Polyoxometalate-Bridged Cu(I)- and Ag(I)-Thiacalix[4]arene Dimers for Heterogeneous Catalytic Oxidative Desulfurization and Azide–Alkyne “Click” Reaction

Abstract

Two remarkable polyoxometalate-bridged Cu(I)-and Ag(I)thiacalix[4]arene dimers, namely, [Cu 4 (SiW 12 O 40 )(L) 2 (DMF) 2 ]•2EtOH•DMF (1-Cu) and [Ag 4 (PMo 12 O 40 )(L) 2 ]•OH (1-Ag), were prepared by using a new thiacalix[4]arene, metal cation and polyoxometalate (L = tetra[2-(ethylthio)-1methyl-1H-imidazole]-thiacalix[4]arene). In 1-Cu and 1-Ag, two thiacalix[4]arenes were linked together by one [SiW 12 O 40 ] 4− or [PMo 12O 40 ] 3− anion via two metal cations to give a molecular dimer. Further, adjacent dimers were extended into a high-dimensional supramolecular architecture through hydrogen bonds. Markedly, these molecular dimers are exceedingly stable in organic solvents and then were employed as efficient catalysts for catalytic oxidation desulfurization as well as the azide−alkyne "click" reaction.

Highly Stable Copper(I)–Thiacalix[4]arene‐Based Frameworks for Highly Efficient Catalysis of Click Reactions in Water

“…Notably, catalyst 1‐Cl features efficient catalytic performances for the AAC reactions under relatively mild reaction conditions. For example, the product yield is up to 99 % for the AAC reaction of benzyl azide and phenylacetylene with catalyst 1‐Cl at 60 °C for 8 h. Nevertheless, for related catalysts [Cu 4 (SiW 12 O 40 )(L1)] ⋅ 6 H 2 O ⋅ 2 DMF (L1=resorcin[4]arene‐based ligand) and [Cu 4 (SiW 12 O 40 )(L2) 2 (DMF) 2 ] ⋅ 2 EtOH ⋅ DMF (L2=thiacalix[4]arene‐based ligand), the same AAC reaction was accomplished (99 %) if the reaction temperature was elevated to 80 °C and the reaction time was prolonged to 12 h. In addition, catalyst 1‐Cl features a remarkable recyclability for the AAC reaction. For instance, a product yield of 97 % was still retained in the fifth run, whereas the corresponding yield for the catalyst {[Cu 6 (bpz) 6 (CH 3 CN) 3 (CN) 3 Br] ⋅ 2 OH ⋅ 14 CH 3 CN} n (bpz=3,3′,5,5′‐tetramethyl‐4,4′‐bipyrazole) was only up to 68 % .…”

Self‐Assembly of Polyoxometalate‐Resorcin[4]arene‐Based Inorganic‐Organic Complexes: Metal Ion Effects on the Electrochemical Performance of Lithium Ion Batteries

“…Taking 1 and 1@RGO as an example, the SiÀ O and WÀ O vibrations of [SiW 12 O 40 ] 4À could be found at 970, 920, 884 and 805 cm À 1 . [42] The absorption bands of TMR4 A appeared at 1593-1018 cm À 1 . [43] For FTIR spectrum of 1@RGO, the stretching vibrations of groups from RGO were nearly obscured by the bands of compound 1.…”

“…Therefore, functionalized calix [4]arenes can be considered as excellent candidates to construct POM-resorcin [4]arene-based hybrid materials. [40][41][42][43] The design of POM-resorcin [4]arene-based hybrid complexes opens up a new path to pursue multi-functional materials for LIBs. [44,45] Giving that the negligible conductivity of POM-resorcin [4] arene-based hybrid materials, they are always immobilized on conductive substrates, such as graphene, acetylene black and carbon nanotubes, to give electrode materials with enhanced conductivity.…”

“…And numerous Inorganic‐organic hybrid complexes or cages with elegant structures have been acquired by the assembly of functionalized calix[4]arenes, metal ions and POMs. Therefore, functionalized calix[4]arenes can be considered as excellent candidates to construct POM‐resorcin[4]arene‐based hybrid materials [40–43] . The design of POM‐resorcin[4]arene‐based hybrid complexes opens up a new path to pursue multi‐functional materials for LIBs [44,45] …”

Resorcin[4]arene‐based Cu(I) binuclear and mononuclear complexes as efficient catalysts for azide‐alkyne cycloaddition reactions

“…[ 42–44 ] In this regard, Cu(I)‐based complexes have proven to be promising heterogeneous catalysts. [ 45–47 ]…”