Abstract
The synthesis of a series of allene complexes (POCOP)Ir(ç2 -RC==CR') 1b-4b (POCOP = 2,6-bis(di-tert-butylphosphonito)benzene) via isomerization of internal alkynes is reported. We have demonstrated that the application of this methodology is viable for the isomerization of a wide variety of alkyne substrates. Deuterium labeling experiments support our proposed mechanism. The structures of the allene complexes 1b-4b were determined using spectroscopic data analysis. Additionally, the solid-state molecular structure of complex 2b was determined using single crystal X-ray diffraction studies and it confirmed the assignment of an iridium-bound allene isomerization product. The rates of isomerization were measured using NMR techniques over a range of temperatures to allow determination of thermodynamic parameters. Finally, we report a preliminary step towards developing a catalytic methodology; the allene may be liberated from the metal center by exposure of the complex to an atmosphere of carbon monoxide.
Original language | English |
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Pages (from-to) | 20195-20205 |
Number of pages | 11 |
Journal | Molecules |
Volume | 20 |
Issue number | 11 |
DOIs | |
State | Published - Nov 10 2015 |
Keywords
- Allenes
- Crystal structure
- Iridium
- Isolation
- Isomerization
- Pincer
- Synthesis