Molybdenum Dithiolene Complexes as Structural Models for the Active Sites of Molybdenum(IV) Sulfide Hydrodesulfurization Catalysts
Bibliographic record
Abstract
Abstract The removal of sulfur (as H 2 S) from organosulfur species in petroleum feedstocks (hydrodesulfurization, HDS) is carried out on an enormous scale by using heterogeneous catalysts based on MoS 2 (usually doped with Co). Partially hydrogenated thiophenes are postulated intermediates in the MoS 2 ‐catalyzed hydrodesulfurization of thiophene. The present contribution describes new molecular models for the proposed active sites in HDS catalysis. The models are derived from a mixed‐ligand (push–pull) molybdenum trisdithiolene {[Mo(tfd) 2 (bdt)]; tfd = S 2 C 2 (CF 3 ) 2 , bdt = S 2 C 6 H 4 }: selective intraligand alkyne binding converts the bdt group to a labile Mo‐chelating benzodithiin, which can be substituted with a variety of weak donor ligands. The complexes [Mo(tfd) 2 (dht) 2 ] and [Mo(tfd) 2 (tht) 2 ] (dht = 2,5‐dihydrothiophene; tht = tetrahydrothiophene) were synthesized and crystallographically characterized. The Mo(tfd) 2 substructures closely resemble the presumed active site in MoS 2 HDS catalysts. The coordination geometries at molybdenum are approximately trigonal prismatic, and the metal bears two strongly bound dithiolene (tfd) groups and two comparatively weakly bound thioether ligands (dht or tht). Competitive binding experiments establish that tht binds more strongly to the Mo center than dht ( K eq = 6.5 ± 0.5). Preliminary reactivity studies reveal that [Mo(tfd) 2 (dht) 2 ] decomposes to [Mo(tfd) 3 ], thiophene, and unidentified species upon heating. Further, [Mo(tfd) 2 (tht) 2 ] induces the isomerization of 1,4‐cyclohexadiene to 1,3‐cyclohexadiene at elevated temperatures.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 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".