1, 9‐Dihydro‐purine‐6‐thione Derivatives of the d8–d10 Metal Ions (PdII, PtII, and CuI): Synthesis, Spectroscopy, and Structures

Abstract

AbstractReaction of 1, 9‐dihydro‐purine‐6‐thione (puSH2) in presence of aqueous sodium hydroxide with PdCl2(PPh3)2 suspended in ethanol formed [Pd(κ2‐N7,S‐puS)(PPh3)2] (1). Similarly, complexes [Pd(κ2‐N7,S‐puS)(κ2‐P, P‐L‐L)] (2–4) {L‐L = dppm (m = 1) (2), dppp (m = 3) (3), dppb (m = 4) (4)} were prepared using precursors the [PdCl2(L‐L)] {L‐L = Ph2P–(CH2)m–PPh2}. Reaction of puSH2 suspended in benzene with platinic acid, H2PtCl6, in ethanol in the presence of triethylamine followed by the addition of PPh3 yielded the complex [Pt(κ2‐N7,S‐puS)(PPh3)2] (5). Complexes [Pt(κ2‐N7,S‐puS)(κ2‐P, P‐L‐L)] (6–8) {L‐L = dppm (6), dppp (7), dppb (8)} were prepared similarly. The 1, 9‐dihydro‐purine‐6‐thione acts as N7,S‐chelating dianion in compounds 1–8. The reaction of copper(I) chloride [or copper(I) bromide] in acetonitrile with puSH2 and the addition of PPh3 in methanol yielded the same product, [Cu(κ2‐N7,S‐puSH)(PPh3)2] (9), in which the halogen atoms are removed by uninegative N, S‐chelating puSH– anion. However, copper(I) iodide did not lose iodide and formed the tetrahedral complex, [CuI(κ1‐S‐puSH2)(PPh3)2] (10), in which the thio ligand is neutral. These complexes were characterized with the help of elemental analysis, NMR spectroscopy (1H, 31P), and single‐crystal X‐ray crystallography (3, 7, 8, 9, and 10).