Ligand-Controlled CO2 Activation Mediated by Cationic Titanium Hydride Complexes, [LTiH](+) (L=Cp2 , O)
Shi-Ya Tang1, Nicole J Rijs1, Jilai Li1
1Institut für Chemie, Technische Universtät Berlin, Strasse des 17. Juni 135, 10623, Berlin (Germany).
Chemistry (Weinheim an Der Bergstrasse, Germany)
|May 6, 2015
Summary
Ligand choice significantly impacts titanium hydride complex reactivity with CO2. Cyclopentadienyl ligands stabilize formate intermediates, while oxide ligands promote decarbonylation, offering insights into selective CO2 activation.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Computational Chemistry
Background:
- CO2 activation is crucial for sustainable chemistry.
- Titanium hydride complexes are potential catalysts for CO2 transformations.
- Ligand effects on reactivity are not fully understood.
Purpose of the Study:
- Investigate CO2 activation by titanium hydride complexes with different ligands (Cp2 and O).
- Elucidate the reaction mechanisms and intermediate stability.
- Understand how ligand structure influences CO2 activation pathways.
Main Methods:
- Gas-phase electrospray-ionization mass spectrometry (ESI-MS).
- Traveling wave ion-mobility mass spectrometry (TWIMS).
- Density Functional Theory (DFT) calculations.
Main Results:
- Cp2TiH+ reacts with CO2 via insertion into the Ti-H bond, forming a stable formate intermediate [Cp2Ti(O2CH)]+.
- OTiH+ reacts with CO2, leading to decarbonylation and formation of the hydroxo complex [OTi(OH)]+.
- DFT studies revealed a correlation between hydride affinity and CO2 insertion barriers, highlighting ligand control.
Conclusions:
- Ligand environment dictates the CO2 activation pathway and product distribution in titanium hydride complexes.
- Stable formate intermediates are formed with Cp2 ligands, enabling further reactions.
- Understanding ligand effects is key to designing selective CO2 activation catalysts.
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