Amphibactin siderophores have been isolated from oil-associated Vibrio spp. following the Deepwater Horizon oil spill, and from Alcanivorax borkumensis SK2.

Siderophores are generally considered to be microbial chelating compounds secreted by bacteria to facilitate uptake of iron(III). Certain siderophores, however, have a high affinity for other transition metal ions, including manganese(III), copper(II), molybdenum(VI), and vanadium(V). A new class of microbial ligands produced by methanotrophs, called chalkophores, is produced to facility copper uptake. This review considers the coordination of siderophores to Mn(III), Cu(II/I), Mo(VI) and V(V), and their stability constants relative to Fe(III), when available, as well as the coordination complexes of chalkophores to Cu(I).

The manganese catalyst, (1R,2R)-(-)- [1,2-cyclohexanediamino-N,N'-bis(3,5-di-t-