Preparation, Characterization, and Electrical Properties of a Self-Assembled meso-Pyridyl Porphyrin Monolayer on Gold Surfaces

2005 ◽  
Vol 58 (11) ◽  
pp. 810 ◽  
Author(s):  
Amarchand Sathyapalan ◽  
Anup Lohani ◽  
Sangita Santra ◽  
Saurabh Goyal ◽  
M. Ravikanth ◽  
...  
Keyword(s):  
Soret Band ◽  
Gold Surface ◽  
Scanning Tunneling Spectroscopy ◽  
Uv Absorption ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Force Microscopy ◽  
Gold Substrates ◽  
Assembled Monolayers ◽  
Self Assembled

A meso-pyridyl porphyrin, 5-(4-(2-(4-(S-acetylthiomethyl)phenyl)ethynyl)phenyl)-10,15,20-tris(4-pyridyl) porphyrin was synthesized by coupling of 5-{4-ethynyl}phenyl-10,15,20-tris(4-pyridyl) porphyrin with 4-(S-acetylthiomethyl)-4-iodobenzene under mild palladium coupling conditions. The meso-pyridyl porphyrin was used for the preparation of self assembled monolayers on gold substrates. The gold substrates were made by the thermal evaporation of gold on oxidized Si(100) surfaces. The self-assembled monolayers (SAMs) were characterized using ground state UV absorption and X-ray photoelectron spectroscopic (XPS) techniques and also by scanning probe microscopy (SPM) techniques. The UV-absorption spectra of the porphyrin monolayer exhibited a 10 nm red shift in the Soret band compared to the porphyrin in CHCl3 solution. This indicates that the porphyrin molecules are aligned on the gold substrate in a side-by-side orientation. The typical shifts in the binding energy by XPS revealed that the chemisorption of the thiolate species of the porphyrin to the surface occurs through a strong sulfur–gold bonding mechanism. Basic hexagonal (√3×√3) R 30° well ordered self-assembled monolayers of meso-pyridyl porphyrin was observed by molecular-resolution atomic force microscopy (AFM). Room temperature current–voltage (I–V) spectra by scanning tunneling spectroscopy (STS) at varying set point current were collected to study the electronic transport properties of the monolayers on the gold surface.

Specific Immobilization of Streptavidin on Mixed Self-Assembled Monolayers as Mixing Ratio

2007 ◽  
Vol 121-123 ◽  
pp. 495-498 ◽  
Author(s):  
Jun Hyung Park ◽  
Buyng Su Park ◽  
Gu Huh ◽  
Seung Hyun Lee ◽  
Hyun Sook Lee ◽  
...  
Keyword(s):  
Colorimetric Detection ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Local Domain ◽  
Mixing Ratio ◽  
Tunneling Microscopy ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled

We report on the distribution of mixed self-assembled monolayers (SAMs) composed of biotinylated and diluent alkylthiolates for streptavidin immobilization. Two thiol derivatives, 11-mercapto-1-undecanol (MUOH) and 11-mercaptoundecanoic-(8-biotinylamido-3,6-dioxaoctyl) amide (MBDA), were employed for mixed SAM. These thiols formed self-assembled monolayer without local domain, and streptavidins were immobilized onto biotinylated gold surface without nonspecific binding. In order to find the optimized condition of immobilization of streptavidin, we controlled the mixing ratio of two kind thiols by colorimetric detection assay, and the immobilization was characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and ellipsometer.

scholarly journals Scanning Tunneling Spectroscopy of Insulating Self-Assembled Monolayers on Au(111)

2002 ◽  
Vol 106 (34) ◽  
pp. 8721-8725 ◽  
Author(s):  
André P. Labonté ◽  
Steven L. Tripp ◽  
Ronald Reifenberger ◽  
Alexander Wei
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Assembled Monolayers ◽  
Self Assembled

scholarly journals Design of Therapeutic Self-Assembled Monolayers of Thiolated Abiraterone

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1018 ◽  
Author(s):  
Elżbieta Stolarczyk ◽  
Katarzyna Sidoryk ◽  
Marcin Cybulski ◽  
Marek Kubiszewski ◽  
Krzysztof Stolarczyk
Keyword(s):  
Gold Electrode ◽  
Thioglycolic Acid ◽  
Surface Concentration ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Desorption Process ◽  
Force Microscopy ◽  
Atomic Force ◽  
Assembled Monolayers ◽  
Self Assembled

The aim of our work was to synthetize of a new analogue of abiraterone—thiolated abiraterone (HS-AB) and design a gold surface monolayer, bearing in mind recent advances in tuning monolayer structures and using them as efficient drug delivery systems. Therapeutic self-assembled monolayers (TSAMs) were prepared by chemically attaching HS-AB to gold surfaces. Their properties were studied by voltammetry and atomic force microscopy (AFM). A gold electrode with immobilized thioglycolic acid (HS-GA) was used for comparison. The surface concentration of HS-AB on the gold surface was 0.572 nmol/cm2, determined from the area of the voltammetric reduction peaks (desorption process). The area per one molecule estimated from the voltammetry experiments was 0.291 nmol/cm2. The capacity of thus prepared electrode was also tested. The calculated capacity for the HS-AB modified electrode is 2.90 μF/cm2. The obtained value indicates that the monolayer on the gold electrode is quite well ordered and well-packed. AFM images show the formation of gold nanoparticles as a result of immersing the HS-AB modified gold electrode in an aqueous solution containing 1 mM HAuCl4·3H2O. These structures arise as a result of the interaction between the HS-AB compound adsorbed on the electrode and the AuCl4− ions. The voltammetric experiments also confirm the formation of gold structures with specific catalytic properties in the process of oxygen reduction.

