Synthesis and Electronic Properties of Low-Dimensional Bis(benzene) Vanadium Reduced Mesoporous Niobium Oxide Composites
Bibliographic record
Abstract
The first bis(benzene) vanadium mesoporous niobium oxide composite was synthesized and characterized. The XRD pattern of this material shows a peak (100) centered at 45 A, identical to that of starting material. The nitrogen adsorption and desorption analyses of this material exhibit a slight decrease of BET surface area from 580 m(2) g(-1) to 467 m(2) g(-1) and a concomitant decrease in pore size and volume from 28 A and 0.500 cm(3) g(-1) to 25 A and 0.363 cm(3) g(-1), respectively. The powder EPR spectrum shows eight lines which can be assigned to (51)V from bis(benzene) vanadium as well as other resonances that can be assigned to the corresponding cation. The presence of two or more organometallic vanadium species was further confirmed by UV, (1)H-MAS NMR, and XPS methods. Broadened and shifted Nb 3/2, 5/2 peaks were also observed, providing further evidence that the mesoporous transition metal oxide framework was reduced by the organometallic. SQUID magnetometer measurements on this material show paramagnetic behavior with a small contribution of spin glass behavior. The conductivity of this material was 10(-4) ohm(-1) cm(-1), significantly greater than that measured for the analogous bis(benzene) chromium composite previously studied. Since alkali-metal reduced mesoporous niobium oxide materials are insulating, this conductivity was attributed to the low-dimensional bis-arene vanadium phase in the pores and rationalized according to the balance between the Hubbard potential and the bandwidth estimated for the relevant organometallic species. A bis-1,3,5-tri-tert-butylbenzene yttrium composite was also synthesized; however, complete loss of ligand upon reduction of the mesostructure was observed, indicating that this dopant behaves more like an alkali naphthalene reagent in its reactions with mesoporous niobium oxide than other bis(arene) complexes investigated by our group.
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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".