Multi-responsive diarylethene-phenolphthalein hybrids by multiple stimuli

Multicolor Chromism from a Single Chromophore through Synergistic Coupling of Mechanochromic and Photochromic Subunits

We report a versatile mechanophore exhibiting a vividly detectable, light-regulable multicolor mechanochromism. Such optical features rely on the synergistic coupling of mechanochromic bis-rhodamine (Rh) and photochromic bisthienylethene (BTE). Poly(methyl acrylate)s incorporating this bis-mechanophore can be mechanically activated under sonication. The relative distribution of the two distinctly colored and fluorescent Rh ring-opening products is altered with different magnitudes of applied force. Orthogonal use of the photochromic reaction of the BTE core can strengthen the mechanochromism and gate the mechanofluorescence in polymers. Due to increased conjugation offered by the BTE linker, both force- and light-induced optical signals display high contrast. Combined DFT simulated and experimental results reveal that the three subunits (two Rhs and one BTE) in this chromophore are activated sequentially, thus generating switchable three-colored forms and gradient optical responses.

Stimuli-Responsive Electrochemical Energy Storage Devices

Electrochemical energy storage (EES) devices have been swiftly developed in recent years. Stimuli-responsive EES devices that respond to different external stimuli are considered the most advanced EES devices. The stimuli-responsive EES devices enhanced the performance and applications of the EES devices. The capability of the EES devices to respond to the various external stimuli due to produced advanced EES devices that distinguished the best performance and interactions in different situations. The stimuli-responsive EES devices have responsive behavior to different external stimuli including chemical compounds, electricity, photons, mechanical tensions, and temperature. All of these advanced responsiveness behaviors have originated from the functionality and specific structure of the EES devices. The multi-responsive EES devices have been recognized as the next generation of stimuli-responsive EES devices. There are two main steps in developing stimuli-responsive EES devices in the future. The first step is the combination of the economical, environmental, electrochemical, and multi-responsiveness priorities in an EES device. The second step is obtaining some advanced properties such as biocompatibility, flexibility, stretchability, transparency, and wearability in novel stimuli-responsive EES devices. Future studies on stimuli-responsive EES devices will be allocated to merging these significant two steps to improve the performance of the stimuli-responsive EES devices to challenge complicated situations.

Structure of 7-(3,3,4,4,5,5-hexafluoro-2-(2-methylbenzo[b]thiophen-3-yl)cyclopent-1-en-1-yl)-8-methylquinoline, C24H15F6NS

C24H15F6NS, monclinic, P21/n (no. 14), a = 10.5279(11) Å, b = 21.242(2) Å, c = 10.7096(11) Å, β = 119.1850(10)°, V = 2091.0(4) Å3, Z = 4, R gt(F) = 0.0488, wR ref(F 2) = 0.1441, T = 296(2) K.

Third-Generation Light-Driven Symmetric Molecular Motors

Symmetric molecular motors based on two overcrowded alkenes with a notable absence of a stereogenic center show potential to function as novel mechanical systems in the development of more advanced nanomachines offering controlled motion over surfaces. Elucidation of the key parameters and limitations of these third-generation motors is essential for the design of optimized molecular machines based on light-driven rotary motion. Herein we demonstrate the thermal and photochemical rotational behavior of a series of third-generation light-driven molecular motors. The steric hindrance of the core unit exerted upon the rotors proved pivotal in controlling the speed of rotation, where a smaller size results in lower barriers. The presence of a pseudo-asymmetric carbon center provides the motor with unidirectionality. Tuning of the steric effects of the substituents at the bridgehead allows for the precise control of the direction of disrotary motion, illustrated by the design of two motors which show opposite rotation with respect to a methyl substituent. A third-generation molecular motor with the potential to be the fastest based on overcrowded alkenes to date was used to visualize the equal rate of rotation of both its rotor units. The autonomous rotational behavior perfectly followed the predicted model, setting the stage for more advanced motors for functional dynamic systems.

Structure and photochromism of 1,2-bis[2-methyl-5-(2-chlorophenyl)-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene, C27H16Cl2F6S2

C27H16Cl2F6S2, triclinic, P1̅ (no. 2), a = 8.3612(18) Å, b = 11.8991(7) Å, c = 13.3979(7) Å, α = 94.667(3)°, β = 99.927(3)°, γ = 105.882(3)°, V = 1251.21(12) Å3, Z = 2, R gt(F) = 0.0441, wR ref(F 2) = 0.1345, T = 100(2) K.