Three pendant benzamidines, [Ph-C(NC _6H _5)-{NH(E)}] [E = -(CH _2) _2SMe (1); -(CH _2) _2S ~tBu (2); -o-C _6H _4SMe (3)], are described. Reactions of 1, 2 or 3 with one molar equivalent of Pd(OAc) _2 in CH _2Cl _2 give the palladacyclic complexes, [Ph-C{-NH(η ~1-C _6H _4)}{N(E)}]Pd(OAc) [E = -(CH _2) _2SMe (4); -(CH _2) _2S ~tBu (5); -o-C _6H _4SMe (6)], as mononuclear palladium complexes respectively. A minor product described as 5′, {[Ph-C{-N(C _6H _5)}{-N(CH _2) _2S ~tBu}]Pd(OAc)} _2, was isolated as benzamidinate-bridged dinuclear palladium complex upon recrystallizing from Et 2O/hexane solution. Treatment of 1, 2 or 3 with one molar equivalent of PdCl _2 in the presence of NEt _3 in CH _2Cl _2 gives the palladacyclic complexes, [Ph-C{-NH(η ~1-C _6H _4)}{N(E)}]PdCl [E = -(CH _2) _2SMe (7); -(CH _2) _2S tBu (8); -o-C _6H _4SMe (9)], as mononuclear palladium complexes respectively. The crystal and molecular structures are reported for compounds 5, 5′ and 6-8. The application of these palladacyclic complexes to the Suzuki and Heck coupling reactions was examined.
展开▼
