Patent ID: 8912346

Claim:
A phosphine ligand, the ligand comprising two phenyl groups, a xanthene, the xanthene having an oxygen atom incorporated into a rigid ring structure consisting of two aromatic rings, and a linking phosphorous moiety, the ligand being represented by a formula as follows: wherein, R 1 are the same and are each H, linear, branched or cyclic C 1 -C 20 alkyl, C 6 -C 18 aryl, C 1 -C 20 alkoxy or polyether. All R 3 are the same or dissimilar, and are each H, linear, branched or cyclic C 1 -C 20 alkyl, C 6 -C 18 aryl, halogen, trifluoromethyl, C 1 -C 20 alkoxy, or C 1 -C 20 dialkylamino. X is a bridging moiety selected from a dimethyl-substituted carbon (—CMe 2 -) and silicon (—SiMe 2 ) atom.