Search results for "nanoreactor"

Front Cover Picture: SBA‐15/POSS‐Imidazolium Hybrid as Catalytic Nanoreactor: the role of the Support in the Stabilization of Palladium Species for C…

2019

Charged supramolecular assemblies of surfactant molecules in gas phase

2015

The aim of this review is to critically analyze recent literature on charged supramolecular assemblies formed by surfactant molecules in gas phase. Apart our specific interest on this research area, the stimuli to undertake the task arise from the widespread theoretical and applicative benefits emerging from a comprehensive view of this topic. In fact, the study of the formation, stability, and physicochemical peculiarities of non-covalent assemblies of surfactant molecules in gas phase allows to unveil interesting aspects such as the role of attractive, repulsive, and steric intermolecular interactions as driving force of supramolecular organization in absence of interactions with surround…

SBA-15/POSS-Imidazolium Hybrid as Catalytic Nanoreactor

2019

Supported imidazolium modified polyhedral oligomeric silsesquioxanes (POSS) on SBA-15 have been used as platform for Pd(II) species. The so-obtained material was firstly characterized by means of TGA, solid state NMR, TEM, XPS, SAXS, porosimetry and ICP-OES and it was successfully tested as pre-catalyst in C−C cross couplings, namely Suzuki-Miyaura and Heck reactions. In both cases, the solid proved to be highly efficient and easily recoverable from the reaction mixture. The recyclability was verified for up to seven cycles without showing any activity decrease. Interestingly, only Pd(II) was detected in the reused catalyst in the Heck reaction. Therefore, the versatility of the material w…

Nanoreactors for the multi-functionalization of poly-histidine fragments

2019

Water-soluble MBHA derivatives were found to self-assemble in a water environment to generate aggregates showing core–shell architectures. The aggregates appeared to be capable of working as nanoreactors performing a multi-functionalization of poly-histidine fragments, which after an initial interaction with the solvated oligo(ethylene glycol) shell reach the reactive core.

Study of the growth of ZnS nanoparticles in water/AOT/n-heptane microemulsions by UV-absorption spectroscopy

1999

Abstract ZnS nanoparticles were synthesized at 25°C using water-containing AOT reversed micelles as nanoreactors and characterized by UV–vis spectroscopy. The time dependence of the spectra emphasizes a slow growing process of the ZnS nanoparticles coupled with a change of their photophysical properties. Both processes are well described by power laws. The nanoparticle size can be controlled by the molar ratio R ( R =[water]/[AOT]), i.e. by the micellar size. The deposits obtained by evaporation of the volatile components of the microemulsions are found to be composed of a surfactant matrix containing ZnS nanoparticles smaller and more stable than that in the corresponding microemulsions.

Chemically Fueled Block Copolymer Self‐Assembly into Transient Nanoreactors**

2021

In chemically fueled supramolecular materials, molecular self-assembly is coupled to a fuel-driven chemical reaction cycle. The fuel-dependence makes the material dynamic and endows it with exciting properties like adaptivity and autonomy. In contrast to the large work on the self-assembly of small molecules, we herein designed a diblock copolymer, which self assembles into transient micelles when coupled to a fuel-driven chemical reaction cycle. Moreover, we used these transient block copolymer micelles to locally increase the concentration of hydrophobic reagents and thereby function as a transient nanoreactor.

Metal-Organic Frameworks as Chemical Nanoreactors: Synthesis and Stabilization of Catalytically Active Metal Species in Confined Spaces

2020

ConspectusSince the advent of the first metal-organic frameworks (MOFs), we have witnessed an explosion of captivating architectures with exciting physicochemical properties and applications in a wide range of fields. This, in part, can be understood under the light of their rich host-guest chemistry and the possibility to use single-crystal X-ray diffraction (SC-XRD) as a basic characterization tool. Moreover, chemistry on preformed MOFs, applying recent developments in template-directed synthesis and postsynthetic methodologies (PSMs), has shown to be a powerful synthetic tool to (i) tailor MOFs channels of known topology via single-crystal to single-crystal (SC-SC) processes, (ii) impart…

Amphiphilic Poly(organosiloxane) Nanospheres as Nanoreactors for the Synthesis of Topologically Trapped Gold, Silver, and Palladium Colloids

2003

Amphiphilic poly(organosiloxane) nanospheres with different core−shell architectures are employed as passive nanoreactors for the synthesis of noble metal colloids. The amphiphilic poly(organosiloxane) nanospheres, which have diameters between 15 and 40 nm, possess a hydrophilic interior and a hydrophobic shell. Dispersed in organic solvents such as toluene, it has been achieved to transfer hydrophilic noble metal salts through the solvent into the nanospheres by either liquid−liquid or solid−liquid phase transfer. Subsequently, reduction of the noble metal salt with lithium triethylborohydride led to the formation of 2−5 nm sized noble metal colloids. If the network density of the shell of…

Self-assembly of catalytically-active supramolecular coordination compounds within metal-organic frameworks

2019

[EN] Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal-organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of Pd-II SCCs within the confined space of a pre-formed MOF (SCCs@MOF) and its post-assembly metalation to give a Pd-II-Au-III supra molecular assembly, c…

Active surfaces engineered by immobilizing protein-polymer nanoreactors for selectively detecting sugar alcohols.

2016

We introduce active surfaces generated by immobilizing protein-polymer nanoreactors on a solid support for sensitive sugar alcohols detection. First, such selective nanoreactors were engineered in solution by simultaneous encapsulation of specific enzymes in copolymer polymersomes, and insertion of membrane proteins for selective conduct of sugar alcohols. Despite the artificial surroundings, and the thickness of the copolymer membrane, functionality of reconstituted Escherichia coli glycerol facilitator (GlpF) was preserved, and allowed selective diffusion of sugar alcohols to the inner cavity of the polymersome, where encapsulated ribitol dehydrogenase (RDH) enzymes served as biosensing e…