New Rare Earth Metal Complexes with Nitrogen-Rich Ligands: 5,5′-Bitetrazolate and 1,3-Bis(tetrazol-5-yl)triazenate—On the Borderline between Coordination and the Formation of Salt-Like Compounds
✍ Scribed by Patrick J. Eulgem; Axel Klein; Nicola Maggiarosa; Dieter Naumann; Roland W. H. Pohl
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 412 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
Abstract
From the two nitrogen‐rich ligands BT^2−^ (BT=5,5′‐bitetrazole) and BTT^3−^ (BTT=1,3‐bis(1__H__‐tetrazol‐5‐yl)triazene), a series of novel rare earth metal complexes were synthesised. For the BT ligand, a vast number of these complexes could be structurally characterised by single‐crystal XRD, revealing structures ranging from discrete molecular aggregates to salt‐like compounds. The isomorphous complexes [La~2~(BT)~3~]⋅14 H~2~O (1) and [Ce~2~(BT)~3~]⋅14 H~2~O (2) reveal discrete molecules in which one BT^2−^ acts as a bridging ligand and two BT groups as chelating ligands. The complexes, [M(BT)(H~2~O)~7~]~2~[BT]⋅x H~2~O (3–5), (M=Nd (3), Sm (4), and Eu (5)), are also isomorphous and consist of [M(BT)(H~2~O)~7~]^+^ ions in which only one BT^2−^ acts as a chelate ligand for each metal centre. [Tb(H~2~O)~8~]~2~[BT]~3~⋅x H~2~O (6) and [Er(H~2~O)~8~]~2~[BT]~3~⋅x H~2~O (7) are salt‐like compounds that do not exhibit any significant metal–nitrogen contacts. In the BTT–samarium compound 9, discrete molecules were found in which BTT^3−^ acts as a tridentate ligand with three SmN bonds.