Phase Transfer of CdS Nanocrystals Mediated by Heptamine β-Cyclodextrin

Abstract

A fundamental and systematic study on the fabrication of a supramolecularly assembled nanostructure of an organic ligand-capped CdS nanocrystal (NC) and multiple heptamine β-cyclodextrin ((NH(2))(7)βCD) molecules in aqueous solution has been here reported. The functionalization process of presynthesized hydrophobic CdS NCs by means of (NH(2))(7)βCD has been extensively investigated by using different spectroscopic and structural techniques, as a function of different experimental parameters, such as the composition and the concentration of CD, the concentration of CdS NCs, the nature of the NC surface capping ligand (oleic acid and octylamine), and the organic solvent. The formation of a complex based on the direct coordination of the (NH(2))(7)βCD amine groups at the NC surface has been demonstrated and found responsible for the CdS NC phase transfer process. The amine functional group in (NH(2))(7)βCD and the appropriate combination of pristine capping agent coordinating the NC surface and a suitable solvent have been found decisive for the success of the CdS NC phase transfer process. Furthermore, a layer-by-layer assembly experiment has indicated that the obtained (NH(2))(7)βCD functionalized CdS NCs are still able to perform the host-guest chemistry. Thus, they offer a model of a nanoparticle-based material with molecular receptors, useful for bio applications.

Supramolecular Functionalization and Concomitant Enhancement in Properties of Au25 Clusters

“…Being the most popular supramolecular host molecule, β-cyclodextrin (β-CD), cyclic oligosaccharide comprising seven α- d -glucopyranose units linked by α(1–4) glycosidic bonds, has molecule-accepting cavities which are specific to hydrophobic guest molecules of suitable size and geometry . In addition to other applications, this feature has been exploited for the design and construction of molecular sensors in which the inclusion of the guest molecule triggers a signal which can be detected. , Binding of β-CD molecules to various guest-functionalized materials has been utilized for various applications in water purification and biology. − Owing to the high vulnerability of the 4-( t -butyl)benzyl group to form stable host/guest inclusion complexes with β-CD molecules, we synthesized a new 25 atom gold QC protected by 4-( t -butyl)benzyl mercaptan (BBSH) and explored its precise surface functionalization with β-CD molecules. The partial inclusion complex formed due to the host–guest interactions between β-CD and SBB ligand anchored on the Au 25 cluster may be represented as X∩Y, where X and Y are substrate and receptor molecules, respectively, as suggested by Lehn and colleagues .…”

Lipid-based systems loaded with PbS nanocrystals: near infrared emitting trackable nanovectors

“…In fact the precipitation of the OLEA/TOP capped PbS NCs in aqueous solution occurs, both for liposomes and PEG-modified phospholipid micelles, demonstrating as the lipid structures resulted inadequate to provide a shield against the aqueous environment and highlighting the crucial role played by capping ligand at NC surface, as observed elsewhere. 13,21,22 For example, a very similar behaviour was observed in the incorporation of the trioctylphosphine oxide (TOPO) coated CdSe@ZnS NCs in liposomes by the MVT technique. 13 A suitable NC surface functionalization is thus necessary to promote the effective incorporation of NCs into the lipid micro-heterogeneous systems.…”

Synthesis and characterization of oleic acid stabilized CdTe quantum dots and their properties as luminescence quencher of a pyridine pendented rod-coil homopolymer

“…7. The appearance of the peaks at 1520 cm −1 , 1700 cm −1 and 1060 cm −1 could be attributed to C=C, C=O and C-O, respectively [24,25]. The peaks at 2904 cm −1 and 770 cm −1 ascribed to the long alkyl chain of corresponding oleic acid have appeared.…”