Synthesis of 9‑Fluorenylidenes via Pd-Catalyzed C–H Vinylation with Vinyl Bromides

A facile and efficient approach for the synthesis of 9-fluorenylidenes has been developed via the palladium-catalyzed cross-coupling of 2-iodobiphenyls and vinyl bromides. The reaction involves the C–H activation of 2-iodobiphenyls and dual C–C bond formations. A range of 9-fluorenylidene derivatives, including diphenyldibenzofulvenes, can be synthesized with the reaction

Pd-Catalyzed Alkene-Relayed Intermolecular C–H Alkylation Using Aryl Halide Substrates

Alkene-relayed C–H activation represents a novel strategy for functionalizing C–H bonds selectively. We developed a Pd-catalyzed annulation reaction of 2-iodobiphenyls with maleimides that act as a relay for C–H alkylation. The reaction features broad substrate scope and high efficiency, providing a straightforward method for the synthesis of succinimide-fused 9,10-dihydrophenanthrenes. The reaction using acenaphthylene as the relay has also been developed, which allows easy access to dibenzo[j,l]fluoranthenes

Zwitterionic Poly(aryl ether ketone) with Water-Actuated, Reshaping-Reconfiguration Ability and Triple Shape Memory Effect

We synthesized shape memory poly­(aryl ether ketone) (PAEK) and grafted carboxylic acid pyridine zwitterions onto the main chains for fabricating the zwitterionic PAEK (ZPAEK) material. ZPAEK exhibited a Tg of around 120 °C, great thermal stability, and mechanical performances, and heat-triggered shape memory behaviors, including high shape recovery ratio (over 98.7%) and fixity ratio (over 98%). Besides, we improved the hydrophilicity of PAEK by incorporating carboxylic acid pyridine zwitterions, for the first time, achieving the exceptional water-actuated shape memory behaviors for PAEK at room temperature. Furthermore, the controllable reconfiguration behaviors were achieved through the interaction between carboxylic acid pyridine zwitterions and water molecules. For the sample of any temporary shape, after absorbing water, its previous original shape was eliminated, and the deformed temporary shape could be redefined as the “original” shape to construct an unprecedented shape memory cycle, never returning to the first original shape. Additionally, the excellent triple shape memory behaviors of sample were obtained after absorbing water. After the programmable shape fixation processes, the sample of temporary shape could recover to the original shape through the two stages: one was at 110 °C, and the other was at 140 °C. We did believe the water-actuated, reconfigurable, and triple shape memory ZPAEK could be an ideal substitute material for smart sensors and actuators

Zwitterionic Poly(aryl ether ketone) with Water-Actuated, Reshaping-Reconfiguration Ability and Triple Shape Memory Effect

We synthesized shape memory poly­(aryl ether ketone) (PAEK) and grafted carboxylic acid pyridine zwitterions onto the main chains for fabricating the zwitterionic PAEK (ZPAEK) material. ZPAEK exhibited a Tg of around 120 °C, great thermal stability, and mechanical performances, and heat-triggered shape memory behaviors, including high shape recovery ratio (over 98.7%) and fixity ratio (over 98%). Besides, we improved the hydrophilicity of PAEK by incorporating carboxylic acid pyridine zwitterions, for the first time, achieving the exceptional water-actuated shape memory behaviors for PAEK at room temperature. Furthermore, the controllable reconfiguration behaviors were achieved through the interaction between carboxylic acid pyridine zwitterions and water molecules. For the sample of any temporary shape, after absorbing water, its previous original shape was eliminated, and the deformed temporary shape could be redefined as the “original” shape to construct an unprecedented shape memory cycle, never returning to the first original shape. Additionally, the excellent triple shape memory behaviors of sample were obtained after absorbing water. After the programmable shape fixation processes, the sample of temporary shape could recover to the original shape through the two stages: one was at 110 °C, and the other was at 140 °C. We did believe the water-actuated, reconfigurable, and triple shape memory ZPAEK could be an ideal substitute material for smart sensors and actuators

Zwitterionic Poly(aryl ether ketone) with Water-Actuated, Reshaping-Reconfiguration Ability and Triple Shape Memory Effect

We synthesized shape memory poly­(aryl ether ketone) (PAEK) and grafted carboxylic acid pyridine zwitterions onto the main chains for fabricating the zwitterionic PAEK (ZPAEK) material. ZPAEK exhibited a Tg of around 120 °C, great thermal stability, and mechanical performances, and heat-triggered shape memory behaviors, including high shape recovery ratio (over 98.7%) and fixity ratio (over 98%). Besides, we improved the hydrophilicity of PAEK by incorporating carboxylic acid pyridine zwitterions, for the first time, achieving the exceptional water-actuated shape memory behaviors for PAEK at room temperature. Furthermore, the controllable reconfiguration behaviors were achieved through the interaction between carboxylic acid pyridine zwitterions and water molecules. For the sample of any temporary shape, after absorbing water, its previous original shape was eliminated, and the deformed temporary shape could be redefined as the “original” shape to construct an unprecedented shape memory cycle, never returning to the first original shape. Additionally, the excellent triple shape memory behaviors of sample were obtained after absorbing water. After the programmable shape fixation processes, the sample of temporary shape could recover to the original shape through the two stages: one was at 110 °C, and the other was at 140 °C. We did believe the water-actuated, reconfigurable, and triple shape memory ZPAEK could be an ideal substitute material for smart sensors and actuators

