2018年1月22日
1,2-CH Bond Activation of Pyridine across a Transient Titanium Alkylidene Radical and Re-Formation of the Ti=CHtBu Moiety
Organometallics
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- 巻
- 37
- 号
- 2
- 開始ページ
- 165
- 終了ページ
- 167
- 記述言語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acs.organomet.7b00770
Reduction of the titanium alkylidene [(PNP)Ti=CHtBu(OTf)] (PNP- = N[2-PiPr2-4-methylphenyl]2-) with KC8 in the presence of pyridine results in formation of the transient titanium(III) alkylidene radical [(PNP)Ti=CHtBu)] (A) or the adduct [(PNP)Ti=CHtBu)(NC5H5)] (B), which activates the C-H bond of pyridine to form the titanium(III) pyridyl alkyl complex [(PNP)Ti(CH2tBu)(?2-NC5H4)] (1) in 64% yield as brown microcrystals. Low-Temperature X-band EPR spectroscopy and single-crystal X-ray diffraction studies confirm the identity of 1 as a d1 metal-centric radical with superhyperfine coupling to one nitrogen atom and having a side-on pyridyl moiety, which results in formation of the two isomeric forms 1a,b. Oxidation of 1 with [FeCp∗2][OTf] cleanly promotes α-hydrogen abstraction to re-form [(PNP)Ti=CHtBu(OTf)] with concurrent elimination of pyridine and FeCp∗2. Re-formation of the alkylidene moiety most likely stems from an intermediate such as [(PNP)Ti(CH2tBu)(n2-NC5H4)(OTf)] (C).
- リンク情報
- ID情報
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- DOI : 10.1021/acs.organomet.7b00770
- ISSN : 0276-7333
- eISSN : 1520-6041
- ORCIDのPut Code : 41795237
- SCOPUS ID : 85040954118