High Volatile Antimony(III) Precursors for Metal Oxide Thin Film Deposition

We report the synthesis and characterization of novel antimony(III) complexes: Sb(mpa)₃ (1), Sb(mmpa)₃ (2), Sb(mdpa)₃ (3), Sb(epa)₃ (4), Sb(empa)₃ (5), and Sb(edpa)₃ (6) (mpa = N-methoxypropanamide, mmpa = N-methoxy-2-methyl-propanamide, mdpa = N-methoxy-2,2-dimethylpropanamide, epa = N-ethoxypropanamide, empa = N-ethoxy-2-methylpropanamide, and edpa = N-ethoxy-2,2-dimethylpropanamide, via a salt-elimination reaction with SbCl₃ and sodium-substituted carboxamide. The molecular structure of 6 revealed the formation of a homoleptic conformer with a highly distorted pentagonal bipyramidal geometry, as determined by X-ray crystallography. Thermogravimetric analysis showed excellent volatility at elevated temperatures, with complex 4 displaying the lowest residual mass of 0.16% at 500 °C. For complexes 4, 5, and 6, the temperature at a vapor pressure of 1 Torr and the enthalpy of vaporization were estimated to be 58, 64, and 45 °C and 83.31, 103.58, and 99.93 kJ/mol, respectively.