Electrochemical biosensor, or sensing membrane for electrochemical biosensor containing transition metal complex or oxidation-reduction polymer

A transition metal complex, which is a compound of the following Chemical formula 1, or a salt compound thereof:

• in the formula,
• M is one kind transition metal selected from the group consisting of Fe, Ru, and Os, and
• L is a bidentate ligand comprising pyridine;
• and one structure selected from the group consisting of pyrazole, tetrazole, oxadiazole and thiadiazole, and
• the pyridine is pyridine unsubstituted, or substituted with 1 to 4 selected from the group consisting of C1-4 alkyl group, C1-4 alkoxy group, —(CH2)-O—C1-4 alkyl group, —(CH2CH2)-O—C1-4 alkyl group, and C1-4 alkylamino group, and
• the one selected from the group consisting of pyrazole, tetrazole, and oxadiazole, is each independently unsubstituted, or substituted with 1 to 3 selected from the group consisting of C1-4 alkyl group, C1-4 alkoxy group, —(CH2)-O—C1-4 alkyl group, —(CH2CH2)-O—C1-4 alkyl group,
• and C1-4 alkylamino group, and
• R′4 is hydrogen or substituted or unsubstituted C1-4 alkyl, and
• n′ is an integer selected from 1 to 4, and
• a is 2 or 3, and
• in the substituted C1-4 alkyl group, C1-4 alkoxy group, —(CH2)-O—C1-4 alkyl group, —(CH2CH2)-O—C1-4 alkyl group or C1-4 alkylamino group, a hydrogen atom is substituted with a halogen atom of F, Cl, Br or I, cyano group, hydroxy group, thiol group, nitro group, amino group, imino group, azido group, amidino group, hydrazine group, hydrazono group, oxo group, carbonyl group, carbamyl group, ester group, ether group, carboxyl group or salt thereof, sulfonic acid group or salt thereof, or phosphoric acid or salt thereof, and
• X1 is one kind halogen atom selected from the group consisting of F, Cl, Br and I, and
• b is 0, 1, or 2, and
• c is an integer selected from 1 to 3, and
• X2 is one kind counter ion selected from the group consisting of F, Cl, Br, I and PF6, and
• d is 0, 1, 2, or 3.