A 'Texas-sized' molecular box that forms an anion-induced supramolecular necklace.
The 'blue box' (cyclobis(paraquat-p-phenylene) or CBPQT(4+)), developed by Stoddart and colleagues, forms effective charge transfer complexes with a variety of electron-rich species and has been used to support the formation of a wide range of interlocked structures. However, little effort seems to have been devoted to generalizing the blue box concept. We describe a new flexible tetracationic macrocycle-a 'Texas-sized' molecular box. This positively charged receptor is capable of binding the mono-terephthalate anion, forming pseudorotaxanes. These pseudorotaxanes self-assemble into short supramolecular pseudo-oligorotaxanes in solution and more extended pseudo-polyrotaxanes in the solid state. The supramolecular oligomers formed in solution are environmentally responsive; they undergo deaggregation as the overall concentration of the cationic and anionic constituents is reduced, the temperature is increased, or the protonation state of the threading mono-terephthalate anion is changed.
Gong
Han-Yuan
HY
Department of Chemistry & Biochemistry, The University of Texas, Austin, TX 78712-0165, USA.
Rambo
Brett M
BM
Karnas
Elizabeth
E
Lynch
Vincent M
VM
Sessler
Jonathan L
JL
D000838:Anions / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007093:Imidazoles / Q000737:chemistry; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D043862:Rotaxanes / Q000737:chemistry*
D000838:Anions; D007093:Imidazoles; D047028:Macrocyclic Compounds; D043862:Rotaxanes; C029899:imidazole