Unsymmetrical methine and polymethine dye-molecules for fluorescent intracellular applications

An unsymmetrical dye having the formula:

• wherein R represents a group of from 1 to 25 carbon atoms and is selected from the group consisting of alkyl, alkenyl, aralkyl, hydroxyalkyl, alkoxyalkyl, aryloxyalkyl, aminoalkyl, carboxyalkyl, and arylthioalkyl, the ring containing Z1 is monocyclic pyridinium and wherein Z1 can be substituted with one or more substituents selected from the group of lower alkyl, nitro, halogen, carboxyl, sulfonic acid, amino and phosphoric groups, Y1 represents a group containing non-metallic atoms necessary to complete a cyclic or polycyclic ring with the atoms to which it is attached and may contain one or more members from the group consisting of nitrogen, oxygen, selenium, or sulfur and up to 25 carbon atoms and can be substituted with one or more substituents selected from the group consisting of lower alkyl, nitro, halogen, carboxylic, sulfonic, hydroxyl, primary amino, secondary amino groups, and wherein Q represents ═CH—, ═CH—CH═CH—, or ═CH—CH═CH—CH═CH—groups X−is an anion selected from the group consisting of Cl−, Br−, I−, ClO4−, SO4−2, CH3COO—, and CH3CH2COO—, with the proviso that when Y1 is nitrogen Q is not ═CH—.