Copper(I) tert-Butylthiolato Clusters as Single-Source Precursors for High-Quality Chalcocite Thin Films: Precursor Chemistry in Solution and the Solid State

Polymeric (CuS t Bu) ∞ ( 1 ) undergoes reaction with trialkylphosphines to form the cuprous thiolato phosphine complexes [(CuS t Bu) 4 (PR 3 ) 2 ] (R = Me ( 2a ), Et ( 2b )) in high yield. In contrast to 2b, in polar solvents (CH 2 Cl 2, tetrahydrofuran), complex 2a is in equilibrium with the ion pair Cu(PMe 3 ) 4 + Cu 5 (S t Bu) 6 - ( 3 ) and other species such as (CuS t Bu) x (PMe 3 ) 2 ( x = 6 ( 4 ), 8 ( 5 )). Clusters 2 − 4 were isolated analytically pure and fully characterized in solution by multinuclear nuclear magnetic resonance (NMR) spectroscopy and in the solid state by single-crystal X-ray diffraction and 31 P magic angle spinning NMR spectroscopy, while the structure of compound 5 was determined by single-crystal X-ray diffraction. Thermal analysis (TGA/DTA) and examination of the volatile byproducts suggest stepwise phosphine loss and C−S bond cleavage by isobutene elimination as the predominant thermolysis pathways of this new Cu 2 S precursor class.