But, some of them still suffer from ACQ effect (Scheme 1), blocking their applications in bioimaging. 4-Dicyanomethylene-2,6-dimethyl-4H-pyran (DCM) and its derivatives are featured with highly twisted conformations, D-π-A conjugated system and tunable ICT related structure, which are usually employed as luminescent materials due to their red fluorescence and high quantum yield, , ]. ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ] Until now, to design and prepare new AIE materials with satisfied features still attracts continued interesting.
#Mettler toledo mp220 serial#
Over the past two decades, AIE based materials have gained extensive studies and achieved a serial of achievements in various fields, including OLED, biomaterials, etc. Fortunately, aggregation-induced emission (AIE), proposed firstly by Tang group in 2001, brought a brilliant way for improving the luminescent behaviors of fluorophores at high concentration or solid state. However, fluorescent materials sometimes suffer from aggregation-caused quenching (ACQ) at their high concentration or solid state, hindering their further applications, , ].
Small organic fluorescent materials, especially those for fluorescent probes and cell imaging, attract extensive attention in recent years, , ]. Significantly, the low cell cytotoxicity as well as wide pH-independence (4.0–10.0) fluorescent response towards viscosity allow them to be utilized for tracing monensin-stimulated viscosity increase in living cells. In addition, selective and sensitive fluorescence responses of ImDCM-1 and ImDCM-2 towards viscosity can be observed. In contrast, ImDCM-2 exhibits a distinct red-shift and further enhancement in emission with water fraction increasing from 70% to 80%, then the further increment of water induces decrease in emission, which may be ascribed to formation of J-aggregates, followed by size and solubility changes of aggregates. The further increasing water leads to fluorescence bathochromic-shift and enhancement of ImDCM-1, probably arising from variation in size and solubility of aggregates. Two imidazole decorated 4-dicyanomethylene-2,6-dimethyl-4H-pyran (DCM) derivatives, namely ImDCM-1 and ImDCM-2, have been designed and synthesized, which show aggregation-induced emission (AIE) features in THF-water mixture due to inhibition of intramolecular rotation (water fractions 80% and 70% for ImDCM-1 and ImDCM-2, respectively).