Syntheses of nonracemic ortho-mercurated and ortho-ruthenated complexes of 2-[tricarbonyl(η6-phenyl)chromium]pyridine

The reaction of racemic orthomercurated (eta(6)-arene)tricarbonylchromium complexes with bis [(eta(6) -eymene)ruthenium(II)dichloride] affords the corresponding dinuclear (Cr,Ru) products with moderate yields, which have been satisfactorily characterized by X-ray diffraction analysis. The synthesis of nonracemic orthomercurated (eta(6) -arene)tricarbonylchromium complexes has been attempted starting from enantio-enriched homo- and heteroleptic Pd-(II) bischelated complexes. Both enantiomers of ortho-mercurated 2-[tricarbonyl( eta(6) -phenyl)chromium] pyridine have been synthesized by reaction of a heteroleptic Pd(II) bischelated with HgCl2. The two mercury(II) complexes were also submitted to a transmetalation reaction with bis [(eta(6) -cymene)ruthenium(II)dichloride] and yielded the corresponding nonracemic (Cr, Ru) products, with enantiomeric excesses ranging from 82 to 89% as suggested by H-1 NMR analyses in the presence of BINPHAT anion.