| abstract |
(57) [Problem] To provide a stable oxygen carrier exhibiting high oxygen transport efficiency without externally adding an axial base ligand. SOLUTION: The following general formula (I): (Where n is the number of methylene groups, R 1 is an alkylene group, R 2 Is a substituent that does not inhibit the coordination of imidazole to the central metal, M is a transition metal ion or hydrogen atom in the fourth to fifth periods, X − is a halogen ion selected from a chloride ion, a bromine ion, and an iodine ion, and m is 0 or an integer obtained by subtracting 2 from the valence of the metal ion). |