Radical abstraction vs. oxidative addition mechanisms for the activation of the S–H, O–H, and C–H bonds using early transition metal oxides

2021 ◽  
Author(s):  
Isuru R. Ariyarathna ◽  
Evangelos Miliordos
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Oxidative Addition ◽  
Early Transition Metal ◽  
Early Transition

Calculations on the ZrO+/NbO+ (bare and ligated) + H2S/H2O/CH4 reactions show that H–S is easily activated with either oxo or oxyl ZrO+/NbO+, O–H bears larger barriers for both, and C–H is readily activated only with the oxyl form.

Early Transition Metal Oxides and a Pinch of Salt: New Synthetic Routes to Titanates and Niobates

1996 ◽  
Vol 453 ◽  
Author(s):  
M. J. Geselbracht ◽  
R. J. Scarola ◽  
D. Ingram ◽  
C. Green ◽  
J. H. Caldwell
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Molten Salts ◽  
Calcium Titanate ◽  
Mixed Metal Oxides ◽  
Mixed Metal ◽  
Early Transition Metal ◽  
Synthetic Routes ◽  
Early Transition

AbstractMolten salts have traditionally been used as recrystallizing solvents for the crystal growth of mixed metal oxides. In recent years, many examples of the direct preparation of mixed metal oxides from molten salt solutions have been reported. We have been exploring the use of chloride melts as a reaction media to prepare complex early transition metal oxides. Specific examples of new synthetic routes to interesting titanates and niobates will be presented. In one case, we have prepared a series of layered niobate perovskite solid acids from molten salts at temperatures well below those traditionally used in solid state syntheses. In the second case, we have discovered a new synthetic route to a poorly characterized reduced calcium titanate that is otherwise very difficult to make. The synthesis and characterization of these two classes of compounds will be described.

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