Mechanochemical Synthesis of Chromium(III) Complexes Containing Bidentate PN and Tridentate P-NH-P and P-NH-P′ Ligands
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Chromium(III) complexes bearing bidentate {NH 2 (CH 2 ) 2 PPh 2: PN, ( S,S )-[NH 2 (CHPh) 2 PPh 2 ]: P’N} and tridentate [Ph 2 P(CH 2 ) 2 N(H)(CH 2 ) 2 PPh 2: P-NH-P, ( S,S )-( i Pr) 2 PCH 2 CH 2 N(H)CH(Ph)CH(Ph)PPh 2: P-NH-P′] ligands have been synthesized using a mechanochemical approach. The complexes { cis -[Cr(PN)Cl 2 ]Cl ( 1 ), cis -[Cr(P’N)Cl 2 ]Cl ( 2 ), mer -Cr(P-NH-P)Cl 3 ( 3 ), and mer -Cr(P-NH-P′)Cl 3 ( 4 )} were obtained in high yield (95–97%) via the grinding of the respective ligands andthe solid Cr(III) ion precursor [CrCl 3 (THF) 3 ] with the aid of a pestle and mortar, followed by recrystallization in acetonitrile. The isolated complexes are high spin. A single-crystal X-ray diffraction study of 2 revealed a cationic chromium complex with two P’N ligands in a cis configuration with P′ trans to P′ with chloride as the counteranion. The X-ray study of 4 shows a neutral Cr(III) complex with the P-NH-P′ ligand in a mer configuration. The difference in molecular structures and bulkiness of the ligands influence the electronic, magnetic, and electrochemical properties of the complexes as exhibited by the bathochromic shifts in the electronic absorption peaks of the complexes and the relative increase in the magnetic moment of 3 (4.19 μ β ) and 4 (4.15 μ β ) above the spin only value (3.88 μ β ) for a d 3 electronic configuration. Complexes 1 – 4 were found to be inactive in the hydrogenation of an aldimine [( E )-1-(4-fluorophenyl)- N -phenylmethanimine] under a variety of activating conditions. The addition of magnesium and trimethylsilyl chloride in THF did cause hydrogenation at room temperature, but this occurred even in the absence of the chromium complex. The hydrogen in the amine product came from the THF solvent in this novel reaction, as determined by deuterium incorporation into the product when deuterated THF was used.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".