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, H-1- and C-13-NMR and liquid mass (with electrospray and APCI interfaces) spectrometries. The H-1-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 bur the existence of a neutral molecular form of complexes in solution could not be demonstrated. (C) 2001 Elsevier Science B.V. All rights reserved.