ELECTRONIC EFFECT OF SUBSTITUENTS ON CYCLOPALLADATION OF THE SOLVATEDPALLADIUM(II) COMPLEXES WITH N-BENZYL TRIAMINE [PD(SOL)((4-XC6H4CH2)NH(CH2)(3)NR(CH2)(3)NH2)](2- R = PH, H, AND ME - X = H, ET, ME, MEO, CL, AND NO2)() (SOL = SOLVENT )

The solvated palladium(II) complexes with the potentially cyclopallada ting monobenzyl triamine ligand, [Pd(CH3CN)(BnPhdptn)](BF4)(2) (1) (Bn Phdptn = inopropyl)-N'-benzyl-N-phenyl-1,3-propanediamine), [Pd(CH3CN) (Bndptn)](BF4)(2)(2) (Bndptn = N-(3-aminopropyl)-N'-benzyl-1,3-propane diamine), [Pd(CH3CN)(4-XC(6)H(4)CH(2)dptn)](BF4)(2) (4-XC(6)H(4)CH(2)d ptn = N-(3-aminopropyl)-N'-(4-substituted benzyl)-1,3-propanediamine; X = Me (3), MeO (4), Cl (5), and NO2 (6)), and [Pd(CH3CN)(4-XC(6)H(4)C H(2)Medptn)](BF4)(2) (4-XC(6)H(4)CH(2)Medptn = N-(3-aminopropyl)-N'-(4 -substituted benzyl)-N-methyl-1,3-propanediamine; X = Et (8), Me (9), MeO (10), Cl (11), and NO2 (12)) have been synthesized. The kinetics f or the cyclopalladation of 1-6, [Pd(CH3CN)(BnMedptn)](BF4)(2) (7) (BnM edptn = inopropyl)-N'-benzyl-N-methyl-1,3-propanediamine), 8-12 in N,N -dimethylformamide (DMF), and 7, 9, 11, and 12 at 25 degrees C in dime thyl sulfoxide (DMSO) have been investigated. The Hammett rho values f or the rate constants at 25 degrees C obtained by variation of the 4-s ubstituent on the benzyl group were -0.73 for 2-6 and -0.87 for 7-12 i n DMF, and -0.67 for 7, 9, 11, and 12 in DMSO using the substituent co nstants for the meta position, sigma(m). The difference in the rate co nstants for 1, 2, and 7 at 25 degrees C in DMF and the negative rho va lues confirmed that the present cyclopalladation proceeds by the elect rophilic attack of the palladium(II) center on the ortho benzyl carbon . We have also discussed the electronic effects of the solvent and the N-substituent of the bound triamine on the rho values to arrive at a conclusion for the reaction mechanism of [Pd(solvent)(N-benzyltriamine )]-type complexes.