Buchwald-Hartwig coupled conjugated microporous polymer for efficient removal COVID-19 antiviral drug famciclovir from waters: Adsorption behavior and mechanism.

The consumption of famciclovir (FCV) has been increased dramatically since the outbreak of coronavirus in 2019, and the pollution and harm of FCV in waters are concerned. Here, by utilizing aryl halides on 2, 4, 6-tris(4-bromophenyl)- 1, 3, 5-triazine (BPT) and primary amine groups on benzidine (BZ), a novel conjugated microporous polymer, namely BPT-BZ-CMP, was synthesized by Buchwald-Hartwig coupling reaction and applied in the removal of FCV from aqueous solution firstly. The synthesized BPT-BZ-CMP were characterized by various methods, including FTIR, SEM, BET, and Zeta-potential. Due to the micropore structure and high specific surface area, it took only 30 min for BPT-BZ-CMP to adsorb FCV to reach an equilibrium, and the maximum adsorption capacity was 347.8 mg·g-1. The Liu and pseudo-second-order kinetic models properly fit the adsorption equilibrium and kinetic data, respectively. The adsorption process was a spontaneous process, and the hydrogen bonding, π-π interaction and C-H···π interaction enhanced the adsorption of FCV on BPT-BZ-CMP. BPT-BZ-CMP maintained a good adsorption capacity after four consecutive adsorption-desorption cycle experiments. This study confirmed the potential of BPT-BZ-CMP as efficient sorbent to remove FCV from aqueous solutions.

Hexagonal boron nitride nanosheets based magnetic solid phase extraction for the extraction of phenoxy carboxylic acid herbicides from water samples followed by high-performance liquid chromatography-tandem mass spectrometry.

High-efficiency caption of pesticide residue is of vital significance for environmental safety monitoring. Herein, a hexagonal boron nitride nanosheets-based magnetic composite (Fe3O4@h-BNNSs) was synthesized and applied for the magnetic solid phase extraction (MSPE) of five phenoxy carboxylic acid (PCA) herbicides from water samples. Based on the π-π interaction, hydrogen bond and halogen bond, the Fe3O4@h-BNNSs composite showed excellent adsorption ability towards PCA herbicides. Several main variables that influenced the extraction efficiencies of PCA herbicides were investigated and optimized via single-factor experiment. Combining this Fe3O4@h-BNNSs composite-based MSPE with high-performance liquid chromatography-tandem mass spectrometry, a novel sensitive method for the analysis of PCA herbicides was developed. Under the most favorable conditions, the proposed method displayed good linear ranges (20.0-10000.0 ng L-1), low limits of detection (5.6-10.3 ng L-1), satisfactory precisions (1.1-6.8%) and recoveries (76.6-107.2%). Overall, the present work can be a versatile and worthy utility for the determination of PCA herbicides from different water samples.

Magnetic boron nitride nanosheets as a novel magnetic solid-phase extraction adsorbent for the determination of plant growth regulators in tomatoes.

A novel magnetic boron nitride nanosheets (Fe3O4@BNNSs) composite-based magnetic solid-phase extraction (MSPE) method was employed to analyse six plant growth regulators (PGRs) in tomatoes combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The novel Fe3O4@BNNSs composite was prepared via an in situ chemical coprecipitation process and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Several factors that may affect the extraction efficiencies were optimized. Under the optimal factors, low limits of detection (0.002-0.010 ng g-1), good linear ranges (0.05-10 ng g-1) and satisfactory precisions (intra-day: 1.2%-3.9%; inter-day: 2.1%-6.9%) were achieved. The established approach was successfully employed to extract and determine PGRs in tomatoes, and the spiked recoveries were between 85.2 and 109.0%.

Effectively removing indole-3-butyric acid from aqueous solution with magnetic layered double hydroxide-based adsorbents.

The magnetic layered double hydroxide-based materials (MLDHs) with the metal composition of Mg(II)Al(III) were synthesized by different conditions as the adsorbent for removal of a phytohormone, indole-3-butyric acid (IBA). The morphological characteristics of MLDHs were studied through various characterization methods such as XRD, SEM, TEM, FTIR, BET, Zeta-potential and VSM. The adsorption results showed that the adsorption capacity of MLDH-1 synthesized by co-precipitation method with ammonia as the base source was the best (maximum 522.6 mg/g). The extent of adsorption in the pH range of 3.0-9.0 was observed to be no noticeable change. From the economical point of view, 1.0 g/L MLDH-1 composites were selected as optimum parameter. For a given adsorbent concentration (Cs), its kinetics and adsorption isotherm followed the pseudo-second-order and Liu isotherm model, respectively. The adsorbed sample can be easily magnetically separated and regenerated with NaNO3. The adsorption process was spontaneous and exothermic, including two path stages: surface adsorption of lamellar and interlayer anion exchange. The research makes a contribution to evaluating the ability of MLDHs in IBA removal and helping the public to understand the mechanism of adsorption process.

Kinetic, thermodynamic and isotherm investigations of Cu2+ and Zn2+ adsorption on LiAl hydrotalcite-like compound.

LiAl hydrotalcite-like compound (LiAl HTlc) was synthesized via a hydrothermal method and used to adsorb Cu2+ and Zn2+ for investigating the adsorption characteristics of heavy metal cations. The X-Raydiffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscopy (TEM) characterizations revealed the interconnecting flower-like layered structure of LiAl HTlc. The adsorption kinetics and isotherms of Cu2+ and Zn2+ on LiAl HTlc agreed with the pseudo-second-order model and the Langmuir model at a given sorbent concentration (Cs), respectively. The Cs-effect on the adsorption kinetics and isotherms was observed, and the Langmuir-surface component activity (SCA) equation could be utilized to characterize the effect of Cs in the adsorption isotherms. The adsorption process was spontaneous and endothermic. The adsorption mechanism denoted that the adsorption process was controlled using two main mechanisms, i.e., surface complexation and isomorphic substitution. This is the first report, to the best of our knowledge, on the usage of LiAl HTlc for the removal of heavy metal cations Cu2+ and Zn2+ from a solution. LiAl HTlc is a promising sorbent for treating water containing heavy metal cations.

