Coadsorption of Octanethiol and Dialkyldithiocarbamate on Au(111)

Yuan

et al. 2015

Sci Rep

Insight into the nature of metal-sulfur bond, a meaningful one in life science, interface chemistry and organometallic chemistry, is interesting but challenging. By utilizing the localized surface plasmon resonance properties of silver nanoparticles, herein we visually identified the photosensitivity of silver-dithiocarbamate (Ag-DTC) bond by using dark field microscopic imaging (iDFM) technique at single nanoparticle level. It was found that the breakage of Ag-DTC bond could be accelerated effectively by light irradiation, followed by a pH-dependent horizontal or vertical degradation of the DTC molecules, in which an indispensable preoxidation process of the silver was at first disclosed. These findings suggest a visualization strategy at single plasmonic nanoparticle level which can be excellently applied to explore new stimulus-triggered reactions, and might also open a new way to understand traditional organic reaction mechanisms.

Section: Resultsmentioning

confidence: 97%

Visual Identification of Light-Driven Breakage of the Silver-Dithiocarbamate Bond by Single Plasmonic Nanoprobes

Yuan

et al. 2015

Sci Rep

“…Basic conclusions arising from presented research remain in opposition to few available literature reports. Comparative stability studies, which were described for DTC- and thiolate-based SAMs unequivocally indicate the higher energy of DTCs chemisorption on gold in comparison to thiol assembly (Park et al, 2010 ; Raigoza et al, 2012 ). It should be however underlined, that their scope of work was limited only to simple, N,N-disubstituted DTC derivatives.…”

Section: Resultsmentioning

confidence: 98%

“…It is noteworthy, that similar trend was observed for alkyl DTC and thiolate monolayers (ferrocene-C16-DTC and ferrocene-C16-SH) by Eckermann et al ( 2010 ), where the ratio of the surface densities calculated for thiolate and DTC monolayers was 3.46. Lower surface density of DTC derivatives is typically explained by the occurrence of steric hindrance resulting from bidentate Au-DTC chelation and thus attenuation of hydrophobic interactions of alkyl chains (Eckermann et al, 2010 ; Raigoza et al, 2012 ). It should be however noted, that surprisingly high density of DNA-Ads, together with relatively high stability of adsorbed DNA additionally confirms the assumption of large contribution of co-adsorption in the overall effect observed for DTC monolayers.…”

Section: Resultsmentioning

confidence: 99%

“…Among methods of gold biofunctionalization, these based on monolayers of compounds capable of chemisorption via terminal, sulfur-containing groups, mainly thiol derivatives, and more rarely other such as disulfides, sulfides, thioesters, isothiocyanates, or dithiocarbamates (DTCs) (Ulman, 1996 ; Mandler and Kraus-Ophir, 2011 ). Despite the common use of thiolate chemisorption, there is a number of reported disadvantages, limiting the use of such strategy for a construction of functional receptor layers for biosensing (Schoenfisch and Pemberton, 1998 ; Raigoza et al, 2012 ). Park et al ( 2010 ) reported the lability of monodentate linkage of alkanethiols with gold, which negatively affects the resolution of patterns obtained via thiol self-assembly on Au substrates.…”

Section: Introductionmentioning

confidence: 99%

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SPRi-Based Biosensing Platforms for Detection of Specific DNA Sequences Using Thiolate and Dithiocarbamate Assemblies

2018

The framework of presented study covers the development and examination of the analytical performance of surface plasmon resonance-based (SPR) DNA biosensors dedicated for a detection of model target oligonucleotide sequence. For this aim, various strategies of immobilization of DNA probes on gold transducers were tested. Besides the typical approaches: chemisorption of thiolated ssDNA (DNA-thiol) and physisorption of non-functionalized oligonucleotides, relatively new method based on chemisorption of dithiocarbamate-functionalized ssDNA (DNA-DTC) was applied for the first time for preparation of DNA-based SPR biosensor. The special emphasis was put on the correlation between the method of DNA immobilization and the composition of obtained receptor layer. The carried out studies focused on the examination of the capability of developed receptors layers to interact with both target DNA and DNA-functionalized AuNPs. It was found, that the detection limit of target DNA sequence (27 nb length) depends on the strategy of probe immobilization and backfilling method, and in the best case it amounted to 0.66 nM. Moreover, the application of ssDNA-functionalized gold nanoparticles (AuNPs) as plasmonic labels for secondary enhancement of SPR response is presented. The influence of spatial organization and surface density of a receptor layer on the ability to interact with DNA-functionalized AuNPs is discussed. Due to the best compatibility of receptors immobilized via DTC chemisorption: 1.47 ± 0.4 · 1012 molecules · cm−2 (with the calculated area occupied by single nanoparticle label of ~132.7 nm2), DNA chemisorption based on DTCs is pointed as especially promising for DNA biosensors utilizing indirect detection in competitive assays.

“…The sample is prepared by depositing a single layer of OT on Au(111) substrate using the standard method described in our previous works. , The sample is then transferred into an ultrahigh vacuum (UHV) system equipped for an Omicron Fermi STM. Imaging was performed with electrochemically etched tungsten tips.…”

Section: Methodsmentioning

confidence: 99%

Two-Dimensional van der Waals Supramolecular Frameworks from Co-Hosted Molecular Assembly and C₆₀ Dimerization

et al. 2020

A two-dimensional van der Waals supramolecular framework is created by self-assembled cocrystallization of C 60 and octanethiol molecules on the Au(111) surfaces. The framework is characterized by the two-dimensional C 60 network, in which the pores are filled by RS-Au-SR (R = CH 3 (CH 2 ) 7 S) staples. The framework is stabilized by cooperative interactions involving collective self-assembly instead of the commonly observed pairwise interactions between the nearest neighbors. The pairing of two adjacent C 60 molecules and the formation of C 60 dimer are visualized by low temperature scanning tunneling microscopic imaging, in conjunction with first-principles calculations, suggesting a charge transfer in each C 60 dimer. Such van der Waals C 60 supramolecular framework with intermolecular charge transfer, serving a rare example in artificial 2D molecular crystal for inert C 60 molecules, is very promising in applications of optics and devices.