Molecular tectonics: pyridyl containing thiacalix[4]arene based tectons for the generation of 2- and 3-D silver coordination networks

Three thiacalix[4]arene-based Cu(i) coordination polymers: catalytic activities for azide-alkyne cycloaddition reactions and luminescence properties

Three new coordination polymers, [Cu₂(CN)(L)(OCH₃)]·CH₃OH·3H₂O (1), [Cu₃(Br)₃(L)] (2) and [Cu(I)(L)]·1.5H₂O (3), have been solvothermally prepared by reacting L (5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra[(3-pyridylmethyl)oxy]-2,8,14,20-tetrathiacalix[4]arene) with Cu(i) halide. 1 and 2 exhibit layers. 3 displays a chain, a supramolecular layer constructed by hydrogen bonds. The performance of 1-3 was examined as heterogeneous catalysts for azide-alkyne cycloaddition reactions. Most strikingly, 1 and 2 show predominant efficiency with high regioselectivity and excellent recyclability. Remarkably, solids 1-3 all have luminescence characteristics under irradiation with a UV lamp.

The Role of Calix[n]arenes and Pillar[n]arenes in the Design of Silver Nanoparticles: Self-Assembly and Application

Silver nanoparticles (AgNPs) are an attractive alternative to plasmonic gold nanoparticles. The relative cheapness and redox stability determine the growing interest of researchers in obtaining selective plasmonic and electrochemical (bio)sensors based on silver nanoparticles. The controlled synthesis of metal nanoparticles of a defined morphology is a nontrivial task, important for such fields as biochemistry, catalysis, biosensors and microelectronics. Cyclophanes are well known for their great receptor properties and are of particular interest in the creation of metal nanoparticles due to a variety of cyclophane 3D structures and unique redox abilities. Silver ion-based supramolecular assemblies are attractive due to the possibility of reduction by “soft” reducing agents as well as being accessible precursors for silver nanoparticles of predefined morphology, which are promising for implementation in plasmonic sensors. For this purpose, the chemistry of cyclophanes offers a whole arsenal of approaches: exocyclic ion coordination, association, stabilization of the growth centers of metal nanoparticles, as well as in reduction of silver ions. Thus, this review presents the recent advances in the synthesis and stabilization of Ag (0) nanoparticles based on self-assembly of associates with Ag (I) ions with the participation of bulk platforms of cyclophanes (resorcin[4]arenes, (thia)calix[n]arenes, pillar[n]arenes).

A novel Ag(i)-calix[4]arene coordination polymer for the sensitive detection and efficient photodegradation of nitrobenzene in aqueous solution

Nitrobenzene (NB) is a widespread and highly toxic organic pollutant in water, and consequently its detection and removal have attracted considerable attention. In the present study, we designed and synthesized a novel coordination polymer, [AgL_0.5(NO₃)]_n (1), {L = 25,26,27,28-tetra[(3-pyridylmethyl)oxy]calix[4]arene}, from AgNO₃ and a tetra-pyridyl-functionalized calix[4]arene ligand, which possessed a 2D network based on [Ag₄L(NO₃)₄] units. The 1-modified glassy carbon electrode (1/GCE) exhibited good electrocatalytic activity toward the reduction of NB, offering the selective detection of NB in a wide linear range (1-2450 μM) and a low detection limit (0.62 μM). Furthermore, it displayed excellent photocatalytic activity for the degradation of NB in aqueous solution under UV light. The kinetics of the catalytic degradation reaction and the stability of the catalyst were also studied. These results indicated that compound 1 is a favorable material for the effective determination and degradation of NB, which makes it a promising candidate in both monitoring water quality and treating wastewater.

Synthesis of para- and meta-imino- or -amino-methyl pyridyl-appended p-tert-butyl-calix[4]arene or p-tert-butyl-thiacalix[4]arene in 1,3-alternate conformation

The multistep synthesis of eight new ligands based on calix[4]arene or thiacalix[4]arene backbones blocked in a 1,3-alternate conformation and bearing four pyridyl units is presented.

Inverted molecular cups: 1-D and 2-D Ag(i) coordination polymers from resorcinarene bis-thiacrowns

Exo-cavity binding into resorcinarene based inverted molecular cups creates 1-D and 2-D silver coordination polymers with argentophilic interactions.

Synthesis and structural studies of 1,4-di(2-pyridyl)-1,2,3-triazole dpt and its transition metal complexes; a versatile and subtly unsymmetric ligand

Structural analysis of the 1,4-di(2-pyridyl)-1,2,3-triazole ligand and its transition metal complexes of varying lability demonstrate the coordination chemistry selectivity of this subtly unsymmetric ligand.

Molecular tectonics: dimensionality and geometry control of silver coordination networks based on pyrazolyl appended thiacalixarenes

Combinations of six new tetrakis-pyrazolyl appended calix[4]arenes derivatives, blocked in 1,3-A conformation as coordinating tectons, with AgX salts (X = NO₃⁻, BF₄⁻, XF₆⁻ (X = P, As and Sb)) lead to nine new silver coordination networks.

The first study about the relationship between the extractability of thiacalix[4]arene derivatives and the position of the coordination binding sites

Three organic ionophores (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3-alternate conformation, bearing two pyridyl coordinating moieties (ortho for 2, meta for 3 and para for 4), have been synthesized and characterized in the solid state. The solvent extraction experiments with the metal ions showed that the ability of these derivatives to complex with Ag(+) appeared to be largely dependent on the position of the nitrogen atoms of the pyridyl ring. Two different complexation modes have been confirmed by 1H NMR titration. Ionophore 2 armed with two pyridyl moieties, complexed with Ag(+) cation through N···Ag(+)···S interactions; however, ionophore 3 and ionophore 4 complexed with Ag(+) through metal-nitrogen (N···Ag(+)) interactions. The DFT computational studies were consistent with the experimental findings. These findings will provide us with an important rule to design an appropriate thiacalix[4]arene ionophore in the future. Another study on the possibility for application of ionophores 2-4 for the treatment of waste water containing Cr(VI) and Cr(III), showed that ionophore 3 was useful in the application of the solvent extraction method in selective treatment of waste water containing Cr(VI) and Cr(III) prior to discharge.

Molecular tectonics: generation of grid and porous diamondoid coordination networks by calixarene based tectons

Combinations of tetrakis meta-pyridyl appended tetrathia- or tetrathiamercapto-calix[4]arene in 1,3-A conformation with MX₂ (M = Cd, Co or Fe, X = Cl or Br), behaving as a neutral metallatecton, lead to 2D grid type and 3D porous diamondoid coordination networks.