Cobalt complexes chiral cyclopentadienyls

The first diastereomerically pure planar-chiral cyclopentadienyl-cobalt complexes have been synthesised by reaction of [CoCl(PPh3)3] with a (1,2,4-trisubstituted cyclopentadienyl) anion having a (-)-menthyl group, in the presence of diarylacetylenes. Removal of the menthyl group afforded the first optically pure enantiomers of planar-chiral cyclopentadienylcobalt conq>lexes.The molecular structure including absolute configuration of one species was established by single crystal X-ray analysis i. 

Finally, all three types of chirality were claimed to occur in the first optically pure planar-chiral cyclopentadienyl cobalt complex 329, which uniquely contained three different types of chirality, planar, carbon-centered, and helical chirality (Figure 64). ... 

Chiral Metal Atoms in Optically Active Organo-Transition-Metal Compounds, 18, 151 13C NMR Chemical Shifts and Coupling Constants of Organometallic Compounds, 12, 135 Compounds Derived from Alkynes and Carbonyl Complexes of Cobalt, 12, 323 Conjugate Addition of Grignard Reagents to Aromatic Systems, I, 221 Coordination of Unsaturated Molecules to Transition Metals, 14, 33 Cyclobutadiene Metal Complexes, 4, 95 Cyclopentadienyl Metal Compounds, 2, 365... 

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