Complexes Derived from Unconjugated Dienes

Complexes Derived from Unconjugated Dienes Nickel, Platinum, and Palladium.— N.m.r. studies show that complexes of the formula (diene)MCla (M = Pt or Pd) and [(diene)RhCl]a (diene = bicyclo[3,3,1 ]-nona-2,6-diene) have two identical metal-olefin bonds, which are asymmetric with respect to the two olefinic carbon atoms. " The complex (cod)PtCla reacts readily with MeaSnR compounds (R=aryl) to give both mono- and di-aryl complexes of the formula (cod)PtCla-a (aryl)3 (x=l or 2) a similar reaction occurs with the [(cod)PtCl(PMeaPh)]+ cation to yield the mono-aryl product. The cod may be easily displaced from these complexes by ligands such as... 

The cyclooctatriene mixture also reacts with 4r-C5HsC CO)2 to give two isomers of formula n CgHsCo-ir-CgHio (97,108,117). In this case, the less stable isomer, a red solid m.p. 46° C, is derived from bicyclo[4.2.0]octa-2,4-diene, while the more stable isomer, a yellow solid m.p. 98° C, is derived from cycloocta-l,3,5-triene. NMR studies show that, in the latter complex, coordination takes place via a pair of unconjugated, chelate double bonds, the olefin being in a tub conformation (XXXI). In agreement with this, the protonated species is very unstable. This work, and the related studies on... 

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