Mono- and bis(cyclopalladation) of the bis(ferrocenylimine) [(eta(5)-C5H5)Fe{(eta(5)-C5H4)-CH=N-(C6H3-2-CH3)-}](2)

The reaction of the novel bis(ferrocenylimine) [(eta(5)-C5H5)Fe{(eta(5)-C5H4)-CH=N-(C6H3-2-CH3)-}](2) (1) with Na-2[PdCl4] and NaCH3COO . 3H(2)O in methanol in a 1:2:2 or a 1:1:1 molar ratio produces the polynuclear di-mu-chloro-bridged cyclopalladated compounds [Pd-2(eta(5)-C5H5)Fe[(eta(5)-C5H3)-CH=N-(C6H3-2-CH3)-]}(2)(mu-Cl)(2)](2) (2a) or [Pd{(eta(5)-C5H5)Fe[(eta(5)-C5H3)-CH=N-C6H3- 2-(CH3)-4-{(C6H3-2'-CH3)-N=CH-(eta(5)-C5H4)}]Fe(eta(5)-C5H5)}(mu-Cl)](2) (2b) respectively, which arise from the activation of two (for 2a) or one (for 2b) sigma(C-sp2,C-ferrocene-H) bonds. Addition of triphenylphosphine to benzene suspensions of compounds 2 produces the cleavage of the 'Pd(mu-Cl)(2)Pd' units and the formation of [Pd-2{eta(5)-C5H5)Fe[(eta(5)-C5H3)-CH=N-(C6H3-2-CH3)-]}Cl-2(2)(PPh(3))(2)] (3a), or [Pd{(eta(5)-C5H5)Fe[(eta(5)-C5H3)-CH=N-C6H3-2-(CH3)-4-{C6H3-(2'-CH3)-N=CH-(eta(5)-C5H4)}]Fe(eta(5)-C5H5)}Cl(PPh(3))] (3b) Proton and P-31 NMR studies on compounds 3 confirm the existence of two (in 3a) or one (in 3b) five-membered palladocycles fused with the ferrocenyl units, and a trans arrangement of the PPh(3) ligand and the imine nitrogen. Electrochemical studies of these compounds are also reported.