2-Azetidinones as Precursors of Pincer Ligands: Preparation, Structure, and Spectroscopic Properties of CC鈥睳-Osmium Complexes

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• 作者：Luis Casarrubios ; Miguel A. Esteruelas ; Carmen Larramona ; Jaime G. Muntaner ; Enrique O帽ate ; Miguel A. Sierra
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：November 16, 2015
• 年：2015
• 卷：54
• 期：22
• 页码：10998-11006
• 全文大小：562K
• ISSN：1520-510X

文摘

A metal-promoted degradation of 2-azetidinones to afford CC鈥睳-pincer ligands is reported. The hexahydride complex OsH₆(PⁱPr₃)₂ (1) reacts with (卤)-cis-1-(4-methoxyphenyl)-3-phenoxy-4-(pyridin-2-yl)azetidin-2-one (I), (卤)-cis-1-(4-methoxyphenyl)-3-phenoxy-4-(isoquinolin-2-yl)azetidin-2-one (II), and (卤)-cis-1-(4-methoxyphenyl)-3-phenoxy-4-(quinolin-2-yl)azetidin-2-one (III) to give the respective OsH₂(PⁱPr₃)₂(CC鈥睳) (2鈥?b>4) complexes, which add HBF₄路OEt₂ to yield [OsH₂(PⁱPr₃)₂(CC鈥砃)]BF₄ (5鈥?b>7). These salts are the result of the addition of the proton of the acid to the dianionic CC鈥睳-pincer ligand. The hydride ligands of these compounds undergo quantum mechanical exchange coupling, which has been experimentally quantified according to a two-dimensional harmonic oscillator model, where J_ex is determined by the separation between the hydrides, their hard sphere radius, and a 谓 parameter describing the H鈥揗鈥揌 vibrational wag mode allowing the movement along the H鈥揌 vector. The comparison of the results reveals that the phenomenon is particularly intense for 5鈥?b>7. Furthermore, in these compounds, the separation between the hydrides is 鈭?.1 脜 shorter than in the respective neutral species 2鈥?b>4, whereas the hydride hard sphere radius increases by 鈭?0%, and the 谓 value decreases by 鈭?0%.