Synthesis and coordination chemistry of aminophosphine derivatives of adenine

Abstract

Two aminophosphine derivatives of adenine N⁹-(N^2′-diphenylphosphinoaminoethyl)adenine L1 and N⁹-(N²′-diphenylphosphino-N^2′-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(μ-Cl)(η⁵-C₅Me₅)}₂], [{IrCl(μ-Cl)(η⁵-C₅Me₅)}₂], [{Rh(μ-Cl)(cod)}₂], [{RuCl(μ-Cl)(η³:η³-C₁₀H₁₆)}₂] and [{RuCl(μ-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.