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A rapid in situ synthesis of electrochromic covalent organic frameworks (EC‐COFs) was proposed by using green electrochemical interface polymerization of N,N,N’,N’‐tetrakis(4‐aminophenyl)‐1,4‐benzenediamine (TPDA) and 2,5‐dihydroxyterephthalaldehyde (DHBD). The synthetized TPDA‐DHBD films exhibit stable polymorphic color variations under different applied potentials, which can be attributed to the redox state changes of bis(triphenylamine) and imine electroactive functional groups within the COFs skeleton. TPDA‐DHBD represents markedly different electrochromisms from red to cyan due to the steric hindrance effect caused by the presence of UO22+, demonstrating the unique tunability of COFs materials. This work offers a new feasible idea for rapid EC‐COFs synthesis and tunable EC‐COFs realization. [ABSTRACT FROM AUTHOR]

Saioa Cobo is a Junior Professor at the Laboratoire de Chimie de Coordination, University of Toulouse in France. She recently published her first article as a submitting corresponding author in Angewandte Chemie. Her research focuses on switchable molecular materials, photochromism, spin crossover, and electrochromism. Cobo's passion for chemistry was ignited during her master internship, where she discovered switchable materials. She finds chemistry fun because it is interconnected with everything in life. Cobo values the power of curiosity and fresh perspectives that her students bring, which often push her to explore new ideas. She recharges by traveling and experiencing different cultures. Cobo believes that research advancements are faster when achieved collectively. She enjoys taking walks or practicing hobbies in her spare time. Her favorite time of day is the morning when the lab is calm. Cobo's motto is "The world belongs to those who wake up early" and "Don't put off until tomorrow what can be done today." She values role models who remain upright and not be tempted by what is forbidden. Cobo would not change the path she has taken as each experience has shaped who she is today. Her favorite musician is Alejandro Sanz, and if she were stranded on a desert island, she would choose The Pillars of the Earth by Ken Follett as her one book. Cobo's recent study was inspired by a conference where she read a paper by Stoddart and realized the connection between her compounds [Extracted from the article]

Developing bioinspired camouflage materials that can adaptively change color in the visible and infrared (IR) regions is an intriguing but challenging task. Herein, we report an emerging strategy for fabricating dynamic visible and IR camouflage materials by the controlled in situ growth of novel photopolymerizable blue phase liquid crystals with cubic nanoarchitectures onto highly aligned MXene nanostructured thin films. The resulting MXene‐integrated 3D soft photonic crystals exhibit vivid structural colors and reversible switching between a bright colored state and a dark black state under a low DC electric field. As an illustration, proof‐of‐concept pixelated devices that allow for pixel‐controllable electrochromism are demonstrated. Furthermore, a free‐standing electrochromic flexible film of such 3D soft photonic crystals is fabricated, where visible electrochromism and thermal camouflage are enabled by leveraging the superior electrothermal conversion and low mid‐IR emissivity of MXene nanomaterials. [ABSTRACT FROM AUTHOR]

Two coordinated metallacycles (rhomboid for M1, hexagonal for M2) with selenoviologens (SeV2+) pendants were synthesized via coordination‐driven hierarchical self‐assembly. M1/M2 with rigid and discrete metallacyclic cores showed tunable optoelectronic properties due to strong π–π stacking and push–pull electron structures. Femtosecond transient absorption (fs‐TA) revealed that the formation of macrocyclic structure can not only enhance the stability of radical cation, but also improve the efficiency of intramolecular charge transfer and produce a long‐lived charge separation state. The electrochromic performances of M1/M2‐based devices were exhibited to show decent radical stabilization. By using M1/M2 as the photocatalyst, the improved catalytic efficiency (>80 %) of visible‐light‐induced cross‐dehydrogenative coupling (CDC) reactions was achieved due to the highly stable radical cations and long‐lived charge separation states, which were also confirmed by fs‐TA. [ABSTRACT FROM AUTHOR]

Thermochromic phosphors are intriguing materials for realizing thermochromic behaviors of light‐emitting diodes. Here a highly luminescent and stable thermochromic phosphor based on one‐dimensional Cu4I6(4‐dimethylamino‐1‐ethylpyridinium)2 is reported. This unique ionic copper‐iodine chain‐based hybrid exhibits near‐unity photoluminescence efficiency owing to the through‐space charge‐transfer character of relevant electronic transitions. More importantly, an alternative mechanism of thermochromic phosphorescence was unraveled, supported by a first principles simulation of concerted copper atom migration in the copper‐iodine chain. Furthermore, we successfully fabricate a bright thermochromic light‐emitting diode using this Cu4I6(4‐dimethylamino‐1‐ethylpyridinium)2 thermochromic phosphor. Our reported flexible ionic copper‐iodine chain‐based thermochromic luminescent material represents a new type of cost‐effective functional phosphor. [ABSTRACT FROM AUTHOR]

