7-Methyl-6-furylpurine forms dinuclear metal complexes with N3,N9 coordination

Two dinuclear metal complexes bearing the purine derivative 7-methyl-6-furylpurine (ib) as a ligand are reported. In [Ag-2(1b)(2)(DMSO)(2)](ClO4)(2)center dot DMSO and [Cu-2(1b)(2)(NO3)(2)], two bridging purine derivatives coordinate the two metal ions via their N3 and N9 positions. In the silver(I) complex, the coordination environment of each metal ion is completed by a DMSO ligand, whereas an additional nitrato ligand coordinates to each copper(I) ion. The intramolecular Ag center dot center dot center dot Ag distance of 11069(5) A is in agreement with the presence of a weak argentophilic interaction, whereas the Cu center dot center dot center dot Cu distance of 2.9382(4) angstrom is too long to be indicative of a cuprophilic interaction. The compounds represent the first examples of dinuclear complexes comprising two N3,N9-bridging purine derivatives without any additional bridging ligand.