N‐Analogues of Metal Acetylacetonates: Bis(1,2,6,7‐tetracyano‐3, 5‐diimino‐3, 5‐dihydropyrrolizinido)metal( II ), (Metal = Fe, Ni, Cu, Zn); Crystal Structure of the Copper Derivative

The title compounds 2 contain new complex ligands. These compounds are formed from anion 1, which isomerizes in a metal-promoted reaction. An X-ray structure analysis was carried out for 2 (M = Cu). Complex 2 (M = Fe) can easily be reduced to the analogous diaminopyrrolizidine FeII complex.