Abstract:
The building blocks of [(5-C5H4-C2-R]2Fe (R = pyridine-4-yl, pyridine-3-yl, and 2,2'-bipyridine-5-yl) and [(5-C5H4-C2-C6H2(OR')2-C2-R]2Fe (R = pyridine-4-yl, pyridine-3-yl, 2,2'-bipyridine-5-yl, 1,10-phenanthroline-3-yl and R' = n-C3H7) were investigated. The former was accessible by reactions of 1,1'-diiodoferrocene with R-C2-H. X-ray analyses of the bis(pyridine)s revealed the eclipsed conformer. While the latter was prepared via a pre-organized precursor [(5-C5H4-C2-C6H2(OR')2-C2-R]2Fe (R = triisopropylsilyl). One-pot, two-step reactions furnished the conversion of R from triisopropylsilyl to N-ligands. Macrocycles [((5-C5H4-C2-4-C5H4N)2Fe]2Ni2(NO3)4, [((5-C5H4-C2-3-C5H4N)2Fe]2Ag2(ClO4)2, and [((5-C5H4-C2-3-C5H4N)2Fe]2Pd2Cl4 were obtained and characterized crystallographically. They represent rigid, 2 nm-sized, molecular polygons defined by the centers of Cp rings. No Fe-Fe coupling except weak Fe-Ni and Fe-Ag interactions has been established by CV experiments. Weak antiferromagnetic Ni-Ni interaction was found. Complexes of the tetradentate ligands were demonstrated.