Kinetics, thermodynamics, and effect of BPh3 on competitive C-C and C-H bond activation reactions in the interconversion of allyl cyanide by [Ni(dippe)].

Reaction of [(dippe)Ni(micro-H)](2) with allyl cyanide at low temperature quantitatively generates the eta(2)-olefin complex (dippe)Ni(CH(2)=CHCH(2)CN) (1). At ambient temperature or above, the olefin complex is converted to a mixture of C-CN cleavage product (dippe)Ni(eta(3)-allyl)(CN) (3) and the olefin-isomerization products (dippe)Ni(eta(2)-crotonitrile) (cis- and trans-2), which form via C-H activation. The latter are the exclusive products at longer reaction times, indicating that C-CN cleavage is reversible and the crotononitrile complexes 2 are more thermodynamically stable than eta(3)-allyl species 3.

Cleavage of carbon-carbon bonds in aromatic nitriles using nickel(0).

The nickel(0) fragment [(dippe)Ni] has been found to react with a variety of aromatic nitriles. Initial pi-coordination to the C=C and Ctbd1;N bonds of 2-cyanoquinoline is found to lead ultimately to C-CN oxidative addition. 3-Cyanoquinoline reacts similarly, although no eta(2)-CN complex is observed.

Platinum(II) Complexes with Constructive and Destructive Interaction of Diphosphane and Binaphthol Ligands.

Eight molecules with different conformations are present in the unit cell of the Pt complex 1, which contains a mismatched arrangement of the chiral ligands Chiraphos and Binol (i.e., (S,S)-Chiraphos prefers the δ conformation, whereas (R)-Binol tends to induce the λ conformation in the diphosphane).