title: Syntheses and Reactivity Studies of Square-Planar Diamido-Pyridine Complexes Based on Earth-Abundant First-Row Transition Elements.
abstract: The new square-planar complexes M[NNN](pyridine) (M = Fe (1), Co(2); NNN = 2,6-bis(2,6-diisopropylphenylamidomethyl)pyridine) were synthesized and fully characterized to investigate small molecule activation on this platform and also associated ligand innocence. The equatorial pyridine solvent moiety could not be removed; a new bis-ligand species Co[NNN.H]2 (3) was synthesized in low yield while attempting to make the base-free derivative. Attempts to prepare the Ni analogue of 1 and 2 instead yielded crystals of a di-imino-pyridine complex Ni[PDI]Cl (4) (PDI = 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine), following loss of methylene backbone hydrogen atoms. Structural analysis indicates that the PDI ligand is a mono-anionic radical. This susceptibility of the ligand to oxidative dehydrogenation was also shown when the reaction of 2 with 2 equiv of trityl chloride yielded a new complex with an asymmetric imino-amino pyridine ligand Co[NNN']Cl2 (5) (NNN' = 2-(2,6-(diisopropylphenyliminomethyl)-6-(diisopropylphenylamidomethyl)-pyridine) in good yield.
authors.affiliation: †Chemistry Division, ‡Materials Science and Technology Division, and §Materials and Physics Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
authors.forename: Owen T
authors.initials: OT
authors.lastname: Summerscales
authors.affiliation: †Chemistry Division, ‡Materials Science and Technology Division, and §Materials and Physics Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
authors.forename: Jamie A
authors.initials: JA
authors.lastname: Stull
authors.affiliation: †Chemistry Division, ‡Materials Science and Technology Division, and §Materials and Physics Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Scott
authors.affiliation: †Chemistry Division, ‡Materials Science and Technology Division, and §Materials and Physics Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Gordon