Variations on a one-dimensional theme in the copper–diphosphonatoalkane system: The structures of [Cu2(bisterpy){HO3P(CH2)2PO3H}2] · xH2O (x = 0 and 6), [Cu2(bisterpy)(H2O)2{HO3P(CH2)2PO3H}](NO3)2 and [Cu2(bisterpy)(NO3)2{HO3P(CH2)3PO3H}] · 2H2O (bisterpy

The hydrothermal reactions of a Cu(II) source, bisterpy, and an organodiphosphonate yield a family of one-dimensional materials: [Cu2(bisterpy){HO3P(CH2)2PO3H}2] (1), [Cu2(bisterpy){HO3P(CH2)2PO3H}2] · 6H2O (2 · 6H2O), [Cu2(bisterpy)(H2O)2{HO3P(CH2)2PO3H}](NO3)2 (3), and [Cu2(bisterpy)(NO3)2{HO3P(CH2)3PO3H}] · 2H2O (4 · 2H2O). In all cases, axially distorted ‘4 + 1’ Cu(II) square pyramids are linked through dipodal bisterpy and diphosphonate rods into the chain structures. However, the variability in the apical ligand of the copper results in considerable structural variability within the common one-dimensional theme. The one-dimensional Cu(II)/bisterpy/organodiphosphonate structure is also observed as an embedded subunit in the two-dimensional [Cu2(bisterpy)(H2O)2(H4Mo4O14){O3P(CH2)2PO3}] (5) where the unusual, neutral polyoxomolybdate {H4Mo4O14} serves to crosslink these chains into a network structure.