Biomimetic Zinc Complexes With A New Tripodal Nitrogen‐Donor Ligand: Tris[2‐(1‐methyl‐4‐tolylimidazolyl)phosphane] (Pim Me, p Tol )

The new potentially threefold-chelating ligand tris[2-(1-methyl-4-tolylimidazolyl)]phosphane (PimMe,pTol) has been prepared. The p-tolyl substituents on the imidazole rings form a shielded hydrophobic cavity. The first X-ray-structure analysis of this ligand system confirms the proposed structure. The reaction of PimMe,pTol with ZnX2 salts (X = Cl, Br, I, NO3) yields monomeric ZnII complexes. The X-ray crystal structures of [PimMe,pTolZnCl]2(ZnCl4) and [PimMe,pTolZnNO3]NO3 prove that the Zn2+ centres are in a tetrahedral environment with threefold N-imidazole coordination. This arrangement mimics the active centre of carbonic anhydrase (CA).