Complex Chemistry of a Chiral Terpyridine Ligand Based on (1 R )‐(+)‐Camphor

A terpyridine‐type 2,2′‐(2,6‐Pyridinediyl)bis[(5 S ,5′ S ,8 R ,8′ R )‐5,6,7,8‐tetrahydro‐8,9,9‐trimethyl‐5,8‐methanoquinoline ligand was synthesized by a double Kröhnke‐type cyclization with starting materials obtained from (1 R )‐(+)‐camphor and pyridine‐2,6‐dicarboxylic acid. The terpy‐ligand and its iron(II), nickel(II), ruthenium(II) and palladium(II) complexes were characterized structurally and spectroscopically. Structural analysis of the iron(II), nickel(II), ruthenium(II) revealed five coordinated complexes with short M‐N distances to the central pyridine nitrogen atom and longer M‐N distances to the outer pyridine nitrogen atoms. The outer pyridine nitrogen atoms together with the two chlorido ligands form the basal coordination site. To obtain the electronic structure of the complexes, DFT calculations were performed. With palladium(II), a cyclometalated complex was obtained. The chiral N, N,C‐cyclometalated palladium complex revealed a distorted square planar coordination environment caused by steric congestion between the chlorido ligand and the alkyl substituents of the ligand.