Naslov
Generation and dissociation pathways of singly and doubly protonated bisguanidines in the gas phase

Autori
Tintaru, Aura ; Roithová, Jana ; Schröder, Detlef ; Charles, Laurence ; Jušinski, Iva ; Glasovac, Zoran ; Eckert-Maksić, Mirjana

Izvornik
Journal of Physical Chemistry A (1089-5639) 112 (2008), 47; 12097-12103

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
density functional theory; dications; guanidinium ions; mass spectrometry; proton affinities
(ensity functional theory; dications; guanidinium ions; mass spectrometry; proton affinities)

Sažetak
Para-bisguanidinyl benzene 1 and its N-permethylated derivative 2 are both sufficiently strong bases to afford not only the monocations [1+H]+ and [2+H]+, but also the doubly protonated ions, [1+2H]2+ and [2+2H]2+, in the gas phase. The title ions generated via electrospray ionization are probed by collision-induced dissociation experiments which inter alia reveal that the dicationic species [1+2H]2+ and [2+2H]2+ can even undergo fragmentation reactions with maintenance of the two-fold charge. Complementary results from density functional theory predict PAs above 1000 kJ mol-1 for the neutral compounds, i.e. PA(1) = 1025 kJ mol-1 and PA(2) = 1067 kJ mol-1. Due to the stabilization of the positive charge in the guanidium ions and the para-phenylene spacer separating the basic sites, even the monocations bear sizable proton affinities, i.e. PA([1+H]+) = 740 kJ mol-1 and PA([2+H]+) = 816 kJ mol-1.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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