Electron super-rich radicals. III. On the peculiar behavior of the aminodihydroxymethyl radical in the gas phase.
In contrast to previously reported electron-super-rich trihydroxy-, triamino- and diaminohydroxymethyl radicals, the title aminodihydroxymethyl radical (1) generates a fraction of metastable species in the form of their deuterium isotopologues. The lifetimes of metastable radicals produced by femtosecond collisional electron transfer to aminodihydroxymethyl cations exceed 4 mus. The main fraction of 1 dissociates by fast loss of a hydroxyl hydrogen atom to form carbamic acid. Loss of an amino hydrogen atom is less facile and becomes <10% competitive at high internal energies or if the main dissociation is slowed down by deuterium isotope effects. RRKM calculations of unimolecular rate constants on a CCSD(T)/aug-cc-pVTZ potential energy surface gave a reasonably good fit for the competitive dissociations of 1 but not for the fraction of nondissociating radicals. The metastable species are attributed to excited electronic states which are predicted to have favorable Franck-Condon factors for being formed by collisional electron transfer.
Gregersen
Joshua A
JA
Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, USA.
Hao
Changtong
C
Turecek
Frantisek
F
D004583:Electrons; D005740:Gases / Q000737:chemistry*; D007554:Isotopes / Q000737:chemistry; D007700:Kinetics; D008744:Methylamines / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D005740:Gases; D007554:Isotopes; D008744:Methylamines