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)(2)L] (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)(3)tdma] (tdma = tris[3,5-dimethyl-1-pyrazolyl)methyl]amine (6), have been prepared, and characterised by elemental analyses, conductivity, IR, H-1 and C-13 NMR spectroscopy and liquid mass spectrometry (with electrospray and APCI interfaces). The H-1 NMR spectra and molar conductance of [Rh2Cl2(cod)(2)L] 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)(3)tdma] 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 C-3-symmetry. (C) 2004 Elsevier B.V. All rights reserved.