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Infrared Spectra of CH3–MH through Methane Activation by Laser-Ablated Sn, Pb, Sb, and Bi Atoms
journal contribution
posted on 2012-08-23, 00:00 authored by Han-Gook Cho, Lester AndrewsMethane activation has been carried out by laser-ablated
Sn, Pb,
Sb, and Bi atoms. All four metals generate the insertion complex (CH3–MH), but subsequent H-migration from C to M to form
CH2–MH2 and CH–MH3 complexes
is not observed. Our previous and present experimental and computational
results indicate that the higher oxidation state complexes become
less favored with increasing atomic mass in groups 14 and 15, which
is opposite the general trend found for transition metals. The C–H
bond insertion evidently occurs during reaction on sample condensation,
and the product dissociates on broad-band photolysis afterward. The
insertion complex contains a near right angle C–M–H
moiety because of high p contribution from the metal center to the
C–M and M–H bonds unlike many transition-metal analogues.
The computed methylidene structures for these main group metals are
not agostic possibly because of the absence of valence d-orbitals.