Anion-orchestrated formation in the crystalline state of [2]pseudorotaxanearrays

[GRAPHICS] In contrast with dibenzo[24]crown-8 (DB24C8), when tetrabenzo[24]crown-8 (T B24C8) is mixed with dibenzylammonium hexafluorophosphate (DBA-PF6) in nonc ompetitive solvents, the thermodynamically driven noncovalent synthesis of the threaded 1:1 complex-a [2]pseudorotaxane-does not occur. However, on cr ystallization from solution-in a process which is presumably kinetically co ntrolled-TB24C8 molecules and DBA(+) cations form an array of [2]pseudorota xanes stabilized by a plethora of [C-H ... F] hydrogen bonds to highly orde red, interstitially located PF6- anions.