| 摘要 |
PROBLEM TO BE SOLVED: To obtain a dibenzoindocarbocyanine-based coloring matter, represented by a specific formula and capable of providing an optical information recording medium, improved in light fastness without deteriorating both optical characteristics such as reflectance and reliability even when preserved and used under sunlight. SOLUTION: This dibenzoindocarbocyanine coloring matter of formula I (R1 to R3 are each an alkyl; A is an anion such as a halogen, ClO4 <-> , BF4 <-> or formula II; X is a halogen), e.g. 1,1'-dibutyl-3,3,3',3'-tetramethyl-4,5,4',5'- dibenzoindocarbocyanine iodide bromide. Furthermore, the compound is preferably obtained by dissolving a compound having the general formula after removing X from formula I in a solvent such as chloroform, then dripping, e.g. a chloroform solution of the halogen thereinto and thermally stirring the resultant mixture solution at 40-60 deg.C for 2-4hr. |
