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Small molecule activation by sila/germa boryne species
Harsha S Karnamkkott1, Sujit Das1, Totan Mondal2
1Department of Chemistry, Indian Institute of Technology Madras, Chennai, India.
Journal of Computational Chemistry
|December 22, 2023
Summary
Main group elements like boron can now activate small molecules, mimicking metal complexes. Theoretical studies show boron species can bind carbon monoxide (CO) but not nitrogen (N2), with a calculated energy barrier for CO binding.
Area of Science:
- Main group chemistry
- Organometallic chemistry mimicry
- Computational chemistry
Background:
- P-block elements' limited ability in π-backbonding restricts small molecule activation.
- Main group metallomimetics offer a new pathway for small molecule activation.
- Boron species have shown potential in mimicking transition metal functions.
Purpose of the Study:
- To theoretically investigate the binding of carbon monoxide (CO) and nitrogen (N2) at the boron center of elusive sila/germa boryne species.
- To explore the potential of these boron species to mimic transition metal complexes in small molecule activation.
- To analyze the electronic structure and bonding characteristics influencing CO and N2 binding.
Main Methods:
- Density Functional Theory (DFT) calculations.
- Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) analyses.
- Energy Decomposition Analysis (EDA) coupled with Natural Orbital for Chemical Valence (NOCV).
Main Results:
- CO binds effectively to the boron center due to strong sigma-donor ability, while N2 binding is predicted to be weak.
- A calculated energy barrier of 13-14 kcal/mol for CO binding was observed, attributed to changes in B-Si bond character and bond angle.
- The study confirmed the ability of these boron species to bind and activate CO, mimicking transition metal complexes.
Conclusions:
- Elusive boryne species, stabilized by donor ligands, can activate CO, demonstrating a metallomimetic capability.
- The electronic and structural changes upon CO binding facilitate its activation.
- Further binding of metal carbonyl fragments (e.g., Fe(CO)4, Ni(CO)3) at the silicon center is feasible after CO binding to boron.
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