Study of the reactivity of tris(pyrazolyl)amine and bis(pyrazolyl)amine ligands toward Rh(I). Crystal structure of [Rh3Cl3(cod)3tdma] · CH3CN (tdma=tris[(3,5-dimethyl-1-pyrazolyl)methyl]amine), a C3-symmetric compound

Rh(I) compounds [Rh2Cl2(cod)2L] (L=tris[(1-pyrazolyl)methyl]amine (tpma) (1), tris[2-(1-pyrazolyl)ethyl]amine (tpea) (2), tris[2-(3,5-dimethyl-1-pyrazolyl)ethyl]amine (tdea) (3), bis[2-(1-pyrazolyl)ethyl]amine (bpea) (4) and bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]amine (bdea) (5)), and [Rh3Cl3(cod)3tdma] (tdma=tris[3,5-dimethyl-1-pyrazolyl)methyl]amine (6), have been prepared, and characterised by elemental analyses, conductivity, IR, 1H and 13C NMR spectroscopy and liquid mass spectrometry (with electrospray and APCI interfaces). The 1H NMR spectra and molar conductance of [Rh2Cl2(cod)2L] complexes suggested the presence of 1:1 electrolyte species [Rh(cod)L]+ [RhCl2(cod)]− in solution. A combined electrospray and APCI liquid mass spectrometry study confirmed the presence of both [Rh(cod)L]+ and [RhCl2(cod)]− ions in solution, but the neutral molecular form of complexes in solution was not found. The crystal structure of complex [Rh3Cl3(cod)3tdma] was resolved by X-ray diffraction. The molecular structure is unusual and consists of a ligand tdma coordinated to three “RhCl(cod)” units with a C3-symmetry.