Notizen / Notes [Li 2 (THF) 4 DAD] und [DAD — H][ZrCl 5 (THF)]: Neue Strukturvarianten phenylsubstituierter 1,4‐Diaza‐1,3‐dien‐Liganden

[Li 2 (THF) 4 DAD] and [DAD — H][ZrCl 5 (THF)]: New Types of Phenyl‐;Substituted 1,4‐Diaza‐1,3‐diene Ligands Two extreme situations in 1,4‐ d iaza‐1,3‐ d iene (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 [Li 2 (THF) 4 DAD] ( 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 ZrCl 4 · DAD ( 3a ) by HCl in THF gives the ionic complex [ZrCl 5 (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.