A facile method of confining gold nanoparticles (AuNPs) in silica nanochannels aligned perpendicularly to an underlying electrode surface is reported. The nanochannel surface carrying a layer of (3‐aminopropyl)triethoxy silane (APTS) displays a strong electrostatic interaction with AuCl4?, eventually resulting in the confinement of AuNPs inside the nanochannels after chemical reduction. As‐prepared AuNPs in APTS‐modified mesoporous silica film (APTS‐MSF) are highly dispersed with a narrow size distribution. Furthermore, these AuNPs are free of protecting ligands and exhibit a good electrochemical catalytic activity toward the oxidation of ascorbic acid. 相似文献
Utilizing weak interactions to effectively recover and separate precious metals in solution is of great importance but the practice remains a challenge. Herein, we report a novel strategy to achieve precise recognition and separation of gold by regulating the hydrogen-bond (H-bond) nanotrap within the pore of covalent organic frameworks (COFs). It is found that both COF-HNU25 and COF-HNU26 can efficiently capture AuIII with fast kinetics, high selectivity, and uptake capacity. In particular, the COF-HNU25 with the high density of H-bond nanotraps exhibits an excellent gold uptake capacity of 1725 mg g−1, which is significantly higher than that (219 mg g−1) of its isostructural COF (COF-42) without H-bond nanostrap in the pores. Importantly, the uptake capacity is strongly correlated to the number of H-bonds between phenolic OH in the COF and [AuCl4]− in water, and multiple H-bond interactions are the key driving force for the excellent gold recovery and reusability of the adsorbent. 相似文献
In this work, we describe the direct covalent attachment of protein recognition elements (biotin) with the carboxyl groups present on the walls of polyimide nanochannels. Subsequently, these biotinylated channels were used for the bio‐specific sensing of protein analytes. Moreover, surface charge of these asymmetric nanochannels was reversed from negative to positive via the conversion of carboxyl groups into terminated amino groups. The negatively charge (carboxylated) and positively charged (aminated) channels were further used for the electrochemical sensing of bovine serum albumin (BSA, pI = 4.7). These biorecognition events were assessed from the changes in the ionic current flowing through the nanochannel.
The thioether functionalized aminosilanes Me2Si(NH‐C6H4‐2‐SR)2 (R = Ph, Me) were lithiated with nBuLi and subsequently reacted with AgCl in the presence of PMe3 or with [AuCl(PMe3)]. In the case of Me2Si(NH‐C6H4‐2‐SPh)2 the dinuclear complexes [M2{Me2Si(NC6H4‐2‐SPh)2}(PMe3)2] (M = Ag; Au) were isolated. The analogous reactions starting from Me2Si(NH‐C6H4‐SMe)2 afforded the dinuclear gold complex [Au2{Me2Si(NC6H4‐2‐SMe)2}(PMe3)2] and the tetranuclear silver complex [Ag4{Me2Si(NC6H4‐2‐SMe)2}2(PMe3)2]. In the dinuclear compounds of the type [M2{Me2Si(NC6H4‐2‐SR)2}(PMe3)2], each of the silylamide N atoms is connected to a M(PMe3) group to give a nearly linear N–M–P arrangement with Ag–N and Au–N bonds in the range of 212.0(4)–213.3(4) pm and 205.3(3)–208.1(9) pm, respectively. [Ag4{Me2Si(NC6H4‐2‐SMe)2}2(PMe3)2] consists of a central Si2N4Ag2 ring with linearly coordinated Ag atoms (Ag‐N: 223.1(4)–222.1(4) pm) and two peripheral Ag(PMe3) units, which are connected to the amido N atoms in a chelating mode. The relatively short transannular Ag ··· Ag separation (277.6(1) pm) within the Si2N4Ag2 ring hints for argentophilic interactions. The peripheral Ag atoms are three coordinated with Ag–N distances of 233.9(4)–242.8(4) pm. 相似文献
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