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

由于（二烷基胺）噻唑二聚体具有很强的给电子能力，是染料化学研究中的重要材料。本文研究了由（二烷基胺）噻唑二聚体衍生的偶氮染料和吲哚胺染料的合成、结构和紫外-可见吸收光谱。采用芳胺重氮化、二烷基胺噻唑二聚体偶联法制备偶氮染料。偶氮染料在568 ~ 737 nm （ε=24000 ~ 88000）和404 ~ 475 nm （ε=9200 ~ 52000）处分别有一、二次吸收。2)偶氮染料为平面染料，苯基与双噻唑基的二面角为8.5度。3)偶氮染料具有很强的吸电子取代基，如4-（全氟烷基磺酰基）-和2,4-二硝基苯，观察到负溶剂变色。用（二烷基胺）噻唑二聚体与芳基亚硝基化合物反应，再用金属盐加热，以中低收率制得吲哚明染料。四氟硼酸镍为最佳。1)在648 ~ 725 nm （ε=3900 ~ 55000）处观察到第一个吸收带；2)根据取代基和MO计算发现这些受损染料表现出分子内电荷转移显色体系。3)双噻唑基和芳胺基之间的二面角越接近于垂直，由于HOMO能级的增加，化合物越显色。因此，（二氨基）噻唑二聚体是非常独特的化合物。偶氮染料和吲哚明染料在近红外区出现第一吸收带。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.