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)(H 2 O) 4 ]·(H 2 bptc)·2H 2 O ( 1 ) and [Ni(4,4‘-bipy)(H 2 O) 4 ]·0.5(btc)·H 2 O ( 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)(H 2 O) 4 ] 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.