Figure 3 (a) 1H NMR spectra of Mix-BINDFOH,
UG1 and AG1. (b) The single-crystal X-ray crys-tallography of AG6. (c)
Arrangement of molecules of AG6.
of 1.07 nm (Figure 3b). The waistline length of the center triangle
aperture is about 0.625 nm, and the bottom edge length is 0.534 nm. The
fluorene skeleton in the waist side of AG6 showed the opposite
conformation, and the dihedral angle of the top biphenyl group was
77.98°. Additionally, a series of intermolecular interactions in AG6
were also measured. Three C−H···π interactions (distances: 2.879 Å,
2.831 Å and 2.871 Å) between fluorene and biphenyl were discovered in
the tetramers, along with significant π⋯π interactions (distance: 3.392
Å) between two fluorenes.