CATALYSIS BY COMPLEXES .37. ETA-3,ETA-2,ETA-2-DODECA-2(E),6(E),10(Z)-TRIEN-1-YLNICKEL(II)-TETRAKIS[3,5-BIS(TRIFLUOROMETHYL)PHENYLBORATE AS A CATALYST FOR 1,4-CIS-POLYMERIZATION OF BUTADIENE - ACTIVITY AND SELECTIVITY OF C-12-ALLYLNICKEL(II) CATION

The complex given in the title was synthesized from eta-3,eta-2,eta-3-dodeca-2(Z),6(E),10(Z)-triene-1,12-diyl-nickel(II) by partial protolysis with the acid HX.2Et2O or with the dimethylanilinium salt PhNMe2H+X- of the "non-coordinating" tetrakis[3,5-bis(trifluormethyl)phenyl] borate anion X and was characterized by elemental analysis, C-13 NMR spectroscopy and conductivity measurements in solution. The complex catalyses the 1,4-cis-polymerization of butadiene with high activity and selectivity. Thus the importance of the allylnickel(II) cation stabilized by double bond coordination from the growing chain has been established for the catalysis of the 1,4-cis-polymerization, and a transition state of the insertion reaction without participation of the anion must be taken into consideration.