ИСТИНА

We have recently observed that copper(I)-catalyzed cycloaddition of azides to calixarenes bearing several propargyl units at narrow rim may process in a cascade-like manner involving all the available triple bonds within the same calixarene molecule rather than ones from a neighboring molecule.1 We have found also that copper complexation within the tight coordination environment created by propargyl groups and triazole units might affect significantly the multiple cycloaddition process. For better understanding the effect of a strong binding units onto the CuAAC transformations of propargylated calixarenes and also to create the potential switching functionality within the molecules, we have developed a series of calixarenes bearing both propargyl/triazolyl and isomeric picolyl units at narrow rims (Figure 1). By both direct and inverted propargylation/picolylation of parent calix[4]arene the molecules with alternating propargyl and α-, β- or γ-picolyl groups were synthesized and studied in CuAAC reactions with azides including fluorescent 1-azidopyrene, 1-azidomethylpyrene and 2-azidomethylnaphthalene. The selectivity of the azides addition to the hybride molecules were studied along with the complexation properties of the resultant triazolated/picolylated calixarenes towards selected transition metal cations. For the comparative purpose the receptor properties of the structurally related triazolated calixarenes having no pyridine units were also studied.