Journal of Physical Chemistry A, Vol.116, No.21, 5139-5144, 2012
Highly Fluorescent Slipped-Cofacial Phthalocyanine Dimer as a Shallow Inclusion Complex with alpha-Cyclodextrin
Supramolecular control of the pi-stacked configuration of aqueous phthalocyanine (Zn[Pc(SO3)(4)]) was achieved, allowing organization of a J-type slipped-cofacial dimer with per-O-methylated alpha-cyclodextrin (TMe-alpha-CDx) by the aid of host-guest interactions. Pristine Zn[Pc(SO3)(4)] forms nonfluorescent face-to-face aggregates in water. The pi-stacked configuration was controlled in the slipped-cofacial dimer, which was formed as a shallow inclusion complex with TMe-alpha-CDx, giving remarkably enhanced fluorescence with a very small Stokes shift. Organization of the J-type slipped-cofacial dimer as a 2:2 Zn[Pc(SO3)(4)] TMe-alpha-CDx complex was achieved through pi-stacking of the unencapsulated segment of Zn[Pc(SO3)(4)] shallowly encapsulated by a small TMe-alpha-CDx cavity.