To study monomeric complexes of our SCS iron framework in the absence of strong phosphine donors, we next treated 5-Et2O with ligands containing S and N donors, which gave the products in Scheme 4 within 1 hour at room temperature. Their syntheses, NMR spectra, and IR spectra are described here, and their magnetism, EPR spectra and electronic structures are described in following sections. Addition of a bulky thiolate (potassium 2,6-dimesitylphenylthiolate) to 5-Et2O in THF generated complex 7 in 97% yield. Addition of 18-crown-6 followed by crystallization furnished 7-crown (Figure ). 7-Crown displays an axially coordinated THF molecule and a nearly square pyramidal geometry with τ5 = 0.08 (Figure ). The Fe-C, average Fe-SPincer, and Fe-SAr, bond lengths are 2.0006(17) Å, 2.244(6) Å, and 2.2758(5) Å, respectively. Addition of Et2O, arenes, or alkanes to solid 7 prior to the addition of 18-crown-6 led to a color change from orange to green, indicating the formation of the THF-free analogue (8) in non-coordinating solvents.