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Three naphthorosarins, antiaromatic expanded porphyrins bearing different meso substituents (NRos 1–3), designed to self-assemble into columnar liquid crystalline (LC) structures, were synthesized and characterized using polarized optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), as well as supporting computational calculations. The substituents were found to play a crucial role in modulating the LC behaviour. [ABSTRACT FROM AUTHOR]

Despite the fact that triphenylamine derivatives have been widely explored as hole-transporting materials, studies on charge transport properties in the liquid crystal phase have been overlooked. Here, it is reported that triphenylamine liquid crystals can attain very high hole mobility values in a hexagonal columnar mesophase, up to μ ≈ 5 cm2 V−1 s−1. The columnar liquid crystalline phase was obtained by a proper design of a supramolecular mesogen, and this is unprecedented for triphenylamine liquid crystals. In fact, the supramolecules were formed by hydrogen-bonded 1 : 3 complexes of a star-shaped triazine core and three triphenylamine peripheral units. The resulting hexagonal columnar mesophase acts as a successful scaffold that confines TPA units at the periphery of columns. Challenging DFT theoretical investigations into a model based on such supramolecular systems involving a large number of atoms were undertaken to explore the stability and geometry of the complexes and their electronic properties. [ABSTRACT FROM AUTHOR]

For more than one hundred years, several treatments against malaria have been proposed but they have systematically failed, mainly due to the occurrence of drug resistance in part resulting from the exposure of the parasite to low drug doses. Several factors are behind this problem, including (i) the formidable barrier imposed by the Plasmodium life cycle with intracellular localization of parasites in hepatocytes and red blood cells, (ii) the adverse fluidic conditions encountered in the blood circulation that affect the interaction of molecular components with target cells, and (iii) the unfavorable physicochemical characteristics of most antimalarial drugs, which have an amphiphilic character and can be widely distributed into body tissues after administration and rapidly metabolized in the liver. To surpass these drawbacks, rather than focusing all efforts on discovering new drugs whose efficacy is quickly decreased by the parasite's evolution of resistance, the development of effective drug delivery carriers is a promising strategy. Nanomaterials have been investigated for their capacity to effectively deliver antimalarial drugs at local doses sufficiently high to kill the parasites and avoid drug resistance evolution, while maintaining a low overall dose to prevent undesirable toxic side effects. In recent years, several nanostructured systems such as liposomes, polymeric nanoparticles or dendrimers have been shown to be capable of improving the efficacy of antimalarial therapies. In this respect, nanomaterials are a promising drug delivery vehicle and can be used in therapeutic strategies designed to fight the parasite both in humans and in the mosquito vector of the disease. The chemical analyses of these nanomaterials are essential for the proposal and development of effective anti-malaria therapies. This review is intended to analyze the application of nanomaterials to improve the drug efficacy on different stages of the malaria parasites in both the human and mosquito hosts. [ABSTRACT FROM AUTHOR]

With a view to understand the supramolecular assemblies that bring together certain molecules to form innovative functional materials with high-potential applications, the present review focuses on recent examples of molecular structures that are capable of establishing self-assemblies both in bulk and in solvents. This review demonstrates that appropriate rod- and V-shaped, disc-like and star-shaped molecules as well as high-molecular-weight compounds, either dendrimers or polymers, exhibit a dual ability. Intermolecular interactions that provide liquid crystalline order in bulk may also manifest in solution and this can lead to nanomaterials in the form of nanoaggregates. Through bottom-up approaches that involve the self-assembly of molecules driven by hydrogen bonding, π–π stacking, electrostatic or hydrophilic–hydrophobic interactions, appropriate molecules are able to induce a variety of thermotropic mesophases in bulk as well as aggregates with morphologies such as nanoparticles, nanofibers, nanorods or nanotubes in liquid media including systems in which solvents are immobilized and form gel materials. The aim of this work is to highlight the versatility of mesogenic molecules, opening the door to a wide number of possibilities, as well as to help this topic to enter into a more mature period. [ABSTRACT FROM AUTHOR]

