Synthesis of a Ditopic Verdazyl Ligand and its Coordination to Nickel

The goal of this research project was to prepare a self-assembled grid complex with a ditopic bis-verdazyl ligand and nickel(II) ions. A verdazyl is a relatively stable type of organic free radical in which the unpaired electron is delocalized over four nitrogen atoms. The ditopic verdazyl ligand was synthesized in six steps, and its coordination to metal ions, in particular Ni2+, was investigated. The hypothesized complex of the ligand with Ni2+ is potentially functional as a molecular magnet due to the free radical nature of the ligand; hence, the complex could be useful for information storage. The ligand was definitively characterized by mass spectrometry and ESR. The results of variable temperature ESR performed on the ligand dissolved in toluene at low temperatures indicate that the ground state of the diradical ligand is a singlet state rather than a triplet state. Infrared spectroscopy was also performed on the ligand and the resulting spectra indicated the presence of the correct functional groups of the ligand that was planned in the original design of the project.