Formation of a Pillar[5]arene-Based Two-Dimensional Poly-Pseudo-Rotaxane: Threading and Crosslinking by the Same Guest Molecules

Abstract

A one-pot reaction of the A1/A2-thiopyridyl pillar[5]arene L with silver(I) trifluoroacetate in the presence of the linear dinitrile guest C8, [CN(CH2)(n)CN, n=8], afforded the first example of a two-dimensional (2D) poly-pseudo-rotaxane {[(mu(4)-Ag)(2)(C8@L)(2)(mu-C8)](CF3CO2)(2)}(n). Surprisingly, in this structure the C8 guest not only threads into the pillar[5]arene unit but also crosslinks the 1D coordinative polymeric arrays. The formation of the 2D poly-pseudo-rotaxane is driven by an adaptive rearrangement of the components that minimizes the steric clashes not only between the threaded guests but also between the threaded and crosslinked guests where crosslinking occurs. A pathway for the formation of the 2D poly-pseudo-rotaxane is proposed.