Easily Prepared Chiral Scorpionates: Tris(2-oxazolinyl)boratoiridium(I) Compounds and Their Interactions with MeOTf

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• 作者：Benjamin Baird ; Andrew V. Pawlikowski ; Jiachun Su ; Jerzy W. Wiench ; Marek Pruski ; Aaron D. Sadow
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：November 17, 2008
• 年：2008
• 卷：47
• 期：22
• 页码：10208-10210
• 全文大小：116K
• 年卷期：v.47,no.22(November 17, 2008)
• ISSN：1520-510X

文摘

Optically active C<sub>3sub>-symmetric monoanionic ligands are uncommon in organometallic chemistry. Here we describe the synthesis of readily prepared tris(4S-isopropyl-2-oxazolinyl)phenylborate [To<sup>Psup>] and fluxional, zwitterionic four- and five-coordinate iridium(I) compounds [Ir(To<sup>Psup>)(η<sup>4sup>-C<sub>8sub>H<sub>12sub>)] (4) and [Ir(To<sup>Psup>)(CO)<sub>2sub>] (5). The highly fluxional nature of 4 and 5 makes structural assignment difficult, and the interaction between the iridium(I) center and the [To<sup>Psup>] ligand is established by solid-state and solution <sup>15sup>N NMR methods that permit the direct comparison between solution and solid-state structures. Although iridium cyclooctadiene 4 is a mixture of four- and five-coordinate species, the dicarbonyl 5 is only the five-coordinate isomer. The addition of electrophiles MeOTf and MeI provides the oxazoline N-methylated product rather than the iridium methyl oxidative addition product. N-Methylation was unequivocally proven by through-bond coupling observed in <sup>1sup>H−<sup>15sup>N HMBC experiments.