Chiral Thin Films of Metal Oxide

Abstract

In this paper, we describe for the first time the synthesis of new chiral nanosized metal oxide surfaces based on chiral self-assembled monolayers (SAMs) coated with metal oxide (TiO2) nanolayers. In this new type of nanosize chiral surface, the metal oxide nanolayers enable the protection of the chiral self-assembled monolayers while preserving their enantioselective nature. The chiral nature of the SAM/TiO2 films was characterized by variety of unique techniques, such as second-harmonic generation circular dichroism (SHG-CD), quartz crystal microbalance, and chiral adsorption measurements with circular dichroism spectroscopy. The chiral resolution abilities of the SAMs coated with metal oxide (TiO2) nanolayers were investigated in the crystallization of a racemic mixture of threonine and glutamic acid. Our proposed methodology for the preparation of nanoscale chiral surfaces described in this article could open up opportunities in other fields of chemistry, such as chiral catalysis.

pH-triggered formation of nanoribbons from yeast-derived glycolipid biosurfactants

“…The range of applications is very broad: encapsulation of biomolecules, drug release, cell adhesion, antimicrobial activity, tissue engineering, nanoreactors, nanoelectronics, wound healing, hydrogelation, scaffolding and templates for nanowires, nanoparticles, and mineralization. [19][20][21][22][23][24][25][26][27][28][29] The mechanisms leading to chiral structures have been matter of intense research. Initial theoretical studies date from the late 1980s and early 1990s, [30][31][32] but the general rationale describing the morphological evolution of micelles to twisted and helical ribbons, and nally to nanotubes has only recently started to be unraveled by combining a variety of experimental, theoretical and structural approaches.…”

Enantioselective Colloidosomes Based on Chiral Silica Nanoparticles

“…In recent years, research on chirality at the nanoscale has been particularly relevant . Different nano‐systems, such as chiroptical molecular switches, chiral nanosurfaces, chiral nanoparticles, chiral plasmonic nanostructures, and chiral mesoporous materials were shown to be useful for chiral chemistry. Overall, the field of chiral nanotechnology shows exceptionally strong promise for developing chiral catalysts, bio‐recognition, and chiral separation processes.…”

Exchange Interactions Drive Supramolecular Chiral Induction in Polyaniline

“…[ 13–18 ] Anyhow, the strategy to exploit the presence of a chiral catalyst to induce asymmetry, in inorganic systems, is reported to efficiently introduce chiral properties in bulk systems, as reported, for instance, in elegant and highly interesting recent papers by Mogi, Kuhn, Avnir, Naaman, Switzer and Di Nuzzo. [ 19–30 ] Indeed, the same approach of a bulk chiral catalyst to induce asymmetry is exploited to yield organic polymers featuring an intrinsically chiral super‐structure, [ 29,31,32 ] and in the case of electropolymerized systems. [ 26,33 ] In the last decades chiral induction is also marked by a quite interesting development concerning the field of chiral induction in polydialkylfluorenes and in the field of nanomaterials in general.…”

“…[ 19–30 ] Indeed, the same approach of a bulk chiral catalyst to induce asymmetry is exploited to yield organic polymers featuring an intrinsically chiral super‐structure, [ 29,31,32 ] and in the case of electropolymerized systems. [ 26,33 ] In the last decades chiral induction is also marked by a quite interesting development concerning the field of chiral induction in polydialkylfluorenes and in the field of nanomaterials in general. [ 34–37 ] Within this picture we selected the electropolymerization of aniline (PANI) in the presence of camphor sulfonic acid as a case study, aiming to unfold the physics underlying the mechanism allowing for the induction of chirality in the final supermolecular structure.…”