Synthesis, characterization and evaluation of fluorocarbon-containing rhodium(I) complexes for biphasic hydroformylation reactions

A series of fluorocarbon-containing salicylaldimine and iminophosphine Schiff base ligands and their Rh(I) complexes were synthesized. The synthesized ligands and complexes were characterized using different analytical and spectroscopic techniques including (1H, 13C{1H}, 31P{1H} and 19F{1H} NMR spectroscopy), FT-IR spectroscopy, mass spectrometry (ESI and EI), and elemental analysis. In addition, single crystal X-ray diffraction was also used for characterization for complexes 1 and 2. Consequently, the Rh(I) synthesized complexes were evaluated as catalyst precursors in the hydroformylation of 1-octene. The hydroformylation results showed that the iminophosphine and salicylaldimine-based catalyst precursors are active and selective under mild conditions, converting 1-octene to mostly aldehydes.

Graphical abstractA series of fluorocarbon-containing salicylaldimine and iminophosphine Schiff-base rhodium(I) complexes have been synthesized and characterized by NMR and IR spectroscopies, ESI-mass spectrometry, and elemental analyses. The molecular structures of two mononuclear complexes were determined by single crystal X-ray diffraction analysis. The rhodium complexes were evaluated as hydroformylation catalyst precursors under biphasic conditions and are active and chemoselective under mild conditions, but show poor recyclablity.Figure optionsDownload full-size imageDownload as PowerPoint slide