Abstract
A series of air-stable trigonal bipyramidal Fe(III) complexes supported by a redox non-innocent NNN pincer ligand, Cz (tBu)(Pyr(R))(2) (-) (R = iPr, Me, or H), were synthesized, fully characterized, and utilized for the investigation of the interaction between acetone and the Fe(III) center. The magnetic moments determined from the paramagnetic (1)H NMR spectra in conjunction with EPR and Mössbauer spectroscopy indicate the presence of a high-spin ferric center. Cyclic voltammetry studies feature two quasi-reversible events corresponding to a metal-centered Fe(III/II) reduction around -0.40 V (vs. Fc) and a ligand-centered Cz (tBu)(Pyr(R))(2)/Cz (tBu)(Pyr(R))(2) (•+) oxidation at potentials near +0.70 V (vs. Fc). UV-Visible spectroscopy in CH(2)Cl(2) showcases ligand-metal charge transfer (LMCT) bands, as well as coordination of acetone to Cz (tBu)(Pyr(H))(2)FeCl(2). In situ IR spectroscopy and solution conductivity (κ) measurements of Cz (tBu)(Pyr(R))(2)FeCl(2) with varied equivalents of acetone reveal that acetone is weakly associated with the iron center.