Syntheses and structures of Li, Fe, and Mo derivatives of N,N′-bis(2,6-diisopropylphenyl)-o-phenylenediamine

Abstract

Double deprotonation of N,N'-bis(2,6-diisopropylphenyl)-o-phenylenediamine (H2L) with n-BuLi in THF yields the dilithium complex Li2L(thf)3. The reaction of Li2L(thf)3 with FeBr2(thf)2 and subsequent replacement of the solvent with toluene yield LFe(η(6)-toluene), which can also be synthesized from Fe(HMDS)2(thf) and H2L in toluene. The NMR data, bond lengths obtained from an X-ray diffraction study, and DFT calculations indicate that the diamide ligand L(2-) undergoes oxidization to a radical ligand L(1-). Reaction of LFe(η(6)-toluene) with 1 atm CO yields the tricarbonyl complex LFe(CO)3. MoCl4(thf)2 reacts with two equivalents of Li2L(thf)3 to yield (LiL)2MoCl2(thf)4 in which the phenylene backbone of the ligand has been dearomatized. One-electron oxidation of Li2L(thf)3 by EuCl3(dme)2 yields the open-shell species LiL(OEt2), which was characterized by X-ray crystallography and EPR spectroscopy.