Synthesis and characterization of excited state intramolecular proton transfer based 2-hydroxylaryl imidazole fluorescent materials

Dynamics of Intramolecular Excited State Proton Transfer in Emission Tunable, Highly Luminescent Imidazole Derivatives

“…The luminescence property of each dye was compared to that of the corresponding, non-ESIPT reference compound, in which proton transfer was deliberately blocked. The spectroscopic properties of the new samples compare quite well with those of similar imidazole-based ESIPT compounds …”

Realizing Molecular Pixel System for Full-Color Fluorescence Reproduction: RGB-Emitting Molecular Mixture Free from Energy Transfer Crosstalk

“…The hydroxy-substituted tetraphenylimidazole derivatives are typical ESIPT molecules, which emit strong fluorescence not merely in the solution but more intensely in the solid state. It is rationalized that the steric crowding of the four phenyl rings prevents tight stacking of the active chromophores, thereby maintaining appropriate intermolecular distances to suppress intermolecular nonradiative decay pathways. − A highly efficient amplified spontaneous emission as well as organic light-emitting diodes (OLEDs) was successfully demonstrated with the ESIPT-active imidazole molecules incorporating multifunctional substituents. ,,, Although we have already developed and demonstrated a series of nine imidazole ESIPT derivatives whose emission wavelength was widely tuned from 470 to 630 nm, they still lack one exhibiting green K* emission (500 nm < λ max < 550 nm). In addition, the highest energy emitting fluorophore, 2-(1,4,5-triphenyl-1 H -imidazol-2-yl)phenol (HPI, λ max = 472 nm, Figures b and a) in the series does not show deep blue emission but only sky blue emission, which is rather insufficient for the full-color reproduction.…”

Application of Multi-component Reaction in Synthesis of Multi- substituted Imidazoles

“…辛烷(DABCO) [31] 、生物柴油碳基催化剂(bioglycerolbased carbon catalyst) [32] 、L-脯氨酸(L-Proline) [33] , 溴代磷 酸二乙酯(DEP, diethyl bromophosphate) [34] 和醋酸 [35] [36] , 产率为 71%～96%. 合成 表 2 不含金属的催化剂催化合成多取代咪唑 Table 2 Synthesis of multi-substituted imidazoles catalyzed by metal-free catalyst [38] 、四氟化硼 1-丁基咪唑 盐 ([Hbim]BF 4 ) [39] [40] 、N-甲基-2-吡咯烷酮硫酸氢盐([NMP]-HSO 4 ) [41] 、1,3-吡啶二磺酸硫酸氢盐([Dsim]HSO 4 ) [42] 、1-甲基咪唑三氟乙酸盐([Hmim]TFA) [43] , 以及负载型离子 液体 SILLP [44] 1 The structure of some ionic liquids 表 3 离子液体催化剂催化合成多取代咪唑 Table 3 Synthesis of multi-substituted imidazoles catalyzed by ionic liquids 3, Entries 1, 7) [39,44] 或 微波辐射(Table 3, Entry 3) [40] , 会大幅度缩短反应时间, 如以二醛为原料, 在微波辐射 2～6 min, 在中性离子液 体[HeMIM]BF 4 中合成双三取代咪唑衍生物 [40] [48] 、硅藻土 K10 负载钛催化剂(K10-Ti) [49] 、 硅胶负载高氯酸(SiO 2 -HClO 4 ) [50] 、硅胶负载硫酸氢钠 (SiO 2 -NaHSO 4 ) [51] 、3-哌嗪-N-丙基硅烷(3-PNPS)负载氯 磺 酸 (SBPPSA) [52] 、 改 性 硅 胶 负 载 ( 偶 联 ) 硫 醇 (mercaptopropylsilica, MPS) [53] [54] 、磺化淀粉或硅胶负载型 AlCl 3 [CSC-star-SO 3 -AlCl 2 ] [55] 、 含 磺 酸 基 的 聚 合 物 poly-(AMPS-co-AA) [56] , 甚至硅胶 [57] 图 2 部分负载催化剂的结构 Figure 2 The structure of some supported catalyst 表 4 负载型催化剂催化合成多取代咪唑 Table 4 Synthesis of multi-substituted imidazoles catalyzed by supported catalyst 应, 反应时间需延长, 而产率也会有所降低 [51] (Table 4, Entries 5, 8).…”