Síntese e caracterização de complexos fosfínicos/diimínicos de rutênio II

Abstract

This work describes the synthesis and characterization of three new mononuclear ruthenium (II) complexes containing symmetric diimine ligands and monophosphine. The complexes were obtained by replacing a PPh3 group (triphenylphosphine) with a diiminic ligand, in the sphere of coordination of the precursor complex [RuCl2(PPh3)3], in an argon atmosphere, using toluene as solvent. The diimine ligands used in the synthesis of these complexes have methyl groups in the ortho and / or para positions of the aromatic rings and were synthesized from condensation reactions of anilines and glyoxal (dialdehyde with formula C2H2O2) in the presence of water and isopropanol as a solvent. Three other diimic ligands have also been synthesized which have methyl, ethyl and isopropyl groups in the ortho or para positions of the aromatic rings and which are promising to synthesize new combination complexes due to their different steric characteristics. The results of the electronic absorption spectroscopy in the UV / Vis region, aided by DT-DFT calculations, and the analysis by vibrational spectroscopy in the IV region, suggest the coordination of the diiminic ligand to the precursor complex. The electrochemical analyzes by cyclic voltammetry for the complexes showed values of oxidation and reduction potentials consistent with their structures. The 1H NMR spectra for the diiminic ligands showed signals close to 8.44 and 8.11 ppm, which refer to the hydrogen nucleus linked to the iminic carbons. The 13C NMR spectra for the diiminic ligands showed signals close to 163.50 and 159.00 ppm, which refer to the carbon nucleus of the iminic groups, directly linked to the nitrogen atoms. The 31P {1H} NMR spectra for the [RuCl2(PPh3)2(2,4,6-Trime)] and [RuCl2(PPh3)2(2,6-Dime)] complexes showed that the phosphines are magnetically equivalentes and, therefore, these complexes have cis nomenclature directed to chlorine.