Synthesis and crystal structure of tricarbonyl(eta(6)-flavanone)chromium(0)

The reaction of flavanone with Cr(CO)6 gives two diastereomeric complexes 1 (cis) and 2 (trans) with the general formula [CT(CO)(3)(C15H12O2)] Due to the existence of an asymmetric carbon atom in the gamma-pyrone ring, the tw o isomers are chiral. Both complexes were characterized by elemental microa nalysis as well as by IR, NMR, UV, and mass spectroscopy. The X-ray analysi s of 1 has shown that the Cr(CO)(3) tripod is complexed to the benzene ring in an eclipsed conformation. The phenyl group adopts a cis configuration w ith respect to the tricarbonylchromium moiety, and the gamma-pyrone ring is oriented in a 1,2-diplanar conformation.