Pyrrole-Based Ti(III) and Ti(IV) PNP Pincer Complexes : Insertion of Ketones into the Ti(IV)-Phosphorus Bond
© 2023 The Authors. Published by American Chemical Society.
| Veröffentlicht in: | Organometallics. - 1998. - 42(2023), 20 vom: 23. Okt., Seite 2999-3004 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2023
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| Zugriff auf das übergeordnete Werk: | Organometallics |
| Schlagworte: | Journal Article |
| Zusammenfassung: | © 2023 The Authors. Published by American Chemical Society. The synthesis, characterization, and reactivity of pyrrole-based Ti(III) and Ti(IV) PNP pincer complexes are described. [P(NH)P-iPr] (1) reacts with [TiCl4(THF)2] at room temperature in the presence of NEt3 to afford the Ti(IV) complex [Ti(PNPiPr)(Cl)3]. This complex reacts with acetone and cyclopentanone to give complexes [Ti(PNOacet-iPr)(Cl)3] and [Ti(PNOcyclo-iPr)(Cl)3], respectively. Insertion of the ketone into the Ti(IV)-P bond took place, forming a new tridendate PNO-ligand. Treatment of [TiCl3(THF)3] with the lithium salt of [P(NH)P-iPr] afforded, upon workup, complex [Ti(PNP-iPr)(Cl)2(THF)], a paramagnetic complex with an μeff value of 1.8(1) μB which corresponds to one unpaired electron and a formal oxidation state of +III. This compound does not react with ketones. A mechanistic proposal based on DFT calculations is presented. Ketone insertion proceeds via an associative reaction initiated by ketone coordination at the metal center, followed by the opening of the five-membered chelate ring, and finally an intramolecular nucleophilic attack of the noncoordinated phosphine arm at the carbonyl atom of the ketone. All complexes were characterized by X-ray crystallography |
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| Beschreibung: | Date Revised 28.10.2023 published: Electronic-eCollection Citation Status PubMed-not-MEDLINE |
| ISSN: | 0276-7333 |
| DOI: | 10.1021/acs.organomet.3c00327 |