Organic/Hybrid Nanoparticles and Single‐Walled Carbon Nanotubes: Preparation Methods and Chiral Applications

Abstract

Nanoparticles are molecular-sized solids with at least one dimension measuring between 1-100 nm or 10-1000 nm depending on the individual discipline's perspective. They are aggregates of anywhere from a few hundreds to tens of thousands of atoms which render them larger than molecules but smaller than bulk solids. Consequently, they frequently exhibit physical and chemical properties somewhere between. On the other hand, nanocrystals are a special class of nanoparticles which have started gaining attention recently owing to their unique crystalline structures which provide a larger surface area and promising applications including chiral separations. Hybrid nanoparticles are supported by the growing interest of chemists, physicists, and biologists, who are researching to fully exploit them. These materials can be defined as molecular or nano-composites with mixed (organic or bio) and inorganic components, where at least one of the component domain has a dimension ranging from a few Å to several nanometers. Similarly, and due to their extraordinary physical, chemical, and electrical properties, single-walled carbon nanotubes have been the subject of intense research. In this short review, the focus is mainly on the current well-established simple preparation techniques of chiral organic and hybrid nanoparticles as well as single-walled carbon nanotubes and their applications in separation science. Of particular interest, cinchonidine, chitosan, and β-CD-modified gold nanoparticles (GNPs) are discussed as model examples for organic and hybrid nanoparticles. Likewise, the chemical vapor deposition method, used in the preparation of single-walled carbon nanotubes, is discussed. The enantioseparation applications of these model nanomaterials is also presented.

The Reciprocal Principle of Selectand-Selector-Systems in Supramolecular Chromatography †

“…Unspecified chiral ( n,m )-SWCNTs were tested as CSPs for the enantioseparation of twelve classes of racemic pharmaceuticals by nano-LC [73,74]. The finding would require that the commercially available chiral (6,7)-SWCNT (carbon >90%, 0.7–0.9 nm diameter by fluorescence) obtained from Sigma-Aldrich was nonracemic or even enantiomerically pure.…”

Туннельный Ток Между Структурными Элементами Тонких Графен/Нанотрубных Пленок

“…Применениям ОУНТ посвящено много работ. Как неоднократно показано, ОУНТ могут использоваться в полевых транзисторах [10], в нанохроматографии [11], различных сенсорах [12]. При этом нанотрубки образуют сетки с разветвленной структурой.…”

Cyclodextrin‐Functionalised Nanomaterials for Enantiomeric Recognition

“…The difference between intrinsically chiral and modified achiral nanomaterials arises from where chirality originates from, whereby in the case of modified achiral nanomaterials, the chirality feature is introduced by incorporation of chiral structures (molecules). Intrinsically chiral nanomaterials could either be chiral by nature (e. g. carbon nanotubes) or could be prepared by chiral template‐driven process (e. g. chiral Au nanoclusters) . To achieve a desired chiral recognition, achiral nanomaterials are often functionalized with small chiral molecules like amino acids, larger molecules (e. g. cyclodextrins) or achiral nanoparticles (NPs) are interconnected to form chiral superstructures .…”