om8b00371_si_001.pdf (1.33 MB)
Mechanisms and Reactivity of Tl(III) Main-Group-Metal–Alkyl Functionalization in Water
journal contribution
posted on 2018-08-15, 21:06 authored by Samantha
J. Gustafson, Michael M. Konnick, Roy A. Periana, Daniel H. EssMetal-mediated C–H activation
reactions generate metal–alkyl
intermediates that can be converted into carbon–oxygen bonds
through functionalization reactions. While the mechanisms and reactivity
of C–H activation reactions have been well studied for transition-metal
complexes, much less is known about functionalization reactions, especially
for main-group-metal–alkyl complexes. Here we report density
functional theory calculations on the reaction thermodynamics and
kinetic pathways for main-group, p-block-metal TlIII–methyl
functionalization reactions in water using a combination of continuum
and explicit/continuum solvent models. Specifically, we examined the
oxygen functionalization of (OAc)TlIII(CH3)2 and (OAc)2TlIII(CH3) in
water where in both cases functionalization gives methyl acetate and
methanol. Our calculations suggest that (OAc)TlIII(CH3)2 is thermodynamically and kinetically stable
against bond homolysis, heterolysis, protonolysis, and all reductive
functionalization pathways. Functionalization is only possible after
methyl anion group transfer to TlIII(OAc)3 to
give (OAc)2TlIII(CH3). Our calculations
suggest that this monomethyl structure is functionalized by acetate
dissociation to give a Tl monocation and then a one-step nucleophilic
functionalization where water and acetate have competitive transition
states.