Thermally Robust Gold and Silver Iminopyrrolidinates for Chemical Vapor Deposition of Metal Films

Dimeric silver(I) and gold(I) tert -butyl-imino-2,2-dimethylpyrrolidinates were synthesized and characterized by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), single-crystal X-ray diffraction, and chemical vapor deposition (CVD) experiments. The motivation for this work arose from the excellent thermal stability of the previously reported analogous copper(I) compound and included the completion of a series of potential precursors for atomic layer deposition. These compounds are stable in air and soluble in aromatic or chlorinated solvents. In the solid state, TGA and DSC showed these compounds to be thermally stable up to 170 °C and to have good evaporation yields up to 240 °C. Gas phase decomposition temperatures were 140 °C for the silver compound and 300 °C for the gold compound, as determined by CVD experiments, where these compounds decomposed to produce metallic films. Reduction of the metal ions via dehydrogenation of the ligands is proposed as a thermolysis pathway.