A novel cyclopalladated complex with a diferrocenyl Schiff base ligand: Synthesis, structure, electrochemical and catalytic properties

The N-(diferrocenylmethylene)aniline Schiff base Fc(2)C = NPh (1) (Fc = ferrocenyl, Ph = phenyl) was synthesized by the reaction of diferrocenyl-methanone with aniline, and its structure was determined for the first time in this paper. The crystal structure of the novel cyclopalladated complex (Fc(2)C = NPh)PdClPPh3 (2) was analyzed by single crystal X-ray diffraction. The structure of ligand 1 displays an anti-configuration for the ferrocenyl groups bonded to the C atom of the C=N bond lying on the opposite side to the phenyl ring. The structure of complex 2 shows a four-coordinated structural type and the two ferrocenyl moieties bridged through the C atom of the C=N bond remain in the anti-configuration; the structure also contains a bicyclic system of the coordinated Cp ring and a five-membered metallacycle. The electrochemical properties of ligand 1 and complex 2 were studied by cyclic voltammetry, and the results reveal that there is a stronger electronic communication between the two ferrocenyl units in 2. The results of a catalytic evaluation show that complex 2 is highly active as a catalyst for the Suzuki C-C coupling reaction and the biphenyl product gotten in this reaction can be obtained in 93% yield. (C) 2014 Elsevier Ltd. All rights reserved.