A metal-ligand complex according to formula: where: M is scandium, yttrium, or a lanthanide metal having an oxidation state of +3; X is a ligand chosen from (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -CH 2 Si(R C) 3-Q (OR C) Q, -Si(R C) 3-Q (OR C) Q, -OSi(R C) 3-Q (OR C) Q, -CH 2 Ge(R C) 3-Q (OR C) Q, -Ge(R C) 3-Q (OR C) Q, -P(R C) 2-W (OR C) W, -P (R C) 2-W (OR C) W, -N(R C) 2, -NH(R C), -N(Si(R C) 3) 2, -NR C Si(R C) 3, -NHSi(R C) 3, -OR C, -SR C, -NO 2, -CN, -CF 3, -OCF 3, -S R C, -S 2 R C, -OS 2 R C, -N=C(R C) 2, -N=CH(R C), -N=CH 2, -N=P(R C) 3, -OC R C, -C OR C, -N(R C)C R C, -N(R C)C H, -NHC R C, -C N(R C) 2, -C NHR C, -C NH 2, a halogen, B(R Y) 4, Al(R Y) 4, or Ga(R Y) 4, or a hydrogen, wherein each R C is independently a substituted or unsubstituted (C 1 -C 30)hydrocarbyl, or a substituted or unsubstituted (C 1 -C 30)heterohydrocarbyl, and each Q is 0, 1, 2 or 3, and each W is 0, 1, or 2; each R Y is -H, (C 1 -C 30)hydrocarbyl, or halogen atom; each T is independently Lewis Base; n is 0, 1, or 2, when n is 1, X and T are optionally linked, when n is 2, X and one of T are optionally linked; the metal-ligand complex is overall charge-neutral; each Z is independently chosen from -O-, -S-, -N(R N)-, or -P(R P)-, wherein the dotted line optionally defines a dative bond; R 1 and R 16 are independently selected from the group consisting of (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -Si(R C) 3, -Ge(R C) 3, -P(R P) 2, -N(R N) 2, -OR C, -SR C, -NO 2, -CN, -CF 3, R C S -, R C S 2 -, -N=C(R C) 2, R C C O-, R C OC -, R C C N -, (R C) 2 NC -, or halogen; 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, and R 15 are independently selected from -H, (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -Si(R C) 3, -Ge(R C) 3, -P(R P) 2, -N(R N) 2 -OR C, -SR C, -NO 2, -CN, -CF 3, R C S -, R C S 2 -, (R C) 2 C=N-, (R C) 2 P=N-, R C C O-, R C OC -, R C C N -, (R C) 2 NC -, and halogen; provided that when M is yttrium or a lanthanide metal, R 1 is not -H, phenyl or tert- butyl; and R 16 is not -H, phenyl or tert -butyl; L is (C 1 -C 40)hydrocarbylene or (C 1 -C 40)heterohydrocarbylene; and each R C, R P, and R N in formula is independently a (C 1 -C 30)hydrocarbyl, (C 1 -C 30)heterohydrocarbyl, or -H. M is scandium, yttrium, or a lanthanide metal having an oxidation state of +3; X is a ligand chosen from (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -CH 2 Si(R C) 3-Q (OR C) Q, -Si(R C) 3-Q (OR C) Q, -OSi(R C) 3-Q (OR C) Q, -CH 2 Ge(R C) 3-Q (OR C) Q, -Ge(R C) 3-Q (OR C) Q, -P(R C) 2-W (OR C) W, -P (R C) 2-W (OR C) W, -N(R C) 2, -NH(R C), -N(Si(R C) 3) 2, -NR C Si(R C) 3, -NHSi(R C) 3, -OR C, -SR C, -NO 2, -CN, -CF 3, -OCF 3, -S R C, -S 2 R C, -OS 2 R C, -N=C(R C) 