The present application discloses methods for producing a hexadentate bimetallic complex. A method may comprise contacting an acyliminepyridine compound, a metal salt, and an amine to form a mixture; and recovering the hexadentate bimetallic complex from the mixture. A method may also comprise forming at least one imine bond in the presence of a metal salt, metal complex, or combinations thereof. The metal salt may be iron, cobalt, nickel, chromium, vanadium or mixtures thereof. The acyliminepyridine compound may be a mono-acyliminepyridine in instances where the amine is a diamine. In such instances, the mono-acyliminepyridine compound to diamine molar ratio may be in the range of about 2:1; and the mono-acyliminepyridine compound to metal salt molar ratio may be in the range of about 1:1. Methods for preparing an acyliminepyridine compound for use in preparation of a hexadentate bimetallic complex are also disclosed. Such methods may comprise contacting a di-acylpyridine with a first amine to form a first mixture, and recovering the acyliminepyridine compound from the first mixture.