Abstract
In order to probe the ligand properties we have examined a series of Cr(CO)5L and Ni(CO)3L complexes using density functional theory (DFT). The ligands included in our study are N-heterocyclic carbenes (NHCs) and Bertrand-type carbenes. Our study shows that the carbene-metal bonds of imidazol-2-ylidenes (1), imidazolin-2-ylidenes (2), thiazo-2-ylidenes (3), and triazo-5-ylidenes (4) are significantly stronger than those of Bertrand-type carbenes (5-7). The force constants of C-O in complexes are related to the property of isolated carbenes such as proton affinity (PA), electronegativity (χ), and charge transfer (ΔN). NHCs and Bertrand-type carbenes are identified as nucleophilic, soft ligands. Carbene stabilization energy (CSE) computations indicate that carbenes 1 and 4 are the most stable species, while 2 and 3 are less stable. In contrast to NHCs, CSE of carbenes 5-7 are much smaller, and their relative stabilities are in the order (amino)(aryl) carbenes 7e-7g > (amino)(alkyl) carbenes 7a-7d > (phosphino)(aryl) 6d-6e, and (phosphino)(silyl) carbenes 5a-5c > no)(alkyl) carbenes 6a-6c.
Original language | English (US) |
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Pages (from-to) | 5867-5875 |
Number of pages | 9 |
Journal | Journal of Organometallic Chemistry |
Volume | 690 |
Issue number | 24-25 |
DOIs | |
State | Published - Dec 1 2005 |
Externally published | Yes |
Keywords
- Electronegativity
- Electrophilicity
- Hardness
- N-heterocyclic carbene
- Nucleophilicity
ASJC Scopus subject areas
- Biochemistry
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry