Strukturen der Alkalimetallsalze aromatischer, heterocyclischer Amide: Synthese und Struktur von Kronenether‐Addukten der Alkalimetall‐Carbazolide

Abstract

The synthesis of six alkali metal carbazolide crown ether complexes is reported: Potassium-carbazolide(18-crown-6) (1), rubidium-carbazolide(18-crown-6) (2), rubidium-carbazolide(15crown-5) (3), cesium-carbazolide(18-crown-6) (4), cesium-carbazolide-bis(15-crown-5) (5), and cesium-carbazolide-bis(benzo-15crown-5) (6). The complexes 1 to 6 were synthesized from the alkali metal carbazolide (obtained in solution by metalation of carbazole with KH or Rb-and Cs-hexamethyldisilazide) and the corresponding crown ether. The structures of 1, 3, 4, and 5 could be determi- Einleitung 1)Im Rahmen unserer systematischen Untersuchungen zur Struktur der Alkalimetallsalze heterocyclischer Amide berichteten wir kürzlich über die Synthese und Struktur von Kronenether-Komplexen der Alkalimetall-Pyrrolide und -Indolide [1,2]. In der vorliegenden Arbeit leisten wir nun einen Beitrag zur Synthese und Struktur der Alkalimetall-Carbazolide. Das Carbazolid-Anion (Abb. 1, rechts) ist verwandt mit dem Pyrrolid-und dem Indolid-Anion (Abb. 1, links, und 1, Mitte) und lässt sich wie letztere leicht durch Deprotonierung des neutralen NH-sauren Amins (hier: Carbazol) herstellen. Wie Pyrrolid und Indolid ist auch Carbazolid fähig, über das freie Elektronenpaar am Stickstoffatom eine dative N-Metall-σ-Bindung zu bilden. Dane-1581 ned by X-ray diffraction. Complex 1 is mononuclear, the carbazolide anion shows an η 1 (N)-coordination to the metal cation. The complexes 3 and 4 are dinuclear with a central metal 2 N 2 -ring. Compound 5 has a salt-like structure with a sandwich-like [Cs(15crown-5) 2 ] ϩ cation and an uncoordinated carbazolide anion.

Structural Studies of Cesium, Lithium/Cesium, and Sodium/Cesium Bis(trimethylsilyl)amide (HMDS) Complexes

“…This absence of structural information may be due to the increased reactivity of heavier alkali metals and the considerable hazards involved with their synthesis. As well as CsHMDS, other donor-free structurally characterized cesium secondary amide compounds, including salts of (trimethylsilyl)­(phenyldimethylsilyl)­amide, bis­(diphenylphosphanyl)­amide, 1,1-bis­(trimethylsilyl)-2-phenylhydrazide, carbazole, and N­(C 6 F 5 )­{C­(CF 3 ) 3 }, have been reported . To the best of our knowledge, only six cesium salts of the aforementioned utility amides have been structurally characterized.…”

Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes

“…In previous literature examples, increasing alkali metal ionic radius tends to favour the adoption of a multi‐hapto binding motif through the five‐membered condensed ring of the carbazolyl ligand 5. 7, 11 The behaviour of the K + ion within dimer 2 appears to be closer to that in the powder X‐ray diffraction structure of the unsolvated caesium carbazolyl complex Cs(NC 12 H 8 ), which in the main displays a combination of η 1 ‐nitrogen and η 6 ‐arene interactions in the solid state 8…”

Structure Determination of Unsolvated Potassium, Rubidium, and Cesium Carbazolates

“…Solid-state structures of solvated alkali-metal carbazolates have been determined by us and others. Dimeric and monomeric complexes are found, along with compounds with uncoordinated carbazolate anions. 6b,c, …”