Chalcogenoxanthylium dyes for purging blood pathogens and for photodynamic therapy

1. A compound having the structure of Formula I:

wherein E is Se and A − is an anionic group selected from the group consisting of halides, sulfonates; carboxylates; hexafluorophosphate, and tetrafluoroborate; and

I)

i) W, X, Y, and Z are hydrogen;

ii) R 1 ′, R 2 ′, R 1 ″ and R 2 ″ are independently hydrogen or C 1 through C 8 branched or unbranched alkyl, and, optionally,

1) R 1 ′ and R 2 ′ are alkyl groups connected such that they comprise a 3-, 4-, 5-, 6- or 7-membered ring

which, optionally, bears alkyl or aryl substituents;

and/or

2) R 1 ″ and R 2 ″ are alkyl groups connected such that they comprise a 3-, 4-, 5-, 6- or 7-membered ring

which, optionally, bears alkyl or aryl substituents;

iii) R is a C 1 through C 8 alkyl, aryl, heteroaryl, substituted aryl or substituted heteroaryl group;

or

II)

i) W, X, Y and Z are independently hydrogen or C 1 through C 8 alkyl;

ii) R 1 ′, R 2 ′, R 1 ″ and R 2 ″ are independently hydrogen or C 1 through C 8 alkyl, and wherein R 1 ′ and Y are connected such that they comprise a five, six or seven-membered ring

and/or R 2 ′ and Z are connected such that they comprise a five-, six- or seven-membered ring

and/or R 1 ″ and W are connected such that they comprise a five-, six- or seven-membered ring

and/or R 2 ″ and X are connected such that they comprise a five-, six- or seven-membered ring:

and

iii) R is a C 1 through C 8 alkyl, aryl, substituted aryl, heterocyclic or substituted heterocyclic group.

2. A compound as claim 1 wherein R is an aryl group which is mono-, di-, or tri-substituted with one or more of the following substituents: —CO 2 Me, —CO 2 H, dialkylamino groups having alkyl groups which are independently C 1 through C 8 ; C 1 through C 8 alkyl, C 1 through C 8 alkoxy, and heterocyclic groups.

3. A compound as claim 1 wherein R is an aryl group which is mono-, di-, or tri-substituted with one or more substituents selected from the group consisting of —NMe 2 , —NHEt, —NH 2 , —Me, —OMe, 1,3-oxazole, 1,3-diazole, 4,5-dihydro-1,3-oxazole, and 4,5-dihydro-1,3-thiazole.

4. A compound as in claim 1 wherein A − is an anionic group selected from the group consisting of Cl, tosylate; and acetate.

5. A compound as in claim 1 wherein R 1 ′, R 2 ′, R 1 ″, and R 2 ″ are methyl.

6. A compound as claim 1 wherein R 1 ′, R 2 ′, R 1 ″, or R 2 ″ is an ethyl, dimethylamino or ethylamino group.

7. A compound as in claim 5 , wherein R is an aryl group which bears a heterocyclic substituent at position 2.

8. A compound of claim 1 wherein R 1 ′, R 2 ′, R 1 ″, and R 2 ″ are methyl, and R is NMe 2 , NH 2 , Me, ortho-benzoic acid, ortho-methoxybenzoate, ortho-2-amino-2-methylpropyl ester and 2,4,6-trimethylphenyl.

9. A compound of claim 8 wherein A − is chloride or hexafluorophosphate.