Synthesis and properties of tribranched chromophores with triazine and fluorene units

Two tribranched chromophores,1,3,5-triazine as electron deficient core,9,9-dimethylfluorene asπ-conjugated bridge, diphenylamino(4a) and naphthylamino(4b) as electron-donating end-groups,were successfully prepared via Buchwald-Hartwig coupling reaction.Their linear photophysical and two-photon absorption(TPA) properties were investigated by absorption, fluorescence and nonlinear transmission method,respectively.The absorption cut-offs of the chromophores are below 550 nm and both chromophores have strong fluorescence emission.The compound 4a(206.3 GM) exhibits larger TPA cross-section than 4b (57.8 GM) in the femtosecond regime at 800 nm.     

Using Two Simple Methods of Ar?ArF Self‐Assembly and Isolation Chromophores to Further Improve the Comprehensive Performance of NLO Dendrimers

Herein, through a combination of divergent and convergent approaches, coupled with the utilization of the powerful Sharpless “click chemistry” reaction, two series of high‐generation nonlinear optical (NLO) dendrimers have been conveniently prepared in high purity and satisfactory yields. Perfluoroaromatic rings and isolation chromophores were introduced to further improve their comprehensive performance. Thanks to the effects of Ar? Ar^F self‐assembly and the isolation chromophores, coupled with perfect 3D spatial isolation from the highly branched structure of the dendrimer, G5‐PFPh‐NS displayed very large NLO efficiency (up to 257 pm V^?1), which is, to the best of our knowledge, the new record highest value reported so far for simple azo chromophore moieties. High‐quality wide optical transparency and good stability were also achieved.     

Efficient synthesis of β‐(1,6)‐linked oligosaccharides through microwave‐assisted glycosylation

A microwave‐assisted glycosylation method was developed for efficient synthesis of oligosaccharides. Di‐functional AB monomers, 2,3,4‐tri‐O‐acetyl‐α‐d ‐galactopyranosyl bromide ( 3a ) and 2,3,4‐tri‐O‐acetyl‐α‐d ‐glucopyranosyl bromide ( 3b ) were designed and synthesized as weakly reactive monomers to avoid unwanted glycosylation or degradation during preparation and storage. The glycosylations of these monomers gave low conversions and low molecular weight oligosaccharides at rt, reflux, and under low microwave energy irradiation. However, the glycosylation became very effective when high microwave energy was applied, giving 100% conversion and producing oligosaccharides with M_n = 4.76 kDa for 3a and M_n = 4.05 kDa for 3b. The acetylated oligosaccharides were further subjected to deprotection for structural analysis, which indicated the oligosaccharides contain predominantly linear β‐(1,6)‐glycosyl linkages. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3693–3699     

Water‐soluble fluorene‐based copolymers incorporated methoxyphenol moieties: Novel polymeric chemodosimeters for hypochlorous acid

A series of water‐soluble copolymers, named N‐PFPx (x = 10, 25, and 50), and their model compound 6,6',6'',6'''‐(2,2'‐(2‐hydroxy‐5‐methoxy‐1,4‐phenylene)bis(9H‐fluorene‐9,9,2‐triyl))tetrakis(N,N,N‐trimethylhexan‐1‐aminium) bromide (FMOPF) were synthesized by Suzuki coupling reaction of fluorene derivatives and p‐methoxyphenol. For the polymers with relatively low contents of methoxyphenol (N‐PFP10 and N‐PFP25), the absorption and fluorescence spectra could be mainly ascribed to the polyfluorene, whereas for the polymer N‐PFP50 and the model compound FMOPF, the absorption and fluorescence spectra could be assigned to the fluorene‐alt‐methoxyphenol. All the conjugated polymers (CPs), regardless of the content of methoxyphenol moieties, exhibit good sensitivity to hypochlorite/hypochlorous acid (HClO) because of the superquenching effect of CPs. On the contrary, the absorption changes of the polymers N‐PFPx on the addition of hypochlorite/HClO depend on the content of methoxyphenol moieties. As the content of methoxyphenol moieties increase, the changes of absorption spectra become more intense. Considering the sensitivity and selectivity, the polymer N‐PFP10 and N‐PFP25 have been demonstrated to be good polymeric fluorescent probes to hypochlorite under the aqueous condition. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Regioirregular ambipolar naphthalenediimide‐based alternating polymers: Synthesis,characterization, and application in field‐effect transistors

In this work, we report the synthesis, characterization, and application of two regioirregular naphthalenediimide (NDI)‐based alternating conjugated polymers, namely P1 and P2 , in which nitrile‐substituted moiety, 2,3‐bis(thiophen‐2‐yl)acrylonitrile and NDI moiety act as donor and acceptor unit, respectively. The two regioirregular polymers possess low‐lying LUMO energy levels of ?3.92 eV for P1 and ?3.96 eV for P2 . Both polymers possess typical dual‐band UV?Vis?NIR absorption profiles of NDI‐based polymers, and show broadened and red‐shifted absorption spectra in the solid state compared with those in solutions. Field‐effect transistor devices with top‐gate bottom‐contact configuration were used to evaluate the polymers' semiconducting properties. The two polymers exhibited promising and air‐stable ambipolar charge transport characteristics. Thin film microstructure investigations (AFM and 2D‐GIXRD) suggest both polymers formed continuous and smooth thin films, and adopted predominantly face‐on molecular packing in the solid state. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3627–3635