Ferrocene-Linked Thymine/Uracil Conjugates: Base Pairing Directed Self-Assembly and Supramolecular Packing

Ferrocene-linked bis(nucleobase) (1a−c) and chimeric nucleobase (1d) conjugates have been synthesized
from mono- and bis(hydroxybutyl)ferrocene 6 via Mitsunobu reaction as the key step. X-ray crystallographic studies of ferrocene bis(nucleobase) conjugates reveal two-dimensional supramolecular
organizations of backbones through self-assembled Watson−Crick and reverse Watson−Crick type pairs.
Ferrocene−bis(thymine) conjugate self-assembles by reverse Watson−Crick pairing, while the corresponding bis(uracil) conjugate self-assembles by alternating WC and reverse WC type pairing. Such
continuous assemblies are not seen in monosubstituted ferrocene nucleobase conjugates which form only
planar sheets. The results are interesting from the point of understanding and engineering supramolecular
assemblies through rational design of base pairing patterns.