Synthesis of Near Infrarad Absorbing Dyes Derived from (Dialkylamino) thiazole Dimers

由于(二烷氨基)噻唑二聚体表现出很强的给电子能力，这些化合物在染料化学中是很有趣的材料。本文研究了由(二烷氨基)噻唑二聚体合成的偶氮染料和吲哚类染料的合成、结构和紫外-可见吸收光谱。通过芳胺重氮化，然后与(二烷氨基)噻唑二聚体偶联，以中等产率合成了偶氮染料。偶氮染料的一、二次吸收峰分别位于568-737(ε=24000-88000)和404-475(ε=9200-52000)nm。2)双噻唑基为平面结构，苯基和双噻唑基之间的二面角为8.5°，偶氮染料为平面结构。3)具有很强吸电子取代基的偶氮染料，如4-(全氟烷基磺酰基)-和2，4-二硝基苯基，在溶剂变色反应中观察到负性溶剂变色现象。其中以四氟硼酸镍(II)的效果最好。1)在648-725 nm处观察到第一吸收带(ε=3900-55000)；2)根据取代基和分子轨道计算，这些受阻染料表现为分子内电荷转移发色体系。3)双噻唑基和芳氨基之间的二面角越接近垂直方向，化合物越深色，这是由于HOMO能级的增加，因此，(二烷氨基)噻唑二聚体是非常独特的化合物。本研究制备的偶氮染料和吲哚青染料在近红外区出现了第一吸收带。这些信息在染料化学领域是全新的。

Since (dialkylamino) thiazole dimers show very strong electron-donating ability, these compound are interesting materials in dyes chemistry. The synthesis, structure, and UV-Vis absorption spectra of azo and indamine dyes deerived from (dialkylamino) thiazole dimers are examined in this report.Azo dyes were synthesized by the diazotization of arylamines followed by coupling with (dialkylamino) thiazole dimers in moderate yields. The azo dyes showed 1) the first and second absorption were abserved at 568-737 (ε=24000-88000) and 404-475 (ε=9200-52000) nm, respectively. 2) bithiazolyl moiety was planar and the dihedral angle between the phenyl and bithiazolyl moieties were 8.5 degree, the azo dye being planar. 3) the nagative solvatochromism was observed for azo dyes having very strong electron-withdrawing substituents such as the 4-(perfluoroalkylsulfonyl)- and 2,4-dinitrophenyls.Indamine dyes were obtained by the reaction of (dialkylamino) thiazole dimers with arylnitroso compounds followed by heating with metal salts in low to moderate yields. Nickel (II) tetrafluoroborate was the best one. 1) the first absorption bands were observed at 648-725 nm (ε=3900-55000), 2) these indamined dyes are found to show intramolecular charge-transfer chromophoric system on the basis of substituent and MO calculation. 3) the near the dihedral angle between the bithiazolyl and arylamino moieties to parpendicular, the more bathochromic the compound, due to increase in the energy level of HOMO.Thus, (dialkylamino) thiazole dimers are very unique compounds. Azo and indamine dyes prepared in this study showed their first absorption bands in the near infrared reagion. These informations are completely new in the field of dye chemistry.