N-羟乙基取代2,3,3-三甲基吲哚方酸菁染料的铜离子识别性能

RECOGNITION OF N-HYDROXYETHYL SUBSTITUTED2,3,3-TRIMETHYLINDOLENINE SQUARAINE DYE TOWARDS Cu^(2+)

以2,3,3-三甲基-3 H吲哚为原料,与2-溴乙醇发生烷基化反应后得到N-羟乙基-2,3,3-三甲基-3 H吲哚溴盐中间体,再将所得的季铵盐与方酸脱水缩合反应得到方酸菁染料。在吲哚烷基化反应中,n(2,3,3-三甲基-3 H吲哚)∶n(2-溴乙醇)=1∶1.1,在78℃反应8.5h,收率为50.73%;在脱水缩合反应中,n(N-羟乙基-2,3,3-三甲基-3 H-吲哚)∶n(方酸)=2∶1,在118℃反应24h,收率为51.25%。该染料对于金属铜离子具有较高的灵敏性和选择性,方酸菁染料在铜离子作用下吸收和发射光谱中主峰均发生蓝移,且铜离子识别范围在(1~5.5)×10-5 mol/L,染料与铜离子的结合比为2∶1,推测了染料与铜离子的结合机理。

After alkylation reaction with 2-bromothanol,N-hydroxyethyl substituted 2,3,3-trimethylindolenine quaternary ammonium salts was synthesized using 2,3,3-trimethylindolenine as material.Then the final squaraine dye was obtained by the condensation reaction between prepared quaternary ammonium salts and squaric acid.The yield was 50.73 ％ in the alkylation reaction when 2,3,3-trimethylindolenine and 2-bromoethanol （molar ratio of 1 ∶ 1.1） reacted for 8.5 h at 78 ℃.The yield was 51.25％ in the dehydration condensation reaction when N-hydroxyethyl substituted 2,3,3-trimethylindolenine and squaric acid（molar ratio of 2 ∶ 1） reacted for 24 h at 118 ℃.The investigation of ion metal recognition gave the result of the high sensitive and selective recognition towards Cu2＋.Under the effect of Cu2＋,the main peak of SQ showed obvious blue shift in absorption and emission spectra and the recognition limits of Cu2＋ ranged from 1 × 10-5mol/L to 5.5 × 10-5mol/L.The study of job plot indicated that the binding ratio between SQ and Cu2＋ was 2 ∶ 1.Based on this result,a probable binding mechanism about SQ and Cu2＋ was proposed.