The reaction of AlMe3 with (t-Bu3PN)(2)TiMe2 1 proceeds via competitive reactions of metathesis and C-H activation leading ultimately to two Ti complexes: [(mu(2)-t-Bu3PN)Ti(mu-Me)(mu(4)-C)(AlMe2)(2)](2) 2, [(t-Bu3PN)Ti(mu(2)-t-Bu3PN)(mu(3)-CH2)(2)(AlMe2)(2)(AlMe3)] 3, and the byproduct (Me2Al)(2)(u-CH3)(u-NP(t-Bu-3)) 4. X-ray structural data for 2 and 3 are reported. Compound 3 undergoes thermolysis to generate a new species [Ti(mu(2)-t-Bu3PN)(2)(mu(3)-CH2)(mu(3)-CH)(AlMe2)(3)] 5. Monitoring of the reaction of 1 with AlMe3 by P-31{H-1} NMR spectroscopy revealed intermediates including (t-Bu3PN)TiMe3 6. Compound 6 was shown to react with AlMe3 to give 2 exclusively Kinetic studies revealed that the sequence of reactions from 6 to 2 involves an initial C-H activation that is a second-order reaction, dependent on the concentration of Ti and Al. The second-order rate constant k(1) was 3.9(5) x 10(-4) M-1 s(-1) (DeltaH(not equal) = 63(2) kJ/mol, DeltaS(not equal) = -80(6) J/mol.K). The rate constants for the subsequent C-H activations leading to 2 were determined to be k(2) = 1.4(2) x 10(-3) s(-1) and k(3) = 7(1) x 10(-3) s(-1). Returning to the more complex reaction of 1, the rate constant for the ligand metathesis affording 4 and 6 was k(met) = 6.1(5) x 10(-5) s-1 (DeltaH(not equal) = 37(3) kJ/mol, DeltaS(not equal) = -203(9) J/mol.K). The concurrent reaction of 1 leading to 3 was found to proceed with a rate constant of k(obs) of 6(1) x 10(-5) s(-1) (DeltaH(not equal) = 62(5) kJ/mol, DeltaS(not equal)= -118(17) J/mol.K). Using these kinetic data for these reactions, a stochastic kinetic model was used to compute the concentration profiles of the products and several intermediates with time for reactions using between 10 and 27 equivalents of AlMe3. These models support the view that equilibrium between 1.AlMe3 and 1.(AlMe3)(2) accounts for varying product ratios with the concentration of AlMe3. In a similar vein, similar equilibria account for the transient concentrations of 6 and an intermediate en route to 3. The implications of these reactions and kinetic and thermodynamic data for both C-H bond activation and deactivation pathways for Ti-phosphinimide olefin polymerization catalysts are considered and discussed.