CARACTERIZACION ESPECTROSCOPICA Y ANALISIS TERMICO DE LOS COMPLEJOS TRIFENILFOSFINA-RUTENIO(II) CONTENIENDO EL LIGANDO 2,6-DIMETILPIRAZINA Y OTROS N-HETEROCICLICOS

the complexes [rucl2(2,6-dmpz)2(pph3)2] and [rucl2(co)(pph3)2(n-het)] (n-het is imidazol (imz) 2,6-dimethylpyrazine (2,6-dmpz) and pyrazine (pz)) pph3 = triphenilphosfine), were synthized from rucl2(pph3)3 and a n-heterocyclic ligand. the complexes were characterized by spectroscopic techniques. the vibrational spectrum of [rucl2(2,6-dmpz)2(pph3)2] indicat that chlorine atoms are in cis position. the spectrum is from 31p-nmr indicated that phosphines are in position trans. the electronic spectra of these complexes exhibited intense bands of charge transfer assigned to the transitions of the occupied dp orbitals of ruthenium to the empty pp * orbitals of the n-heterocyclic rings. the curve of dsc (differential scanning calorimetryc) indicates that the complexe dichlorobis(2,6-dimethyilpirazine)bis(triphenylphosphine)ruthenium(ii) suffers an exothermic phase transition at 231 0c. from the tga the exothermic phase transition is due to a loss of mass that is characterized as to tha dissociation of one of 2,6-dmpz and a pph3. the thermal studies of the complexes of the type rucl2(co)(pph3)2(n-het), where n-het is a 2,6-dmpz, imz and pz, by dsc and tga indicate that thermal stability of ths complexes depend on the nucleophilicity of the nitrogen ring.