Method for converting perylen-3,4:9,10-tetracarboxylic acid diimides into a form suitable for use as a fluorescent dye

Abstract

Novel crystalline forms of and a process for converting perylene-3, 4:9, 10-tetracarboximide of the general formula I to a form used as a fluorescent dye. The process including: a) dissolving or suspending the perylene-3, 4:9, 10-tetracarboximide in a solvent to obtain a solution or suspension; and b1) cooling the solution obtained in step a) to a temperature at or below the crystallization temperature of the perylene-3, 4:9, 10-tetracarboximide and, if the solvent is organic, removing excess solvent until the first crystals form, otherwise, adding water or dilute aqueous solutions of the solvent until the first crystals form, and maintaining the solution at that temperature for further crystallization; or b 2 ) cooling the suspension obtained in step a) to or below the crystallization temperature when the temperature in step a) was above the crystallization temperature, and maintaining the suspension at the temperature for further crystallization to form one or more solvate crystals.

1 . A process for converting a perylene-3, 4:9, 10-tetracarboxylic diimide of formula I 
     
       
         
         
             
             
         
       
       to a fluorescent dye, 
       wherein R 1  and R 2  are each unbranched, branched or cyclic C 1 -C 8 -alkyl,
 said process comprising: 
 a) dissolving or suspending said perylene-3, 4:9, 10-tetracarboxylic diimide in an organic or inorganic solvent, said solvent having a molecular volume of ≦230 Å 3 , at a first temperature of from 0 to 250° C. to obtain a solution or a suspension, 
 b) cooling said solution or said suspension obtained in step a) by a process consisting of b1) or b2),
 b1) cooling said solution obtained in step a) to a second temperature at or below the crystallization temperature of said perylene-3, 4:9, 10-tetracarboxylic diimide of formula I and, in the case of an organic solvent, if desired at the same time removing excess solvent until the first crystals form, or, in the case of an inorganic solvent, adding water or dilute aqueous solutions of the solvent until the first crystals form, wherein further crystallization continues in said solution at said second temperature after the first crystals form, or 
 b2) cooling said suspension obtained in step a) to said second temperature at or below the crystallization temperature when the temperature in step a) was above the crystallization temperature, wherein further crystallization continues in said solution at said second temperature after the first crystals form to form one or more solvate crystals, 
 
 c) isolating said one or more solvate crystals formed in step b) and 
 d) then removing said solvent from said one or more solvate crystals. 
 
     
   
   
       2 . The process according to  claim 1 , wherein said solvent is
 a di-C 1 -C 4 -alkyl sulfoxide; a sulfolane;   an unsubstituted or N—C 1 -C 6 -alkyl-substituted C 4 -C 6 -lactam;   an unsubstituted or N—C 1 -C 6 -alkyl-substituted aliphatic C 1 -C 6 -carboxamide;   an aliphatic nitrile having from 2 to 12 carbon atoms; an aromatic nitrile which may be substituted by C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy and/or halogen;   an aliphatic C 1 -C 12 -carboxylic acid or a C 1 -C 6 -alkyl ester thereof having a total number of carbon atoms of less than or equal to 12;   a hydroxy-C 2 -C 6 -carboxylic acid or an ester thereof;   a C 2 -C 6 -alkylene carbonate;   a benzoic acid; a naphthoic acid;   a C 1 -C 8 -alkyl benzoate, a di-C 2 -C 4 -alkyl phthalate;   a monohydric or polyhydric, saturated or unsaturated, aliphatic or cycloaliphatic C 4 -C 12 -alcohol; an araliphatic alcohol;   a mono- or oligo-C 2 -C 3 -alkylene glycol mono- and -di-C 1 -C 8 -alkyl- and monophenyl ether;   an aliphatic C 3 -C 12 -ketone; an aromatic ketone which may be substituted by C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy and/or halogen;   an aliphatic or cycloaliphatic C 4 -C 12 -ether; an aromatic ether which may be substituted by C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy and/or halogen;   a heterocycle;   an aromatic hydrocarbon which may be substituted by C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy, C 1 -C 6 -alkylamino, di-C 1 -C 3 -alkylamino, chlorine and/or nitro;   an aliphatic or cycloaliphatic C 6 -C 18 -hydrocarbon; a chloro hydrocarbon;   or a mixture or combination thereof.   
   
   
       3 . A crystalline solvate of said perylene-3,4:9,10-tetracarboxylic diimide of the formula I according to  claim 1 , which comprises 1 or 2 mol of solvent per mole of perylene-3,4:9,10-tetracarboxylic diimide. 
   
   
       4 . A method for coloring one or more organic and/or inorganic polymeric materials, said method comprising applying the fluorescent dye obtained by the process according to  claim 1  to said one or more organic and/or inorganic polymeric materials. 
   
   
       5 . A method for producing an electrooptical component, said method comprising incorporating the fluorescent dye obtained by the process according to  claim 1  to said electrooptical component as one or more emitter materials.