self-assembly in a variety of alcoholic solvents at low concentrations leading to the formation of novel nanostructured supramolecular alcogels. The gels responded to thermal, mechanical, optical and chemical stimuli. Solubility studies, gelation ability tests and computer modeling of a series of structurally related squaramides proved the existence of a unique combination of non-covalent molecular interactions and favorable hydrophobic/hydrophilic balance in that drive the anisotropic growth of alcogel networks. The results have also revealed a remarkable effect of ultrasound on both the gelation kinetics and the properties of the alcogels.
Hyperthermia therapy is a medical treatment based on the exposition of body tissue to slightly higher temperatures than physiological (i.e., between 41 and 46 °C) to damage and kill cancer cells or to make them more susceptible to the effects of radiation and anti-cancer drugs. Among several methods suitable for heating tumor areas, magnetic hyperthermia involves the introduction of magnetic micro/nanoparticles into the tumor tissue, followed by the application of an external magnetic field at fixed frequency and amplitude. A very interesting approach for magnetic hyperthermia is the use of biocompatible thermo-responsive magnetic gels made by the incorporation of the magnetic particles into cross-linked polymer gels. Mainly because of the hysteresis loss from the magnetic particles subjected to a magnetic field, the temperature of the system goes up and, once the temperature crosses the lower critical solution temperature, thermo-responsive gels undergo large volume changes and may deliver anti-cancer drug molecules that have been previously entrapped in their networks. This tutorial review describes the main properties and formulations of magnetic gel composites conceived for magnetic hyperthermia therapy.
An unprecedented cationic supramolecule [(Cp′′Fe(η 5 ‐P 5 )) 12 {CuNCMe} 8 ] 8+ 2.66 nm in diameter was selectively isolated as a salt of the weakly coordinating anion [Al{OC(CF 3 ) 3 } 4 ] − for the first time and characterized by X‐ray structure analysis, PXRD, NMR spectroscopy, and mass spectrometry. Its metal‐deficient core contains the lowest possible number of Cu atoms to connect 12 pentaphosphaferrocene units, providing a supramolecule with fullerene topology which, topologically, also represents the simplest homologue in the family of metal‐deficient pentaphosphaferrocene‐based supramolecules [{Cp R Fe(η 5 ‐P 5 )} 12 (CuX) 20− n ]. The 12 vacant metal sites between the cyclo‐P 5 rings, the largest number attained to date, make this compound a facile precursor for potential inner and outer modifications of the core as well as for functionalization via the substitution of labile acetonitrile ligands.
The reaction of the organometallic diarsene complex [Cp2Mo2(CO)4(η2‐As2)] (1) with Ag[Al{OC(CF3)3}4] (Ag[TEF]) yielded the AgI monomer [Ag(η2‐1)3][TEF] (2). This compound exhibits dynamic behavior in solution, which allows directed selective synthesis of unprecedented organometallic–organic hybrid assemblies upon its reaction with N‐donor organic molecules by a stepwise pathway, which is supported by DFT calculations. Accordingly, the reaction of 2 with 2,2′‐bipyrimidine (L1) yielded the dicationic molecular compound [{(η2‐1)2Ag}2(μ‐L1)][TEF]2 (3) or the 1D polymer [{(η2‐1)Ag}(μ‐L1)]n[TEF]n (4) depending on the ratio of the reactants. However, its reactions with the pyridine‐based linkers 4,4′‐bipyridine (L2), 1,2‐bis(4‐pyridyl)ethylene (L3) and 1,2‐bis(4‐pyridyl)ethyne (L4) allowed the formation of the 2D polymers [{(η2‐1)Ag}2(μ‐Lx)3]n[TEF]2n [Lx=L2 (5), L3 (6), L4 (7), respectively]. Additionally, this concept was extended to step‐by‐step one‐pot reactions of 1, [Ag(CH3CN)3][Al{OC(CF3)2(CCl3)}4] ([Ag(CH3CN)3][TEFCl]) and linkers L2–L4 to produce the 2D polymers [{(η2‐1)Ag}2(μ,Lx)3]n[TEFCl]2n [Lx=L2 (8), L3 (9), L4 (10), respectively].
A new highly solid-state luminescent phase of a previously reported weakly luminescent Cu I 8 Pd II 1 dicationic assembly is reported revealing the high geometrical versatility of this moiety that importantly alters its luminescent properties. This very minor new species B c is based on a different conformer scaffold than the one encountered in the previously reported B o form and, essentially differs from B o by displaying shorter Cu I -Cu I intermetallic distances. DFT calculations allow concluding that the predominance in the solidstate of the weakly luminescent and less stable B o phase is due to the extra stability induced by a larger number of intermolecular non-covalent π-CH interactions in its crystalline packing and not by the intrinsic stability of the Cu I 8 Pd II 1 dicationic moiety. Calculations also revealed that a more stable conformation B calc is expected in vacuum, which bears a different distribution of Cu I -Cu I intermetallic distances than the dications in B o and B c phases. Taking into account that the geometrical alterations are associated to drastic changes of luminescence properties, this confer to the Cu I 8 Pd II 1 assembly high potentiality as stimuli-sensitive luminescent materials. Indeed, by applying mechanical or thermal stress to samples of B o phase, new phases B g and B m , respectively, were obtained. Alterations of the solid-state photophysical properties of these new species compared to those recorded for B o are reported together with a combined experimental and computed study of the structures/properties relationships observed in these phases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.