Synthesis and characterization of [HRu(CO)(CH3CN)(TPPTS)3]BF4: Catalytic properties in the aqueous-biphasic hydroformylation of olefins

The new water soluble complex [HRu(CO)(CH3CN)(TPPTS)3]BF4 (TPPTS = tris[(m-sulfonated)phenyl]phosphine P(m-C6H4SO3Na)3) has been synthesized by ligand exchange techniques from the corresponding PPh3 derivative in a methoxyethanol–water mixture. The new complex was characterized by FTIR, UV–vis, and 1H NMR and 31P {1H} NMR spectroscopy and used as catalyst precursor for the aqueous biphasic hydroformylation of several olefins and their mixtures under moderate reaction conditions. The catalytic activity order found was: 1-hexene > allylbenzene > 2,3-dimethyl-1-butene > styrene > cyclohexene. The sulphur tolerance of this complex was also investigated using thiophene as a model molecule; it was found that the new complex maintains its activity when the thiophene concentration is below 500 ppm. The mercury test in independent experiments showed no interference of the Hg at all with the evolution of the reaction, demonstrating that the catalysis is performed by molecular species. The recyclable nature of the complex was demonstrated during 1-hexene hydroformylation where at the end of each catalytic reaction all the metal remains in the aqueous phase.

Graphical abstractThe synthesis and characterization of the water soluble complex [HRu(CO)(CH3CN)(TPPTS)3]BF4 is described. This complex was obtained by ligand exchange procedures and characterized by FT-IR 1H NMR, 1H {31P} NMR and 31P NMR techniques. These analyses confirmed that the ruthenium complex has a hexacoordinated arrangement. The complex was used as a catalytic precursor for the aqueous biphasic hydroformylation of several olefins and olefins mixtures. The observed catalytic activity was 1-hexane > allylbenzene > 2,3-dimethyl-1-butene > styrene > cyclohexene. The catalyst was shown to be resistant to sulphur positions. Figure optionsDownload full-size imageDownload high-quality image (12 K)Download as PowerPoint slide