Phosphine-functionalised tris(pyrazolyl)methane ligands and their mono- and heterobimetallic complexes.

The synthesis, characterisation and reactivity of new phosphine-functionalised tris(pyrazolyl)methane ligands (TpmPR2, 2a-c, with R = Ph, nBu, iPr) are presented. The reaction of 2a-c with [Rh(CO)2Cl]2 furnished N,P-heterochelate carbonyl complexes (3a-c), which were used to quantify the donor abilities of the ligands via IR spectroscopy. The coordination flexibility was demonstrated by treating representative members of this new ligand class with [CpRu(acn)3][PF6] (acn = acetonitrile), [(tht)AuCl] (tht = tetrahydrothiophene) and [Pd(allyl)Cl]2 providing either a N,N,P-heteroscorpionate complex (4) or the P-coordinated complexes (5,6) without any involvement of the pyrazolyl entities. With 2a and [Pd(cod)Cl2], another P,N-heterochelate complex (7) was obtained, which served as a precursor for a heterobimetallic complex containing palladium and copper (8). Detailed NMR spectroscopic and X-ray crystallographic investigations have been performed on all new complexes.