On, off and intermediate coordination of a bridgehead triarylamine donor in tripodal complexes: towards the tuning of coordinative bond distance.

A series of first row transition metal complexes of the tripodal ligand 2,2',2"-nitrilotribenzoic acid H3L has been prepared and characterised by X-ray crystallography: Mononuclear [M(L)]- species [Cu(H2O)4]3[Cu(L)(H2O)]6.25H2O (2), [Co(H2O)6][Co(L)(H2O)].8H2O (4), [Zn(H2O)6][Zn(L)(H2O)].

Redox-triggered on/off coordination of a bridgehead nitrogen donor in a tripodal iron complex.

We report the unprecedented redox-triggered on/off coordination of a bridgehead nitrogen donor in an iron complex of the tripodal ligand 2,2',2''-nitrilotribenzoate; the complex is an efficient redox catalyst for H2O2 oxidation of hydroquinone while complexes of related ligands are inactive.