Synthesis and coordination of a pair of isomeric ferrocene phosphinoamines.

Ferrocene P,N-ligands have been extensively studied due to their favorable catalytic properties. This contribution focuses on a pair of new, isomeric ferrocene phosphinoamines, FcNHCH 2 CH 2 PPh 2 (1) and FcN(Me)CH 2 PPh 2 (2), which were prepared from aminoferrocene, converted to the respective phosphine selenides (1-Se and 2-Se) and further studied as ligands in Pd(II) complexes containing the 2-(dimethylamino-κ N)phenyl-κ C 1 auxiliary (LNC) ligand. Thus, cleavage of the dimeric precursor [(LNC)Pd(μ-Cl)] 2 with the phosphinoamines afforded the corresponding phosphine complexes [(LNC)PdCl(1 -κ P)] (5) and [(LNC)PdCl(2 -κ P)] (6) with trans -P,N configuration. The subsequent removal of the chloride ligand with AgClO 4 from 5 produced the cationic bis-chelate complex [(LNC)PdCl(1 -κ2 P,N)]ClO 4 (7), whereas an analogous reaction with 6 gave no defined product. The phosphinoamines and their complexes were characterized by elemental analysis and common spectroscopic methods, and the crystal structures of 1, 2 , and 7 were determined by single-crystal X-ray diffraction analysis. A cyclic voltammetry study, supported by DFT calculations, revealed that the primary electrochemical oxidation of these compounds occurs at the ferrocene unit. [ABSTRACT FROM AUTHOR]