Compounds with Unbridged Dative Metal−Metal Bonds of Formula (R<sub>3</sub>P)<sub>2</sub>(OC)<sub>3</sub>OsW(CO)<sub>5</sub> and Related Complexes
Bibliographic record
Abstract
Complexes of formula (R 3 P) 2 (OC) 3 OsW(CO) 5 and similar complexes have been prepared from W(CO) 5 (THF) and Os(CO) 3 (PR 3 ) 2 in CH 2 Cl 2 /hexane at room temperature. The analogous Cr complexes could not be synthesized except for [MeC(CH 2 O) 3 P] 2 (OC) 3 OsCr(CO) 5 and (Me 2 PCH 2 CH 2 PMe 2 )(OC) 3 OsCr(CO) 5, that is, with sterically undemanding P substituents. Tungsten compounds with P ligands with cone angles greater than ∼125° could also not be prepared. The crystal structures of (Me 2 PCH 2 CH 2 PMe 2 )(OC) 3 OsM(CO) 5 (M = Cr, W), [MeC(CH 2 O) 3 P] 2 (OC) 3 OsW(CO) 5 ( 2 ), (OC) 3 (Me 3 P) 2 OsW(CO) 5 ( 3 ), [MeC(CH 2 O) 3 P](OC) 3 (Me 3 P)OsW(CO) 5 ( 4 ), and [(MeO) 3 P](OC) 3 (Me 3 P)OsW(CO) 5 ( 5 ) reveal that all have unbridged OsM bonds that are considerably longer than the corresponding OsM bond in (Me 3 P)(OC) 4 OsM(CO) 5 . The P ligands have an axial, radial arrangement except in 3, where the PMe 3 ligands have a trans, diradial orientation. In 4 and 5 the phosphite ligands are in the site trans to the OsW bond even though they have smaller cone angles than the PMe 3 ligand. Solution NMR data indicates that for 2 and 3 both the ax, rad and dirad isomers are present; for 4 both ax, rad forms are present, whereas for 5 only the solid state form is found. There was no evidence in solution for the dirad forms of 4 and 5 . (The 13 C NMR spectra of the compounds also indicated that 2 J PC becomes zero for PMC angles of about 103°.) The unusual site preference of the P ligands in these molecules is interpreted in terms of steric effects and an electronic preference for a good π-acceptor ligand to adopt the position trans to the dative metal−metal bond. Complexes 2, 3, and 5 react with PPh 3 in CH 2 Cl 2 at room temperature over 2 days to give W(CO) 5 (PPh 3 ) and Os(CO) 3 (PR 3 )(PR‘ 3 ) in the order 3 > 5 > 2 .
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.003 | 0.003 |
| Meta-epidemiology (broad) | 0.004 | 0.001 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 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; both teacher heads agree on what is shown here.
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".