The new facial tripod ligand 3,3-bis(1-methylimidazol-2-yl)propionic acid and carbonyl complexes thereof containing manganese and rhenium

The new facially coordinating tripod ligand 3,3-bis(1-methylimidazol-2-yl)propionate (bmip) has been studied. A synthetic route to sodium 3,3-bis(1-methylimidazol-2-yl)propionate (Na[bmip], 2a) and its hydrochloride (Hbmip · 2HCl, 2b) is reported. The electronic properties of Hbmip were calculated by DFT methods and are compared to those of structurally similar bis(pyrazol-1-yl)acetic acids. The ligand was applied in the synthesis of the two tricarbonyl complexes [Re(bmip)(CO)3] (3) and [Mn(bmip)(CO)3] (4). Methyl 3,3-bis(1-methylimidazol-2-yl)propionate (bmipme) (1), which is the precursor of Hbmip, and the complexes [Re(bmip)(CO)3] (3) and [Mn(bmip)(CO)3] (4) were characterised by single crystal X-ray analysis.