om6b00420_si_001.pdf (1.58 MB)
Download filePhotofragmentation Pathways for Gas-Phase Lanthanide Tris(isopropylcyclopentadienyl) Complexes
journal contribution
posted on 2016-10-05, 13:54 authored by Yulun Han, Dmitri S. Kilin, P. Stanley May, Mary T. Berry, Qingguo MengPhotofragmentation
mechanisms of gas-phase lanthanide tris(isopropylcyclopentadienyl)
complexes, Ln(iCp)3, were studied through experimental
photoionization time-of-flight mass spectrometry (PI-TOF-MS). A DFT-based
time-dependent excited-state molecular dynamics (TDESMD) algorithm,
under standard approximations, was used to simulate the photofragmentation
process. Two competing reaction pathways, intact ligand stripping and ligand cracking within the metal–ligand
complex, were hypothesized based on experimental data. It was evident
that intramolecular hydrogen, methyl, and isopropyl abstraction play
an important role in the ligand-cracking reaction pathway, leading
to metal carbide and metal hydrocarbide products. The TDESMD simulations
also produced branching reaction pathways for ligand ejection and ligand cracking and further suggested that
both pathways are initiated by ligand-to-metal charge transfer. Although
the simulations reproduced several of the proposed reactions and several
of the products of cracking observed in the PI-TOF mass spectra, differences
between the simulation and experimental results suggest specific directions
for improvement in the computational model.