Relationship between molecular structures and thermogravimetric properties of gallium-amidinate based compounds

Abstract

The ability to predict the thermal properties of molecular compounds is essential for their successful integration into vapor-phase processes such as atomic layer deposition (ALD) and chemical vapor deposition (CVD), as well as in catalysis and materials synthesis. In this work, we present a systematic study of 24 gallium amidinate complexes, designed to explore the relationship between molecular structure and thermal behavior. The series encompasses a range of structural variations: different ligand substituents, molecular symmetry, and co-ligands. Structural characterization, including in some cases single-crystal X-ray diffraction, was combined with detailed thermal analysis using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) under both atmospheric and reduced pressure conditions. The results reveal clear correlations between thermal properties and ligand architecture, with features such as alkyl chain type, methyl group presence, and overall symmetry playing key roles in determining volatility and stability. Importantly, both symmetric and dissymmetric complexes were found to possess the desired thermal characteristics for vapor-phase deposition processes. Beyond offering valuable design principles for gallium precursors, the dataset generated herein provides a foundation for improving predictive models—empirical and AI-driven alike—towards the rational development of next-generation functional molecular compounds.