Preparation and electronic properties of rhenium(V) complexes with bis(diphenyl phosphino)ethane
Bibliographic record
Abstract
Complexes of bis(diphenylphosphino)ethane (dppe) of the types ReOX3(dppe) and ReO(OR)X2(dppe) (with X= Cl or Br, and R = Me, Et, Pr, Ph, cyclohexyl (Cy), or -CH2CH2OH) were prepared to evaluate the influence of ligand changes on the low-energy dd transitions in these Re(V) low-spin d2 systems. Arylimido compounds Re(NR)Cl3(dppe) (with R = Ph and p-ClC6H4) were also obtained. X-ray diffraction studies on ReO(OPr)Cl2(dppe), ReO(OPh)Br2(dppe), and ReO(OCy)Cl2(dppe) confirmed the presence of the trans O=Re-OR unit and showed that the structural characteristics of the Re-O-R segment are not affected by the presence of a bulky cyclohexyl substituent or an aromatic phenyl group. The structure of the arylimido complex Re(p-ClC6H4N)Cl3(dppe) was also determined. The electronic absorption spectra of the ReOX3(dppe) compounds include two low-energy components at ~11 500 and ~16 000 cm1, assigned to the two spin-allowed dd transitions expected for these low-symmetry systems. Substitution of the oxo ligand by an arylimido group has little effect on the lower-energy component, but moves the two components closer together. Replacing the halogen trans to the Re=O bond by an alkoxo group shifts the whole system to higher energies. These variations were found to correlate well with the energies of the frontier orbitals determined from DFT calculations. While attempting to prepare ReOCl3(dppe) from ReOCl3(PPh3)2, the Re(III) compound fac-ReCl3(PPh3){Ph2PC2H4PPh2(O)} was obtained, in which one end of dppe had become a phosphine oxide. Upon standing in DMSO, this compound gave the octahedral compound ReCl4{Ph2PC2H4PPh2(O)}, in which the formation of a chelate ring involving a phosphine and a phosphine oxide was ascertained by X-ray diffraction.Key words: rhenium, crystal structure, DFT calculations, dd electron transitions.
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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 | 0.001 |
| 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 | 0.000 | 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".