Synthesis of tungsten complexes that contain hexaisopropylterphenyl-substituted triamidoamine ligands, and reactions relevant to the reduction of dinitrogen to ammonia
Why this work is in the frame
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Bibliographic record
Abstract
[HIPTN 3 N]WCl (WCl) can be synthesized readily by adding H 3 [HIPTN 3 N] to WCl 4 (DME) followed by LiN(SiMe 3 ) 2 ([HIPTN 3 N] 3 = [(HIPTNCH 2 CH 2 ) 3 N] 3 where HIPT = 3,5-(2,4,6-i-Pr 3 C 6 H 2 ) 2 C 6 H 3 = HexaIsoPropylTerphenyl). Reduction of WCl with KC 8 in benzene under N 2 yields WN=NK. WN=NK is readily oxidized in THF by ZnCl 2 to yield zinc metal and WN 2 . Reduction of WN 2 to [WN 2 ] is reversible at 2.27 V vs. FeCp 2 +/0 in 0.1 mol/L [Bu 4 N][BAr′ 4 ]/PhF electrolyte (Ar′ = 3,5-(CF 3 ) 2 C 6 H 3 ), while oxidation of WN 2 to [WN 2 ] + is also reversible at 0.66 V. Protonation of WN=NK by [Et 3 NH][OTf] in benzene yields WN=NH essentially quantitatively. Protonation of WN=NH at N β with [H(OEt) 2 ][BAr′ 4 ] in ether affords [W=NNH 2 ][BAr′ 4 ] quantitatively. Electrochemical reduction of [W=NNH 2 ][BAr′ 4 ] in 0.1 mol/L [Bu 4 N][BAr′ 4 ]/PhF is irreversible at scan rates of up to 1 V/s. Addition of NaBAr′ 4 and NH 3 to WCl in PhF yields [W(NH 3 )][BAr′ 4 ]. Electrochemical reduction of [W(NH 3 )][BAr′ 4 ] in 0.1 mol/L [Bu 4 N][BAr′ 4 ]/PhF is irreversible at 2.06 V vs. FeCp 2 +/0 at a scan rate of 0.5 V/s. Treatment of [W(NH 3 )][BAr′ 4 ] with triethylamine and [FeCp 2 ][PF 6 ] in C 6 D 6 , followed by LiN(SiMe 3 ) 2 , yielded W≡N. Treatment of [W(NH 3 )][BAr′ 4 ] with LiBHEt 3 (1 mol/L in THF) results in formation of WH, which is converted to WH 3 upon exposure to an atmosphere of H 2 . Attempts to prepare WN=NH by treating WN 2 with [2,6-LutH][BAr′ 4 ] and CoCp 2 yielded only [W=NNH 2 ][BAr′ 4 ]. [W=NNH 2 ][BAr′ 4 ] is reduced to W=NNH 2 by CoCp * 2 , but this species disproportionates to yield WN=NH, W≡N, and ammonia. Reduction of [W(NH 3 )][BAr′ 4 ] with CoCp * 2 does not yield any observable W(NH 3 ). Attempted catalytic reduction of dinitrogen using WN 2 as the catalyst under conditions identical or similar to those employed for catalytic reduction of dinitrogen by MoN 2 and related Mo complexes failed. Single crystal X-ray studies were carried out on W-N=NK, WN 2 , W-N=NH, [W=NNH 2 ][BAr′ 4 ], and [W(NH 3 )][BAr′ 4 ].Key words: dinitrogen, reduction, tungsten, ammonia.
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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) | 0.000 | 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) | 0.000 | 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 it