Scanning tunneling microscopy tip-assisted modification of Ti(IV) dithiothreitol self-assembled monolayers on Au(111): restructuring of the gold surface

2013 ◽  
Vol 91 (5) ◽  
pp. 364-368
Author(s):  
M.L. Cappello ◽  
K.A. Hardy ◽  
A.R. MacDairmid ◽  
M.C. Gallagher ◽  
J.T. Banks
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Gold Surface ◽  
Titanium Isopropoxide ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Negative Sample ◽  
Tunneling Microscopy ◽  
Sample Bias ◽  
Assembled Monolayers ◽  
Self Assembled

Au(111) surfaces modified by exposure to a dilute solution of a Ti(IV)/dithiothreitol ligand to metal charge transfer complex (Ti(DTT)2) show a remarkable response to continuous scanning by scanning tunneling microscopy (STM). Vacancy islands on the gold surface, which are formed during the self-assembly of the molecular overlayer, coarsen and even merge during STM scanning at negative sample bias. In certain instances, the vacancy islands even line up to form parallel nanostructures. We believe the effect is due to mechanical interactions between tip and sample, which is enhanced by electrostatic effects. The Ti(DTT)2 complex is anchored to the gold surface via Au−S bonds, but due to the fact that there are multiple thiol groups, there may be “uncoordinated” thiols left “dangling”. The tip-induced modification involves the interaction of the tip with these “dangling” sulfurs, which in turn causes movement of single complex molecules with the attached sulfur-bonded gold. Under negative sample bias, the electric field weakens the binding between the sulfur-bonded gold atoms and the surrounding gold atoms in the surface allowing for the observed tip-induced dynamics. In contrast with the Ti(DTT)2 complex, a similar Ti(IV)/3-mercapto-1,2-propanediol complex (Ti(MPD)2) does not exhibit any tip-induced effects. In this case, there are no dangling sulfurs to interact with the STM tip. In addition, similarly prepared dithiothreitol, dithiothreitol titanium isopropoxide, and 3-mercapto-1,2-propanediol self-assembled monolayers (without dangling sulfurs) do not exhibit the tip-induced effect.

Nanoporous Thin Films Formed from Photocleavable Diblock Copolymers on Gold Substrates Modified with Thiolate Self-Assembled Monolayers

Langmuir ◽  
2020 ◽  
Vol 36 (31) ◽  
pp. 9259-9268 ◽  
Author(s):  
Takashi Ito ◽  
Herman Coceancigh ◽  
Yi Yi ◽  
Jay N. Sharma ◽  
Fred C. Parks ◽  
...  
Keyword(s):  
Thin Films ◽  
Diblock Copolymers ◽  
Self Assembled Monolayers ◽  
Gold Substrates ◽  
Assembled Monolayers ◽  
Self Assembled

Preparation and Characterization of γ-Aminopropyltrimethoxysilane and Octadecyltrichlorosilane Self-Assembled Monolayers on Titanium Films

2008 ◽  
Vol 373-374 ◽  
pp. 472-475 ◽  
Author(s):  
C.G. Sun ◽  
Hui Chen Zhang
Keyword(s):  
Ultraviolet Radiation ◽  
Friction Force ◽  
Self Assembled Monolayers ◽  
Sliding Velocity ◽  
Friction Property ◽  
Titanium Film ◽  
Photochemical Process ◽  
Force Microscopy ◽  
Assembled Monolayers ◽  
Self Assembled

In this work, the self-assembled monolayers of γ-aminopropyltrimethoxysilane and octadecyltrichlorosilane were prepared on titanium films, radiated and solidified by ultraviolet radiation/ozone photochemical process. The characterization and friction properties of titanium film, APS SAMs, OTS SAMs and the radiated APS SAMs, OTS SAMs were explored by atomic force microscopy and friction force microscopy. The effects of functional groups, sliding velocity, load and ultraviolet radiation/ozone photochemical process on friction properties of SAMs were analyzed. The experimental results show that the titanium film coated with SAMs, especially under ultraviolet radiation/ozone, is exhibited with a good friction property. The friction property of APS SAMs is better than OTS SAMs under or no ultraviolet radiation/ozone. The friction force increases with the increasing of sliding velocity and decreases with the increasing of load.

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