Syntheses Of Resorcin[4] Arene-based Cu(Ⅰ) Complexes And Study In Azide-alkyne Cycloaddition Reaction

In this paper,three fascinating resorcin[4]arene-based Cu(Ⅰ）complexes,namely,[Cu Cl(TPC4R)](1),[Cu Br(TPC4R)](2)and [Cu2I2(TPC4R)](3)were prepared by solvothermal reaction of a pyrimidine-functionalized resorcin[4]arene ligand(TPC4R)with Cu Cl2·2H2O,Cu Br2 and Cu I,respectively.Powder X-ray diffraction(PXRD),fourier transform infrared(FT-IR),UV-vis absorption spectroscopy,solid-state emission and thermogravimetric analysis(TGA)were used to characterize the properties of the complexes.The application of complexes 1 and 2 in the azide-alkyne cycloaddition reaction was further studied.Crystal structures of complexes 1 and 2 are isostructural,where two Cu(Ⅰ）ions were linked by two TPC4 R ligands and two Cl-(or Br-)anions to form a binuclear Cu(Ⅰ）unit.Adjacent binuclear Cu(Ⅰ）units were extended into a supramolecular layer through H-bonding interractions.In 3,two Cu(Ⅰ）ions were connected by one TPC4 R ligand and two I-anions to form a mononuclear complex.The mononuclear units were linked by hydrogen bonds to produce a supramolecular chain.In view of the fact that complexes 1 and 2 have Cu(Ⅰ）active reaction sites,their catalytic activity in azide-alkyne cycloaddition reaction was studied.The result demonstrated that they exhibited high catalytic activity for the azide-alkyne cycloaddition reactions during the syntheses of 1,2,3-triazoles and β-OH-1,2,3-triazoles.In addition,the amount of catalyst,solvent type and reaction temperature have effects on the activities of the catalytic systems.For most of the selected substrates,the conversions could reach 99% with 1 and 2 as catalysts.Complex 1,as a heterogeneous catalyst,can be recovered well after catalytic reaction.The catalytic activity of complex 1 still remained after it was reused for four times.This work provides a feasible way for the assembly of resorcin[4]arene-based Cu(Ⅰ）complexes and their application in the azide-alkyne cycloaddition reactions.