Two‐Photon Chemistry in Ruthenium 2,2′‐Bipyridyl‐Functionalized Single‐Wall Carbon Nanotubes
Bibliographic record
Abstract
Ruthenium polypyridyl complexes are widely used as light harvesters in dye-sensitized solar cells. Since one of the potential applications of single-wall carbon nanotubes (SWCNTs) and their derived materials is their use as active components in organic and hybrid solar cells, the study of the photochemistry of SWCNTs with tethered ruthenium polypyridyl complexes is important. A water-soluble ruthenium tris(bipyridyl) complex linked through peptidic bonds to SWCNTs (Ru-SWCNTs) was prepared by radical addition of thiol-terminated SWCNT to a terminal C=C double bond of a bipyridyl ligand of the ruthenium tris(bipyridyl) complex. The resulting macromolecular Ru-SWCNT (approximately 500 nm, 15.6% ruthenium complex content) was water-soluble and was characterized by using TEM, thermogravimetric analysis, chemical analysis, and optical spectroscopy. The emission of Ru-SWCNT is 1.6 times weaker than that of a mixture of [Ru(bpy)(3)](2+) and SWCNT of similar concentration. Time-resolved absorption optical spectroscopy allows the detection of the [Ru(bpy)(3)](2+)-excited triplet and [Ru(bpy)(3)](+). The laser flash studies reveal that Ru-SWCNT exhibits an unprecedented two-photon process that is enabled by the semiconducting properties of the SWCNT. Thus, the effect of the excitation wavelength and laser power on the transient spectra indicate that upon excitation of two [Ru(bpy)(3)](2+) complexes of Ru-SWCNT, a disproportionation process occurs leading to delayed formation of [Ru(bpy)(3)](+) and the performance of the SWCNT as a semiconductor. This two-photon delayed [Ru(bpy)(3)](+) generation is not observed in the photolysis of [Ru(bpy)(3)](3+); SWCNT acts as an electron wire or electron relay in the disproportionation of two [Ru(bpy)(3)](2+) triplets in a process that illustrates that the SWCNT plays a key role in the process. We propose a mechanism for this two-photon disproportionation compatible with i) the need for high laser flux, ii) the long lifetime of the [Ru(bpy)(3)](2+) triplets, iii) the semiconducting properties of the SWNT, and iv) the energy of the HOMO/LUMO levels involved.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 source (direct Gemma or distilled Codex), 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".