Multilaterale Festkörpermetathesereaktionen zur Herstellung von Materialien mit Heteroanionen: das [Si(CN₂)₄]⁴⁻‐Ion

Abstract

Die Suche nach nichtoxidischen anorganischen Verbindungen hat über einfache Metallboride, -carbide, -nitride und -silicide hinaus zur Entwicklung von interessanten Materialien geführt, in deren Strukturen mehrere nichtmetallische Elemente miteinander kombiniert sind. Hierzu gehören gut bekannte Verbindungen wie Ti(C,N) [1] [7] Hartstoffe (BC 2 N), [8] Leuchtstoffe (Nitridosilicate), [9] Supraleiter (LuNi 2 (B 2 C), [10,11] La 3 Ni 2 (BN) 2 N), [12] Sensoren (Li 2 SiN 2 ), [13] ionische Flüssig-keiten und Leitsalze in Batterien (Li[B (CN) 4 ]). [14] ¾hnlich wie binäre Metallboride, -carbide, und -nitride können manche dieser Verbindungen über direkte Festkör-perreaktionen aus geeigneten Elementkombinationen (oder Vorstufenverbindungen) bei hohen Reaktionstemperaturen, z. B. bei 1600-1700 8C hergestellt werden, wie die Carbidonitridosilicate SE 2 [Si 4 N 6 C] mit SE = Tb, Ho, Er.[15] Eine Alternative zur Anwendung hoher Reaktionstemperaturen sind Festkörpermetathesereaktionen, die für Synthesen von Metallcarbiden und -nitriden gut belegt sind. [16, 17] Seit einiger Zeit werden Festkörpermetathesereaktionen auch zur Synthese von Nitridoboraten der Seltenerdelemente [18] (La 3 B 3 N 6 ), Carbodiimiden der Seltenerd- [19]

Crystallization of the Fundamental Tetracyanamidometallates Li4[Si(CN2)4] and Li4[Ge(CN2)4] from Polymeric Li‐T‐(NCN)‐I Precursors (T=Si, Ge)

“…Representative pseudo-binary members are characterized as M(CN 2 ) and M 2 (CN 2 ) 3 with M being a main group metal (e. g. Ca, [7] In, [8] Sn, [6] or Bi [9] ), a transition metal (e. g. Zr, Hf, [10,11] Cr, [12] Mn, [13] Fe, [14] Co, Ni [15] or Zn [16] ), or a rare-earth (RE) [1] metal. An attractive but less-common field of compounds within the chemistry of (NÀ C�N) 2À ions are tetracyanamidometallate compounds, evidenced by the [T(NCN) 4 ] nÀ ion, in which T represents a main group element such as Si, [17,18,19] Ge, [20] Al [21,22] or Ga. [23] The compounds ARE[Si(NCN) 4 ] (A = K, Rb, Cs; RE = rare earth) were reported to exhibit outstanding optical properties (photoluminescence and/or second harmonic generation = SHG) and to behave stable in air. So far, their preparations depart from appropriate mixtures of a hexafluorometallate, e. g. K 2 SiF 6 plus RECl 3 and Li 2 (CN 2 ) to yield KRE[Si(NCN) 4 ].…”

Synthesis and Characterization of the First Tetracyanamidogallate

“…SSM preparations of compounds that contain tetracyanamidometallate ions might be considered a starting point for the development of a combined solid‐state coordination chemistry 7–9. Some of these reactions require careful preparation conditions, because the compounds appear to be thermally labile, as expected for inorganic coordination compounds.…”

A Luminescent Material: La3Cl(CN2)O3 Doped with Eu3+ or Tb3+ Ions

“…Also oxide‐containing carbodiimide compounds are known for RE 2 O 2 (CN 2 )10–13 and RE 2 (CN 2 )(SiO 4 ) 14. Recently, tetracyanamidometal compounds were reported for Li M 2 [Al(CN 2 ) 4 ] ( M = Eu, Sr)15 and A( RE )[Si(CN 2 ) 4 ] (A = K, Rb, Cs),16 which can be prepared by SSM. Most rare earth carbodiimides are synthesized by the reaction of Li 2 (CN 2 ) with rare earth halides to yield LiCl or LiF as side products of the salt metathesis 7…”