Transition metal complexes with (pyridyl)imidazole ligands

A test strip comprising:

• a working electrode;
• a counter electrode;
• wherein the working electrode comprises an analyte-responsive enzyme and a mediator complex, the mediator complex having the formula:
• wherein c is a negative, neutral, or positive charge represented by −1 to −5, 0, or +1 to +5, inclusive, respectively;
• d is a number of counter ions, X, from 0 to 5, inclusive;
• M is osmium or ruthenium;
• L1 is a methylamino substituted pyridine;
• L2 is a negatively charged ligand;
• and
• L and L′ are independently:
• wherein R′1 is a substituted or an unsubstituted alkyl, alkenyl or aryl;
• each of Ra and Rb is independently —H, —F, —Cl, —Br, —I, —NO2, —CN, —CO2H, —SO3H, —NHNH2, —SH, —OH, —NH2, or substituted or unsubstituted alkoxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoxy, alkylamino, dialkylamino, alkanoylamino, arylcarboxamido, hydrazino, alkylhydrazino, hydroxylamino, alkoxylamino, alkylthio, alkenyl, aryl, or alkyl;
• each of Re and Rd is independently —H, —F, —Cl, —Br, —I, —NO2, —CN, —CO2H, —SO3H, —NHNH2, —SH, —OH, —NH2, or substituted or unsubstituted alkoxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoxy, alkylamino, dialkylamino, alkanoylamino, arylcarboxamido, hydrazino, alkylhydrazino, hydroxylamino, alkoxylamino, alkylthio, alkenyl, aryl, or alkyl, or a combination of Re and Rd forms a saturated or an unsaturated 5- or 6-membered ring;
• and
• each of R′3 and R′4 is independently —H, —F, —Cl, —Br, —I, —NO2, —CN, —CO2H, —SO3H, —NHNH2, —SH, —OH, —NH2, or substituted or unsubstituted alkoxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoxy, alkylamino, dialkylamino, alkanoylamino, arylcarboxamido, hydrazino, alkylhydrazino, hydroxylamino, alkoxylamino, alkylthio, alkenyl, aryl, or alkyl, or a combination of R′3 and R′4 forms a saturated or an unsaturated 5- or 6-membered ring.