SummarySupramolecular gels are an important and interesting class of soft materials that show great potential for many applications. Most of them have been discovered serendipitously, and understanding the supramolecular self-assembly that leads to the formation of the gel superstructure is the key to the directed design of new organogels. We report herein the organogelating property of four stereoisomers of the simple steroid 2,3-dihydroxycholestane. Only the isomer with the trans-diaxial hydroxy groups had the ability to gelate a broad variety of liquids and, thus, to be a super-organogelator for hydrocarbons. The scope of solvent gelation was analysed with regard to two solvent parameters, namely the Kamlet–Taft and the Hansen solubility parameters. The best correlation was observed with the Hansen approach that revealed the existence of two clear gelation zones. We propose a general model of self-assembly through multiple intermolecular hydrogen bonds between the 1,2-dihydroxy system, which is based on experimental data and computational simulations revealing the importance of the di-axial orientation of the hydroxy groups for the one-dimensional self-assembly. Under controlled conditions, the fibrillar superstructure of the organogel was successfully used as a template for the in-situ sol–gel polymerization of tetraethoxysilane and the further preparation of silica nanotubes. We propose that the driving forces for templating are hydrogen bonding and electrostatic interactions between the anionic silicate intermediate species and the self-assembled fibrillar network.

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We report the synthesis of a smart novel hybrid with reversible photoswitchable luminescence properties modulated by light. Combination of a low molecular weight organgelator (LMOG) and CdSe/ZnS core-shell semiconductor nanoparticles capped with trioctylphosphine oxide ligands produces a luminescent, stable and transparent material. Modulation of the luminescence properties was succesfully achieved using a diarylethene photochromic compound, with good resistance to fatigue ca. 22 cycles. Interestingly, the morphology of the organogel fibers was preserved in the hybrid, while a partial luminescent quenching of the nanoparticle was observed. This material could have implication for on-and-off photoswitching applications.An integrated multifunctional QD-organogel hybrid with reversible photoswitchable luminescent properties is reported, combining the intrinsic properties of CdSe/ZnS core-shell QDs, a none-cholesteryl steroid organogel and a photochromic diarylethene.

In this communication, we report on a novel and versatile low-molecular-weight organogelator. The methanolic gel exhibits an exceptional water-enhanced stability as evidenced by a 30 °C increase in Tg with up to 10%v/v of water. This atypical property not observed with other solvents makes of this supramolecular gel a highly stable matrix compatible with aqueous interfaces. As a proof of principle we present the sensing performance of a symmetric tricarbocyanine fluorophore bearing a Zn(II)chelator unit. The system retained its remarkable physical integrity for a long period of time opening new possibilities for other organic-aqueous interface applications.

Five new CC bonded steroidal homodimers derived from deoxycholic acid, pregnenolone, and progesterone were synthesized by an olefin metathesis reaction assisted by microwave heating. Microwave improved the yield and accelerated the reaction allowing the use of less catalyst with good results (2.5 mol %). Due to the bulky nature of the steroidal skeleton the more favorable E-dimers were formed as the sole or major products depending on the linker length.