Matrix infrared spectroscopic and electronic structure investigations of the lanthanide metal atom-methyl fluoride reaction products CH3-LnF and CH2-LnHF: the formation of single carbon-lanthanide metal bonds.

Lanthanide metal atoms, produced by laser ablation, were condensed with CH(3)F in excess Ar at 8 K. New infrared absorption bands are assigned to the first insertion CH(3)LnF and oxidative addition methylene lanthanide hydride fluoride CH(2)LnHF products on the basis of (13)C and deuterium substitution and density functional theory calculations of the vibrational frequencies. It is also possible to observe the cationic species CH(3)LnF(+) for some Ln. For Ln = Eu and Yb, only CH(3)LnF is observed. CH(3)LnF in the Ln formal +2 state is predicted to be more stable than CH(2)LnHF with the Ln in the formal +3 oxidation state. CH(3)-LnF forms a single bond between Ln and C and is a substituted methane. Similar to CH(2)-LnF(2), CH(2)-LnHF does not form a π-bond between Ln and C and is best described as a LnHF-substituted CH(3) radical, with an unpaired p electron on C weakly interacting with the unpaired f electrons on the Ln. The calculated potential energy surface for the CH(3)F + La → CH(3)-LaF/CH(2)-LaHF shows a number of intermediates and transition states on multiple paths. The reaction mechanism involves the potential formation of LaF and LaHF intermediates.