Unexpected Coordination Modes of the Tris(imidazolyl)phosphane Oxide Ligand 4‐TIPOiPr in the Chloro Complexes of Zinc,Cobalt and Nickel

The coordination chemistry of the water soluble phosphane oxide ligand tris2‐isopropylimidazol‐4(5)‐yl]phosphane oxide, 4‐TIPO^iPr, has been explored. A variety of 3d‐metal halide complexes have been prepared and the crystal structures of the solvates (4‐TIPO^iPr)ZnCl₂]·MeOH·¹/₂dioxane ( 1 ·MeOH·¹/₂dioxane), (4‐TIPO^iPr)CoCl₂]·H₂O·2dioxane ( 2 ·H₂O·2dioxane) and (4‐TIPO^iPr)₂Ni(MeOH)₂]Cl₂·2MeOH ( 3 ·2MeOH) have been determined. All three structures show unprecedented coordination modes of the 4‐TIPO^iPr ligand. Both zinc and cobalt complexes are coordinated in a bidentate κ²N fashion, whereas the nickel atom is coordinated by two ligands in a κN,O mode using one imidazolyl substituent and the P=O oxygen atom.