A Facile Route to Backbone‐Tethered N‐Heterocyclic Carbene (NHC) Ligands via NHC to aNHC Rearrangement in NHC Silicon Halide Adducts. Issue 7 (22nd December 2014)

• Record Type: Journal Article
• Authors: Schneider, Heidi; Schmidt, David; Radius, Udo
• Is Part Of: Chemistry. Volume 21:Issue 7(2015)
• Page Start: 2793
• Page End: 2797
• Publication Date: 2014-12-22
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201406264
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The reaction of 1, 3‐diisopropylimidazolin‐2‐ylidene (<italic>i</italic>Pr<sub>2</sub>Im) with diphenyldichlorosilane (Ph<sub>2</sub>SiCl<sub>2</sub>) leads to the adduct (<italic>i</italic>Pr<sub>2</sub>Im)SiCl<sub>2</sub>Ph<sub>2</sub><bold>1</bold>. Prolonged heating of isolated <bold>1</bold> at 66 °C in THF affords the backbone‐tethered bis(imidazolium) salt [(<sup>a</sup>H<italic>i</italic>Pr<sub>2</sub>Im)<sub>2</sub>SiPh<sub>2</sub>]<sup>2+</sup> 2 Cl<sup>−</sup><bold>2</bold> ("<sup>a</sup>" denotes "abnormal" coordination of the NHC), which can be synthesized in high yields in one step starting from two equivalents of <italic>i</italic>Pr<sub>2</sub>Im and Ph<sub>2</sub>SiCl<sub>2</sub>. Imidazolium salt <bold>2</bold> can be deprotonated in THF at room temperature using sodium hydride as a base and catalytic amounts of sodium <italic>tert</italic>‐butoxide to give the stable N‐heterocyclic dicarbene (<sup>a</sup><italic>i</italic>Pr<sub>2</sub>Im)<sub>2</sub>SiPh<sub>2</sub><bold>3</bold>, in which two NHCs are backbone‐tethered with a SiPh<sub>2</sub> group. This easy‐to‐synthesize dicarbene <bold>3</bold> can be used as a novel ligand type in transition metal chemistry for the preparation of dinuclear NHC complexes, as exemplified by the synthesis of the homodinuclear copper(I) complex [{<sup>a</sup>(ClCu<italic>i</italic>Pr<sub>2</sub>Im)}<sub>2</sub>SiPh<sub>2</sub>] <bold>4</bold>.</p> </abstract>