Density functional theory study of substituent effects on gas-phase heterolytic Fe-N bond energies of m-G-C6H4NHFe(CO)2(η5-C5H5) and m-G-C6H4N(COMe)Fe(CO)2(η5-C5H5)
Bibliographic record
Abstract
The nature and strength of metal–ligand bonds in organotransition-metal complexes are crucial to the understanding of organometallic reactions and catalysis. Quantum chemical calculations at different levels of theory have been used to investigate heterolytic Fe-N bond energies of meta -substituted anilinyldicarbonyl(η 5 -cyclopentadienyl)iron [ m -G-C 6 H 4 NH(η 5 -C 5 H 5 )Fe(CO) 2 , abbreviated as m -G-C 6 H 4 NHFp ( 1 ), where G=NO 2 , CN, COMe, CO 2 Me, CF 3 , Br, Cl, F, H, Me, MeO and NMe 2 ] and meta -substituted α-acetylanilinyldicarbonyl(η 5 -cyclopentadienyl)iron [ m -G-C 6 H 4 N(COMe)(η 5 -C 5 H 5 )Fe(CO) 2 , abbreviated as m -G-C 6 H 4 N(COMe)Fp ( 2 )] complexes. The results show that BP86 and TPSSTPSS can provide the best price/performance ratio and more accurate predictions in the study of Δ H het (Fe-N)′s. ΔΔ H het (Fe-N)′s ( 1 and 2 ) conform to the captodative principle. There are excellent linear free energy relations among ΔΔ H het (Fe-N)′s and the experimental and computational substituent effects on acidities of m -G-C 6 H 4 NH 2 , the differences of acidic dissociation constants (Δp K a s) of N H bonds for m -G-C 6 H 4 NH 2 for series 1 or the substituent σ m constants. The former correlations imply that the govering factors for these bond scissions are similar; the latter ones suggest that polar effects of meta -substituents show the dominant role to the magnitudes of Δ H het (Fe-N)′s. And these correlations are in accordance with Hammett linear free energy relationships . The Fe-N bonds in series 1 are stronger than those in series 2 . Therefore m -G-C 6 H 4 N(COMe) - are more stable than m -G-C 6 H 4 NH - . The absolute magnitudes of AEs, AE α-COMe s and AE α-COMe, para -G s are far larger than MEs, ME α-COMe s and ME α-COMe, para -G s. The influences of MEs, ME α-COMe s and ME α-COMe, para -G s are subtle. A better understanding of organometallic bond energies can suggest whether proposed new catalytic systems may work well.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".