Spin Crossover Behavior of N-Confused C-Scorpionate Complexes of Iron(II) Trifluoromethanesulfonate
Date of Award
Master of Science (MS)
An understanding of the molecular properties that influence highly-cooperative SCO behavior is critical in the development of new electronic materials. The purpose of this thesis work is to more fully examine whether hydrogen bonding interactions can be used to assemble iron(II) scorpionate complexes and whether this leads to abruptness in the SCO behavior. In this contribution, new N-confused C-scorpionate ligands are prepared with two ‘normal’ pz* groups ( = 3,5-dimethylpyrazol-1yl) and a ‘confused’ pyrazolyl with either an N-H, HL*, or an N-Tosyl (Tosyl = p-toluenesulfonyl), TsL*, bound to a central methine. These bulky ligands complement those previously described, HL and TsL, that had less-bulky, unsubstituted, ‘normal’ pyrazol-1-yls. For these four related Nconfused C-scorpionate ligands, the 2:1 and 1:1 ligand:silver complexes are prepared and characterized both structurally and spectroscopically. The complexes’ stoichiometric reactivity and catalytic activity for aziridination of styrene are also reported. The solution- and solid-state properties of the iron(II) N-confused C-scorpionate complex, [Fe(HL*)2](OTf)2, which unexpectedly displayed multiple solid-state structures and solvates, are also discussed. The synthesis, solid-state characterization, and SCO of both compounds will be described in detail.