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

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