Towards novel functional polymers: Ring-opening polymerization of L-lactide with p-tert-butylthiacalix[4]arene derivatives

© 2020 Elsevier B.V. Oligo−/polylactides functionalized with p-tert-butylthiacalix[4]arenes in three conformations (cone, partial cone, 1,3-alternate) were synthesized by ring-opening polymerization. Conformational isomers of p-tert-butylthiacalix[4]arene tetrapropanolamide derivatives differing in relative position of hydroxyl groups were introduced into reaction with L-lactide in presence of catalytic amounts of tin (II) octoate in DMSO and 1,2-dimethylbenzene. It was shown that oligo−/polyester molecular weight depends on macrocycle's conformation and solvent used for L-lactide ROP. Highest molecular weight was achieved for 1,3-alternate conformation and 1,2-dimethylbenzene, while on the contrary in DMSO higher molecular weight was achieved for cone stereoisomer. Regardless molecular weight of oligo−/polylactides synthesized, 1,3-alternate stereoisomer derivatives are characterized by higher thermal stability, indicating that the relative position of oligo−/polylactides fragments, which are pre-oriented by cyclophane core is the key factor determining thermal stability of oligo−/polylactides synthesized. Modification of polyesters with thiacalixarene fragment bestows them with sorption activity towards rhodamine 6G in contrast to non-modified polylactide

Novel lactide derivatives of p-tert-butylthiacalix[4]arene: Directed synthesis and molecular recognition of catecholamines

© 2020 Three stereoisomeric forms of p-tert-butylthiacalix[4]arene (cone, partial cone, and 1,3-alternate conformations) have been proposed as macrocyclic scaffold to obtain dendrimer-like compounds. Modification of the macrocycle with fragments containing both amide and lactide groups made it possible to obtain original analogs of dendrimers with symmetric and asymmetric structures. These compounds are capable of binding catecholamines (dopamine, epinephrine, and norepinephrine). The influence of the macrocyclic platform conformation of the compounds obtained on the efficiency and selectivity of their complexation with catecholamines was established by UV–visible, fluorescence and NMR spectroscopy. It was found that the 1,3-alternate conformation of the macrocycle core was the most favorable for binding all the guests. In case of the cone conformation, selectivity of binding of epinephrine and norepinephrine was observed. Location of catecholamines in the resulting complexes against the macrocyclic platform affected the efficiency of interaction of the synthesized thiacalixarenes with guests

Iminodiacetic derivatives of p-tert-butylthiacalix[4]arene: Synthesis and influence of conformation on the aggregation with bismarck brown Y

Three conformers (cone, partial cone and 1,3-alternate) of tetrasubstituted at the lower rim p-tert-butylthiacalix[4] arene derivatives with iminodiacetic fragments were synthesized and characterized. It was shown by spectral methods (UV-Vis,1H NMR and DOSY spectroscopy, DLS) and TEM that the monodisperse nano-sized particles are formed by self-assembly of synthetic octaacids in water with azo dye Bismarck brown Y in the case of the partial cone and 1,3-alternate conformations. It was found that the dye associates with the acid binding sites of the macrocycle. © ISUCT Publishing

Nanostructured polyelectrolyte complexes based on water-soluble thiacalix[4]Arene and pillar[5]arene: Self-assembly in micelleplexes and polyplexes at packaging DNA

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Controlling the self-assembly of polyfunctional compounds in interpolyelectrolyte aggregates is an extremely challenging task. The use of macrocyclic compounds offers new opportunities in design of a new generation of mixed nanoparticles. This approach allows creating aggregates with multivalent molecular recognition, improved binding effciency and selectivity. In this paper, we reported a straightforward approach to the synthesis of interpolyelectrolytes by co-assembling of the thiacalix[4]arene with four negatively charged functional groups on the one side of macrocycle, and pillar[5]arene with 10 ammonium groups located on both sides. Nanostructured polyelectrolyte complexes show effective packaging of high-molecular DNA from calf thymus. The interaction of co-interpolyelectrolytes with the DNA is completely different from the interaction of the pillar[5]arene with the DNA. Two different complexes with DNA, i.e., micelleplex- and polyplex-type, were formed. The DNA in both cases preserved its secondary structure in native B form without distorting helicity. The presented approach provides important advantage for the design of effective biomolecular gene delivery systems

Iminodiacetic derivatives of p-tert-butylthiacalix[4]arene: Synthesis and influence of conformation on the aggregation with bismarck brown Y

Three conformers (cone, partial cone and 1,3-alternate) of tetrasubstituted at the lower rim p-tert-butylthiacalix[4] arene derivatives with iminodiacetic fragments were synthesized and characterized. It was shown by spectral methods (UV-Vis,1H NMR and DOSY spectroscopy, DLS) and TEM that the monodisperse nano-sized particles are formed by self-assembly of synthetic octaacids in water with azo dye Bismarck brown Y in the case of the partial cone and 1,3-alternate conformations. It was found that the dye associates with the acid binding sites of the macrocycle. © ISUCT Publishing

Towards universal stimuli-responsive drug delivery systems: Pillar[5]arenes synthesis and self-assembly into nanocontainers with tetrazole polymers

In this work, we have proposed a novel universal stimulus-sensitive nanosized polymer system based on decasubstituted macrocyclic structures—pillar[5]arenes and tetrazole-containing polymers. Decasubstituted pillar[5]arenes containing a large, good leaving tosylate, and phthalimide groups were first synthesized and characterized. Pillar[5]arenes containing primary and tertiary amino groups, capable of interacting with tetrazole-containing polymers, were obtained with high yield by removing the tosylate and phthalimide protection. According to the fluorescence spectroscopy data, a dramatic fluorescence enhancement in the pillar[5]arene/fluorescein/polymer system was observed with decreasing pH from neutral (pH = 7) to acidic (pH = 5). This indicates the destruction of associates and the release of the dye at a pH close to 5. The presented results open a broad range of opportunities for the development of new universal stimulus-sensitive drug delivery systems containing macrocycles and nontoxic tetrazole-based polymers

Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene

New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86-134 nm in diameter in water at a concentration of 1 × 10-4 M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral. A distinctive feature of the compounds is the pronounced dependence of their spectral (emission and chiroptical) properties on the polarity of the solvent and the length of the linker between the macrocyclic and fluorophore parts of the molecule. © 2017 Padnya et al

Water-soluble pillar[5]arene sulfo-derivatives self-assemble into biocompatible nanosystems to stabilize therapeutic proteins

Pillar[5]arenes containing sulfonate fragments have been shown to form supramolecular complexes with therapeutic proteins to facilitate targeted transport with an increased duration of action and enhanced bioavailability. Regioselective synthesis was used to obtain a water-soluble pillar[5]arene containing the fluorescent label FITC and nine sulfoethoxy fragments. The pillar[5]arene formed complexes with the therapeutic proteins binase, bleomycin, and lysozyme in a 1:2 ratio as demonstrated by UV–vis and fluorescence spectroscopy. The formation of stable spherical nanosized macrocycle/binase complexes with an average particle size of 200 nm was established by dynamic light scattering and transmission electron microscopy. Flow cytometry demonstrated the ability of macrocycle/binase complexes to penetrate into tumor cells where they exhibited significant cytotoxicity towards A549 cells at 10−5–10−6 M while maintaining the enzymatic activity of binase

Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene

New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86-134 nm in diameter in water at a concentration of 1 × 10-4 M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral. A distinctive feature of the compounds is the pronounced dependence of their spectral (emission and chiroptical) properties on the polarity of the solvent and the length of the linker between the macrocyclic and fluorophore parts of the molecule. © 2017 Padnya et al