Solid State Structures and Phosphine Exchange Reactions of (1-Me-Indenyl)(PR<INF>3</INF>)Ni−Cl

The complexes (1-Me-Ind)(PR<INF>3</INF>)Ni−Cl (Ind = indenyl; R = Me (<BO>2</BO>), Cy (<BO>3</BO>), Bu (<BO>4</BO>), and (CH<INF>2</INF>)<INF>2</INF>(CF<INF>2</INF>)<INF>5</INF>CF<INF>3</INF> (<BO>5</BO>)) have been prepared by the direct reaction of the corresponding (PR<INF>3</INF>)<INF>2</INF>NiCl<INF>2</INF> with Li(1-Me-Ind) or via phosphine exchange reactions with (1-Me-Ind)(PR‘<INF>3</INF>)Ni−Cl (R‘ = Ph (<BO>1</BO>) and Me). Solution NMR and single-crystal X-ray diffraction studies of the structures of <BO>2</BO> and <BO>3</BO> have allowed an analysis of the mode of coordination of the 1-Me-Ind ligand both in the solid state and in solution. Kinetic studies have shown that the substitution of PPh<INF>3</INF> in (1-Me-Ind)(PPh<INF>3</INF>)Ni−Cl by PCy<INF>3</INF> follows a second-order rate (associative mechanism) with the following kinetic parameters:  K<INF>2</INF> (× 10^-2 M^-1 s^-1) = 1.1 ± 0.1 at 233 K, 1.9 ± 0.4 at 245 K, 15 ± 2 at 284 K, 21 ± 2 at 293 K, and 34 ± 7 at 303 K; ΔH^&thermod; = 6.40 ± 0.07 kcal/mol; ΔS^&thermod; = −40 ± 4 eu. The implications of these results for the mechanisms of the polymerization reactions catalyzed by these complexes have been discussed.