Novel cationic poly(ester amide) dendrimers have been synthesized by copper(i) azide–alkyne cycloaddition (CuAAC) of a tripropargylamine core and azide-terminated dendrons, in turn prepared by iterative amide coupling of the new monomer 2,2′-bis(glycyloxymethyl)propionic acid (bis-GMPA). The alternation of ester and amide groups provided a dendritic scaffold that was totally biocompatible and degradable in aqueous media at physiological and acidic pH. The tripodal dendrimers naturally formed rounded aggregates with a drug that exhibited low water solubility, camptothecin, thus improving its cell viability and anti-Hepatitis C virus (anti-HCV) activity. The presence of numerous peripheral cationic groups enabled these dendrimers to form dendriplexes with both pDNA and siRNA and they showed effective in vitro siRNA transfection in tumoral and non-tumoral cell lines. [ABSTRACT FROM AUTHOR]

The self-assembly behaviour both in bulk and in water of amphiphilic dendrimeric derivatives based on bis-MPA is the central theme of this article. The designed molecules possess two parts with different polarity; this feature is the key factor that forces their self-assembly in water into supramolecular architectures, due to hydrophobic interactions between the lipophilic fractions of the molecules, and the appearance of mesomorphic order in bulk in response to a variation of temperature (thermotropic liquid crystals). The effects provoked by the hydrophilic/lipophilic balance of the molecule were studied varying the generation of the corresponding dendrons and combining them via CuAAC click chemistry in order to obtain symmetrical and unsymmetrical final Janus dendrimers. The ability of the aggregates formed in water to encapsulate hydrophobic drugs has also been explored. [ABSTRACT FROM AUTHOR]

Fully consistent X-ray data and molecular dynamics simulations on new star-shaped liquid crystals yield two nanosegregated architectures with a coaxial stacking of two functional discotic units: tris(triazolyl)triazine and triphenylene. Analysis of lattice order along the principal axes reveals preferential staggered arrangement of the stacked molecules in the columnar assembly. [ABSTRACT FROM AUTHOR]

Two series of new V-shaped acids derived from 1,3,4-oxadiazoles are described. These acids were used to prepare supramolecular complexes through hydrogen bonding with 2,4-diamino-6-dodecylamino-1,3,5-triazine in a 3 : 1 ratio, respectively. The formation of the complexes was studied by infrared and NMR techniques. The thermal behaviour and mesomorphic properties of all the complexes were investigated by polarized light optical microscopy, differential scanning calorimetry and X-ray diffraction. Hexagonal and rectangular columnar mesophases were observed for all complexes at room temperature, without evidence of crystallization. The results of circular dichroism studies allowed us to propose that in the liquid crystalline state these materials adopt a helical columnar organization and this chirality can be controlled by irradiation with CPL. Furthermore, the complexes display strong blue luminescence in solution and in the mesophase. [ABSTRACT FROM AUTHOR]

Two series of polycatenar molecules consisting of a π-conjugated rigid core derived from 3-hexen-1,5-diyne coupled to different types of benzoic acid derivatives have been prepared and their potential as multifunctional materials has been investigated. The size ratio between the rigid core and the benzoate-derived groups, which vary in bulk, is crucial to address self-organization, thus indicating the delicate balance of forces involved in liquid crystalline (LC) behaviour. LC nematic, crystalline or LC columnar behaviour is observed depending on the structure of the benzoate moiety. Hexagonal two-dimensional columnar organization is attained for mesogens with benzoate-derived groups bearing six and nine alkoxylic tails. The stacking unit of the columnar organizations is different depending on the total number of tails, twelve or eighteen, with two molecules and half a molecule per columnar stratum, respectively. Macroscopic properties related to molecular structure, such as luminescence, chirality and electroactivity, have also been studied. Luminescent behaviour is observed for all mesogenic materials, which show higher Stokes shifts than in solution. In addition, supramolecular chirality in the mesophase has been observed for a chiral mesogen. Finally, the photoconducting behaviour of two of the columnar materials has been evaluated. [ABSTRACT FROM AUTHOR]

This tutorial reviewprovides insight into helical columnar assemblies based on thermotropic as well as lyotropic liquid crystals on the basis of the structural characteristics that promote hierarchical self-organization. The structural features of molecular materials that can present helical organizations imply the action of different driving forces that include π-interactions, hydrogen bonding or metal-coordination. In addition, columnar liquid crystals offer the possibility of combining these interactions towards the control of the geometry and orientation of the supramolecular organization leading to well-defined helical columnar assemblies. [ABSTRACT FROM AUTHOR]

Self-assembling cyclic peptides decorated with mesogens form porous columnar mesophases in which, depending on the number of hydrocarbon chains, double or single channels are formed along each column. [ABSTRACT FROM AUTHOR]