Metallionen und H 2 O 2 . IV . Über Struktur und Aktivität der den H 2 O 2 ‐Zerfall katalysierenden Cu 2+ ‐Komplexe. II. Einfluss der Zahl der freien Koordinationsstellen

The Cu 2+ chelates of the bidentate ligands 2,2′‐bipyridine (I; [2]), N, N′‐diglycyl‐1,5‐diaminopentane (VI), ethylenediamine (II; [2]), glycine (V) and pyrophosphate (III; [2]) are found–parallel to the spectrochemical series–to be more active in catalysis of H 2 O 2 decomposition than the chelates of the terdentate ligands–antiparallel to the spectrochemical series–iminodiacetic acid (IX), glycylglycine (VIII), 2, 2′‐diaminodiethylamine (VII) and 2, 2′, 2″‐terpyridine (IV; [2]), the activity decreasing in the given series. If all four coordination positions of Cu 2+ are engaged ( e.g. complex with N, N′‐di‐(2‐aminoethyl)‐ethylenediamine (X)) the complex is inactive. The catalytic activity of the Cu 2+ ‐chelates is parallelled by the tendency to form ternary peroxo complexes.