Bulky 4,6-disubstituted tetraphenylethene-naphthalimide dyad: synthesis, copolymerization, stimuli-responsive fluorescence and cellular imaging.

We report the design and synthesis of a tetraphenylethene substituted with naphthalimide at the 4, 6 positions, named NI-2TPE. NI-2TPE exhibits strong solvent-dependent emission properties with combined ICT and AIE characteristics in THF-H2O systems. This probe was used directly on test papers to distinguish normal organic solvents using their emission colours under UV light based on its AIE and ICT nature. Thanks to the vinyl group in NI-2TPE, we synthesized a copolymer of NIPAM and NI-2TPE, termed P(NIPAM-co-NI-2TPE). The resulting polymer is highly soluble and fluorescent in water (ΦF = 15.4%). Due to the well-known thermo-responsive character of NIPAM, P(NIPAM-co-NI-2TPE) exhibits an interesting fluorescence change in response to various temperatures. Due to the thermo-induced shrinking of the PNIPAM chain, the fluorescence intensity gradually increased from 20 to 34 °C. As the temperature further increased from 34 to 90 °C, the fluorescence intensity decreased sharply, which was caused by the well-known thermal effects. Furthermore, we synthesized a P(HEA-co-NI-2TPE-TPP acrylate) copolymer, in which HEA is a hydrophilic unit, TPP is a mitochondria label and NI-2TPE a fluorescent probe. The corresponding polymer probe is highly soluble in water with FLQY = 7% and we have further applied this probe as a mitochondria targeted imaging tracker in HeLa cells successfully.

Single-wavelength-controlled in situ dynamic super-resolution fluorescence imaging for block copolymer nanostructures via blue-light-switchable FRAP.

Photoswitchable fluorophores are promising in single-molecule optical devices and super-resolution fluorescence imaging, especially in single-molecule photo-activated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM). However, the scarcity of current photoswitchable fluorophores stimulates researchers to develop complicated optical systems and processing software, in accordance with the limited photoswitchable fluorescent proteins and organic fluorophores. Previous efforts to develop synthetic photoswitchable fluorophores have exhibited their promising potential in super-resolution fluorescence imaging. Here, we have designed and synthesized a fluorescence molecular switch with reversible green emission, a napthalimide-hexaarylbiimidazole conjugate (NI-N-HABI), which exhibits strong fluorescence in the emissive state, with fast thermal fading of the photochromism and spontaneous fluorescence recovery after photobleaching (FRAP) induced by blue-light. The photoswitchable fluorophore enables the red-edge wavelength of the optical response to red-shift from the initial near-UV region at less than 400 nm, to 500 nm. The relatively fast fading speed of NI-N-HABI and its sensitivity to longer blue-light irradiation (400-500 nm) have allowed simplification of the optical microscopic system from a two-wavelength laser source to a single-wavelength laser. We applied NI-N-HABI in single-wavelength-controlled in situ dynamic super-resolution fluorescence imaging for the self-assembly and solvent annealing of amphiphilic block polymers, with 50 nm of optical resolution. Single-wavelength-controlled dynamic super-resolution fluorescence imaging facilitates nanoscale optical visualization for the dynamic physical and chemical fluctuation processes of stimuli-responsive nanostructures.

Optical nanoimaging for block copolymer self-assembly.

One approach toward optical nanoimaging involves sequential molecular localization of photoswitchable fluorophores to achieve high resolution beyond optical limit of diffraction. Block copolymer micelles assembled from polystryrene-block-poly(ethylene oxide) block copolymers (PSt-b-PEO) are visualized in optical nanoimaging by staining the polystyrene blocks with spiropyrans (SPs). SPs localized in hydrophobic phase of block copolymer micelles exhibit reversible fluorescence on-off switching at alternating irradiation of UV and visible light. Phase-selective distribution of SPs in block copolymer micelles enables optical nanoimaging of microphase structures of block copolymer self-assembly at 50-nm resolution. To date, this is the sturdiest realization of optical nanoimaging with subdiffraction resolution for solution self-assembly of block copolymers.

A trident dithienylethene-perylenemonoimide dyad with super fluorescence switching speed and ratio.

Photoswitchable fluorescent diarylethenes are promising in molecular optical memory and photonic devices. However, the performance of current diarylethenes is far from satisfactory because of the scarcity of high-speed switching capability and large fluorescence on-off ratio. Here we report a trident perylenemonoimide dyad modified by triple dithienylethenes whose photochromic fluorescence quenching ratio at the photostationary state exceeds 10,000 and the fluorescence quenching efficiency is close to 100% within seconds of ultraviolet irradiation. The highly sensitive fluorescence on/off switching of the trident dyad enables recyclable fluorescence patterning and all-optical transistors. The prototype optical device based on the trident dyad enables the optical switching of incident light and conversion from incident light wavelength to transmitted light wavelength, which is all-optically controlled, reversible and wavelength-convertible. In addition, the trident dyad-staining block copolymer vesicles are observed via optical nanoimaging with a sub-100 nm resolution, portending a potential prospect of the dithienylethene dyad in super-resolution imaging.