Synthesis and Characterization of Diacylthiourea and Diacylthioureato Cu(I) Complexes

Abstract

A series of six disubstituted diacylthioureas 1,3‐ and 1,4‐C6H4[C(O)NHC(S)NR1R2]2 (L1‐6) were synthesized with varied Rn substituents (R1 = R2 = Et for L1‐2; R1 = R2 = Bn for L3‐4; R1 = iPr and R2 = Ph for L5 (1) and L6 (2)). Treatment of Ln with Cu(I) halide precursors CuX(PPh3)3 (X = Cl, Br, I) produced the discrete binuclear adducts Ln[CuX(PPh3)2]2 (3‐11 and 14‐16; n = 1‐3 and 6) by binding to Cu(I) centres via the monodentate‐S mode. In contrast, L4 and L5 yielded only the chloride products of binuclear L4[CuCl(PPh3)2]2 (12) and mononuclear L5CuCl(PPh3)2 (13), respectively, with one S arm in the latter remaining dangling, while bromide or iodide analogues were not available for L4 and L5, possibly due to the steric hindrance imposed by larger halide anions or bulky isopropyl substituents. The reactions of Ln with nitrate [Cu(NO3)(PPh3)2]led to the double‐deprotonation of ligand protons to generate dianions Ln' (1,3‐/1,4‐C6H4[C(O)NC(S)NR1R2]22‐) and led to the consequent formation of binuclear diacylthioureato Cu(I) complexes Ln'[Cu(PPh3)2]2 (n=1 (17), 2 (18), 4 (19)) via the κ‐O,S‐bidentate mode. The obtained ligands and complexes were spectroscopically and structurally characterized. These Cu(I) products (3‐19) were experimentally used as catalysts for the oxidation of 1‐phenylethanol.