Synthesis and coordination chemistry of aminophosphine derivatives of adenine

Two aminophosphine derivatives of adenine N^9-(N^2ʹ-diphenylphosphinoaminoethyl)adenine L1 and N^9-(N^2ʹ-diphenylphosphinoN2ʹ-n-propylaminoethyl)adenine L2 were synthesized. Oxidation of L1 and L2 with H2O2, elemental sulfur or elemental selenium led to the corresponding oxidized products 5-10. Both L1 and L2 behave as monodentate ligands towards late transition metals. Reaction of compound L1 or L2 with [AuCl(tht)], [{RhCl((mu)-Cl)((eta)^5-C5Me5)}2], [{IrCl((mu)-Cl)((eta)^5-C5Me5)}2], [{Rh((mu)-Cl)(cod)}2], [{RuCl ((mu)-Cl)((eta)^3:(eta)^3-C10H16)}2] and [{RuCl((mu)-Cl)(p-MeC6H4iPr)}2] gave the corresponding "dangling" monodentate complexes 11-20, leaving the adenine ring free for complementary hydrogen bonding. Interaction of L1 and L2 with [MX2(cod)](M = Pt; X = Cl, Me) in 2 : 1 molar ratio also gave monodentate complexes 21 and 22. All compounds have been fully characterized by microanalysis, IR, 31P-{1H} NMR, 1H NMR and EI/CI/FAB MS spectroscopies. 1H-{31P} NMR, 1H-1H-COSY or 1H-13C correlation experiments were used to confirm the spectral assignments. Four compounds were structurally characterized by crystallographic X-ray analysis.