A series of vibrantly coloured π-conjugated electrochromic polymers (ECPs) were designed and synthesized with the goal of extracting structure–property relationships from subtle changes in steric strain or relaxation.
We report a straightforward strategy of accessing a wide variety of colors through simple predictive color mixing of electrochromic polymers (ECPs). We have created a set of brown ECP blends that can be incorporated as the active material in user-controlled electrochromic eyewear. Color mixing of ECPs proceeds in a subtractive fashion, and we acquire various hues of brown through the mixing of cyan and yellow primaries in combination with orange and periwinkle-blue secondary colors. Upon oxidation, all of the created blends exhibit a change in transmittance from ca. 10 to 70% in a few seconds. We demonstrate the attractiveness of these ECP blends as active materials in electrochromic eyewear by assembling user-controlled, high-contrast, fast-switching, and fully solution-processable electrochromic lenses with colorless transmissive states and colored states that correspond to commercially available sunglasses. The lenses were fabricated using a combination of inkjet printing and blade-coating to illustrate the feasibility of using soluble ECPs for high-throughput and large-scale processing.
This contribution describes an advanced compartmentalized micellar nanoreactor that possesses a reversible photoresponsive feature and its application toward photoregulating reaction pathways for incompatible tandem catalysis under aqueous conditions. The smart nanoreactor is based on multifunctional amphiphilic poly(2-oxazoline)s and covalently cross-linked with spiropyran upon micelle formation in water. It responds to light irradiation in a wavelength-selective manner switching its morphology as confirmed by dynamic light scattering and cryo-transition electron microscopy. The compartmental structure renders distinct nanoconfinements for two incompatible enantioselective transformations: a rhodium–diene complex-catalyzed asymmetric 1,4-addition occurs in the hydrophilic corona, while a Rh-TsDPEN-catalyzed asymmetric transfer hydrogenation proceeds in the hydrophobic core. Control experiments and kinetic studies showed that the gated behavior induced by the phototriggered reversible spiropyran to merocyanine transition in the cross-linking layer is key to discriminate among substrates/reagents during the catalysis. The smart nanoreactor realized photoregulation to direct the reaction pathway to give a multichiral product with high conversions and perfect enantioselectivities in aqueous media. Our SCM catalytic system, on a basic level, mimics the concepts of compartmentalization and responsiveness Nature uses to coordinate thousands of incompatible chemical transformations into streamlined metabolic processes.
are useful for communicating text and complex images via reflective displays in electronic paper devices, wearable "smart glasses," and transmissive panel monitors. Essential to the utility of such materials is the ability to repeatedly transition between two optical states in a rapid, on-demand fashion.π-Conjugated electrochromic polymers (ECPs) are a class of electrochromic materials that offer an appealing platform for the realization of true black-to-transmissive electrochromism. ECPs can undergo full colored-to-colorless transitions on rapid time scales (often in second to subsecond regimes, [1] with high coloration efficiencies, contrasts (Δ%T at λ max ) up to 70%, switching stability over thousands to hundreds of thousands of cycles, and in many cases, colorless states that can be refreshed by a small current or voltage pulse. [1,2] Moreover, ECPs can be readily tuned for color through straightforward chemical modification of the polymer backbone. The addition of solubilizing aliphatic or polar side chains allows for these materials to be processed as electronic inks in low-cost and large-scale processing techniques, such as inkjetprinting, along with blade-, spray-, and slot die coating. [3][4][5][6][7][8][9][10] In recent years, a deeper understanding of the structure-property relationships that control the color and switching properties of ECPs has enabled the development of extensive libraries of cathodically coloring polymers. These materials have been successfully integrated into plastic [5,11,12] and paper-based [7,13,14] electrochromic devices, making them promising candidates for flexible or transient electronic displays.While most colored-to-transmissive ECPs have π-electronic structures that have been carefully modified to absorb specific wavelengths of visible light for achieving highly saturated colors, a black ECP must absorb across the entire visible spectrum in its colored state. Meanwhile, the transmissive state of the material must absorb as little visible light as possible in the same wavelength range for optimal contrast and optical clarity. Developing a material that undergoes such drastic spectral changes upon application of an electrical bias presents a unique materials design challenge. An additional complexity arises when seeking to develop black-to-transmissive electrochromic materials that are able to transition through intermediate shades of gray, as well. Next-generation electrochromic technologies, such as dimmable fenestration, eyewear integrated displays, and optical shutters require materials that reversibly transition between highly transmissive and broadly absorbing achromatic states, often with minimal intermediate coloration. In this work, it is shown how the properties of dioxythiophene-based electrochromic polymers (ECPs) can be leveraged through straightforward color mixing to yield high-contrast, black-to-transmissive materials with low driving voltages (<1 V), extended functional lifetimes, and minimal transient chromaticity.Drawing from a family of five soluble co...
This contribution introduces poly(2-oxazoline)-based shell cross-linked micelles (SCMs) as nanoreactors to realize one-pot redox-driven deracemizations of secondary alcohols in aqueous media. TEMPO and Rh-TsDPEN moieties are spatially positioned into the hydrophilic corona and the hydrophobic micelle core, respectively. TEMPO catalyzes the oxidation of racemic secondary alcohols into ketones, while Rh-TsDPEN catalyzes the asymmetric transfer hydrogenation (ATH) of these ketones to afford enantioenriched secondary alcohols. Both catalysts, the Rh-TsDPEN complex and TEMPO, are incompatible with each other and the SCMs are designed to provide indispensable catalyst site isolation. Kinetic studies show that the SCMs enhance the reactivity of the immobilized catalysts, in comparison to those for the unsupported analogues under the same reaction conditions. Our nanoreactors can perform deracemizations on a broad range of secondary alcohol substrates and are reusable in a continuous manner while maintaining high activity.
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