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

In this study, three fascinating resorcin[4]arene-based Cu(I) complexes, named [CuCl (TPC4R)] (1), [CuBr (TPC4R)] (2), and [Cu2I2(TPC4R)] (3) were prepared by using a pyrimidine-functionalized resorcin[4]arene ligand (TPC4R). In 1 and 2, two Cu(I) ions were linked by two TPC4R and two Cl- (or Br-) anions to form binuclear units. The adjacent units were extended into supramolecular layers through H bonds. In 3, two Cu(I) ions were connected by one TPC4R and two I- anions to form a mononuclear complex. The mononuclear units were connected by hydrogen bonds to produce a supramolecular chain. Significantly, 1 and 2 exhibit high efficiency and universality for azide-alkyne cycloaddition reactions in the synthesis 1,2,3-triazoles and beta-OH-1,2,3-triazoles. It has been found that the amount of catalyst, solvent type and reaction temperature have considerable influences on the activities of catalytic systems. The conversions of catalysts 1 and 2 could reach 99% for most of the selected substrates. It was found that after repeatedly used for 4 times, the catalytic activity of 1 did not decrease apparently.

Automated summary

In this study, three novel Cu(I) complexes based on resorcin[4]arene were synthesized, with 1 and 2 forming binuclear units and 3 forming a mononuclear complex. These complexes exhibit high efficiency and universality in the synthesis of 1,2,3-triazoles and beta-OH-1,2,3-triazoles, with catalyst conversions reaching 99%.