Covalent organic frameworks (COFs) are appealing photocatalysts for toxic chemical degradation. Great efforts have been devoted to regulate the photocatalytic performance of COFs by tuning their organic building blocks, but the relationship between COF linkage and photochemical properties has rarely been explored. Herein, we report the synthesis and characterisation of a novel aminal-linked porphyrinic COF, namelyPor-Aminal-COF.Por-Aminal-COF (0.25 mol %) showed excellent photocatalytic activity toward the detoxification of the sulfur mustard simulant with a half-life (t 1/2 ) of 5 min, which is far lower than that of traditional imine-linked Por-COF (t 1/2 = 16 min). Transient absorption spectroscopy indicated that the aminal linkages of Por-Aminal-COF facilitated the intersystem crossing process. Thus, Por-Aminal-COF showed higher triplet-state generation efficiency compared with Por-COF, consequently promoting the activation of oxygen molecular to singlet oxygen.

The origins of the chiroptical activities of inorganic nanostructures have perplexed scientists, and deracemization of high-nuclearity metal nanoclusters (NCs) remains challenging. Here, we report a single-crystal structure of Rac-Ag70 that contains enantiomeric pairs of 70-nuclearity silver clusters with 20 free valence electrons (Ag70), and each of these clusters is a doubly truncated tetrahedron with pseudo-T symmetry. A deracemization method using a chiral metal precursor not only stabilizes Ag70 in solution but also enables monitoring of the gradual enlargement of the electronic circular dichroism (CD) responses and anisotropy factor gabs. The chiral crystals of R/S-Ag70 in space group P21 containing a pseudo-T-symmetric enantiomeric NC show significant kernel-based and shell-based CD responses. The small symmetry breaking of Td symmetry arising from local distortion of Ag−S motifs and rotation of the apical Ag3 trigons results in large chiroptical responses. This work opens an avenue to construct chiral medium/large-sized NCs and nanoparticles, which are promising for asymmetric catalysis, nonlinear optics, chiral sensing, and biomedicine.

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A novel electrode based on orange peel derived C-dots decorated CuO nanorods (CR@C-dot) modified lead pencil (LP) electrode has been fabricated for highly sensitive and selective monitoring of dopamine (DA). Prior to the functionalization with C-dot, electrochemical efficacy of CR was evaluated and compared with CuO nano-needles (CN) and nano-spheres (CS). The morphology, surface area and composition of synthesized nanoparticles was confirmed through field emission scanning electron microscopy (FE-SEM), N 2 -adsorption-desorption isotherm, X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Our results indicated that CR has high electrocatalytic activity compared to CN and CS by expositing greater fraction of catalytic active sites, large surface area and short diffusion pathways. The electrochemical efficacy of CR is further enhanced by decorating with orange peel derived C-dots, which surprisingly lead to the integrations of surfaceactive sites with current collectors with minimum resistance by acting as an electron transport mediator and providing more surface defects. The developed CR@Cdot sensor enables highly sensitive and selective recognition of DA detection (0.0007 μM), over good linear range (5-2250 μM) with rapid response time. the developed CR@C-dot sensor was successfully used to monitor the DA from deboned chicken, thus suggesting reliability of the developed electrode.

Stable stimulus-responsive materials are highly desirable due to their widespread potential applications and growing demand in recent decades. Despite the fact that viologen derivatives have long been known as excellent photochromic and electrochromic materials, the development of stable viologen-based multifunctional smart materials with short coloration times remains an exciting topic. To obtain photochromic and electrochromic dual responsive materials, embedding the viologen ligand into a robust metal oxide cluster to increase its stability and sensitivity is an effective strategy. Herein, a viologen-based metal–organic polyhedron (MOP) {[Zr6L3(μ3-O)2(μ2-OH)6Cp6]·8Cl·CH3OH·DMF} [Zr-MOP-1; H2L·2Cl = 1,1′-bis­(4-carboxyphenyl)-4,4′-bipyridinium dichloride, and Cp = η5-C5H5] was successfully prepared and characterized. It consists of trinuclear Zr–oxygen secondary building units and exhibits reversible photochromic and electrochromic dual responsive behaviors. As expected, the designed robust viologen-based nanocage with a V2E3 (V = vertex, and E = edge) topology can maintain its stability and rapid photo/electrochromic behaviors with an obvious reversible change in color from purple (brown) to green, mainly due to the enclosed cluster structure and the abundant free viologen radicals that originate from the effective Cl → N and O → N electron transfers. Spectroelectrochemistry and theoretical calculations of this Zr-MOP were also performed to verify the chromic mechanism.