Imidazole-based bifunctional chelates for the “fac-[Re(CO)3]+” core

Three monocationic rhenium(I) complexes of the type [Re(CO)3(L)]Br, containing the bis-imidazole tridentate ligands bis-(2-(1-methylimidazolyl)methyl)amine (L1), bis-(2-(1-methylimidazolyl)methyl)aminoethanol (L2) and bis-(2-(benzimidazolyl)ethyl)sulfide (L3), were prepared and characterized by 1H NMR and IR spectroscopy. The complex salt [Re(CO)3(L2)]Br (2) was also characterized by X-ray crystallography. The structure consists of discrete monocationic monomers with a fac-[Re(CO)3]+ coordination unit, and the remaining three sites are occupied by one amine and two imidazolyl nitrogen donor atoms.

This paper presents the syntheses of tridentate bis-imidazole type ligands, and the study of their coordination chemistry with [Re(OH2)3(CO)3]Br or (NEt4)2[ReBr3(CO)3] as Re(I) precursor compounds. Crystal structure evidence for one of the analogues shows that the tridentate ligand adopts a facial arrangement around the Re(I) ion, imposed by the fac-[Re(CO)3]+ core.Figure optionsDownload as PowerPoint slide