Abstract
Both the bisphosphine and bisphosphinite pincer complexes ( tBu4PCP)IrH2 and (tBu4POCOP)IrH2 can cocatalyze alkane metathesis in tandem with olefin metathesis catalysts, but the two complexes have different resting states during catalysis, suggesting that different steps are turnover-limiting in each case. This led to the hypothesis that a complex with intermediate properties would be catalytically more active than either of these two species. Accordingly, "hybrid" phosphine-phosphinite pincer ligands (PCOP) and the corresponding iridium complexes were synthesized (3c-e). In tandem with olefin-metathesis catalyst MoF12, (tBu4PCOP)IrH2 displays significantly higher activity for the metathesis of n-hexane than does (tBu4PCP)IrH 2 or (tBu4POCOP)IrH2. (tBu2PCOP iPr2)IrH4 (3d) is even more active (>30-fold more active than (tBu4POCOP)IrH2) and affords nearly 4.6 M alkane products after 8 h at 125 C.
Original language | English |
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Pages (from-to) | 2505-2514 |
Number of pages | 10 |
Journal | ACS Catalysis |
Volume | 3 |
Issue number | 11 |
DOIs | |
Publication status | Published - Nov 1 2013 |
Keywords
- alkane metathesis
- dehydrogenation
- homogeneous catalysis
- iridium
- pincer complexes
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)