Iridium Cyclooctene Complex That Forms a Hyperpolarization Transfer Catalyst before Converting to a Binuclear C–H Bond Activation Product Responsible for Hydrogen Isotope Exchange

[IrCl(COE)2]2 (1) reacts with pyridine (py) and H2 to form crystallographically characterized IrCl(H)2(COE)(py)2 (2). 2 undergoes py loss to form 16-electron IrCl(H)2(COE)(py) (3), with equivalent hydride ligands. When this reaction is studied with parahydrogen, 1 efficiently achieves hyperpola...

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Bibliographic Details
Published in:	Inorganic chemistry Vol. 55; no. 22; pp. 11639 - 11643
Main Authors:	Iali, Wissam, Green, Gary G. R, Hart, Sam J, Whitwood, Adrian C, Duckett, Simon B
Format:	Journal Article
Language:	English
Published:	United States American Chemical Society 21-11-2016
Subjects:	Communication
Online Access:	Get full text
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Summary:	[IrCl(COE)2]2 (1) reacts with pyridine (py) and H2 to form crystallographically characterized IrCl(H)2(COE)(py)2 (2). 2 undergoes py loss to form 16-electron IrCl(H)2(COE)(py) (3), with equivalent hydride ligands. When this reaction is studied with parahydrogen, 1 efficiently achieves hyperpolarization of free py (and nicotinamide, nicotine, 5-aminopyrimidine, and 3,5-lutudine) via signal amplification by reversible exchange (SABRE) and hence reflects a simple and readily available precatayst for this process. 2 reacts further over 48 h at 298 K to form crystallographically characterized (Cl)(H)(py)(μ-Cl)(μ-H)(κ-μ-NC5H4)Ir(H)(py)2 (4). This dimer is active in the hydrogen isotope exchange process that is used in radiopharmaceutical preparations. Furthermore, while [Ir(H)2(COE)(py)3]PF6 (6) forms upon the addition of AgPF6 to 2, its stability precludes its efficient involvement in SABRE.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0020-1669 1520-510X
DOI:	10.1021/acs.inorgchem.6b02560