Bis-(4-(2-pyridylmethyleneiminophenyl))disulfide — A chelating ligand capable of self assembly on gold surface and its complexes with M(BF4)2 and M(ClO4)2; MCo, Cu and Ni. Experimental and theoretical study

2007 ◽  
Vol 515 (11) ◽  
pp. 4649-4661 ◽  
Author(s):  
E.K. Beloglazkina ◽  
A.G. Majouga ◽  
N.V. Zyk ◽  
R.D. Rakhimov ◽  
I.V. Yaminsky ◽  
...  
Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2393
Author(s):  
Artur Trembułowicz ◽  
Agata Sabik ◽  
Miłosz Grodzicki

The surface of quasi-hexagonal reconstructed Au(100) is used as the template for monolayer pentacene (PEN) self-assembly. The system is characterized by means of scanning tunneling microscopy at room temperature and under an ultra-high vacuum. A new modulated pattern of molecules with long molecular axes (MA) arranged along hex stripes is found. The characteristic features of the hex reconstruction are preserved herein. The assembly with MA across the hex rows leads to an unmodulated structure, where the molecular layer does not recreate the buckled hex phase. The presence of the molecules partly lifts the reconstruction—i.e., the gold hex phase is transformed into a (1×1) phase. The arrangement of PEN on the gold (1×1) structure is the same as that of the surrounding molecular domain on the reconstructed surface. The apparent height difference between phases allows for the distinction of the state of the underlying gold surface.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Shira Yochelis ◽  
Eran Katzir ◽  
Yoav Kalcheim ◽  
Vitaly Gutkin ◽  
Oded Millo ◽  
...  

Many intriguing aspects of molecular electronics are attributed to organic-inorganic interactions, yet charge transfer through such junctions still requires fundamental study. Recently, there is a growing interest in anchoring groups, which considered dominating the charge transport. With this respect, we choose to investigate self-assembly of disilane molecules sandwiched between gold surface and gold nanoparticles. These assemblies are found to exhibit covalent bonds not only between the anchoring Si groups and the gold surfaces but also in plane crosslinks that increase the monolayer stability. Finally, using scanning tunneling spectroscopy we demonstrate that the disilane molecules provide strong electrical coupling between the Au nanoparticles and a superconductor substrate.


2016 ◽  
Vol 40 (12) ◽  
pp. 10116-10126 ◽  
Author(s):  
Ghodrat Mahmoudi ◽  
Farhad Akbari Afkhami ◽  
Himanshu Sekhar Jena ◽  
Parisa Nematollahi ◽  
Mehdi D. Esrafili ◽  
...  

Self-assembly of Zn(ii) compounds is influenced by a counter ion and non-covalent interactions.


RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 45716-45726 ◽  
Author(s):  
V. Vinod Kumar ◽  
Lowrence Rene Christena ◽  
P. Praveen ◽  
Meenakshi Sundaram Muthuraman ◽  
Nagarajan Saisubramanian ◽  
...  

A methionine based phenolic chelating ligand together with PSS, PVA, PVP and SDS capping agents produced an unusual self-assembly of AgNPs and strong anti-biofilm effect.


Author(s):  
Chloe Graham

It has been estimated that 100 million terajoules of energy is used every year to combat friction. For perspective, this corresponds to one fifth of the world’s total energy expenditure. This significant amount leaves plenty of room for improvement. To reduce the environmental and financial impact of friction, lubricants are usually placed in mechanical systems and act as a barrier between moving parts. Lubricants come in many forms but they all have low energy slip mechanisms and resistance to conformational change under pressure. Chemicals with these properties can be predicted through some educated guesswork and computational simulations. Its advantageous to look at novel lubricants computationally because each small reaction can be analyzed, whereas in the lab it may be difficult to see the molecular mechanisms taking place in such short time spans. Additionally, computation is more environmentally friendly than hands-on testing because no chemicals are used. My research studies compounds found in nature and assesses their potential for use as lubricants. The focus of my studies has been on layered systems of melamine molecules that self-assemble into two-dimensional structures through hydrogen bonding. The layered nature of this system is similar to that of graphite – an effective layered lubricant; however, the reversibility of self-assembly may allow the layered structure to reform when disrupted during sliding to increase the robustness of the system. In this presentation, I will discuss the results of my simulations, with an emphasis on the structure of the system, the slip mechanism, slip energetics and friction forces.


Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1079
Author(s):  
Zhishan Su ◽  
Changwei Hu ◽  
Nasir Shahzad ◽  
Chan Kyung Kim

The reaction mechanism and origin of asymmetric induction for conjugate addition of cyanide to the C=C bond of olefin were investigated at the B3LYP-D3(BJ)/6-31+G**//B3LYP-D3(BJ)/6-31G**(SMD, toluene) theoretical level. The release of HCN from the reaction of ethyl cyanoformate (CNCOOEt) and isopropanol (HOiPr) was catalyzed by cinchona alkaloid catalyst. The cyanation reaction of olefin proceeded through a two-step mechanism, in which the C-C bond construction was followed by H-transfer to generate a cyanide adduct. For non-catalytic reaction, the activation barrier for the rate-determining C-H bond construction step was 34.2 kcal mol−1, via a four-membered transition state. The self-assembly Ti(IV)-catalyst from tetraisopropyl titanate, (R)-3,3′-disubstituted biphenol, and cinchonidine accelerated the addition of cyanide to the C=C double bond by a dual activation process, in which titanium cation acted as a Lewis acid to activate the olefin and HNC was orientated by hydrogen bonding. The steric repulsion between the 9-phenanthryl at the 3,3′-position in the biphenol ligand and the Ph group in olefin raised the Pauli energy (ΔE≠Pauli) of reacting fragments at the re-face attack transition state, leading to the predominant R-product.


Langmuir ◽  
2008 ◽  
Vol 24 (17) ◽  
pp. 9566-9574 ◽  
Author(s):  
Mathieu Linares ◽  
Patrizia Iavicoli ◽  
Krystallia Psychogyiopoulou ◽  
David Beljonne ◽  
Steven De Feyter ◽  
...  

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