Supramolecular Coordination Complexes with 5-Sulfoisophthalic Acid and 2,5-Bipyridyl-1,3,4-Oxadiazole: Specific Sensitivity to Acidity for Cd(II) Species

Abstract

A series of CdII, CoII, NiII, and PbII mixed-ligand coordination complexes 1−8 based on 5-sulfoisophthalic acid (H3sip) and the bent dipyridyl ligand 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) or its 4-pyridyl N-donor analogue (4-bpo) have been synthesized and fully characterized by IR spectra, microanalyses, and single crystal and powder X-ray diffraction techniques. The significant pH effect on assembly of the CdII complexes 1−4 has been demonstrated, which leads to the formation of distinct crystalline products, whereas the CoII, NiII, and PbII systems 5−8 are independent to pH condition of the synthetic reaction. Complexes 1−8 display various coordination motifs with different existing forms, conformations, and coordination modes of the organic ligands. Further, extended supramolecular networks are constructed via secondary interactions such as hydrogen-bonding and aromatic stacking. Solid-state properties of thermal stability and fluorescence for these crystalline materials are also presented.

Crystal structure of poly[aqua(μ2-2,5-bis(4-pyridyl)-1,3,4-oxadiazole-κ2 N,N)(μ2-1,3-phenylenediacetato-κ3 O,O′:O′′)cobalt(II)], C22H18CoN4O6

“…On the other hand, exobidentate rodlike N,N′-donor ligands can have signi cant in uence on the assembly systems of multicarboxylate ligands and metal centers. 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (bpo) with certain spacers between the two 4-pyridyl rings may also lead to fascinating architectures with interesting properties [10,11]. The crystal structure of the title complex comprises a phda ligand, a Co(II) ion and a bpo molecule per asymmetric unit ( gure …”

Synthesis, crystal structures and photocatalytic properties of four silver(I) coordination polymers based on semirigid bis(pyrazole) and carboxylic acid co-ligands

“…2b). The adjacent 2D layers are further connected by two kinds of pÁÁÁp stacking interactions between parazole rings from distinct L2 ligands with centroid-to-centroid distances of 3.5865 (19) and 3.6144(19) Å , respectively, resulting in a 3D supramolecular network (Fig. 2c).…”

“…In addition, Ag(I) coordination polymers (CPs) often show AgÁÁÁAg [10], AgÁÁÁp [11], AgÁÁÁN [12] and AgÁÁÁO [13] interactions, as well as noncovalent intermolecular interactions such as hydrogen bonding [14] and pÁÁÁp interactions [15], as well as exhibiting high-dimensional structures and interesting optoelectronic properties. However, it is still difficult to control the final supramolecular architectures because of various parameters such as the selection of metals with different coordination geometries [16], the nature of the ligands used [17], the metal-ligand ratio [18], solvent system [19], pH of the reaction [20] and temperature [21]. The synthetic strategy of mixing both N-donor and polycarboxylate ligands has been proved to be a fruitful approach for the construction of CPs with intriguing multidimensional structures.…”

Recent advances in CdII coordination polymers: Structural aspects, adaptable assemblies, and potential applications

“…Interestingly, supramolecular assemblies based on 5-sulfoisophthalic acid (H 3 sip), 4-bpo or 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo), and various metal ions (Cd II , Co II , Ni II , or Pb II ) at different pH values suggest the specific sensitivity to acidity/basicity only for the Cd II species [78]. In the resulting Cd II complexes, different existing forms and binding modes of the organic ligands result in their distinct compositions and coordination patterns (mononuclear, 1-D tape, 1-D zigzag chain, and 2-D layer).…”