Monomeric Iron Heteroarylalkenolates: Structural Design Concepts and Investigations on Their Application in Chemical Vapor Deposition

Aryl substituted β-alkenol 1-(dimethyl-1,3-thiazol-2-yl)-3,3,3-trifluoropropenol (DMTTFP) was employed as an efficient metal chelator to obtain volatile monomeric precursors containing Fe<sup>II</sup> and Fe<sup>III</sup> centers. [Fe­(DMTTFP)<sub>2</sub>] (<b>1</b>) and [Fe­(DMTTFP)<sub>2</sub>­(OBu<sup><i>t</i></sup>)] (<b>2</b>) were synthesized by reacting suitable starting materials with DMTTFP. The molecular structures were elucidated by single-crystal X-ray diffraction analyses, which revealed a distorted tetrahedral and a trigonal-bipyramidal arrangement of ligands around iron atoms in <b>1</b> and <b>2</b>, respectively. Magnetic investigations confirmed [Fe­(DMTTFP)<sub>2</sub>] to exhibit a thermally populated spin-state transition that becomes apparent below 10 K. The high-spin state was gradually transferred to a low-spin state on cooling, suggesting a nonmagnetic ground state. [Fe­(DMTTFP)<sub>2</sub>­(OBu<sup><i>t</i></sup>)] exhibited enhanced stability, sufficient volatility, and decomposition behavior serving as an efficient Fe<sup>III</sup> precursor for the growth of iron oxide layers on an Al<sub>2</sub>O<sub>3</sub> substrate via chemical vapor deposition.