Nitrosoarene Dimerization on Two- and Three-dimensional Gold Surfaces

Abstract

Abstract. In the present study, we investigated nitrosoarene dimerization on an Au(111) and on the surface of gold nanoparticles (AuNPs). High-resolution STM images revealed that 8-thiocyanatooctyl-4-nitrosobenzoate (NCS(CH 2 ) 8 OOCC 6 H 4 NO) forms well-ordered monolayer on an Au(111) surface displaying hexagonal 3 3 3 3  structure. AFM data indicated that this compound also dimerize on an Au(111) surface thus forming bilayers. On contrary, adsorption of 6-(4-nitrosophenoxy)hexane-1-thiol (HS(CH 2 ) 6 OC 6 H 4 NO) on an Au(111) leads only to poorly organized monolayer.Furthermore, it was found that nitrosoarene derivatives 8-thiocyanatooctyl-4-nitrosobenzoate (NCS(CH 2 ) 8 OOCC 6 H 4 NO) and 3-thiocyanatopropyl-4-nitrosobenzoate (NCS(CH 2 ) 3 OOCC 6 H 4 NO) are present as dimers on the surface of AuNPs. There is no appreciable quantity of dimeric species with free thiocyanate termini indicating interlinkage of AuNPs through azodioxide bonds. Besides the characteristic surface plasmon band, UV-vis spectra showed an additional red-shifted band that might have origin in aggregation of AuNPs. This was further supported by TEM revealing the appearence of larger aggregates in addition to smaller AuNPs.(doi: 10.5562/cca2023)

Dimerization of Aromatic C-Nitroso Compounds

“…Only recently has the dimerization of nitrosoarenes been studied on surfaces. 228,229 Studies of molecular adsorption have typically focused on interactions with the underlying surface or within the adlayer itself, but the adsorption of nitrosoarenes introduces the additional possibility of creating self-assembled bilayers by allowing adsorbed nitroso compounds to react with others that are free in solution. For example, Vancǐk and co-workers used Au•••S interactions to bind sulfur-containing nitrosoarenes on Au (111), and they were able to observe both monomeric and dimeric forms of the adsorbed compounds by scanning tunneling microscopy (STM) and atomic force microscopy (AFM).…”

Aromatic C-Nitroso Compounds and Their Dimers: A Model for Probing the Reaction Mechanisms in Crystalline Molecular Solids

“…It is demonstrated how the enhancement of the dimerization rate is induced by the Sulphur-containing derivatives of aromatic C-nitroso compounds were also adsorbed on three-dimensional (3D) surface of gold nanoparticles [65]. As revealed by IR and UV-VIS spectroscopy, and transmission electron microscopy (TEM), dimerization of aromatic C-nitroso compounds by interparticle interaction of exposed nitroso groups seem to induce the aggregation of gold nanoparticles.…”

“…Nitrosobenzene molecules functionalized with the alkyl chains and sulphur headgroups at the p-position can be adsorbed on an Au(111) surface by forming SAMs [64,65]. Such systems were studied by scanning tunnelling microscopy (STM) and atomic force microscopy (AFM).…”

Comparison of DFT Methods for the Investigation of the Reduction Mechanisms of Aromatic Nitro- and Nitroso Compounds

“…Hydroxylamine can be isolated or in next step reduced to amine (5). The reaction is often accompanied by formation of dimerization products, which has been the focus of many recent studies.…”

“…The reaction is often accompanied by formation of dimerization products, which has been the focus of many recent studies. [4][5][6][7] The reduction of aromatic nitro compounds has been extensively studied using spectroscopic, electrochemical and, in recent years, computational approaches. [8][9][10][11][12][13][14] Although the available data strongly suggests that the reduction mechanism includes free radicals, its detailes, with identification and characterization of all involved species, have not unequivocally been established.…”