Supramolecular Open-Framework of a Bipyridinium-Carboxylate Based Copper Complex with High and Reversible Water Uptake

Abstract

The rigid zwitterionic ligand 1,1′‐bis(4‐carboxylatphenyl)‐(4,4′‐bipyridinium) (pc1) and copper(II) ions give rise to a linear complex [Cu(pc1)2(H2O)4]2+, which self assembles in a pseudo tetragonal supramolecular arrangement leading to the supramolecular open‐framework [Cu(pc1)2(H2O)4](Cl)2·8H2O exhibiting an open structure including water molecules and chlorides in pores. The dehydration of this material occurs at relatively low temperature (70 °C) and results in structure modification accompanied by shrinking of the crystals. Characterization of the obtained material by FT‐IR spectroscopy reveals appearance of coordinated carboxylates groups, which may indicate the formation of coordination polymer after dehydration. Water adsorption (maximum uptake 0.23 g H2O per g) on dehydrated material allows to restore the initial structure. A large hysteresis in water adsorption‐desorption isotherm is characteristic of a significant modification of the structure during the hydration‐dehydration cycle which is in line with the structural transition determined from thermodiffractometry and FT‐IR spectroscopy.

Reversible Breathing Process and Associated Thermochromism of a Stacked-Layer Porous Supramolecular Material

“…Another possibility of constructing these 2-D soft porous crystals is the use of tectons which are able to self-assemble with weak interactions and form porous supramolecular networks (PSN). One of the compounds recently published in this class is the [Cu­(pc1) 2 (H 2 O) 4 ]­(Cl) 2 ­·8H 2 O where the [Cu­(pc1) 2 (H 2 O) 4 ] 2+ complexes (pc1 = 1,1-bis­(4-carboxylatphenyl)-(4,4-bipyridinium)) self-assemble through hydrogen bonds involving the free carboxylate groups and the water molecules linked to copper ions leading to an open 2-D supramolecular network. In this regard, the self-assembly of cationic and anionic complexes capable of being involved in well-identified intermolecular interactions such as hydrogen bonds could be made.…”

“…These characteristics have also been observed in a family of compounds named "elastic layer-structured metal− organic frameworks (ELMs)". 23 24 where the [Cu(pc1) 2 (H 2 O) 4 ] 2+ complexes (pc1 = 1,1-bis(4-carboxylatphenyl)-(4,4-bipyridinium)) self-assemble through hydrogen bonds involving the free carboxylate groups and the water molecules linked to copper ions leading to an open 2-D supramolecular network. In this regard, the self-assembly of cationic and anionic complexes capable of being involved in well-identified intermolecular interactions such as hydrogen bonds could be made.…”

Adsorption of Polar Volatile Organic Compounds by a Crystalline Network Structure Based on a Bis(benzimidazole)NiCl2 Complex

“…Furthermore, the hydrogen-bond networks can provide hydrogen-bond sites that interact weakly with volatile carbonyl compounds. The characteristics of metal-complex-based hydrogen-bond networks have been investigated for more than two decades (for selected reviews, see refs − ; for recent examples, see refs − ); nevertheless, the adsorption/desorption properties of volatile carbonyl compounds in such networks have not been explored, except in the case of acetone. − Takamizawa et al have measured the adsorption isotherm of acetone in a hydrogen-bond network derived from [Co­(ethylenediamine) 3 ]­Cl 3 . The Beatty group has investigated the desorption of co-crystallized acetone from the crystals of [M­(2,4-pyridine dicarboxylate) 2 ] 2– , where M was Cu or Zn. , Castillo and co-workers have confirmed that a [Cu 2 (μ-adenine) 4 Cl 2 ]­Cl 2 -based hydrogen-bond network can adsorb acetone .…”