Extended metal atom chain (EMAC) complexes of first-row transition metals with metal−metal bonds have the potential to elicit unique magnetic properties and reactivities. Until now, the library of EMAC complexes with late-first-row transition metals was incomplete because of the omission of a triiron species with Fe−Fe bonding. Herein we report the synthesis and preliminary investigation of the first linear, triiron(II) complex containing close Fe−Fe interactions. The complex is supported by three dianionic 2,6-bis[(trimethylsilyl)amido]pyridine ligands (L), with an overall composition of Fe 3 L 3 , and pseudohelical ligand coordination stabilizing the local trigonal-planar geometry at each iron. Fe 3 L 3 was characterized by X-ray diffraction, 1 H NMR, cyclic voltammetry, electronic absorption, and Mossbauer spectroscopies. Evans method analysis indicated a large uncompensated spin and an S = 6 ground state, suggesting ferromagnetic coupling in the triiron chain, likely due to direct exchange.

The title complex, [Li2Ni(C11H21N3Si2)2(C4H8O)2], is a trimetallic complex of two LiI cations and a NiII cation bridged by two N,N′-(pyridine-2,6-diyl)bis(trimethylsilylamide) ligands that crystallizes in the Fdd2 space group. The molecule has C 2 rotational symmetry, with the NiII cation located on the twofold axis. The coordination sphere of the NiII cation is composed of two amido N and two pyridyl N-atom donors in a distorted square-planar geometry. The LiI cations are coordinated by two amido N-atom donors and a tetrahydrofuran molecule with a long interaction with a pyridyl N-atom donor. The coordinating tetrahydrofuran ligand and a trimethylsilyl group are disordered. Intra- or intermolecular hydrogen bonding, as well as π–π stacking, are not observed between the molecules, likely indicating that weak electrostatic interactions are the dominant feature leading to the crystal structure.