The bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]ether ligand (L1) reacts with [Rh(COD)(THF)2][BF4] generated in situ, giving [Rh(COD)(L1-κ2N,N)] [BF4] ([BF4]). The 1,5-cyclooctadiene ligand is displaced by carbon monoxide to generate [Rh(CO)2(L1)][BF4] ([BF4]) in which in the solid state, the ligand L1 adopts a facial κ3N,N,O bonding mode. This is the first example of such a coordination mode for this ligand, which generally prefers a 'T-shaped' meridional bonding mode. In solution [BF4] exists as a mixture of two isomers in rapid equilibrium on the NMR time scale, [Rh(CO)2 (L1-κ2N,N)]+ ([2a]+) and the major compound [Rh(CO)2(L1-κ 3N,N,O)]+[2b]+. [BF4] looses easily one molecule of carbon monoxide at room temperature leading to [Rh(CO)(L1-κ3N,N,O)] [BF4] ([BF4]) in which L1 adopts a 'T-shaped' meridional bonding mode. Carbon monoxide addition in solution regenerates rapidly [BF4]. The single-crystal X-ray structures of [BF4], [2b][BF4] and [BF4] are reported. © 2003 Elsevier B.V. All reserved.
|Journal||Journal of Organometallic Chemistry|
|Publication status||Published - 1 Oct 2003|
- Ether-pyrazole ligand
- Hemilabile ligand
- Rhodium(I) complexes
- Tridentate ligand