Four Soft Donors and a Hard Centre: Rhodium Complexes of a Novel Tetrakis(NHC)-Encapsulated Crown Ether Ligand
✍ Scribed by Sumi Shrestha; Carolina Gimbert-Suriñach; Mohan Bhadbhade; Stephen B. Colbran
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 455 KB
- Volume
- 2011
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
2,3,13,14‐Tetrakis(bromomethyl)dibenzo‐18‐crown‐6 (1) has been demonstrated to be a versatile synthetic intermediate for constructing multinucleating ligands with a hard‐donor, crown ether centre. By using this intermediate, novel salts of tetrakis(imidazoliomethyl)dibenzo‐18‐crown‐6, [H~4~L^1^]X~4~ (2: X^–^ = Br^–^; 4: X^–^ = PF~6~^–^), and tetrakis(benzimidazoliomethyl)dibenzo‐18‐crown‐6, [H~4~L^2^]X~4~ (3: X^–^ = Br^–^; 5: X^–^ = PF~6~^–^), were prepared. These salts are precursors to novel tetrakis(N‐heterocyclic carbene) complexes spanned by a crown ether bridge capable of binding various hard metal ions. Thetetrakis(imidazoliomethyl) salt 4 was used to prepare the bimetallic rhodium complexes [{(cod)Rh}~2~(μ‐L^1^)][PF~6~]~2~ (6) and [{(CO)~2~Rh}~2~(μ‐L^1^)][PF~6~]~2~ (7). These complexes selectively bind alkali metal ions.