Improved Yields of Dichlorobis(triphenylphosphine)nickel(II) and Related Compounds by Employing Triethyl Orthoformate as an In Situ Dehydrating Agent: Rational Improvement of a Classic Undergraduate Inorganic Synthesis
Bibliographic record
Abstract
The addition of a small excess of triethyl orthoformate to an alcoholic mixture of NiCl 2 ·6H 2 O and triphenylphosphine (PPh 3 ) results in an increase in the typical isolated yield of [NiCl 2 (PPh 3 ) 2 ] from below 50% to over 85%. The impact of water when present in the reaction medium in this system is discussed, and results from the application of the same synthetic approach to the syntheses of [NiBr 2 (PPh 3 ) 2 ], [NiCl 2 (dppe)], and [NiBr 2 (dppe)] are presented. A simple synthesis of NiCl 2 ·2H 2 O by the dehydration of NiCl 2 ·6H 2 O at 80 °C can be performed as an optional step to decrease the quantity of triethyl orthoformate required for the preparation of [NiCl 2 (PPh 3 ) 2 ] and/or [NiCl 2 (dppe)]. The experiments are flexible and accommodate a variety of laboratory schedules and student skill levels. Each synthesis can be readily completed within a 3 h laboratory period.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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 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".