Fluorescent polymeric materials containing lipid soluble rhodamine dyes

A fluorescent polymeric material comprising a polymeric particle and at least one lipid-soluble rhodamine dye comprising the following core structure:

• wherein
• R1 and R8 are each, independently of one another, selected from the group consisting of hydrogen, (C1-C20) alkyl and halo, or one of R1 or R8 is part of an optionally substituted benzo group with R2 or R7, respectively, and the other one of R1 and R8 is selected from hydrogen, (C1-C20) alkyl and halo;
• R2 is selected from the group consisting of hydrogen, (C1-C20) alkyl and halo, or alternatively, R2 is taken together with R1 or R2′ to form part of an optionally substituted benzo group;
• R2′ is selected from the group consisting of hydrogen, (C1-C20) alkyl and halo, or alternatively, R2′ is taken together with R2 to form part of an optionally substituted benzo group, or alternatively, R2′ is taken together with R3′ to form an optionally substituted 5- or 6-membered ring;
• R3′ is selected from the group consisting of hydrogen, and (C4-C20) alkyl, or alternatively R3′ is taken together with R2′ to form an optionally substituted 5- or 6-membered ring;
• R3″ is selected from the group consisting of (C4-C20) alkyl, or alternatively R3″ is taken together with R4 to form an optionally substituted 5-membered ring;
• R4 is selected from the group consisting of hydrogen, C1-C20) alkyl and halo, or alternatively R4 is taken together with R3″ to form an optionally substituted 5-membered ring;
• R4′ is selected from the group consisting of hydrogen, (C1-C20) alkyl and halo;
• R5′ is selected from the group consisting of hydrogen, C1-C20) alkyl and halo;
• R5 is selected from the group consisting of hydrogen, C1-C20) alkyl and halo, or alternatively R5 is taken together with R6″ to form an optionally substituted 5-membered ring;
• R6′ is selected from the group consisting of (C4-C20) alkyl, or alternatively R6′ is taken together with R7′ to form an optionally substituted 5-membered ring;
• R6″ is selected from the group consisting of hydrogen, and (C4-C20) alkyl, or alternatively R6″ is taken together with R5 to form an optionally substituted 5-membered ring;
• R7′ is selected from the group consisting of hydrogen, (C1-C20) alkyl and halo, or alternatively, R7′ is taken together with R6′ to form an optionally substituted 5-membered ring, or alternatively, R7′ is taken together with R7 to form part of an optionally substituted benzo group;
• R7 is selected from the group consisting of hydrogen, (C1-C20) alkyl and halo, or alternatively, R7 is taken together with R7′ or R8 to form part of an optionally substituted benzo group;
• R11 and R15 are each hydrogen or are each F or Cl;
• R12, R13 and R14 are each hydrogen or are each F or Cl;
• wherein at least one of R3′, R3″, R6′ and R6″ is a (C4-C20) alkyl;
• and
• wherein the lipid-soluble rhodamine dye is incorporated into the polymeric particle non-covalently.