Design,Synthesis And Properties Investigation Of Π-bridged Phenyls And Ninhydrin Hydrazones Based D-A Type Probes

A D-π-A(or D-A)type organic molecule,consisting of an electron donor,π-skeleton,and an electron acceptor,has been widely applied to some fields such as sensors,organic field-effect transistors(OFETs),organic light-emitting diodes(OLEDs),organic photovoltaic cells(OPVs)and even organic lasers functional materials due to intramolecular charge transfer property(ICT).Therefore,it has attracted a lot of attention from researchers.It is no doubt that changing π-spacer can affect ICT,which is an effective strategy to modify the performance of D-π-A molecules.In order to investigate the influence of π-bridged basic units(benzene ring and C = C)on ICT and to modify the detection performance of the probe,we used methoxy group as electron donor group(D),dicyanovinyl group as acceptor units(A)to design and synthesize three D-π-A molecules with benzene ring or C = C as π-spacer.Their photophysical properties were determined by UV-vis absorption spectra and fluorescence spectra and their structure characteristics were analyzed by X-ray diffraction of single crystals(XRD).The experimental data show that using C = C instead of the benzene ring will lead to the red shif of UV-vis absorption spectra and fluorescence spectra,and the fluorescence intensity(quantum yield)will also decrease significantly.Then,they were used as the sensor to detect hydrazine,the detection limits of them were 5.82 μM,2.64 μM and 1.28 μM.The investigation on the response mechanism revealed that the dicyanovinyl group reacts with hydrazine to produce the corresponding hydrazone,leaded to break of the intramolecular charge transfer(ICT)and resulted in the change of UV-vis absorption spectrum and fluorescence spectrum.Finally,the visual detection of gaseous hydrazine was successfully realized by using a paper strip based on 1-3.In addition,two ninhydrin hydrazones compounds of SBR-1 and SBR-2 were synthesized from ninhydrin hydrate and phenylhydrazine as raw material.The two compounds were characterized by NMR,HRMS and XRD,and were applied to the detection of iodide ions.