2, -N=CH(R C), -N=CH 2, -N=P(R C) 3, -OC R C, -C OR C, -N(R C)C R C, -N(R C)C H, -NHC R C, -C N(R C) 2, -C NHR C, -C NH 2, a halogen, B(R Y) 4, Al(R Y) 4, or Ga(R Y) 4, or a hydrogen, wherein each R C is independently a substituted or unsubstituted (C 1 -C 30)hydrocarbyl, or a substituted or unsubstituted (C 1 -C 30)heterohydrocarbyl, and each Q is 0, 1, 2 or 3, and each W is 0, 1, or 2; each R Y is -H, (C 1 -C 30)hydrocarbyl, or halogen atom; (C 1 -C 40)heterohydrocarbyl, -CH 2 Si(R C) 3-Q (OR C) Q, -Si(R C) 3-Q (OR C) Q, -OSi(R C) 3-Q (OR C) Q, -CH 2 Ge(R C) 3-Q (OR C) Q, -Ge(R C) 3-Q (OR C) Q, -P(R C) 2-W (OR C) W, -P (R C) 2-W (OR C) W, -N(R C) 2, -NH(R C), -N(Si(R C) 3) 2, -NR C Si(R C) 3, -NHSi(R C) 3, -OR C, -SR C, -NO 2, -CN, -CF 3, -OCF 3, -S R C, -S 2 R C, -OS 2 R C, -N=C(R C) 2, -N=CH(R C), -N=CH 2, -N=P(R C) 3, -OC R C, -C OR C, -N(R C)C R C, -N(R C)C H, -NHC R C, -C N(R C) 2, -C NHR C, -C NH 2, a halogen, B(R Y) 4, Al(R Y) 4, or Ga(R Y) 4, or a hydrogen, wherein each R C is independently a substituted or unsubstituted (C 1 -C 30)hydrocarbyl, or a substituted or unsubstituted (C 1 -C 30)heterohydrocarbyl, and each Q is 0, 1, 2 or 3, and each W is 0, 1, or 2; each R Y is -H, (C 1 -C 30)hydrocarbyl, or halogen atom; each T is independently Lewis Base; n is 0, 1, or 2, when n is 1, X and T are optionally linked, when n is 2, X and one of T are optionally linked; the metal-ligand complex is overall charge-neutral; each Z is independently chosen from -O-, -S-, -N(R N)-, or -P(R P)-, wherein the dotted line optionally defines a dative bond; R 1 and R 16 are independently selected from the group consisting of (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -Si(R C) 3, -Ge(R C) 3, -P(R P) 2, -N(R N) 2, -OR C, -SR C, -NO 2, -CN, -CF 3, R C S -, R C S 2 -, -N=C(R C) 2, R C C O-, R C OC -, R C C N -, (R C) 2 NC -, or halogen; (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -Si(R C) 3, -Ge(R C) 3, -P(R P) 2, -N(R N) 2, -OR C, -SR C, -NO 2, -CN, -CF 3, R C S -, R C S 2 -, -N=C(R C) 2, R C C O-, R C OC -, R C C N -, (R C) 2 NC -, or halogen; 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, and R 15 are independently selected from -H, (C 1 -C 40)hydrocarbyl, (C 1 -C 40)heterohydrocarbyl, -Si(R C) 3, -Ge(R C) 3, -P(R P) 2, -N(R N) 2 -OR C, -SR C, -NO 2, -CN, -CF 3, R C S -, R C S 2 -, (R C) 2 C=N-, (R C) 2 P=N-, R C C O-, R C OC -, R C C N -, (R C) 2 NC -, and halogen; provided that when M is yttrium or a lanthanide metal, R 1 is not -H, phenyl or tert- butyl; and R 16 is not -H, phenyl or tert -butyl; L is (C 1 -C 40)hydrocarbylene or (C 1 -C 40)heterohydrocarbylene; and each R C, R P, and R N in formula is independently a (C 1 -C 30)hydrocarbyl, (C 1 -C 30)heterohydrocarbyl, or -H.