15min:

SUDESH KUMARI AND DONG-SHENG YANG, Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055.

Dehydrogenation and C-H bond insertion are observed in the reaction of laser-ablated La atoms with propene (C₃H₆) in a pulsed molecular beam source. Several dehydrogenated and inserted products are identified by the time-of-flight mass spectrometry. La(C₃H₄) formed from H₂ elimination and HLa(C₃H₅) formed by C-H bond insertion are characterized by pulsed-field-ionization electron and ion spectroscopy, in combination with density functional theory. Two isomers of La(C₃H₄) are identified from 1,2- and 1,3-dehydrogenation. The adiabatic ionization energies of 1,2- and 1,3-dehydrogenated isomers are measured to be 40506(5) and 40941(5) cm^-1, respectively. For the inserted product HLa(C₃H₅), La atom is bound to the allyl radical in a three-fold binding mode ( ³). It is observed that the ionization energy of the HLa( ³-C₃H₅) insertion complex (41130(5) cm^-1) is close to that of the 1,3-dehydrogented La( ²-C₃H₄) species.