Komplexe von Kupfer(I) mit Glyoxal‐bis‐N‐ t .‐butylimin

Formation of strongly colored complexes of Cu + with glyoxal‐bis‐(N‐ t ‐butylimin) (GLI) is observed in acetonitrile. Optical measurements reveal two complexes, Cu(GLI) + (ṽ max = 26.0 kK, δ = 2800) and Cu(GLI)   2 +(ṽ max = 19.3 kK, ε = 8530). The equilibrium constants (0.1M tetraethylammoniumperchlorate) are log K 1 = 3.9 and log K 2 = 2.5. The equilibrium data are confirmed by potentiometric measurements with a copper electrode. In O‐donor solvents, only the 1:2 complex is observed. Cu(GLI) 2 CIO 4 can be crystallized as a dark red solid which is stable towards atmospheric oxygen.