Exploring a Redox-Active Ionic Porous Organic Polymer in Environmental Remediation and Electrochromic Application.

Here, we report the design and synthesis of a redox-active multifunctional ionic porous organic polymer iPOP-Bpy with exchangeable Br- ions, incorporating viologen as a redox-active building block. The material shows not only excellent iodine uptake capacity in the vapor phase (540 wt %) but also in the organic (1009.77 mg g-1) and aqueous phases (3921.47 mg g-1) with very fast adsorption kinetics in all cases. The material also shows its utility in being used as a solid-state NH3 vapor sensor as it shows very fast color switching in the presence of NH3 vapor. Furthermore, the material found application as a p-type complementary electrochromic electrode and was fabricated into a bilayer device. Excellent coloration efficiency, high switching speed, and good color contrast were obtained as investigated using bias-dependent optical and spectroelectrochemical studies, paving the way for fabricating power-efficient solid-state electrochromic devices.

Cancer-Targeted Chitosan-Biotin-Conjugated Mesoporous Silica Nanoparticles as Carriers of Zinc Complexes to Achieve Enhanced Chemotherapy In Vitro and In Vivo.

Despite being the most common component of numerous metalloenzymes in the human body, zinc complexes are still under-rated as chemotherapeutic agents. Herein, the present study opens up a key route toward enhanced chemotherapy with the help of two ZnII complexes (ZnMBC) synthesized alongside Mannich base ligands to upsurge biological potency. Further, well-established mesoporous silica nanoparticles (MSNs) have been chosen as carriers of the titled metallodrugs in order to achieve anticancer drug delivery. A pH-sensitive additive, namely, chitosan (CTS) conjugated with biotin is tagged to MSNs for the targeted release of core agents inside tumors selectively. In general, CTS blocks ZnMBC inside the mesopores of MSNs, and biotin acts as a targeting ligand to improve tumor-specific cellular uptake. CTS-biotin surface decoration significantly enhanced the cellular uptake of ZnMBC through endocytosis. A panel of four human cancer cell lines has revealed that ZnMBC (1/2)@MSNs-CTS-biotin nanoparticles (NPs) exhibits unprecedented enhanced cytotoxicity toward cancer cells with IC50 values ranging from 6.5 to 28.8 µM through induction of apoptosis. NPs also possess great selectivity between normal and cancer cells despite this potency. Two-photon-excited in vitro imaging of normal (HEK) and cancer (HeLa) cells has been performed to confirm the biased drug delivery. Also, NP-induced apoptosis was found to be dependent on targeting DNA and ROS generation. Moreover, a lower range of LD50 values (153.6-335.5 µM) were observed upon treatment zebrafish embryos with NPs in vivo. Because of the anatomical similarity to the human heart, the heart rate of NP-treated zebrafish has been analyzed in assessing the cardiac functions, which is in favor of the early clinical trials of ZnMBC (1/2)@MSNs-CTS-biotin candidates for their further evaluation as a chemotherapeutic and chemopreventive agent toward human cancers, especially adenocarcinoma.

Synthesis and Characterization of Acid-Responsive Luminescent Fe(II) Metallopolymers of Rigid and Flexible Backbone N-Donor Multidentate Conjugated Ligands.

In this report we have disclosed the syntheses and properties of two new conjugated organic moieties bearing the same coordination sites but possessing different backbone rigidities and rotational flexibilities. Two new metallopolymers have been synthesized from the corresponding ligands under identical reaction conditions, and they have been thoroughly characterized through different techniques to understand the effect of backbone rigidity on the evolution of different properties in these metallopolymers. A FESEM micrograph of the rigid metallopolymer confirms the formation of a rigid nanorod type structure, while long agglomerated nanofiber strands are visible on the substrate in the case of the flexible analogue. All of the newly synthesized materials are fluorescence active. An Fe(II) metallopolymer of the flexible ligand showed huge changes in emission properties in the presence of different acids and showed a possibility of it being used as a thin film acid vapor sensor. All of the materials showed reversible electrochemical activity, and both of these polymers have shown electroluminescence when an appropriate potential is applied.

Tuning of nonvolatile bipolar memristive switching in Co(III) polymer with an extended azo aromatic ligand.

We have fabricated a unique memristive device by molecular engineering and demonstrated that the leakage current tuning in the device is 100 times more efficient than that in a standard device. Molecular analogs of the memristive matrices used here are an electrochemically active conjugated Co(III) polymer (CP) and a nonconjugated Co(III) polymer (NCP), which have been synthesized in good yield and characterized by (1)H NMR spectroscopy. Redox switching of an organic-metallic hybrid polymer generates bistable states with a large ON/OFF ratio that supports random flip-flops for several hours. Thus, we provide a synthetic solution to leakage current restriction, one of the fundamental problems faced when fabricating state-of-the-art electronic devices.