Through space singlet-singlet and triplet-triplet energy transfers in cofacial bisporphyrins held by the carbazoyl spacer
Bibliographic record
Abstract
The through space singlet-singlet and triplet-triplet energy transfers in cofacial bis(etio-porphyrins) rigidly held by the carbazoyl spacer were investigated. The studies on singlet-singlet transfer, which operates via a Förster mechanism, were performed using the zinc porphyrin and free base chromophores as energy donor and acceptor, respectively, while the investigation on triplet-triplet processes was performed using the palladium porphyrin, and the zinc porphyrin and free base chromophores as donor and acceptors, respectively. The rate for singlet-singlet transfer ( k ET ( singlet )) is unexpectedly slower than that reported for other similar, rigidly held bisporphyrins such as H 2( DPO ) Zn ( DPO = 4,6- bis [5-(2,8,13,17- tetraethyl -3,7,12,18- tetramethylporphyrinyl )] dibenzofuran ) and H 2( DPS ) Zn ( DPS = 4,6- bis [5-(2,8,13,17- tetraethyl -3,7,12,18- tetramethyl - porphyrinyl )] dibenzothiophene )). This slower rate is interpreted by the presence of the H -atom exactly located between the two meso-carbons in the dyads. The rates for triplet-triplet transfer are also slow but not too different from that recently reported for H 2( DPX ) Pd ( DPX = 4,5- bis [5-(2,8,13,17- tetraethyl -3,7,12,18- tetramethylporphyrinyl )]-9,9- dimethylxanthene ) and H 2( DPB ) Pd ( DPB = 1,8- bis [5-(2,8,13,17- tetraethyl -3,7,12,18- tetramethylporphyrinyl )] biphenylene ) at 77 K. In such cases, the slow rate is interpreted by a through space energy transfer pathway which operates according to a (small range) Dexter mechanism (since the Förster mechanism is inoperative for triplet-triplet processes). The k ET (triplet) increases at 298 K which is tentatively interpreted by favorable excited state distortions in the triplet state and fluxion processes which ease intramolecular transfers for these dyads in fluid solution in comparison with former glassy matrices.
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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) | 0.001 | 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".