Theoretical study on the difference in the relative strengths of metal-hydrogen and metal-methyl bonds in complexes of early transition metals and complexes of middle to late transition metals

1988 ◽  
Vol 27 (20) ◽  
pp. 3458-3464 ◽  
Author(s):  
Tom Ziegler ◽  
Wendan Cheng ◽  
Evert Jan Baerends ◽  
Walter Ravenek
2020 ◽  
Author(s):  
Marti Lopez ◽  
Francesc Vines ◽  
Michael Nolan ◽  
Frances Illas

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO<sub>2</sub> adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO<sub>2</sub> appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO<sub>2</sub> adsorption energy in transition metal carbide surfaces without requiring DFT calculations.


2020 ◽  
Author(s):  
Marti Lopez ◽  
Francesc Vines ◽  
Michael Nolan ◽  
Frances Illas

Previous work has shown that doping the TiC(001) surface with early transition metals significantly affects CO<sub>2</sub> adsorption and activation which opens a possible way to control this interesting chemistry. In this work we explore other possibilities which include non-transition metals elements (Mg, Ca, Sr, Al, Ga, In, Si, Sn) as well as late transition metals (Pd, Pt, Rh, Ir) and lanthanides (La, Ce) often used in catalysis. Using periodic slab models with large supercells and state-of-the-art density functional theory (DFT) based calculations, we show that, in all the studied cases, CO<sub>2</sub> appears as bent and, hence, activated. However, the effect is especially pronounced for dopants with large ionic crystal radii. These can increase desorption temperature by up to 230K, almost twice the value predicted when early transition metals are used as dopants. However, a detailed analysis of the results shows that the main effect does not come from electronic structure perturbations but from the distortion that the dopant generates into the surface atomic structure. A simple descriptor is proposed that would allow predicting the effect of the dopant on the CO<sub>2</sub> adsorption energy in transition metal carbide surfaces without requiring DFT calculations.


2021 ◽  
Author(s):  
Sujoy Rana ◽  
Jyoti Prasad Biswas ◽  
Sabarni Paul ◽  
Aniruddha Paik ◽  
Debabrata Maiti

The promising aspects of iron in synthetic chemistry are being explored for three-four decades as a green and eco-friendly alternative to late transition metals. This present review unveils these rich iron-chemistry towards different transformations.


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