Reactions of Diethylamine and Ethylene Catalyzed by Pt II or Pt 0 – Transalkylation vs. Hydroamination

PtBr 2 / n Bu 4 PBr (without solvent) or K 2 PtCl 4 /NaBr (in water) have been shown to efficiently catalyze the hydroamination of ethylene by aniline and are poor catalysts for the hydroamination of ethylene by diethylamine. A DFT study on the hydroamination mechanism indicates that the energetic span of the C 2 H 4 /Et 2 NH catalytic cycle is close to that of the C 2 H 4 /PhNH 2 cycle. The poor performance is attributed to rapid catalyst degradation with reduction to metallic platinum. Pt 0 , on the other hand, catalyzes a transalkylation process, partially transforming Et 2 NH into Et 3 N, EtNH 2 and NH 3 . This process is inhibited by C 2 H 4 . Mechanistic considerations for the Pt 0 ‐catalyzed transalkylation process are presented.