Synthesis and Characterization of Palladium Complexes Supported by an NPN-Phosphido Ancillary Ligand
Bibliographic record
Abstract
The Pd II coordination chemistry of the phosphido ligand [(2-Me 2 NC 6 H 4 ) 2 P] − (NPN) is reported, along with the results of studies documenting the utility of such complexes as catalyst precursors for the Heck arylation of olefins. Examples of κ 1 -, κ 2 -, and κ 3 -NPN coordination to Pd are described. The secondary phosphine (NPN)H ( 1 ) was reacted with 0.5 equiv of [(C 3 H 5 )PdCl] 2 to afford the dimeric species [(κ 2 - NP N)PdCl] 2 ( 2 ) in 96% yield. Similarly, the reaction of 1 with 0.33 equiv of [Pd(OAc) 2 ] 3 led to the formation of dimeric [(κ 2 - NP N)PdOAc] 2 ( 3 ) in 98% yield. Complexes 2 and 3 were both crystallographically characterized to reveal dipalladium species that feature bridging phosphido groups, as well as terminal chloride and acetate ligands, respectively. Treatment of 3 with Me 3 SiOTf resulted in the formation of the analogous triflate complex [(κ 2 - NP N)PdOTf] 2 ( 4; 78% yield). Treatment of 2 with (C 3 H 5 )MgCl afforded the thermally sensitive, phosphido-bridged complex [(κ 1 -N P N)Pd(η 3 -C 3 H 5 )] 2 ( 5 ) in 87% yield. The solid-state structure of 5 was confirmed by X-ray crystallography. Precoordination of BPh 3 to the NPN phosphido group was attempted in order to discourage the formation of phosphido-bridged (NPN)Pd species. Thus, the reaction of 1 with 1 equiv each of KCH 2 Ph and BPh 3 led to the formation of [N(P·BPh 3 )N]K ( 6 ), which was isolated in 88% yield. The related complex [N(P·BH 3 )N]H ( 7 ) was prepared by treatment of 1 with BH 3 ·THF, and crystallographic characterization confirmed the preferential coordination of the NPN ligand phosphorus to BH 3 . The reaction of 6 with 0.5 equiv of [Pd(C 3 H 5 )Cl] 2 led to the formation of [κ 3 - N ( P ·BPh 3 ) N ]Pd(η 1 -C 3 H 5 ), which was isolated in 45% yield. Complexes 2 – 4 were established as precatalysts for the Heck coupling of ethyl acrylate and haloarenes.
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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 | 0.000 | 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) | 0.002 | 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 teacher head, 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".