A flexible copper(I)-complexed 4rotaxane containing two face-to-face porphyrinic plates that behaves as a distensible receptor

摘要

A new cyclic 4rotaxane composed of two flexible bis-macrocycles and two rigid axles is described. Each bis-macrocycle consists of two rings attached to antipodal meso positions of a central Zn porphyrin through single C-C bonds. Each ring incorporates a 2,9-diphenyl-1,10-phenanthroline chelation site. The axles contain two coplanar bidentate sites derived from the 2,2'-bipyridine motif. The building blocks were assembled by using a one-pot threading-and-stoppering reaction, which afforded the 4rotaxane in 50 yield. The "gathering-and-threading" effect of copper(I) was utilised in the formation of a 4pseudorotaxane, which was immediately converted to the corresponding 4rotaxane by a quadruple CuAAC stoppering reaction. The rotaxane contains two face-to-face zinc porphyrins, which allowed the coordination of ditopic guest substrates. The rotaxane host showed remarkable flexibility and was able to adjust its conformation to the guest size. It can be distended and accommodate rod-like guests of 2.6 to 15.8 ? in length. Accommodating and flexible! A new cyclic 4rotaxane composed of two flexible bis-macrocycles and two rigid axles is described (see figure). The rotaxane acts as a host for ditopic guest substrates. It shows remarkable flexibility, and is able to adjust its conformation to the guest size. It can be distended and accommodate rod-like guests of up to 15.8 ? in length.