Recent Advances in NHCP Chemistry Featuring Bulky, Electron-Rich, Small-Bite-Angle Ligands

Recent Advances in NHCP Chemistry Featuring Bulky, Electron-Rich, Small-Bite-Angle Ligands 

Kostyuk ef al. (R denotes only the N-substituents investigated in our group). 

Adding the isolated NHCP hgands R-34 (R = Me, Mes, fBu) to copper(I) precursors led to the formation of mostly bridging systems displaying interesting structural motifs in the solid state, as determined by X-ray crystal structure 

Using a copper(I) source such as CuBr-SMej and reacting it with Mes-34 revealed another dinuclear, yet rarely observed structural motif, which hkely is formed driven by steric effects. We presume that by going from the JV-methyl NHCP Me-34 to the more bulky Af-mesityl ligand favors the formation of cluster Mes-54, since the ligands are then at a greater distance from each other. A further increase of steric bulk to the NHCP tBu-34 prevented the formation of a bis-ligated species. Instead, the mono nuclear complex fBu-55 [56] was formed. Extraordinarily, the bromide does not coordinate to the copper center, which has never been observed previously. The only other known complex of the type 

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