Supramolecular encrypted fluorescent security ink compositions

A printed substrate comprising:

• a substrate;
• and
• one or more fluorescent inks on the surface of the substrate, the fluorescent inks comprising:
• (a) a heterorotaxane comprising:
• (i) a substantially linear molecule comprising a central fluorophoric group, a first fluorophoric end group on one end of the substantially linear molecule, and a second fluorophoric end group on the opposite end of the substantially linear molecule;
• (ii) a first macrocyclic ring encircling the central fluorophoric group;
• (iii) a second macrocyclic ring encircling a portion of the substantially linear molecule between the first fluorophoric end group and the central fluorophoric group;
• and
• (iv) a third macrocyclic ring encircling a portion of the substantially linear molecule between the second fluorophoric end group and the central fluorophoric group;
• (b) an encapsulating agent comprising a macrocyclic ring encapsulating one or both of the first and second fluorophoric end groups;
• and
• (c) optionally, a competitive binding agent that competes with one or both of the first and second fluorophoric end groups for binding the encapsulating agent.

A method of authenticating a printed substrate, the printed substrate comprising:

• a substrate;
• and
• a plurality of fluorescent inks forming a polychromic image on the surface of the substrate, the fluorescent inks comprising:
• (a) a heterorotaxane comprising:
• (i) a substantially linear molecule comprising a central fluorophoric group, a first fluorophoric end group on one end of the substantially linear molecule, and a second fluorophoric end group on the opposite end of the substantially linear molecule;
• (ii) a first macrocyclic ring encircling the central fluorophoric group;
• (iii) a second macrocyclic ring encircling a portion of the substantially linear molecule between the first fluorophoric end group and the central fluorophoric group;
• and
• (iv) a third macrocyclic ring encircling a portion of the substantially linear molecule between the second fluorophoric end group and the central fluorophoric group;
• (b) an encapsulating agent comprising a macrocyclic ring encapsulating one or both of the first and second fluorophoric end groups;
• and
• (c) optionally, a competitive binding agent that competes with one or both of the first and second fluorophoric end groups for binding the encapsulating agent;
• the method comprising:
• applying an authentication reagent over the polychromic image, wherein the authentication reagent induces a change in the fluorescence emission spectrum of the polychromic image;
• and comparing the change in the fluorescence emission spectrum of the polychromic image against a known fluorescence emission spectrum change for an authentic printed substrate.