Rhodium complexes of tetradentate tripodal tripyridyl ligands: Phosphate, phosphate monoester, and an unexpected acetimidamide species

The complexes [Rh(N 4 )Cl 2 ]ClO 4 (N 4 = tpa, pmea, pmap, tepa) and [Co(pmea)Cl 2 ]ClO 4 have been prepared and characterised (tpa = tris(2-pyridylmethyl)amine, pmea = bis[(2-pyridyl)methyl]-2-[(2-pyridyl)ethyl]-amine, pmap = bis[2-(2-pyridyl)ethyl]-(2-pyridylmethyl)amine, and tepa = tris[2-(2-pyridyl)ethyl]amine), and the X-ray crystal structures of [Rh(pmea)Cl 2 ]ClO 4 , [Co(pmea)Cl 2 ]ClO 4 ‧0.61H 2 O, and [Rh(tepa)Cl 2 ]ClO 4 are reported. Reaction of the rhodium complexes with Na 3 PO 4 and Na 2 C 6 H 5 PO 4 gives chelated phosphate and phenylphosphate complexes for all but the [Rh( tpa )Cl 2 ] + starting material, as evidenced by Hi Res Mass Spectrometry and 31 P NMR spectroscopy. Reaction of the in situ -generated [Rh(pmap)Cl(MeCN)] 2+ ion with bis(cyclohexylammonium)-t-butylphosphate gives [Rh(pmap)Cl(N-cyclohexylacetimidamide)](ClO 4 ) 2 , which results from attack of cyclohexylamine at the nitrile C atom of coordinated MeCN. The X-ray crystal structure of this complex is reported.