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- Title
Design of 4‐Coordinate Ti Imido Aryloxide on the Surface of Silica for Catalytic Oxo/Imido Heterometathesis.
- Authors
Pichugov, Andrey V.; Bushkov, Nikolai S.; Rumyantsev, Andrey V.; Zhizhin, Anton A.; Aleshin, Dmitry Y.; Strelkova, Tatyana V.; Talanova, Valeria N.; Takazova, Rina U.; Mance, Deni; Allouche, Florian; Mougel, Victor; Dolgushin, Fedor M.; Ustynyuk, Nikolai A.; Zhizhko, Pavel A.; Zarubin, Dmitry N.
- Abstract
We report here the synthesis of 4‐coordinate Ti imido complexes Ti(=NtBu)(OArtBu)2(py) (2) and Ti(=NtBu)(OArtBu)(Me2Pyr)(py) (3) (ArtBu=O‐2,6‐tBu2‐4‐MeC6H2, Me2Pyr=2,5‐dimethylpyrrolyl) and study their grafting onto the surface of partially dehydroxylated silica with the aim to prepare 4‐coordinate Ti imido aryloxide surface species. Study of the resulting materials with IR, solid‐state NMR, elemental and mass balance analyses demonstrates that grafting of bis‐aryloxide complex 2 leads to a predominant formation of silica‐supported Ti amide (≡SiO)Ti(NHtBu)(OArtBu)2(py) resulting from the protonation of the imido ligand with the surface silanols and only a smaller fraction of the desired imido species (≡SiO)Ti(=NtBu)(OArtBu)(py). The use of the tailored complex 3 where one of the aryloxides is replaced with a more reactive pyrrolyl ligand significantly increases the selectivity of grafting leading to the formation of the Ti imido aryloxide (≡SiO)Ti(=NtBu)(OArtBu)(py) as major surface species. The obtained materials show high activity in catalytic oxo/imido heterometathesis supporting the previously proposed hypothesis that electron‐donating environments are favorable for this transformation.
- Subjects
PHENOXIDES; SILICA; CATALYTIC activity; IMIDES; PROTON transfer reactions
- Publication
Helvetica Chimica Acta, 2022, Vol 105, Issue 6, p1
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.202200030