Transition metal complexes with (pyridyl)imidazole ligands
View Patent ↗Novel transition metal complexes of iron, cobalt, ruthenium, osmium, and vanadium are described. The transition metal complexes can be used as redox mediators in enzyme-based electrochemical sensors. The transition metal complexes include substituted or unsubstituted (pyridyl)imidazole ligands. Transition metal complexes attached to polymeric backbones are also described.
1. A complex having the formula:
wherein M is osmium;
L 1 has the formula:
wherein R 7 is a substituted or unsubstituted aryl or a substituted or unsubstituted C1–C12 alkyl;
R 8 is —H or a Cl alkyl; and
a combination of R 9 and R 10 forms a fused, saturated or unsaturated, 5- or 6-membered ring;
L 2 is a halide;
L and L′ are independently:
wherein R′ 1 is a substituted or unsubstituted C1–C6 alkyl;
R′ 3 and R′ 4 are independently —H; and
R a , R b , R c , and R d are independently —H or Cl alkyl;
c is a +1 or +2 charge;
X is an anion; and
d is a number of X sufficient to balance the charge c.
2. The complex of claim 1 , wherein R 7 is a C5 alkyl.
3. The complex of any one of claims 1 and 2 , wherein R 8 is methyl.
4. The complex of any one of claims 1 and 2 , wherein a combination of R 9 and R 10 forms a fused, saturated or unsaturated, 6-membered ring.
5. The complex of any one of claims 1 and 2 , wherein a combination of R 9 and R 10 forms a fused, unsaturated, 6-membered ring.
6. The complex of any one of claims 1 and 2 , wherein L 2 is —F, —Cl, or —Br.
7. The complex of any one of claims 1 and 2 , wherein L 2 is —Cl.
8. The complex of any one of claims 1 and 2 , wherein R′ 1 is a C1–C2 alkyl.
9. The complex of any one of claims 1 and 2 , wherein R′ 1 is a Cl alkyl.
10. The complex of any one of claims 1 and 2 , wherein each of R a and R c is —H.
11. The complex of any one of claims 1 and 2 , wherein each of R a , R b , and R c is —H.
12. The complex of any one of claims 1 and 2 , wherein each of R a , R b , R c , and R d is —H.
13. The complex of any one of claims 1 and 2 , wherein X is a halide.
14. The complex of any one of claims 1 and 2 , wherein X is chloride.
15. A complex having the formula:
wherein M is osmium;
L 1 has the formula:
wherein R 7 is a C1–C 12 alkyl;
R 8 is —H; and
a combination of R 9 and R 10 forms a fused, unsaturated, 6-membered ring;
L 2 is chloride;
L and L′ are independently:
wherein R′ 1 is methyl; and
R′ 3 , R′ 4 , R a , R b , R c , and R d are independently —H;
c is +2;
d is 2; and
X is chloride.
16. The complex of claim 15 , wherein R 7 is a C5 alkyl.
17. The complex of any one of claims 1 , 2 , 15 , and 16 , wherein at least one ligand selected from L, L′, L 1 and L 2 is coupled to a polymeric backbone.
18. The complex of claim 17 , wherein the polymeric backbone comprises at least one functional group that is a ligand of the complex.
19. The complex of claim 18 , wherein the functional group is selected from pyridine and imidazole groups.
20. A sensor comprising:
a working electrode;
a counter electrode;
an enzyme disposed proximate to the working electrode; and
the complex of any one of claims 1 , 2 , 15 , and 16 disposed proximate to the working electrode.
21. The sensor of claim 20 , wherein the complex is coupled to a polymeric backbone via at least one ligand selected from L, L′, L 1 and L 2 .
22. The sensor of claim 21 , wherein the polymeric backbone comprises at least one functional group that is a ligand of the complex.
23. The sensor of claim 22 , wherein the functional group is selected from pyridine and imidazole groups.
24. The sensor of claim 20 , wherein the complex is crosslinked on the working electrode.
25. The sensor of claim 20 , wherein the complex and the enzyme are crosslinked on the working electrode.