Notizen / Notes [Li2(THF)4DAD] und [DAD — H][ZrCl5(THF)]: Neue Strukturvarianten phenylsubstituierter 1,4‐Diaza‐1,3‐dien‐Liganden

[Li2(THF)4DAD] and [DAD — H][ZrCl5(THF)]: New Types of Phenyl‐;Substituted 1,4‐Diaza‐1,3‐diene Ligands Two extreme situations in 1,4‐diaza‐1,3‐diene (DAD) chemistry are described. Reaction of phenyl‐substituted DAD 1a — c with lithium in the molecular ratio of 1:2 affords in high yield the extremely air‐sensitive complexes [Li2(THF)4DAD] (2a — c). The structure of 2b has been determined by X‐ray diffraction. Each of the Li+ ions is coordinated by the two terminal N atoms of the s‐cis‐configurated DAD dianion and by two molecules of THF. Protonation of ZrCl4 · DAD (3a) by HCl in THF gives the ionic complex [ZrCl5(THF)][DAD — H] (4), which contains a protonated [DAD — H]+ cation. The structure of the sterically crowded N = C — C = N skeleton of the [DAD — H]+ cation is not influenced by the positive charge and adopts the unusual Z‐gauche‐Z conformation.