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

Abstract

AbstractDicopper 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.