Tridecacyclene tetraimide, TCTI, an electron‐deficient non‐benzenoid nanocarbon with a C56N4 polycyclic framework was obtained in a concise synthesis. TCTI has a non‐planar structure and forms π‐stacked dimers in the solid state. In solution, it undergoes eight single‐electron reductions, yielding a range of negatively charged states up to an octaanion. Except for the latter species, which has a remarkably large electronic gap, the anions feature extended near‐infrared absorptions, with a particularly strong band at 1692 nm observed for the dianion. A computational analysis of the TCTI anions shows that their stability originates from the combined effects of electron‐deficient imide groups and the local aromaticity of reduced acenaphthylene units. The properties of TCTI make it potentially useful in electrochromic and charge storage applications. [ABSTRACT FROM AUTHOR]

Achieving blueshifted and enhanced emission from purely organic luminophors remains a major challenge. Herein, we report a tetracoordinate boron complex with polymorphism (Y‐phase and O‐phase)‐dependent luminescence. Impressively, the Y‐phase crystals exhibited rare piezochromic luminescent properties such as pressure‐induced blue‐shifted and enhanced emission. The results of theoretical and experimental tests demonstrated that this phenomenon results from the cooperative effect between the restriction of intramolecular motions and alterable charge transfer (CT) behavior during compression. This work provides an ideal model to investigate the optoelectronic properties of boron complexes. Importantly, manipulating the CT behavior through the electrophilicity of boron atoms may become a new principle for the design of piezochromic materials with blueshifted and enhanced emission. [ABSTRACT FROM AUTHOR]

Nanographene (NG) is a potential candidate for organic EC materials because of its large π‐conjugated system, chemical stability, absorption band covering the visible region, and tunable optical properties by postsynthetic modification. We show that NGs carrying redox‐active triphenylamine (TPA) units covalently linked to the NG edge function as EC materials in the NIR region. The hybrid materials can be obtained by the installation of TPA units onto the NG edge and display changes in the absorption spectrum in the NIR region extending to a wavelength of over 2000 nm upon one‐electron oxidation and reduction at low potentials (<1.1 V). Time‐dependent unrestricted density functional theory calculation of a model NG at the UB3LYP/6‐31G(d,p) level of theory suggests that a narrow energy gap between the basal plane and the oxidized TPA unit is responsible for the observed EC function in the NIR region. [ABSTRACT FROM AUTHOR]

Endowing a cholesteric liquid crystal elastomer (CLCE) exhibiting a helicoidal nanostructure with dynamically tailorable functionalities is of paramount significance for its emerging applications in diverse fields such as adaptive optics and soft robotics. Here, a mechanochromic, shape‐programmable and self‐healable CLCE is judiciously designed and synthesized through integrating dynamic covalent boronic ester bonds into the main‐chain CLCE polymer network. The circularly polarized reflection of CLCEs can be reversibly and dynamically tuned across the entire visible spectrum by mechanical stretching. Thanks to the introduction of dynamic boronic ester bonds, the CLCEs were found to show robust reprogrammable and self‐healing capabilities. The research disclosed herein can provide new insights into the development of 4D (color and 3D shape) programmable photonic actuators towards bioinspired camouflage, adaptive optical systems, and next‐generation intelligent machines. [ABSTRACT FROM AUTHOR]

A Kagome structure covalent organic framework (COF) film with three‐state NIR electrochromic properties was designed and synthesized. The COFTPDA‐PDA film is composed of hexagonal nanosheets with high crystallinity and has three reversible color states at different applied potentials. It has high absorption spectra changes in the NIR region, ascribed to the strong intervalence charge transfer (IVCT) interaction of the Class III mixed‐valence systems of the conjugated triphenylamine species. The film showed sub‐second response time (1.3 s for coloring and 0.7 s for bleaching at 1050 nm) and long retention time in the NIR region. COFTPDA‐PDA film shows superior NIR electrochromic properties in term of response time and stability, attributed to the highly ordered porous structure and the π–π stacking structure of the COFTPDA‐PDA architecture. The COFTPDA‐PDA film was applied in mimicking a flip‐flop logic gate with optical memory function. [ABSTRACT FROM AUTHOR]

