Structural characterization and complexation behavior of ferrocene bearing dipeptide chain (-L-Ala-L-Pro-NHPy)

Ferrocene 1 bearing dipeptide chain (-L-Ala-L-Pro-NHPy) was synthesized and characterized by spectroscopy and X-ray crystallography. The single-crystal X-ray structure determination of the ferrocene 1 revealed that a hydrogen-bonded network is formed in an antiparallel manner to give a highly organized assembly, wherein each molecule is connected to two neighboring molecules through N–H⋯N and N–H⋯O intermolecular hydrogen bonds, forming a seven-membered intermolecularly hydrogen-bonded ring. The ferrocene 1 served as a monodentate ligand to form the 2:1 trans-complex 2 with PdCl2(MeCN)2. The rotational barrier of the two pyridyl rings in the palladium(II) complex 2 was 10.1 kcal mol−1.