The Reaction of Tetrakis(dimethylamido)titanium with
Self-Assembled Alkyltrichlorosilane Monolayers Possessing
−OH, −NH<sub>2</sub>, and −CH<sub>3</sub> Terminal Groups
Aravind S. Killampalli
Paul F. Ma
James R. Engstrom
10.1021/ja047922c.s001
https://acs.figshare.com/articles/journal_contribution/The_Reaction_of_Tetrakis_dimethylamido_titanium_with_Self_Assembled_Alkyltrichlorosilane_Monolayers_Possessing_OH_NH_sub_2_sub_and_CH_sub_3_sub_Terminal_Groups/3288055
The reactions of tetrakis(dimethylamido)titanium, Ti[N(CH<sub>3</sub>)<sub>2</sub>]<sub>4</sub>, with alkyltrichlorosilane self-assembled monolayers (SAMs) terminated by −OH, −NH<sub>2</sub>, and −CH<sub>3</sub> groups have been investigated with
X-ray photoelectron spectroscopy (XPS). For comparison, a chemically oxidized Si surface, which serves
as the starting point for formation of the SAMs, has also been investigated. In this work, we examined the
kinetics of adsorption, the spatial extent, and stoichiometry of the reaction. Chemically oxidized Si has
been found to be the most reactive surface examined here, followed by the −OH, −NH<sub>2</sub>, and −CH<sub>3</sub>
terminated SAMs, in that order. On all surfaces, the reaction of Ti[N(CH<sub>3</sub>)<sub>2</sub>]<sub>4</sub> was relatively facile, as evidenced
by a rather weak dependence of the initial reaction probability on substrate temperature (<i>T</i><sub>s</sub> = −50 to 110
°C), and adsorption could be described by first-order Langmuirian kinetics. The use of angle-resolved XPS
demonstrated clearly that the anomalous reactivity of the −CH<sub>3</sub> terminated SAM could be attributed to
reaction of Ti[N(CH<sub>3</sub>)<sub>2</sub>]<sub>4</sub> at the SAM/SiO<sub>2</sub> interface. Reaction on the −NH<sub>2</sub> terminated SAM proved to be
the “cleanest”, where essentially all of the reactivity could be associated with the terminal amine group. In
this case, we found that approximately one Ti[N(CH<sub>3</sub>)<sub>2</sub>]<sub>4</sub> adsorbed per two SAM molecules. On all surfaces,
there was significant loss of the N(CH<sub>3</sub>)<sub>2</sub> ligand, particularly at high substrate temperatures, <i>T</i><sub>s</sub> = 110 °C.
These results show for the first time that it is possible to attach a transition metal coordination complex
from the vapor phase to a surface with an appropriately functionalized self-assembled monolayer.
2005-05-04 00:00:00
XPS
results show
substrate temperature
transition metal coordination
vapor phase
reactive surface
OH
Si surface
substrate temperatures
Langmuirian kinetics
2 ligand
NH
SAM molecules
reaction probability
Ti
CH
terminal amine group