Wilkes Masterpieces and the Naked Nickel

PMe2(Ment), a mixture of the corresponding diastereoisomers (all-trans-Ci2H18)Ni[PMe2(Ment)] was obtained, which could be separated by fractional crystallization. Abstraction of the chiral phosphine by the TT-allyl nickel(II) dimer [(r 3-C3H5)NiBr]2 led to the two enantiomers of 12, which do not race-mize at room temperature [103], They are probably the simplest optically active transition metal complexes known. 

8 Stone and the Family of Olefin Palladium(O) and Platinum(O) Compounds 

This expectation was fulfilled and John Spencer could prepare 19 via the new route in about 70% yield [117]. The platinum(O) compound was found to be oxidatively and thermally more stable than its nickel counterpart 14, and the dry solid could even be handled in air. As shown crystallographically, the metal atom in 19 is, analogous to 14, in a distorted tetrahedral environment as a consequence of the disposition of the four C=C double bonds. The bite angle 

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