Chemical Impact on a Seemingly “Inert” Material:  An Electron Microscopic Case Study of Titanium Activated by Chlorosilanes

Commercial titanium powder, after pretreatment with chlorosilanes, can be used as an “off-the-shelf” McMurry reagent for various types of carbonyl coupling reactions. Electron microscopic studies (SEM, TEM, HRTEM, and electron diffraction) of the activated titanium now reveal the morphological basis for the observed reactivity, which stems from a partial degradation of the passivating oxide layer on the surface as well as from a severe change of the inner structure of the particles. Therefore, altered surface and altered bulk properties cooperatively account for the chemical reactivity of titanium metal activated by purely chemical means. ²⁹Si NMR investigations fully support this view