Synthesis, Characterization, and Crystal Structures of Heteroannular Cyclopalladated Ferrocenylimine-Pyridine Complexes

Two new heteroannular cyclopalladated ferrocenylimine-pyridine derivatives, 2a and 2b, were easily prepared by the reaction of chlorine-bridged binuclear palladium complexes, 1a and 1b, with pyridine in high yields. They were characterized by ESI-MS, H-NMR, and IR spectra. The detailed structures of complexes 2a and 2b were determined by single-crystal X-ray analysis. According to the crystal structure, the palladium atom is bound to the unsubstituted Cp ring, forming a new heteroannular pyridine-cyclopalladated large-membered metallocycle. Complex 2a exists as a dimer in the crystal due to intermolecular CH(CHN)Cl hydrogen bonds, while 2b has a two-dimensional network structure formed by the intermolecular hydrogen bonds between the Cl atom with the adjacent C-H groups of Cp and pyridine.