The unusual dinucleating properties of a simple bidentate Schiff base (LH, 1) in the presence of weakly coordinating methanol solvent lead to the self-assembly of [Fe2II (Lb)2 (Lt)2 (μ - MeOH)] (2) (b and t refer to bridging and terminally bound ligands, respectively). Complex 2 is the first diiron(II) species in which the two metal centers are triply bridged by single atoms in an asymmetric fashion, involving both μ-OPh and μ-OHMe bridges. This binding mode produces an Fe⋯Fe distance of 3.139(1) Å. Dinucleation appears to be driven by a combination of ligand deficiency and solvent-mediated chemistry reminiscent of host-guest interactions. The presence of a μ-MeOH ligand is unprecedented in iron chemistry. Parallel-mode EPR spectra of complex 2 recorded at 4 K show an intense negative signal at g∥ ≈ 16, suggesting the dimeric form exists in solution.
Bibliographical noteFunding Information:
We thank Dr. M.W. Wright (WFU) for assistance with the NMR data acquisitions. This research was supported by the Science Research Fund of WFU (U.B.) and the NIH (GM-38767 to L.Q.).
- Crystal structure
- Diiron(II) complex
- EPR spectroscopy
- Ferromagnetic coupling
- Schiff base