Ammonothermal Synthesis of Alkali-Alkaline Earth Metal and Alkali-Rare Earth Metal Carbodiimides: K5-xMx(CN2)(2+x)(HCN2)(1-x) (M = Sr, Eu) and Na4.32Sr0.68(CN2)(2.68)(HCN2)(0.32)

作者：Mallmann Mathias; Haeusler Jonas; Cordes Niklas; Schnick Wolfgang

来源：Zeitschrift fur Anorganische und Allgemeine Chemie, 2017, 643(23): 1956-1961.

DOI：10.1002/zaac.201700238

<jats:p>Alkali‐alkaline earth metal and alkali‐rare earth metal carbodiimides, namely K<jats:sub>5–</jats:sub><jats:italic><jats:sub>x</jats:sub>M<jats:sub>x</jats:sub></jats:italic>(CN<jats:sub>2</jats:sub>)<jats:sub>2+<jats:italic>x</jats:italic></jats:sub>(HCN<jats:sub>2</jats:sub>)<jats:sub>1–<jats:italic>x</jats:italic></jats:sub> (<jats:italic>x</jats:italic> = 0 – 1) (<jats:italic>M</jats:italic> = Sr, Eu) and Na<jats:sub>4.32</jats:sub>Sr<jats:sub>0.68</jats:sub>(CN<jats:sub>2</jats:sub>)<jats:sub>2.68</jats:sub>(HCN<jats:sub>2</jats:sub>)<jats:sub>0.32</jats:sub>, were synthesized under ammonothermal conditions in high‐pressure autoclaves. The structures of the three compounds can be derived from homeotypic K<jats:sub>5</jats:sub>H(CN<jats:sub>2</jats:sub>)<jats:sub>3</jats:sub> and Na<jats:sub>5</jats:sub>H(CN<jats:sub>2</jats:sub>)<jats:sub>3</jats:sub> by partial substitution of K<jats:sup>+</jats:sup> or Na<jats:sup>+</jats:sup>by Sr<jats:sup>2+</jats:sup> or Eu<jats:sup>2+</jats:sup>. The reactions were carried out in two step syntheses (<jats:italic>T</jats:italic><jats:sub>1</jats:sub> = 673 K, <jats:italic>T</jats:italic><jats:sub>2</jats:sub> = 823 K) starting from sodium or potassium azide, dicyandiamide and strontium or Eu(NH<jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>, respectively. The crystal structures were solved and refined from single‐crystal X‐ray diffraction data [K<jats:sub>4.16</jats:sub>Sr<jats:sub>0.84</jats:sub>(CN<jats:sub>2</jats:sub>)<jats:sub>2.84</jats:sub>(HCN<jats:sub>2</jats:sub>)<jats:sub>0.16</jats:sub>: space group <jats:italic>Im</jats:italic><jats:styled-content>3</jats:styled-content><jats:italic>m</jats:italic> (no. 229), <jats:italic>a</jats:italic> = 7.8304(5) Å, <jats:italic>Z</jats:italic> = 2, <jats:italic>R</jats:italic><jats:sub>1</jats:sub> = 0.024, <jats:italic>wR</jats:italic><jats:sub>2</jats:sub> = 0.052; K<jats:sub>4.40</jats:sub>Eu<jats:sub>0.60</jats:sub>(CN<jats:sub>2</jats:sub>)<jats:sub>2.60</jats:sub>(HCN<jats:sub>2</jats:sub>)<jats:sub>0.40</jats:sub>: space group <jats:italic>Im</jats:italic><jats:styled-content>3</jats:styled-content><jats:italic>m</jats:italic> (no. 229), <jats:italic>a</jats:italic> = 7.8502(6) Å, <jats:italic>Z</jats:italic> = 2, <jats:italic>R</jats:italic><jats:sub>1</jats:sub> = 0.022, <jats:italic>wR</jats:italic><jats:sub>2</jats:sub> = 0.049]. In contrast to the potassium carbodiimides, the sodium‐strontium carbodiimide was only synthesized as microcrystalline powder. The crystal structure was determined by powder X‐ray diffraction and refined by the Rietveld method [Na<jats:sub>4.32</jats:sub>Sr<jats:sub>0.68</jats:sub>(CN<jats:sub>2</jats:sub>)<jats:sub>2.68</jats:sub>(HCN<jats:sub>2</jats:sub>)<jats:sub>0.32</jats:sub>: space group <jats:italic>Im</jats:italic><jats:styled-content>3</jats:styled-content><jats:italic>m</jats:italic> (no. 229), <jats:italic>a</jats:italic> = 7.2412(1) Å, <jats:italic>Z</jats:italic> = 2, <jats:italic>R</jats:italic><jats:sub>wp</jats:sub> = 0.050]. The presence of hydrogencyanamide units ([HNCN]<jats:sup>–</jats:sup>) next to carbodiimide units ([CN<jats:sub>2</jats:sub>]<jats:sup>2–</jats:sup>) in all compounds was confirmed by FT‐IR spectroscopy.</jats:p>

• 出版日期2017-12-13