| abstract |
Bidentate ligand of formula (I), R<SUP>1</SUP>R<SUP>2</SUP>M<SUP>1</SUP>-R-M<SUP>2</SUP>R<SUP>3</SUP>R<SUP>4 </SUP>wherein M<SUP>1 </SUP>and M<SUP>2 </SUP>each indenpendently represent P, As or Sb; R<SUP>1</SUP>, R<SUP>2</SUP>, R<SUP>3 </SUP>and R<SUP>4 </SUP>each independently represent the same or a different optionally substituted organic group and at least one of R<SUP>1</SUP>, R<SUP>2</SUP>, R<SUP>3 </SUP>and R<SUP>4 </SUP>contains a tertiary carbon atom through which the group is linked to M<SUP>1 </SUP>or M<SUP>2</SUP>; and R represents a bridging group based on a trimethylene group connecting M<SUP>1 </SUP>and M<SUP>2 </SUP>of which the middle carbon atom is double bonded to a non-metal element chosen from group 14, 15 or 16 of the periodic table of elements. Catalyst comprising this bidentate ligand and carbonylation process n which this catalyst is used. |