Metal complexes of the tetradentate ligand bis(diacetyl-monoximeimino)propane 1,3 = [(DOH)2pn] are interesting in several respects. They are representatives of molecular systems containing very short hydrogen bonds; moreover, the organo-cobalt derivatives were reported as first examples of stable water-soluble compounds besides Vitamin B12coenzyme and alkylcobalamines1. From this point of view they were extensively investigated as models of Vitamin B122. However, vibrational data concerning these complexes are rather scarce: at our knowledge only a limited assignment was proposed by UHLIG and FRIEDRICH3for some Ni derivatives.