Hybrid Inclusion Materials based on Chiral Nematic Mesoporous Organosilica with incorporated Cyclodextrin Receptors.

The creation of multicomponent materials with desired properties and functions is a challenge of modern materials chemistry. Chiral nematic mesoporous organosilicas have iridescent properties that make them attractive for decoration and sensing. In this paper, we demonstrate the chemical functionalization of chiral nematic mesoporous organosilica films with cyclodextrin.

Controlling the optical properties of chiral nematic mesoporous organosilica films with bioadditives.

Chiral nematic mesoporous organosilica (CNMO) films have unique iridescent properties that make them attractive candidates for decorations, sensing and photonics. However, it has proven difficult to control the colour and porosity of CNMO films. Here, we have explored the addition of a range of biodegradable and eco-friendly additives to tune the helical pitch and, hence, the colour of the CNMO materials.

Halloysite nanotubes enhance the mechanical properties and thermal stability of iridescent cellulose nanocrystal films.

Films of cellulose nanocrystals (CNCs) with chiral nematic organization can show vivid iridescence that arises from their hierarchical structure. Unfortunately, the brittleness of the films limits their potential applications. In this paper, we investigate the incorporation of halloysite nanotubes (HNTs) into CNC films to prepare organic-inorganic composite films with enhanced mechanical properties, while preserving the chiral nematic structure and brilliant iridescence.

Unravelling Structural Dynamics, Supramolecular Behavior, and Chiroptical Properties of Enantiomerically Pure Macrocyclic Tertiary Ureas and Thioureas.

The introduction of urea or thiourea functionality to the macrocycle skeleton represents an alternative way to control conformational dynamics of chiral, polyamines of a figure-shaped periodical structure. Formally highly symmetrical, these macrocycles may adapt diverse conformations, depending on the nature of an amide linker and on a substitution pattern within the aromatic units. The type of heteroatom X in the N-C(═X)-N units present in each vertex of the macrocycle core constitutes the main factor determining the chiroptical properties.

Specific Noncovalent Association of Truncated -Functionalized Triangular Homochiral Isotrianglimines through Head-to-Head, Tail-to-Tail, and Honeycomb Supramolecular Motifs.

Chiral isotrianglimines were synthesized by the [3 + 3] cyclocondensation of (,)-1,2-diaminocyclohexane with C5-substituted isophthalaldehyde derivatives. The substituent's steric and electronic demands and the guest molecules' nature have affected the conformation of individual macrocycles and their propensity to form supramolecular architectures. In the crystal, the formation of a honeycomb-like packing arrangement of the simplest isotrianglimine was promoted by the presence of toluene or -xylene molecules.

One-step Access to Resorcinsalens-Solvent-Dependent Synthesis, Tautomerism, Self-sorting and Supramolecular Architectures of Chiral Polyimine Analogues of Resorcinarene.

Substituted 2,4- and 4,6-dihydroxyisophthalaldehydes were condensed with optically pure and racemic trans-1,2-diaminocyclohexane to form resorcinarene-like polyimine macrocycles (resorcinsalens), the structure and stoichiometry of which were controlled by the choice of the reaction medium. Particularly, the cyclocondensation reactions were driven by the solubility, tautomerization, or by social self-sorting. The resorcinsalens crystallized as inclusion compounds, in which the guest molecules were situated either in channels or in voids.

Enantiopure Tertiary Urea and Thiourea Derivatives of Trianglamine Macrocycle: Structural Studies and Metallogeling Properties.

Synthesis and detailed experimental and theoretical study on new urea and thiourea derivatives of chiral trianglamine are presented. In solution, the urea derivative of the trianglamine adopts cone conformation, whereas a respective thiourea derivative exists in solution predominantly as a partial cone conformer. In the crystalline phase, the thiourea trianglamine derivative adapts partial cone conformation.

Electronic and vibrational exciton coupling in oxidized trianglimines.

Readily available chiral trianglimine and their (poly)oxygenated congeners represent a unique class of macrocyclic rigid compounds optimal for testing electronic and vibrational circular dichroism exciton chirality methods. Electronic and vibrational circular dichroism spectra of such trianglimines are strongly affected by polar substituents in macrocycle skeletons. Double substitution by OH groups in each aromatic fragment of the macrocycle causes sign reversal of the exciton couplet in the region of the strongest UV absorption.