A 1D double-chain assembly based on the monosubstituted Keggin polyoxometalate (POM) with pendant ligands and of formula {[Ag_2(bppy)_3][Ag(bppy)_2][Ag(bppy)]_2PW_(11)Co(bppy)-O_(39)}centre dot 2H_2O (1) [bppy = 5-(4-bromophenyl)-2-(4-pyridinyl)pyr-idine] has been ...