1, 9‐Dihydro‐purine‐6‐thione Derivatives of the d 8 –d 10 Metal Ions (Pd II , Pt II , and Cu I ): Synthesis, Spectroscopy, and Structures

Reaction of 1, 9‐dihydro‐purine‐6‐thione (puSH 2 ) in presence of aqueous sodium hydroxide with PdCl 2 (PPh 3 ) 2 suspended in ethanol formed [Pd(κ 2 ‐N 7 ,S‐puS)(PPh 3 ) 2 ] ( 1 ). Similarly, complexes [Pd(κ 2 ‐N 7 ,S‐puS)(κ 2 ‐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 [PdCl 2 (L‐L)] {L‐L = Ph 2 P–(CH 2 ) m –PPh 2 }. Reaction of puSH 2 suspended in benzene with platinic acid, H 2 PtCl 6 , in ethanol in the presence of triethylamine followed by the addition of PPh 3 yielded the complex [Pt(κ 2 ‐N 7 ,S‐puS)(PPh 3 ) 2 ] ( 5 ). Complexes [Pt(κ 2 ‐N 7 ,S‐puS)(κ 2 ‐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 N 7 ,S‐chelating dianion in compounds 1 – 8 . The reaction of copper(I) chloride [or copper(I) bromide] in acetonitrile with puSH 2 and the addition of PPh 3 in methanol yielded the same product, [Cu(κ 2 ‐N 7 ,S‐puSH)(PPh 3 ) 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(κ 1 ‐S‐puSH 2 )(PPh 3 ) 2 ] ( 10 ), in which the thio ligand is neutral. These complexes were characterized with the help of elemental analysis, NMR spectroscopy ( 1 H, 31 P), and single‐crystal X‐ray crystallography ( 3 , 7 , 8 , 9 , and 10 ).