Yi Wen,Zhou Cheng,Wenxiong Li,Zhi Li,Duijun Liao,Xiaoping Hu,Ning Pan,Deyi Wang,T. Richard Hull
A novel oligomer (PFDCHQ) based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene −10-oxide (DOPO) and ferrocene groups was synthesized successfully, aiming at improving the flame retardant efficiency of diglycidyl ether of bisphenol A epoxy resin (DGEBA). FTIR , 1 H NMR and 31 P NMR were used to confirm the chemical structure of PFDCHQ. The high char yields of 60.3 wt% and 20.1 wt% were obtained for PFDCHQ from TGA results in nitrogen and air atmosphere, respectively. The thermal degradation mechanism of PFDCHQ was investigated by TG-FTIR and Py-GC/MS. The limiting oxygen index (LOI) of EP-5 with 5 wt% loading of PFDCHQ increased to 32.0% and the UL-94 V-0 rating was achieved, showing a notable blowing-out effect. In contrast to EP-0, the peak of the heat release rate (pHRR) and total heat release (THR) of EP-5 decreased by 18.0% and 10.3%. The flame retardant mechanism of PFDCHQ in epoxy resin was studied by TG-FTIR, SEM and Raman. SEM and Raman results indicated the formation of coherent and dense char residue with high degree of graphitization due to the incorporation of PFDCHQ. In UL-94, the blowing-out effect dominantly accounted for the enhanced flame retardancy in combination with optimized char structure. Furthermore, the addition of PFDCHQ improved the Young's modulus compared to EP-0.
In this work, a novel tetra-amine, bis (4-(3, 5-bis (4-amino-2-(trifluoromethyl) phenoxy) phenoxy) phenyl) methanone, was synthesized and then utilized to produce hyperbranched polyamic acids via polycondensation with 4, 4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The resulting hyperbranched polyamic acids underwent termination by (4-amino) phenyl ferrocene and imidization, leading to ferrocene-terminated hyperbranched polyimide (HBPI-Fc). The resulting HBPI-Fc displayed superior solubility in conventional organic solvents and excellent thermal stability. A memory device with a configuration of indium tin oxide (ITO)/HBPI-Fc/Al was fabricated, in which the HBPI-Fc acted as the active layer. The device exhibited bistable electrical conductivity switching and nonvolatile bipolar write-once-read-many-times memory character with two threshold voltages of 2.2 V and −2.6 V, respectively, during positive and negative voltage sweep. The device exhibited an ON/OFF current ratio of 10 4 under a constant bias of −1.0 V and good stability in both ON- and OFF-state during the test period of 10 4 s. The revealed electrical bistability of the HBPI-Fc was found mainly due to the effective charge trapping effect of the electroactive terminal ferrocene groups.
Owing to the lack of target-directed therapies, triple-negative breast cancer (TNBC) is difficult to effectively treat. In this article, a novel organometallic histone deacetylase (HDAC) inhibitor, Fc-SelSA, based on the selenocyanide (SelSA) zinc-binding motif, was synthesized using a ferrocenyl group as the cap to confer activity against TNBC. The synthesized Fc-SelSA was evaluated for bioactivity in vitro and in vivo. An enzymatic assay showed that Fc-SelSA was a potent HDAC inhibitor with a half-maximum inhibitory concentration (IC50) of 14.8 nM. Molecular docking studies of Fc-SelSA with HDAC suggested that the ferrocenyl unit overlaps with the phenyl group of suberoylanilide hydroxamic acid (SAHA) and the amido group of Fc-SelSA can form hydrogen bonds with the D98 and G151 residues of HDAC, but SAHA and SelSA do not show similar interactions. Moreover, Fc-SelSA reactivated the estrogen receptor alpha (ERα) expression, sensitized TNBC cells to the antagonist tamoxifen, and exerted more potent antitumor effects against TNBC MDA-MB-231 tumor xenografts in comparison to SelSA with no obvious side effects. Our results indicate that Fc-SelSA is a potent oral anticancer candidate for HDAC-targeted TNBC therapy and deserves further investigation for clinical application.
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