| 摘要 |
[PROBLEMS] To provide near infrared ray absorbing compounds which are free from antimony and arsenic and which are excellent in stability, particularly in heat resistance, light fastness, and moist heat resistance; and infrared ray absorption filters and optical recording media, which are made by using the compounds and which are excellent in heat resistance and so on. [MEANS FOR SOLVING PROBLEMS] Diimonium compounds represented by the general formula (1) and near infrared ray absorption filters made by using the compounds: (1) wherein R1 to R8 are each independently hydrogen or an optionally substituted aliphatic hydrocarbon group; R9 to R10 are each independently an optionally halogenated aliphatic hydrocarbon group; R11 is substituted or unsubstituted aryl; and A and B may be substituted.
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