Square-planar carbonylchlororhodium(I) complexes containing trans-spanning diphosphine ligands as catalysts for the carbonylation of methanol
Author(s)
Date issued
2005
In
Helv. Chim. Acta
Vol
3
No
88
From page
478
To page
486
Subjects
crystal structure rhodium chloro carbonyl diphosphine complex carbonylation catalyst rhodium chloro carbonyl diphosphine complex
Abstract
The Rh(I) complexes trans-[Rh(diphos)(CO)Cl] [7 (diphos = I (pbpb)), , 8 (diphos = II (nbpb)), and 9 (diphos = III (cbpb))] were synthesized and used as catalysts for the carbonylation of MeOH to AcOH. The trans coordination imposed by the rigid C-spacer framework of the diphos ligands pbpb, nbpb, and cbpb, demonstrated by 31P-NMR and IR spectroscopy of 7-9 and unambiguously confirmed by single-crystal x-ray structure anal. of 7, improved the thermal stability of the Rh(I) system under carbonylation conditions and, hence, the catalytic performance of the complexes. For the catalytic carbonylation of MeOH, the active catalyst could be prepd. in situ from the mixt. of [Rh(CO)2Cl]2 and the corresponding diphos ligand pbpb, nbpb, or cbpb, giving the same results as carbonylation in the presence of the isolated complexes 7, 8 or 9. The highest activity was obsd. for complex 7 (or the mixt. [Rh(CO)2Cl]2/pbpb), the catalytic turnover no. (TON) being 950 after 15 min (170°, 22 bar). [on SciFinder(R)]
Publication type
journal article