A Shape-Persistent Cryptand for Capturing Polycyclic Aromatic Hydrocarbons

A shape-persistent
cryptand 1, containing two face-to-face
oriented electron-deficient 2,4,6-triphenyl-1,3,5-triazine units separated
by approximately 7 Å, and bridged by two rigid 1,8-naphthyridine
linkers and a pentaethylene
oxide loop, is created for capturing polycyclic aromatic
hydrocarbons. Cryptand 1 formed 1:1 complexes with PAH
guest molecules, such as phenanthrene (6), anthracene
(7), pyrene (8), triphenylene (9), and tetraphene (10). The single-crystal structure
of complex 6⊂1 revealed that 6 was
included in the cavity of 1 via face-to-face π···π
stacking interactions. Soaking crystalline 1 in a toluene
solution of anthracene resulted in anthracene from the toluene solution
being picked up by the crystalline solid of 1.