Organometallic rhodium (I) complexes with 1-alkylaminopyrazole ligands

New bidentate NN′ and tridentate NN′N 1-alkylaminopyrazoles were synthesized and characterized by elemental analyses and spectroscopic methods. The reaction of [RhCl(cod)2] (cod=cycloocta-1,5-diene) with one equivalent of L 1-alkylaminopyrazoles afforded Rh2Cl2(L)(cod)2 complexes (L=NN′ and NN′N). These rhodium (I) compounds were studied by IR, 1H- and 13C-NMR and liquid mass (with electrospray and APCI interfaces) spectrometries. The 1H-NMR spectra and molar conductances of these complexes suggested the presence of 1:1 electrolyte species, [Rh(L)cod]+ [RhCl2(cod)]−, in solution. A combined electrospray and APCI liquid mass spectroscopy study confirmed the presence of both [Rh(L)cod]+ and [RhCl2(cod)]− species in solution but the existence of a neutral molecular form of complexes in solution could not be demonstrated.