jp067662g_si_001.pdf (222.57 kB)
Infrared Spectra of the CH3−MX and CH2−MHX Complexes Formed by Reactions of Laser-Ablated Group 3 Metal Atoms with Methyl Halides
journal contribution
posted on 2007-04-05, 00:00 authored by Han-Gook Cho, Lester AndrewsReactions of laser-ablated group 3 metal atoms with methyl halides have been carried out in excess of Ar
during condensation and the matrix infrared spectra studied. The metals are as effective as other early transition
metals in providing insertion products (CH3−MX) and higher oxidation state methylidene complexes (CH2−MHX) (X = F, Cl, Br) following α-hydrogen migration. Unlike the cases of the group 4−6 metals, the
calculated methylidene complex structures show little evidence for agostic distortion, consistent with the
previously studied group 3 metal methylidene hydrides, and the C−M bond lengths of the insertion and
methylidene complexes are comparable to each other. However, the C−Sc bond lengths are 0.013, 0.025,
and 0.029 Å shorter for the CH2−ScHX complexes, respectively, and the spin densities are consistent with
weak C(2p)−Sc(3d) π bonding. The present results reconfirm that the number of valence electrons on the
metal is important for agostic interaction in simple methylidene complexes.