The interest in functional supramolecular systems for the design of innovative materials and technologies, able to fundamentally change the world, is growing at a high pace. The huge array of publications that appeared in recent years in the global literature calls for systematization of the structural trends inherent in the formation of these systems revealed at different molecular platforms and practically useful properties they exhibit. The attention is concentrated on the topics related to functional supramolecular systems that are actively explored in institutes and universities of Russia in the last 10–15 years, such as the chemistry of host–guest complexes, crystal engineering, self-assembly and self-organization in solutions and at interfaces, biomimetics and molecular machines and devices. The bibliography includes 1714 references.

Functional supramolecular systems: design and applications

This review reports on the latest developments (since 2014) in the chemistry of cholesterol and its applications in different research fields. These applications range from drug delivery or bioimaging applications to cholesterol-based liquid crystals and gelators. A brief overview of the most recent synthetic procedures to obtain new cholesterol derivatives is also provided, as well as the latest anticancer, antimicrobial, and antioxidant new cholesterol-based derivatives. This review discusses not only the synthetic details of the preparation of new cholesterol derivatives or conjugates, but also gives a short summary concerning the specific application of such compounds.

Cholesterol-Based Compounds: Recent Advances in Synthesis and Applications.

By controlling the mol ratios of reactants, novel calix[4]resorcinarene–triphenylene monomer, dimer and tetramer were designed and synthesised in yields of 50–60% via Click chemistry. Their structures were characterised by NMR and MS. Their liquid crystalline behaviours were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction analysis. The more triphenylene units on calix[4]resorcinarene resulted in the wider temperature scopes of mesophase and higher phase transition temperatures. The monomer 6 and dimer 7 showed the mixed columnar mesophase with hexagonal columnar structure and disordered lamellar columnar structure, and compound 8 possessed only disordered lamellar columnar mesophase. These research results suggest that calix[4]resorcinarene was a good platform to construct columnar liquid crystal and the mesomorphic properties were greatly influenced by the substituted numbers of mesogen units on calix skeleton.

Synthesis and mesomorphic properties of calix[4]resorcinarene–triphenylene oligomers

Series of triads and pentads of perylene derivatives with two cholesterol units at the bay-position or four cholesterol units on both bay-position and imide position were designed and synthesized in yields of 55–65%. The influence of the different number and position of cholesterol substituents on mesomorphic properties and photophysical properties was studied. The results suggested that, in comparison with similar perylene derivatives with alkyl units at the imide position, the perylene liquid crystals with alkyl units at the bay-positions not only maintained excellent mesomorphic properties but also enhanced the fluorescence greatly. More cholesterol units resulted in a lower mesophase temperature, wider phase transfer temperature range, and higher fluorescence. A long spacer between perylene and cholesterol units led to more excellent mesomorphic properties and higher fluorescence.

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Synthesis, mesomorphic and photophysical properties of novel triads and pentads of perylene liquid crystals with cholesterol units at the bay-position

Novel gallic-calixarene liquid crystals: syntheses and conformation influences on mesomorphism

Novel supramolecular liquid crystals: synthesis and mesomorphic properties of calix[4]arene-cholesterol derivatives

Two novel deep-cavity calix[4]arenes 3 and 4 with large s-triazine π-conjugate systems were designed and synthesized in high yields by reacting calix[4]arene with mono phenyl-substituted cyanuric chloride or further substitution with aniline. The liquid–liquid extraction experiment showed that they possessed excellent extraction abilities towards one cationic and three anionic dyes (Orange I, methylene blue, neutral red, brilliant green). The highest extraction percentage of compound 4 was 88.8 % for brilliant green. The complexation UV–Vis spectra of compounds 3 and 4 with four dyes indicated the existences of complexation action between hosts and guests with 1:1 ratio of complexation in DMSO solution. The association constants suggested that the larger π-conjugate system of compound 4 possessed the stronger complexation abilities than that of compound 3. The association constant of compound 4 with BG was as high as 8.1 × 106 M−1.

Weiwei Liu

Papers

Novel supramolecular liquid crystals: synthesis and mesomorphic properties of calix[4]arene-cholesterol derivatives

Novel deep-cavity calix[4]arene derivatives with large s -triazine conjugate systems: synthesis and complexation for dyes