Hydrogen‐bonded organic frameworks (HOFs) possess various merits, such as high porosity, tunable structure, facile modification, and ready regeneration. These properties have yet to be explored in the context of new functional HOF materials. The facile and inexpensive electrophoretic deposition (EPD) method applied in this study generated a transparent HOF film at room temperature in just 2 min and is applicable to other HOFs. The resulting film exhibited reversible electrochromism with the advantage of long cycle life (>500 cycles). More strikingly, this all‐organic film could be readily regenerated (through rinsing with DMF and redeposition) and showed tunable electrochromic behavior (through low‐cost postsynthetic modification) with the ability to undergo successive color changes, which is difficult to achieve with conventional electrochromic materials. An electrochromic device was manufactured to further demonstrate the application potential of the film. [ABSTRACT FROM AUTHOR]

Herein, the universal design of high‐efficiency stimuli‐responsive luminous materials endowed with mechanochromic luminescence (MCL) and thermally activated delayed fluorescence (TADF) functions is reported. The origin of the unique stimuli‐triggered TADF switching for a series of carbazole–isophthalonitrile‐based donor–acceptor (D–A) luminogens is demonstrated based on systematic photophysical and X‐ray analysis, coupled with theoretical calculations. It was revealed that a tiny alteration of the intramolecular D–A twisting in the excited‐state structures governed by the solid morphologies is responsible for this dynamic TADF switching behavior. This concept is applicable to the fabrication of bicolor emissive organic light‐emitting diodes using a single TADF emitter. [ABSTRACT FROM AUTHOR]

A mixed‐valence {MnII3MnIIIFeII2FeIII2} cyanide‐bridged molecular cube hosting a caesium cation, Cs⊂{Mn4Fe4}, was synthesized and structurally characterized by X‐ray diffraction. Cyclic‐voltammetry measurements show that its electronic state can be switched between five different redox states, which results in a remarkable electrochromic effect. Magnetic measurements on fresh samples point to the occurrence of a spin‐state change near room temperature, which could be ascribed to a metal‐to‐metal electron transfer converting the {FeII−CN−MnIII} pair into a {FeIII−CN−MnII} pair. This feature was only previously observed in the polymeric MnFe Prussian‐blue analogues (PBAs). Moreover, this novel switchable molecule proved to be soluble and stable in organic solvents, paving the way for its integration into advanced materials. [ABSTRACT FROM AUTHOR]

Electroresponsive structurally colored materials composed of ordered arrays of polyaniline@poly(methyl methacrylate) (PANI@PMMA) core-shell nanoparticles have been successfully prepared. The core-shell nanoparticles were synthesized by deposition of PANI shells on the surfaces of the PMMA cores by the oxidative polymerization of anilinium chloride. Ordered arrays were then fabricated by using the fluidic cell method. Because the ordered arrays and the PANI shells generate structural and electrochromic colors, respectively, these core-shell colloidal crystals exhibited colors resulting from the combined effects of these materials. The crystal colors depended greatly on the size of PANI@PMMA particles and could also be varied by the application of a voltage. The electrochromic colors of these arrays were found to be quite different from those exhibited by pure PANI films prepared by electrochemical oxidation. [ABSTRACT FROM AUTHOR]

Keywords: Electrochromism; Photocatalysis; Radical Cation; Selenoviologen; Transient Absorption EN Electrochromism Photocatalysis Radical Cation Selenoviologen Transient Absorption 1 1 1 10/14/22 20221017 NES 221017 B Selenoviologens-appendant metallacycles M1 b (rhomboid) and B M2 b (hexagonal) were synthesized and utilized in electrochromism and photocatalysis, as reported in the Research Article (e202209054) by Gang He et al. Electrochromism, Photocatalysis, Radical Cation, Selenoviologen, Transient Absorption Inside Back Cover: Selenoviologen-Appendant Metallacycles with Highly Stable Radical Cations and Long-Lived Charge Separation States for Electrochromism and Photocatalysis (Angew. [Extracted from the article]

A diruthenium complex with a redox-active amine bridge has been designed, synthesized, and studied by single-crystal X-ray analysis and DFT and TDDFT calculations. It shows three well-separated redox processes with exclusive near-infrared (NIR) absorbance at each redox state. The electropolymerized film of a related vinyl-functionalized complex displays multistate NIR electrochromism with low operational potential, good contrast ratio, and long retention time. Flip-flop, flip-flap-flop, and ternary memories have been realized by using the obtained film (ca. 15-20 nm thick) with three electrochemical inputs and three NIR optical outputs that each displays three levels of signal intensity. [ABSTRACT FROM AUTHOR]

Making sense: A novel polyacetylene composite material with incorporated aligned carbon nanotubes shows rapid changes in both fluorescent intensity and color appearance in response to applied electric currents, and these electrochromatic transitions remain reversible even after a thousand cycles. The composite material is anticipated to be suitable for various other sensing applications. [ABSTRACT FROM AUTHOR]