Base-Free and Bisphosphine Ligand Dialkylmanganese(II) Complexes as Precursors for Manganese Metal Deposition
Bibliographic record
Abstract
The solid-state structures and the physical, solution magnetic, solid-state magnetic, and spectroscopic (NMR and UV/vis) properties of a range of oxygen- and nitrogen-free dialkylmanganese(II) complexes are reported, and the solution reactivity of these complexes toward H 2 and ZnEt 2 is described. The compounds investigated are [{Mn(μ-CH 2 SiMe 3 ) 2 } ∞ ] ( 1 ), [{Mn(CH 2 CMe 3 )(μ-CH 2 CMe 3 ) 2 } 2 {Mn(μ-CH 2 CMe 3 ) 2 Mn}] ( 2 ), [Mn(CH 2 SiMe 3 ) 2 (dmpe)] ( 3; dmpe = 1,2-bis(dimethylphosphino)ethane), [{Mn(CH 2 CMe 3 ) 2 (μ-dmpe)} 2 ] ( 4 ), [{Mn(CH 2 SiMe 3 )(μ-CH 2 SiMe 3 )} 2 (μ-dmpe)] ( 5 ), [{Mn(CH 2 CMe 3 )(μ-CH 2 CMe 3 )} 2 (μ-dmpe)] ( 6 ), [{Mn(CH 2 SiMe 3 )(μ-CH 2 SiMe 3 )} 2 (μ-dmpm)] ( 7; dmpm = bis(dimethylphosphino)methane), and [{Mn(CH 2 CMe 3 )(μ-CH 2 CMe 3 )} 2 (μ-dmpm)] ( 8 ). Syntheses for 1 – 4 have previously been reported, but the solid-state structures and most properties of 2 – 4 had not been described. Compounds 5 and 6, with a 1:2 dmpe/Mn ratio, were prepared by reaction of 3 and 4 with base-free 1 and 2, respectively. Compounds 7 and 8 were accessed by reaction of 1 and 2 with 0.5 equiv or more of dmpm per manganese atom. An X-ray structure of 2 revealed a tetrametallic structure with two terminal and six bridging alkyl groups. In the solid state, bisphosphine-coordinated 3 – 8 adopted three distinct structural types: (a) monometallic [LMnR 2 ], (b) dimetallic [R 2 Mn(μ-L) 2 MnR 2 ], and (c) dimetallic [{RMn(μ-R)} 2 (μ-L)] (L = dmpe, dmpm). Compound 3 exhibited particularly desirable properties for an ALD or CVD precursor, melting at 62–63 °C, subliming at 60 °C (5 mTorr), and showing negligible decomposition after 24 h at 120 °C. Comparison of variable-temperature solution and solid-state magnetic data provided insight into the solution structures of 2 – 8 . Solution reactions of 1 - 8 with H 2 yielded manganese metal, demonstrating the thermodynamic feasibility of the key reaction steps required for manganese(II) dialkyl complexes to serve, in combination with H 2, as precursors for metal ALD or pulsed CVD. In contrast, the solution reactions of 1 – 8 with ZnEt 2 yielded a zinc–manganese alloy with an approximate 1:1 Zn/Mn ratio.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".