Nitrogen-Rich Compounds of the Lanthanoids: The 5,5′-Azobis[1H-tetrazol-1-ides] of some Yttric Earths (Tb, Dy, Ho, Er, Tm, Yb, and Lu)

✍ Scribed by Georg Steinhauser; Gerald Giester; Christoph Wagner; Nicolae Leopold; Johannes H. Sterba; Bernhard Lendl; Max Bichler

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: German
• Weight: 315 KB
• Volume: 92
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200800452

✦ Synopsis

Abstract

A set of N‐rich salts, 3–9, of the heavy lanthanoids (terbium, 3; dysprosium, 4; holmium 5; erbium, 6; thulium, 7; ytterbium, 8; lutetium, 9) based on the energetic 5,5′‐azobis[1__H__‐tetrazole] (H~2~ZT) was synthesized and characterized by elemental analysis, vibrational (IR and Raman) spectroscopy, and X‐ray structure determination. The synthesis of the lanthanoid salts 3–9 was performed by crystallization from concentrated aqueous solutions of disodium 5,5′‐azobis[1__H__‐tetrazol‐1‐ide] dihydrate (Na~2~ZT⋅2 H~2~O; 1) and the respective Ln(NO~3~)~3~⋅5 H~2~O and yielded large rhombic crystals of the type [Ln(H~2~O)~8~]~2~(ZT)~3~⋅6 H~2~O in ca. 70% of the theoretical yield. The compounds 3–9 are isostructural (triclinic space group P$\bar 1$) to the previously published yttrium salt 2; they show, however, a clear lanthanoid contraction of several crystallographic parameters, e.g., the cell volume or the LnO bond lengths of the Ln^3+^ ions and the coordinating H~2~O molecules. The lanthanoid contraction influences the strengths of the H‐bonds, which can be observed as a red shift by 4 cm^−1^ in the characteristic IR band, in particular from 3595 cm^−1^ (3) to 3599 cm^−1^ (9). In good agreement with previous works, 2–9 are purely salt‐like compounds without a coordinative bond between the tetrazolide anion and the Ln^3+^ cation.