[1] CSIC, Inst Catalisis & Petroleoquim, Catalyt Spect Lab, E-28049 Madrid, Spain
[2] Univ Nacl Educ Distancia, Fac Ciencias, Dpto Quim Inorgan & Quim Tecn, E-28040 Madrid, Spain
[3] Univ Extremadura, Fac Ciencias, Dpto Quim Organ & Inorgan, Badajoz, Spain