Synthesis, characterization, and reactivity of scandium chloro, alkyl, aryl, and borohydride complexes, Sc(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)R[N(SiMe<sub>2</sub>CH<sub>2</sub>P<sup>i</sup>Pr<sub>2</sub>)<sub>2</sub>] (R = Cl, Me, Ph, and BH<sub>4</sub>)
Bibliographic record
Abstract
Reaction of ScCl2(THF)[N(SiMe2CH2PiPr2)2] with NaCp(DME) leads to Sc(η5-C5H5)Cl[N(SiMe2CH2PiPr2)2] (1). The X-ray crystal structure shows the scandium centre to reside in a square pyramidal environment with the [N(SiMe2CH2PiPr2)2] - ligand bound in a pseudo-meridional fashion. The 1H NMR spectrum is consistent with a Cs symmetric structure in solution. Metathesis of the chloride ligand with RLi (R = Me, Ph, BH4) yields the five-coordinate species Sc(η5-C5H5)R[N(SiMe2CH2PiPr2)2]. Phenyl 3 and borohydride 4 are isolated as crystalline solids, while methyl 2 resisted crystallization. 2-4 exhibit 1H NMR spectra consistent with Cs symmetric solution structures. Sc(η5-C5H5)Ph[N(SiMe2CH2PiPr2)2] (3) was characterized in the solid state and found to have a similar geometry to that of the parent chloride. Reaction of Sc(η5-C5H5)Me[N(SiMe2CH2PiPr2)2] (2) with NH2R (R = Ph, tBu) yields the amides Sc(η5-C5H5)NHPh[N(SiMe2CH2PiPr2)2] (5) and Sc(η5-C5H5)NHtBu [N(SiMe2CH2PiPr2)2] (6) via σ-bond metathesis routes; these reactions are accompanied by a competing reaction at the scandium-amide bond to produce the protonated ligand, HN(SiMe2CH2PiPr2)2. 5 and 6 are also produced by salt-elimination from the chloride 1 and LiNHR (R = Ph, tBu). Sc(η5-C5H5)(BH4)[N(SiMe2CH2PiPr2)2] (4) reacts with PMe3 to produce the putative hydride, Sc(η5-C5H5)H[N(SiMe2CH2PiPr2)2] (7); this species was identified in solution. An equilibrium between 4, PMe3, 7, and PMe3·BH3 exists which greatly favors the starting scandium-borohydride. Crystals of Sc(η5-C5H5)Cl[N(SiMe2CH2PiPr2)2] (1) are monoclinic, a = 17.409(2), b = 10.0803(7), c = 17.688(2) Å, β = 94.606(8)°, Z = 4, space group P21/c; and those of Sc(η5-C5H5)Ph[N(SiMe2CH2PiPr2)2] (3) are triclinic, a = 10.5129(15), b = 19.124(2), c = 9.114(2) Å, α = 95.582(13), β = 107.047(12), γ = 90.042(11)°, Z = 2, space group P. The structures were solved by Patterson (1) and direct (3) methods and refined by full-matrix least-squares procedures to R = 0.047 and 0.054 (Rw = 0.042 and 0.049) for 2414 and 2844 reflections with I [Formula: see text] 3σ(I), respectively.Key words: scandium, σ-bond metathesis, borohydride.
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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 | 0.000 | 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".