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The strongest CO binding and the highest C-O stretching frequency
Ranajit Saha1, Sudip Pan2, Gernot Frenking3
1Department of Chemistry and Centre for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India. pkc@chem.iitkgp.ernet.in.
Physical Chemistry Chemical Physics : PCCP
|January 6, 2017
Summary
Beryllium complexes with ligands like NCN show strong carbon monoxide (CO) binding. The OCBeSO4 complex exhibits the highest CO stretching frequency, influenced by electronic donation and back-donation interactions.
Area of Science:
- Computational Chemistry
- Quantum Chemistry
- Materials Science
Background:
- Understanding ligand effects on metal-carbonyl interactions is crucial for catalysis and materials design.
- Beryllium (Be) complexes offer unique electronic properties for studying bonding phenomena.
Purpose of the Study:
- To investigate the impact of various ligands (Y) on the carbon monoxide (CO) binding characteristics of BeY complexes.
- To analyze the influence of these ligands on the carbon-oxygen (C-O) stretching frequency (νCO).
Main Methods:
- A theoretical coupled-cluster computational study was employed.
- Calculations focused on neutral BeY complexes with Y = O, CO3, SO4, NH, NCN, and NBO.
Main Results:
- BeNCN demonstrated the highest CO binding affinity, with both carbon- and oxygen-side binding observed.
- OCBeSO4 exhibited the highest νCO among the studied neutral carbonyls.
- Shifts in νCO were correlated with changes in CO orbital polarization and σ-donation/π-back-donation interactions.
Conclusions:
- Ligand choice significantly modulates CO binding strength and vibrational frequencies in Be complexes.
- The electronic interplay of σ-donation and π-back-donation governs the observed shifts in νCO.
- OCBeSO4 and COBeNH display extreme νCO shifts due to minimal π-back-donation and maximal π-back-donation, respectively.
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