Schiff bases derived from aminomethylferrocene and their cyclopalladated derivatives

Article abstract of DOI:10.1016/0022-328X(95)05511-M

Synthesis and characterization of novel Schiff bases derived from aminomethylferrocene of general formula: <(η⁵-C5H5)Fe<(η⁵-C5H4)-CH2-N=CH(C6H4-2-R)>> with R=Cl (1a) and H (1b) are reported.These react with Na2 and Na(CH3COO)*3H2O in methanol at room temperature producing di-μ-chloro-bridged cyclopallated compounds -CH2-(η⁵-C5H4)>Fe(η⁵-C5H5)>(μ-Cl)>>2 (2a, 2b) which contain a ?(Pd-C_sp2 _phenyl) bond.However, for (1b), the activation of the ?(C_sp2_,ferrocene-H) bond also takes place giving <=CH(C6H5)>Fe(η⁵-C5H5)>(μ-Cl)>2 (2b').These dinuclear complexes react with triphenylphosphine (PPh3) with cleavage of the μ-Cl bridges, yielding mononuclear derivatives (3).The results obtained show the strong influence of the so-called endo effect in cyclopalladation reactions of N-donor ferrocenyl ligands.Keywords: Iron; Palladium; Cyclopalladation; Aminoferrocenes; Schiff bases