摘要 |
A pharmaceutically pure form of a seleno- or telluropyrylium dye having the following structural formula: <CHEM> wherein R<1>, R<4>, R<5>, and R<8> are selected from hydrogen, aryl, heteroaryl, or alkyl from one to twelve carbon atoms; R<2>, R<3>, R<6>, and R<7> are selected from hydrogen, alkyl, aryl, alkylthio, arylthio, alkylseleno, arylseleno, alkyltelluro or aryltelluro of from one to twelve carbon atoms; halogen; hydroxy; alkoxy; and amino; R<9>, R<1><0>, and R<1><1> are selected from hydrogen, alkyl and alkoxy of from one to twelve carbon atoms, halogen and cyano; n is 0, 1, or 2; X<1> and X<2> are chalcogenides different from each other except that one is either Se or Te, and Z<-> is a Lewis base. |