Highly Fluorescent Slipped-Cofacial Phthalocyanine Dimer as a Shallow Inclusion Complex with α-Cyclodextrin

Abstract

Supramolecular control of the π-stacked configuration of aqueous phthalocyanine (Zn­[Pc­(SO₃)₄]) was achieved, allowing organization of a J-type slipped-cofacial dimer with per-<i>O</i>-methylated α-cyclodextrin (TMe-α-CDx) by the aid of host–guest interactions. Pristine Zn­[Pc­(SO₃)₄] forms nonfluorescent face-to-face aggregates in water. The π-stacked configuration was controlled in the slipped-cofacial dimer, which was formed as a shallow inclusion complex with TMe-α-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-α-CDx complex was achieved through π-stacking of the unencapsulated segment of Zn­[Pc­(SO₃)₄] shallowly encapsulated by a small TMe-α-CDx cavity