Syntheses of Nonracemic Ortho-Mercurated and Ortho-Ruthenated Complexes of 2-[Tricarbonyl(η⁶-phenyl)chromium]pyridine

The reaction of racemic orthomercurated (η6-arene)tricarbonylchromium complexes with bis[(η6-cymene)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 (η6-arene)tricarbonylchromium complexes has been attempted starting from enantio-enriched homo- and heteroleptic Pd(II) bischelated complexes. Both enantiomers of ortho-mercurated 2-[tricarbonyl(η6-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[(η6-cymene)ruthenium(II)dichloride] and yielded the corresponding nonracemic (Cr, Ru) products, with enantiomeric excesses ranging from 82 to 89% as suggested by 1H NMR analyses in the presence of BINPHAT anion.外消旋邻汞化(η⁶-芳烃)三羰基铬配合物(racemic orthomercurated (η6-arene)tricarbonylchromium complexes)与双[(η⁶-伞花烃)二氯化钌(II)](bis[(η6-cymene)ruthenium(II)dichloride])发生反应，以中等收率得到相应的双核(Cr,Ru)产物，该产物经X射线衍射分析(X-ray diffraction analysis)得到了充分表征。研究人员以对映体富集的均配与异配钯(II)(Pd(II))双螯合配合物为起始原料，尝试合成非外消旋邻汞化(η⁶-芳烃)三羰基铬配合物。通过异配钯(II)(Pd(II))双螯合配合物与氯化汞(II)(HgCl2)的反应，成功合成了邻汞化2-[三羰基(η⁶-苯基)铬]吡啶的两种对映异构体。将这两种汞(II)配合物与双[(η⁶-伞花烃)二氯化钌(II)]进行转金属化反应(transmetalation reaction)，得到了相应的非外消旋(Cr,Ru)产物；经存在BINPHAT阴离子条件下的核磁共振氢谱(1H NMR)分析可知，其对映体过量值(enantiomeric excesses)介于82%至89%之间。