A ligand represented by I: wherein R is selected independently for each occurrence from the group consisting of (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, (C 5 -C 7)aryl, 3-10 membered heteroaryl having 1-4 heteroatoms, (C 5 -C 7)aryl(C 1 -C 6)alkyl, heteroaryl(C 1 -C 6)alkyl wherein the heteroaryl is a 3-10 membered ring having 1-4 heteroatoms, and -(CH 2) m -R 10; R 1, R 2, R 3, and R 4 are selected independently for each occurrence from the group consisting of hydrogen, halogen, (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, 3-10 membered heterocycloalkyl having 1-4 heteroatoms, (C 5 -C 7)aryl, 3-10 membered heteroaryl having 1-4 heteroatoms, (C 5 -C 7)aryl(C 1 -C 6)alkyl, heteroaryl(C 1 -C 6)alkyl wherein the heteroaryl is a 3-10 membered ring having 1-4 heteroatoms, -OR 11, -Si(R 11) 3, and -(CH 2) m -R 10; or any two adjacent instances of R 1, R 2, R 3 and R 4, taken together with the carbons to which they are bound, form a five- or six-membered substituted or unsubstituted aryl or heteroaryl ring; provided that at least two of R 1, R 2, R 3 and R 4 are -OR 11; R 5 and R 9 are selected independently for each occurrence from the group consisting of hydrogen, (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, and 3-10 membered heterocycloalkyl having 1-4 heteroatoms; R 7 is selected independently for each occurrence from the group consisting of (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, and 3-10 membered heterocycloalkyl having 1-4 heteroatoms; R 6 and R 8 are selected independently for each occurrence from the group consisting of hydrogen, (C 1 -C 6)alkyl and halogen; R 10 represents an unsubstituted or substituted (C 5 -C 7)aryl, (C 3 -C 10)cycloalkyl, (C 3 -C 10)cycloalkenyl, 3-10 membered heterocycle having 1-4 heteroatoms, or polycycle, wherein polycycle refers to two or three rings, each ring independently selected from the group consisting of cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and heterocyclyls, in which two or more carbons are shared by adjoining rings; R 11 is selected independently for each occurrence from the group consisting of (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, and 3-10 membered heterocycloalkyl having 1-4 heteroatoms; m is independently for each occurrence an integer in the range 0 to 8 inclusive; and the ligand is achiral or, when chiral, is a single stereoisomer or a mixture of stereoisomers. R is selected independently for each occurrence from the group consisting of (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, (C 5 -C 7)aryl, 3-10 membered heteroaryl having 1-4 heteroatoms, (C 5 -C 7)aryl(C 1 -C 6)alkyl, heteroaryl(C 1 -C 6)alkyl wherein the heteroaryl is a 3-10 membered ring having 1-4 heteroatoms, and -(CH 2) m -R 10; R 1, R 2, R 3, and R 4 are selected independently for each occurrence from the group consisting of hydrogen, halogen, (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, 3-10 membered heterocycloalkyl having 1-4 heteroatoms, (C 5 -C 7)aryl, 3-10 membered heteroaryl having 1-4 heteroatoms, (C 5 -C 7)aryl(C 1 -C 6)alkyl, heteroaryl(C 1 -C 6)alkyl wherein the heteroaryl is a 3-10 membered ring having 1-4 heteroatoms, -OR 11, -Si(R 11) 3, and -(CH 2) m -R 10; or any two adjacent instances of R 1, R 2, R 3 and R 4, taken together with the carbons to which they are bound, form a five- or six-membered substituted or unsubstituted aryl or heteroaryl ring; provided that at least two of R 1, R 2, R 3 and R 4 are -OR 11; R 5 and R 9 are selected independently for each occurrence from the group consisting of hydrogen, (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, and 3-10 membered heterocycloalkyl having 1-4 heteroatoms; R 7 is selected independently for each occurrence from the group consisting of (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, and 3-10 membered heterocycloalkyl having 1-4 heteroatoms; R 6 and R 8 are selected independently for each occurrence from the group consisting of hydrogen, (C 1 -C 6)alkyl and halogen; R 10 represents an unsubstituted or substituted (C 5 -C 7)aryl, (C 3 -C 10)cycloalkyl, (C 3 -C 10)cycloalkenyl, 3-10 membered heterocycle having 1-4 heteroatoms, or polycycle, wherein polycycle refers to two or three rings, each ring independently selected from the group consisting of cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and heterocyclyls, in which two or more carbons are shared by adjoining rings; R 11 is selected independently for each occurrence from the group consisting of (C 1 -C 6)alkyl, (C 3 -C 10)cycloalkyl, and 3-10 membered heterocycloalkyl having 1-4 heteroatoms; m is independently for each occurrence an integer in the range 0 to 8 inclusive; and the ligand is achiral or, when chiral, is a single stereoisomer or a mixture of stereoisomers.