Certain N,N'-dipyridine copper or manganese complexes

摘要

The present invention relates to compositions useful for the detection of oxygen in a humid medium, characterized in that they comprise at least one complex of the formula (LMX).sub.n in which the ligand L is selected from among the groups: ##STR1## where: R represents Cl,Br,NO.sub.2,C.sub. 1-4 -alkoxyl, C.sub.1-4 -alkyl,PPm and p are comprised between 0 and 3,PPq is comprised between 0 and 2,P Pthe substituent R on the pyridine nuclei never occupying a position neighboring the nitrogen atom,P PX=Cl,Br,I,NO.sub. 3,C10.sub.4,PPM represents Cu or Mn, andPP n is equal to 1 or 2,PPas colored indicator of the presence of oxygen in a humid medium, in solution in an acceptable solvent.PPThe present invention also relates to a process for preparing such compositions, and detectors of the presence of oxygen comprising them.