Reactions of Pd(II) with chelate-tethered 2,6-diaminopurine derivatives: N3-coordination and reaction of the purine system.
Alkyldiamine-tethered derivatives of 2,6-diaminopurine, ethylenediamine-N9-propyl-2,6-diaminopurine, L1, and ethylenediamine-N9-ethyl-2,6-diaminopurine, L2, react with Pd(II) to give N3-coordinated complexes. However, the exact nature of the resulting complex is dependent on the reaction conditions. With PdCl(2)(MeCN)(2) in MeCN/H(2)O the expected [PdCl(N3-2,6-DAP-alkyl-en)](+) complex, 1, is formed with L1 chelating the metal center in a tridentate manner through the diamine function and N3 of the purine base. However, under the same conditions the shorter, ethyl-tethered, L2 gives a complex dication, 2, containing a tetradentate ligand forming simultaneously 5-, 6-, and 7-membered chelate rings. This resulting acetamidine, derived by addition to coordinated MeCN, appears to be the first such case involving the 2-amino group of a purine. The ethyl-analogue of 1, [PdCl(N3-2,6-DAP-Et-en)](+) 3, was prepared by reaction of L2 with K(2)PdCl(4) in aqueous media.
Chemical Nanoscience Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
Miguel A
MA
Galindo
David
D
Amantia
Alberto
A
Martinez-Martinez
William
W
Clegg
Ross W
RW
Harrington
Virtudes
V
Moreno Martinez
Andrew
A
Houlton
D015075:2-Aminopurine / Q000031:analogs & derivatives* / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*
D002614:Chelating Agents; D008024:Ligands; D009942:Organometallic Compounds; D015075:2-Aminopurine; C007300:2,6-diaminopurine; D010165:Palladium