Reduced and Oxidized Forms of the Pt-Organometallic Version of Polyaniline
Notice bibliographique
Résumé
This work represents an effort to synthesize all four forms of polyaniline (PANI) in its organometallic versions. Polymers containing substituted 1,4-benzoquinone diimine or 1,4-diaminobenzene units in the backbone exhibiting the general structure (C≡CC(6)H(4)-N═C(6)X(4)═N-C(6)H(4)C≡C-PtL(2))(n) and (C≡CC(6)H(4)NH-C(6)X(4)-NHC(6)H(4)C≡C-PtL(2))(n) along with the corresponding model compounds (C≡CC(6)H(4)-N═C(6)X(4)═N-C(6)H(4)C≡C)(PtL(2)Cl)(2) and (C≡CC(6)H(4)NH-C(6)X(4)-NHC(6)H(4)C≡C)(PtL(2)Cl)(2) (L = PBu(3); X = H, F, Cl) were synthesized. The polymers and corresponding model compounds were characterized (including (1)H and (31)P NMR, IR, mass spectra, elemental analysis, and X-ray structure determinations) and investigated for their redox properties in the absence and in the presence of acid. Their optical properties, including ns transient spectroscopy were also investigated. These properties were interpreted through density functional theory (DFT) and time-dependent DFT (TDDFT) computations. These materials are found to be oligomers (GPC) with thermal stability (TGA) reaching 350 °C. The greatest stabilities were found in the cases with X = F. Using a data bank of 8 X-ray structures of diimine derivatives, a relationship between the C═N bond distance and the dihedral angle between the benzoquinone ring and the flanking phenyl planes is noted. As the size of the substituent X on the benzoquinone center increases, the degree of conjugation decreases as demonstrated by the C═N bond length. The largest dihedral angles are noted for X = Cl. These polymers exhibit drastic chemical differences when X is varied (X = H, F, Cl). The completely reduced polymer (C≡CC(6)H(4)NH-C(6)H(4)-NHC(6)H(4)C≡C-PtL(2))(n) (i.e., X = H) was not chemically accessible whereas in the cases of X = F, Cl, these materials were obtained and represent the first examples of fully reduced organometallic versions of PANI (i.e., leucoemaraldine). For the (C≡CC(6)H(4)-N═C(6)X(4)═N-C(6)H(4)C≡C-PtL(2))(n) polymers, the completely oxidized form for X = H was isolated (pernigraniline), but for X = F and Cl, only the largely reduced mixed-valence form (i.e., emaraldine) was obtained via chemical routes. In acidic solutions, the chemically accessible polymer for X = H, (C≡CC(6)H(4)-N═C(6)H(4)═N-C(6)H(4)C≡C-PtL(2))(n), exhibits two chemically reversible waves indicating that the reduced form (C≡CC(6)H(4)NH-C(6)H(4)-NHC(6)H(4)C≡C-PtL(2))(n) can be generated. The absorption spectra of the highly colored diimine-containing species exhibit a broad charge transfer band (assigned based on DFT calculations (B3LYP); C(6)H(4)C≡C-PtL(2)-C≡CC(6)H(4) → N═C(6)X(4)═N) in the 450-800 nm window red shifting according X = H → Cl → F, consistent with their relative inductive effect. The largest absorptivity is measured for X = H because this polymer is fully oxidized whereas for the cases where X = F and Cl, these polymers exists in the mixed valence form. The ns transient absorption spectra of two polymers (X = F; reduced and mixed-valence polymers) were measured. The triplet excited state in the mixed-valence polymer is dominated by the reduced diamine residue and the T(1)-T(n) absorption of the diimine is entirely quenched.
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Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».