Polythreading of infinite 1D chains into different structural motifs: Two poly(pseudo-rotaxane) architectures constructed by concomitant coordinative and hydrogen bonds

Two new compounds, [Co(4,4'-bipy)(H2O)(4)]center dot(H(2)bptc)center dot 2H(2)O (1) and [Ni(4,4'-bipy)(H2O)(4)center dot 0.5(btc)center dot H2O (2) (4,4'bipy = 4,4'-bipyridine, H(4)bptc = 3,3',4,4'-biphenyltetracarboxylate acid, H(4)btc = 1,2,4,5-benzenetetracarboxylate acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG analysis. and single-crystal X-ray diffraction. X-ray structural analysis revealed that two different structural motifs (1D covalent zigzag chain and 1D hydrogen-bonded ladder for 1 and 1D linear chain and 2D hydrogen-bonded sheet for 2) can be found within their crystal structures. and most intriguingly, they coexist in such a way that 1D covalently bonded chains of composition [M(4,4'-bipy)(H2O4](2+) (M = Co or Ni) thread into the hydrogen-bonded 1D ladders or 2D sheets formed by uncoordinated carboxylate anions and lattice water molecules, giving-rise to overall entangled architectures with unusual poly (pseudo-rotaxane)-type arrangements. Thermal stability of the two compounds was also studied in this paper.