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 FeII and FeIII centers. [Fe­(DMTTFP)2] (1) and [Fe­(DMTTFP)2­(OBut)] (2)
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 1 and 2, respectively. Magnetic investigations confirmed [Fe­(DMTTFP)2] 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)2­(OBut)] exhibited enhanced stability, sufficient volatility, and decomposition
behavior serving as an efficient FeIII precursor for the
growth of iron oxide layers on an Al2O3 substrate
via chemical vapor deposition.