Xanthene compounds having a wavelength in the range from 650 to 1200 nm

A compound of the formula:

• wherein
• R1 and R2 are independently of each other a group of formula
• R3 is hydrogen, —CO2H, or —SO3H;
• R4 is —SO3−, or a group of formula —SO2NR12R13,
• wherein when R4 is not negatively charged, the compound of the formula (I) comprises an anionic counterion;
• R5 is a C1-C24alkyl group, a C3-C10-cycloalkyl group, substituted with one or more substituents R14, a C6-C10aryl-C1-C10alkylene, wherein may be substituted with one or more substituents R14 and the alkylene group may be interrupted by one or more nonadjacent groups selected from 0, S and —NR9;
• a C6-C10aryl group, which may be substituted with one or more substituents R14, or a C2-C14heteroaryl group, which may be substituted with one or more substituents R14;
• R6 is hydrogen, a C1-C24alkyl group, a C1-C24alkoxy group, a C6-C10-aryl group, which may be substituted with one or more substituents R14, and a C1-C24-fluoroalkyl group, fluorine, chlorine or bromine;
• R7 is a C1-C24alkyl group, a C1-C24alkoxy group, a C1-C24-fluoroalkyl group, a group NR10R11, fluorine, chlorine or bromine;
• R8a, R8b and R8c, independently of each other, are selected from a C1-C24alkyl group, a C1-C24alkoxy group, a C1-C24-fluoroalkyl group, fluorine, chlorine or bromine;
• R9 is hydrogen, or a C1-C4alkyl group;
• R10 and R11 independently of each other a C1-C24alkyl group, a hydroxy-C1-C24alkyl group, a C6-C10-aryl group, which may be substituted with one or more substituents R14, or a C3-C10-cycloalkyl group, substituted with one or more substituents R14;
• or
• R10 and R11 together with the nitrogen to which they are bonded form a five, or six membered ring system, which may be interrupted by —O—, —S—, or —NR12′— and may be part of a fused ring system, which may be substituted with one or more substituents R14;
• R12 and R13 are independently of each other hydrogen, a C1-C24alkyl group, a hydroxy-C1-C24alkyl group, a C3-C10-cycloalkyl group, substituted with one or more substituents R14, a C6-C10aryl-C1-C10alkylene, wherein may be substituted with one or more substituents R14 and the alkylene group may be interrupted by one or more nonadjacent groups selected from O, S and —NR12′;
• a C6-C10aryl group, which may be substituted with one or more substituents R14, or a C2-C14heteroaryl group, which may be substituted with one or more substituents R14;
• or
• R12 and R13 together with the nitrogen to which they are bonded form a five, or six membered ring system, which may be interrupted by —O—, —S—, or —NR12′— and may be part of a fused ring system, which may be substituted with one or more substituents R14′;
• R12′ is hydrogen, or a C1-C4alkyl group;
• R14 is a C1-C10alkyl group, a C1-C10alkoxy group, a C1-C10fluoroalkyl group, a nitro group, a cyano group, a hydroxy group, fluorine, chlorine or bromine;
• R14′ is a C1-C10alkyl group, a C1-C10alkoxy group, a C1-C10fluoroalkyl group, a nitro group, a cyano group, a hydroxy group, a —(CH2)n5COOH group, a —(CH2)n5COO− group, fluorine, chlorine or bromine;
• and
• n1 is 0, 1, or 2;
• n2 is 0, 1, or 2, n3 is 0, or 1, n4 is 0, 1, or 2 and n5 is 0, or an integer 1 to 10.