Mono, bis, and tris(phosphoramidate) titanium complexes: synthesis, structure, and reactivity investigations
Bibliographic record
Abstract
A series of variously substituted phosphoramidate titanium complexes bearing dimethylamido ligands are reported. Aryl-substituted ligands impart crystallinity to the systems and allow for the elucidation of the molecular structures via X-ray crystallography. Higher-substituted complexes, including a tris(phosphoramidate)mono(dimethylamido) complex, were isolated and characterized in the solid state, as well as in solution using variable temperature 1H and 31P NMR spectroscopy. The steric bulk possessed by this ligand system, relative to amidate and ureate ligands, has allowed access to a mono(phosphoramidate)tris(dimethylamido) complex. The first solid-state-molecular structure of a mono-ligated 1,3-N,O chelated complex of titanium is reported and compared to the respective bis- and tris-analogues. These complexes were screened for hydroaminoalkylation activity between secondary amines and terminal alkenes and the intramolecular hydroamination of a terminal aminoalkene. Mono(phosphoramidate)tris(dimethylamido) complexes were screened in situ and found to be more active than their respective bis(N,O)-chelated analogues. The elucidation of these complexes allows for a direct comparison to other N,O-chelates of early transition metals, particularly in their hydroaminoalkylation and hydroamination reactivity.
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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) | 0.001 | 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".