Naslov
Dimerization of aromatic C-nitroso compounds as a route to new supramolecular architectures

Autori
Biljan, Ivana ; Bibulić, Petar ; Rončević, Igor ; Varga, Katarina ; Vančik, Hrvoj

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
European Symposium on Organic Reactivity: Book of Abstracts / O'Donoghue, AnnMarie ; Hodgson, David R.W. - Durham : Durham University, 2017, SP6-SP6

Skup
European Symposium on Organic Reactivity (ESOR 2017)

Mjesto i datum
Durham, Ujedinjeno Kraljevstvo, 03.09.2017. - 08.09.2017

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Aromatic C-nitroso compounds ; Dimerization ; Self-assembled layers ; Solid state ; Kinetics

Sažetak
Aromatic C-nitroso compounds can exist as monomers and azodioxide dimers. In solution at room temperature, the dominant species are monomers whereas lowering of temperature or crystallization favors dimerization. The efficacy of solid-state dimerization is influenced by the topochemistry i.e. the vicinity of the reacting nitroso groups. In our recent studies, we investigated dimerization of aromatic C-nitroso compounds on 2D gold surface. We prepared nitrosoarenes with one and two nitroso groups functionalized with sulfur headgroups for adsorption on an Au(111) surface. Self-assembled layers of nitrosoarenes were studied by scanning tunneling microscopy (STM), atomic force microscopy (AFM), ellipsometry and reflection-absorption IR spectroscopy. It was found that in addition to self-assembly into ordered monolayers, nitroso derivatives can dimerize on an Au(111) surface through reaction of exposed nitroso groups with those free in solution and form bilayers. Recently, we prepared a series of bis(4-nitrosophenyl) derivatives with different spacers between two aromatic rings and investigated kinetics of their dimerization in solid state at different temperatures. Starting monomers, obtained by cryogenic photodissociation of the corresponding azodioxides, redimerize upon heating. Dimerization of methane derivative at 200 K proceeds in parallel reactions producing Z- and E-forms of which the latter isomerizes to Z-form through monomer intermediate at 270 K. On the other hand, ethane, methanone and biphenyl derivatives redimerize to E-isomers. Activation energies for solid-state dimerization, estimated by using Arrhenius plots, are in the range of 4-12 kJ mol-1.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA