Threshold photoelectron spectroscopy of cyclopropenylidene, chlorocyclopropenylidene, and their deuterated isotopomeres.
Cyclopropenylidene (c-C(3)H(2)), chlorocyclopropenylidene (c-C(3)HCl), and their deuterated isotopomers were studied by the threshold photoelectron-photoion coincidence (TPEPICO) technique using VUV synchrotron radiation. The carbenes were generated via flash pyrolysis. In all species a change in geometry is visible upon ionization, with significant activity in the C═C, C-C-stretching mode and, in the case of c-C(3)H(2)/D(2), the C-H-bending mode. The electron is removed from an sp(2) like hybrid orbital centered on the carbene C atom. The mass selected threshold photoelectron (TPE) spectra were fitted by a Franck-Condon simulation, yielding the equilibrium geometry of the cation ground state ((1)A(1)). The adiabatic ionization energy IE(ad) of c-C(3)H(2) was determined to be 9.17 eV, in good agreement with calculations and literature values. Two vibrational wavenumbers of the cation were determined experimentally (ν(3)(+) = 1150 cm(-1) and ν(2)(+) = 1530 cm(-1)). Chlorocyclopropenylidene was also studied by TPE spectroscopy and has a similar IE(ad) of 9.17 eV. The spectrum also shows a vibrational progression that corresponds to the C═C- and C-C-stretching modes of the cation. The equilibrium geometry was also determined by a Franck-Condon fit. The IE(ad) of the deuterated isotopomers, c-C(3)D(2) and c-C(3)DCl, were also determined to be 9.17 eV. The spectra confirm the assignments for the nondeuterated species.
Hemberger
Patrick
P
Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Noller
Bastian
B
Steinbauer
Michael
M
Fischer
Ingo
I
Alcaraz
Christian
C
Cunha de Miranda
Bárbara K
BK
Garcia
Gustavo A
GA
Soldi-Lose
Héloïse
H
D003521:Cyclopropanes / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry*; D006844:Hydrocarbons, Cyclic / Q000737:chemistry*; D013058:Mass Spectrometry; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory
D003521:Cyclopropanes; D006844:Hydrocarbons, Cyclic; C555685:chlorocyclopropenylidene; C555684:cyclopropenylidene; D003903:Deuterium