Naslov
Influence of Intramolecular Hydrogen Bond on the Gas-phase Proton Affinity of Guanidines

Autori
Glasovac, Zoran ; Štrukil, Vjekoslav ; Eckert-Maksić, Mirjana ; Schroeder, Detlef ; Kaczorowska, Malgorzata ; Schwarz, Helmut

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

Izvornik
The 15th European Symposium on Organic Chemistry : Abstracts / Guiry, Pat ; Mooney, Ann - Dublin : University Colledge Dublin, 2007, 174-174

Skup
European Symposium on Organic Chemistry (15 ; 2007)

Mjesto i datum
Dublin, Irska, 08.07.2007. - 13.07.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
intramolecular hydrogen bonds; basicity; guanidine compounds

Sažetak
Hydrogen bond is important building block for the self-organization of living organisms as well as in design and manufacturing of important technological materials. Starting from 1968 and the synthesis of 1, 8-bis(dimethylamino)naphthalen – the first proton sponge, the effect of intramolecular hydrogen bonds (IHBs) on basicity of organic compounds has been subject of numerous experimental and theoretical investigations. However, strong organic nitrogen bases possessing flexible intramolecular hydrogen bonds were not investigated in details. Until now, several papers on the gas-phase basicity of polyamines revealed significant increase in basicity with respect to the corresponding monoamines which was ascribed to the formation of IHB upon protonation. Recent investigations showed that presence of the multiple IHBs can significantly increase the basicity of the guanidine moiety. Furthermore, it was shown that increase in basicity is proportional to the number of IHB. Recent measurements of pKa values in acetonitrile for the series of guanidine compounds revealed similar trend. Gas phase proton affinity of guanidine 1 was measured by simple and extended kinetic method [5]. Measured gas-phase proton affinities follow the trend predicted by ab initio and DFT calculations. Increase in number of possible IHB within the series of the investigated guanidines enhances their proton affinities although some saturation effect is observed. Comparison of the results obtained for the series of dimethylaminopropyl- substituted guanidines with the methoxypropyl- ones revealed significantly higher contribution of IHB in former series.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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