Imino functionalised complexes

Figure 3.39 Synthesis of palladium(ll) complexes of imino functionalised NffC.

Note Isomerism in the ligand sphere ofpalladium(II) carbene complexes with imino functionalised carbene chelate ligands is observed with moderately donating solvents like THF and acetonitrile as the solvent has to be hemilabile itself... 

Seeing the dicationic complex in Figure 3.42 that is stabilised by two solvent molecules (weakly coordinating acetonitrile) immediately raises the expectation that two imino functionalised NHC ligands should in principle be able to coordinate in a chelate fashion to the same metal atom. This is realised in a trigonal bipyramidal rhodium(I) complex, where the two carbene moieties are in the axial position [130] (see Figure 3.43). 

Figure 3.42 Cationic palladium complexes with a chelating imino functionalised NHC ligand.

Although the main emphasis with imino functionalised carbene hgands is on their silver complexes, as carbene transfer agents, and on late transition metal complexes - palladium. 

Figure 3,43 Synthesis and structure of rhodium(l) carbene complexes with imino functionalised NffC ligands.

Figure 3.45 Bromination of a goldf I) imino functionalised carbene complex.

Figure 3.46 Proposed reaction mechanism for the triple bromination of a goldf I) carbene complex with an imino functionalised NHC ligand.

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