The acetyl complex (η5-C5H4COCH3)Re(CO)3 reacts with KOtBu and an excess of appropriate ester to provide cyrhetrenyl-β-diketones complexes (η5-C5H4COCH2COR)Re(CO)3 (R = CF3, 1a; CH3, 1b; Ph, 1c). These new 1,3-diketones exist predominantly as enol tautomer, although a enol/keto mixture of approx. 10:1 is present in complexes 1b-c, in chloroform-d solution. The complexes have been characterized by spectroscopic techniques IR, 1H and 13C NMR and mass spectrometry. X-ray crystallography of complex 1b shows that only the enol form occurs in the solid state. The O-C-C-C-O fragment of the molecule is planar with asymmetric enolisation in the direction furthest from the cyrhetrenyl group.
- Organometallic ligand