Transition metal complexes of tris(aminomethyl)phosphine oxide (tampo) – Thermodynamic and X-ray diffraction studies

4 years ago

Transition metal complexes of tris(aminomethyl)phosphine oxide (tampo) – Thermodynamic and X-ray diffraction studies

$Transition metal complexes of tris(aminomethyl)phosphine oxide (tampo) – Thermodynamic and X-ray diffraction studies$

The coordination behaviour of tris(aminomethyl)phosphine oxide (tampo) to selected transition metal ions was studied. In the case of Co(III), Ni(II) and Cu(II) complexes with metal-to-ligand 1:2 stoichiometry, bis(tripodal) tampo coordinations forming octahedral coordination spheres (in the case of Cu(II) complex with significant Jahn-Teller distortion) were found by X-ray diffraction analysis. Based on the potentiometric study, the tripodal coordination of the title ligand is also expected in solution. The stability of the metal complexes follows the Irving-Williams trend. Compared with the structurally “parent” 1,1,1-tris(aminomethyl)ethane (tame) ligand, the complexation of tampo occurs at a lower pH as the consequence of low ligand basicity [logK 1 =6.72(1), logK 2 =5.34(1) and logK 3 =3.82(1)], although the values of the stability constants of the metal complexes are relatively low.

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DOI: S0020169316305898