Phosphane Copper(I) Dicarboxylates: Synthesis and Their Potential Use as Precursors for the Spin‐coating Process in the Deposition of Copper

Dicopper dicarboxylates (R₃P)_mCuXCu(PR₃)_m] ( 5a , X = O₂CCO₂, R = Ph, m = 2; 5b , X = O₂CCO₂, R = nBu, m = 3) were prepared by treatment of Cu₂O] ( 1a ) with HO₂CCO₂H ( 2a ) in presence of PR₃ ( 4a , R = Ph; 4b , R = nBu). A further synthesis approach to mono‐ and dicopper dicarboxylates is given using an electrolysis cell equipped with Cu electrodes and charged with acids H₂X and phosphanes R₃P. Without addition of a base mononuclear (nBu₃P)_mCuXH] ( 6a , m = 3, XH = O₂CCO₂H, 6b , m = 3, XH = O₂CCH₂CO₂H, 6c , m = 3, XH = O₂CCH₂CH₂CO₂H, 6d , m = 2, XH = O₂C‐2‐C₅H₄N‐6‐CO₂H) was formed, whereas in presence of NEt₃ ( 3 ), the dicopper systems (R₃P)_mCuXCu(PR₃)_m] ( 5a , X = O₂CCO₂, R = Ph, m = 2; 5b , X = O₂CCO₂, R = nBu, m = 3; 5c , X = O₂CCH₂CO₂, R = nBu, m = 3; 5d , X = O₂CCH₂CH₂CO₂, R = nBu, m = 3; 5e , X = O₂C‐2‐C₅H₄N‐6‐CO₂, R = nBu, m = 3) were produced. When 6a reacted with (tmeda)Zn(nBu)₂] ( 7 ), trimetallic (tmeda)Zn((nBu₃P)₃CuO₂CCO₂)₂] ( 8 ) was accessible. In this heterobimetallic complex the Zn(tmeda) unit spans two CuO₂CCO₂ entities. The molecular structures of 5a , 6a and 6d in the solid state were determined by single X‐ray structure analysis. Complexes 5a and 6a are monomers, whereas 6d creates in the solid state a linear open chain coordination polymer by hydrogen bridge formation. Characteristic for 6d is the somewhat distorted trigonal bipyrimidal arrangement around the copper atom with the nBu₃P ligands in axial and the C₅H₃NCO₂H oxygen and nitrogen atoms in equatorial positions. In 5a the oxalate connectivity binds in a μ‐1,2,3,4 fashion being part of a planar Cu₂(oxalate) core. TG studies of several mono‐ and dicopper dicarboxylates were carried out. Release of the PR₃ ligands is recognized and the remaining Cu‐(di)carboxylate unit decomposes to afford elemental copper and CO₂. The deposition of copper onto pieces of PVD‐Cu oxidized silicon wafers by applying the spin‐coating process and using 5c and 5d as precursors is discussed.