Synthesis of 2‑Ureido-4-ferrocenyl Pyrimidine Guests. Investigation of Complementary Molecular Recognition of 2,6-Diaminopyridine

Novel 2-ureido-4-ferrocenylpyrimidines have been synthesized from iodoferrocene by a three-step reaction sequence. XRD analysis and spectroscopic data support the presence of an intramolecular hydrogen bond between a nitrogen atom of the pyrimidine ring and an NH group of the urea moiety. Both theoretical calculations and NMR investigations prove the existence of two isomeric forms in solution, both of which can form hydrogen bonds with an appropriate guest via an acceptor–donor–acceptor bonding pattern. Complexation with 2,6-diaminopyridine can be proved either by NMR spectroscopy or by electrochemical measurements.