Patent ID: 7126031

Claim:
A ligand characterized by the general formula: wherein each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , and R 20 is independently selected from the group consisting of hydride, halide, and optionally substituted hydrocarbyl, heteroatom-containing hydrocarbyl, alkoxy, aryloxy, silyl, boryl, phosphino, amino, alkylthio, arylthio, thioxy, seleno, and nitro; optionally two or more R groups can combine together into ring structures, with such ring structures having from 3 to 100 atoms in the ring not counting hydrogen atoms; B is a bridging group having from one to 50 atoms not counting hydrogen atoms; X and X′ are the same or different and are independently selected from the group consisting of oxygen, sulfur, and —PR 30 —, where R 30 is selected from the group consisting of hydride, halide, and optionally substituted hydrocarbyl, heteroatom-containing hydrocarbyl, silyl, boryl, alkoxy, and aryloxy; Y and Y′ are the same or different and are independently selected from the group consisting of optionally substituted amino, phosphino, hydroxy, alkoxy, aryloxy, alkylthio, arylthio and thioxy.