Platinum Complexes of Alkynyl-Substituted Dimethyldihydropyrenes
Bibliographic record
Abstract
A series of photochromic dimethyldihydropyrenes (DHP) bearing ethyne substituents in the 4-position ( R DHP-C≡CH; R = H ( 4 ), acetyl ( 5 ), benzoyl ( 6 ), 1-naphthoyl ( 7 ), benzo[ e ] ( 8 )) were prepared for use as precursors to ethynyl ligands. Dehydrohalogenation of the adduct of these ethynes with various PtCl 2 (L) 2 complexes afforded a series of cis and trans square-planar bis(DHP-ethynyl) platinum complexes, ( R DHP-C≡C) 2 Pt(L) 2 (cis, R = H, L 2 = PEt 3 ( 9 ), acetyl, PEt 3 ( 10 ), benzoyl, PEt 3 ( 11 ), 1-naphthoyl, PEt 3 ( 12 ), benzo[ e ], PEt 3 ( 13 ), benzoyl, PPh 3 ( 14 ), benzo[ e ], PPh 3 ( 15 ); trans, R = H, L 2 = dppe ( 16 ), benzo[ e ], dppe ( 17 ), acetyl, bipy ( 18 ), 1-naphthoyl, bipy ( 19 ), H, phen ( 20 )). The DHP-ethynes bearing acyl and benzo[ e ] substituents on the DHP ( 5 – 8 ) and their platinum complexes ( 10 – 19 ) are photochromic and undergo ring opening to the related cyclophanediene (CPD) isomer on irradiation with visible light (λ >550 nm). In the case of the benzo[ e ]DHP 8, adding a 4-ethynyl substituent increases the rate of photo-opening 4-fold; however, in the acylDHP series 5 – 7, addition of a 4-ethynyl group slows the rate of photo-opening by a factor of about 4. The platinum complexes generally open more slowly than the corresponding alkyne precursors, again by a factor of about 4. The rate of photo-opening does not appear to be affected significantly by the nature of the ancillary ligands or the metal geometry, suggesting that there is poor electronic communication between the platinum center and the DHP π system. The thermal back-reaction from the open CPD to closed DHP form is about 50% faster for the metal complexes than for the DHP-ethyne precursor. The platinum complexes and the DHP-ethynes were characterized by NMR and IR spectroscopy and MS and by X-ray crystallography for metal complexes 10, 11, 14, 15, and 17 .
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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".