Synthesis And Properties Of Isocyanide Or Carbene Coordinated Gold(Ⅰ) Complexes

Highly efficient fluorescent compounds have attracted attention due to their wide application.For all we know,many organic fluorescent dyes are usually utilized in the form of solid or thin film.However,many luminophores emit brightly emission in dilute and are often quenched at condensed solutions.The kind of phenomenon is defined as"aggregation-caused quenching"(ACQ).The existence of quenched compounds has seriously hampered the development of materials science.Until 2001,Academician Tang Benzhong discovered the phenomenon of "aggregation-induced luminescence(AIE)".The AIE phenomenon is absolutely antithesis to the disgusting ACQ effect.The AIE conquers ACQ puzzle and indicates a new approach towards practical application for efficient aggregated luminescent compounds.Emitters with AIE characteristics tend to have weak interactions between molecules,such as π-π interactions,Van der Waals forces,and hydrogen bonds.These interactions are susceptible to external stimuli(light,electricity,heat,pressure)that change their fluorescent emissive.According to the above background,it is of great significance to synthesize luminescent compounds that are sensitive to external stimuli and show AIE properties at the same time.Based on a large number of literature investigations,in this article,some organometallic fluorescent compounds that have AIE and sensitivity to external stimuli was synthesized through a mature reaction route.A pentafluorobenzene structure with a unique effect was introduced into the fluorene unit,and in combination with the coordination ability of isocyanide or carbene,some gold(I)complexes with AIE and stimuli-responsive properties were synthesized.The main research contents are shown as following:(1)Five gold(I)complexes with three fluorene units have been designed and synthesized.The structures of the five target molecules were characterizedby1H NMR,13C NMR,19F NMR spectroscopy and elemental analysis,and the target molecule Ⅱ-4 was affirmed by X-ray single crystal diffraction.The research result of photophysical properties indicated that the target molecules Ⅱ-1,Ⅱ-2 and Ⅱ-3 showed solvatochromism and aggregation-induced fluorescence change characteristics.Target molecule Ⅱ-2 showed fluorescence-changing properties of concentration response.The target molecules Ⅱ-4 and Ⅱ-5 do not have solvatochromism and aggregation-induced fluorescence change properties.(2)we designed and synthesized four gold(Ⅰ)complexes Ⅲ-1-Ⅲ-4 with double isocyanide coordination and four gold(Ⅰ)complexes Ⅲ-5～Ⅲ-8 with double carbene coordination.The eight target molecules were characterized by 31P NMR,1H NMR,13C NMR spectroscopy and high resolution mass spectrometry to confirm their structure.The research result of photophysical properties indicated that the target complexe Ⅲ-1 exhibited polymorphism and emitted yellow-green or blue fluorescence in different aggregation systems,and the target complexes Ⅲ-2 and Ⅲ-4 showed both aggregation-induced emission(AIE),thermochromism and vapochromism characteristics.Ⅲ-3 exhibited vapochromism characteristic at low temperature and aggregation-induced emission(AIE)property.The complexes Ⅲ-5 to Ⅲ-8 are bicarbene compounds containing different anions,and the anions have some influence on their luminescent color.The complexes Ⅲ-5,Ⅲ-6 and Ⅲ-8 all exhibited aggregation-induced emission(AIE)properties.The difference in fluorescence color of the above gold(Ⅰ)complexes is related to the Au-Au interaction intramolecular.The shorter the Au-Au distance endows the red shift of the fluorescence;the longer the Au-Au distance brings the blue shift of the fluorescence.