Exploring the self-assembly dynamics of novel steroid-coumarin conjugates: a comprehensive spectroscopic and solid-state investigation

The design, synthesis, and characterization of seven novel steroid-coumarin conjugates with diverse steroidal nuclei as lipophilic fluorescent materials for bioimaging applications are presented. The conjugates were synthesized through amidation, characterized using spectroscopic and spectrometric methods, and their main photophysical properties were determined. Dioxane : water titration experiments revealed their ability to self-assemble, forming J-aggregates as evidenced by new spectral bands at higher wavelengths. Monocrystal X-ray diffraction analysis disclosed distinctive aggregation patterns exhibiting J- or H-aggregates for selected compounds. Bioimaging studies demonstrated cell membrane localization for most conjugates, with some of them displaying an interesting selectivity for lipid droplets. Notably, the presence of the steroid fragments significantly influenced both the self-assembly patterns and the cellular localization of the fluorescent probes.

α-Cyanostilbene: A Multifunctional Spectral Engineering Motif

The remarkable photophysical phenomenon of aggregation-induced emission offers excellent strategies to obtain the molecular materials possessing unique spectral signatures such as high fluorescence intensity, excellent quantum yield, large Stokes shift...

Fabrication of deoxycholic acid tethered α-cyanostilbenes as smart low molecular weight gelators and AIEE probes for bio-imaging

Four novel deoxycholic acid tethered α-cyanostilbenes were designed, synthesized and characterized using detailed spectroscopic analysis. The synthesized deoxycholic acid tethered α-cyanostilbene derivatives formed stable gels with a variety of solvents, such as xylene, toluene, mesitylene, decane, dodecane etc. The stable gels showed lamellar sheet type structures stacked over each other, consisting of entangled fibres as evident from SEM, TEM and Fluorescence Microscopy images; The synthesized compounds exhibited AIEE behaviour in H₂O/THF mixture, with the maximum emission observed in 70% H₂O/THF fraction along with a bathochromic shift. A solvent thickening experiment was perform to establish the mechanism of AIEE and the AIEE property was explored for bacterial bio-imaging. The synthesized derivatized steroids proved their potential as multifunctional organic materials.

One- and Two-Component Organogels Containing Cyanostilbene without any Auxiliary Substituents

Pyridyl acrylonitrile without traditional auxiliary groups form stable organogels in ethanol. The addition of a second non-gelating cyanostilbene component results in a more stable two-component gel. Single crystal X-ray data reveal the influence of C-H⋅ ⋅ ⋅N, C-H⋅ ⋅ ⋅π, and π-π interactions in the formation of organogels. The morphology of the xerogels was studied by using SEM, which showed the self-assembly of molecules to fibers and sheet-like structures, and phase differences upon the gel formation and the structural phase characterization was measured using powder XRD. Exposure of the organogels to acidic (TFA) vapors results in distinct color changes and loss of gelation properties, thus highlighting the potential of these gels in sensing. The results represent a rare example of two-component organogels using two different cyanostilbene units and show that functional two-component organogels can be formed by utilizing the synergistic effects of the individual components.

Cholesterol-Based Compounds: Recent Advances in Synthesis 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.

Self-Assembled α-Cyanostilbenes for Advanced Functional Materials

In the specific context of condensed media, the significant and increasing recent interest in the α-cyanostilbene (CS) motif [ArCHC(CN)Ar] is relevant. These compounds have shown remarkable optical features in addition to interesting electrical properties, and hence they are recognized as very suitable and versatile options for the development of functional materials. This progress report is focused on current and future use of CS structures and molecular assemblies with the aim of exploring and developing for the next generations of functional materials. A critical selection of illustrative materials that contain the CS motif, including relevant subfamilies such as the dicyanodistyrylbenzene and 2,3,3-triphenylacrylonitrile shows how, driven by the self-assembly of CS blocks, a variety of properties, effects, and possibilities for practical applications can be offered to the scientific community, through different rational routes for the elaboration of advanced materials. A survey is provided on the research efforts directed toward promoting the self-assembly of the solid state (polycrystalline solids, thin films, and single crystals), liquid crystals, nanostructures, and gels with multistimuli responsiveness, and applications for sensors, organic light-emitting diodes, organic field effect transistors, organic lasers, solar cells, or bioimaging purposes.

A3-Type star stilbene and cyanostilbene molecules: synthesis, fluorescence properties and bio-imaging application

In this article, we report star-like stilbene and cyanostilbene molecules exhibiting strong fluorescence, ICT and AIE properties. Star cyanostilbene was found to be an excellent fluorophore for bio-imaging application.