Zwitterionic Poly(aryl ether ketone) with Water-Actuated, Reshaping-Reconfiguration Ability and Triple Shape Memory Effect

We synthesized shape memory poly­(aryl ether ketone) (PAEK) and grafted carboxylic acid pyridine zwitterions onto the main chains for fabricating the zwitterionic PAEK (ZPAEK) material. ZPAEK exhibited a Tg of around 120 °C, great thermal stability, and mechanical performances, and heat-triggered shape memory behaviors, including high shape recovery ratio (over 98.7%) and fixity ratio (over 98%). Besides, we improved the hydrophilicity of PAEK by incorporating carboxylic acid pyridine zwitterions, for the first time, achieving the exceptional water-actuated shape memory behaviors for PAEK at room temperature. Furthermore, the controllable reconfiguration behaviors were achieved through the interaction between carboxylic acid pyridine zwitterions and water molecules. For the sample of any temporary shape, after absorbing water, its previous original shape was eliminated, and the deformed temporary shape could be redefined as the “original” shape to construct an unprecedented shape memory cycle, never returning to the first original shape. Additionally, the excellent triple shape memory behaviors of sample were obtained after absorbing water. After the programmable shape fixation processes, the sample of temporary shape could recover to the original shape through the two stages: one was at 110 °C, and the other was at 140 °C. We did believe the water-actuated, reconfigurable, and triple shape memory ZPAEK could be an ideal substitute material for smart sensors and actuators

Zwitterionic Poly(aryl ether ketone) with Water-Actuated, Reshaping-Reconfiguration Ability and Triple Shape Memory Effect

We synthesized shape memory poly­(aryl ether ketone) (PAEK) and grafted carboxylic acid pyridine zwitterions onto the main chains for fabricating the zwitterionic PAEK (ZPAEK) material. ZPAEK exhibited a Tg of around 120 °C, great thermal stability, and mechanical performances, and heat-triggered shape memory behaviors, including high shape recovery ratio (over 98.7%) and fixity ratio (over 98%). Besides, we improved the hydrophilicity of PAEK by incorporating carboxylic acid pyridine zwitterions, for the first time, achieving the exceptional water-actuated shape memory behaviors for PAEK at room temperature. Furthermore, the controllable reconfiguration behaviors were achieved through the interaction between carboxylic acid pyridine zwitterions and water molecules. For the sample of any temporary shape, after absorbing water, its previous original shape was eliminated, and the deformed temporary shape could be redefined as the “original” shape to construct an unprecedented shape memory cycle, never returning to the first original shape. Additionally, the excellent triple shape memory behaviors of sample were obtained after absorbing water. After the programmable shape fixation processes, the sample of temporary shape could recover to the original shape through the two stages: one was at 110 °C, and the other was at 140 °C. We did believe the water-actuated, reconfigurable, and triple shape memory ZPAEK could be an ideal substitute material for smart sensors and actuators

Enhanced Shape Memory Metal-Coordinated Poly(aryl ether ketone)s with Tunable Gradient-Deformation Behaviors as well as Self-Healing and Reprocessing Abilities

Reversible dynamic bonds are able to crack and recombine upon external stimuli, which endow polymers with exceptional self-healing, reprocessing, and reversible deformation ability. In this paper, we integrated the metal coordination bonds into shape memory poly­(aryl ether ketone) (PAEK) to fabricate smart materials with multifunctionalities. Through tuning the metal ion content and species, the enhancement of shape memory behaviors was achieved, including the high recovery ratio (over 98%) and fixity ratio (over 98%), which was closely related to the synergic effect of the intrinsic motion ability of PAEK matrix and the cracking-recombination of coordination bonds. Besides, through the combination of the components with different Cu2+ contents, in addition to the components with Fe2+ coordination bonds, we fabricated the gradient shape memory structures with controllable shape memory and recovery behaviors. The manipulation of gradient coordination bonds resulted in different shape recovery speeds and directions. Furthermore, due to the dynamic cracking-recombination of coordination bonds, the metal-coordinated PAEK material exhibited the great self-healing and reprocessing performances, which were significant for largely extending its application range

Characterization of DLC1-SAM Equilibrium Unfolding at the Amino Acid Residue Level

Sterile α motif (SAM) domains are found in many different proteins and shown to play important roles in various biological processes. The N-terminal domain of deleted in liver cancer 1 (DLC1) protein is a SAM domain which exists in a monomeric form in aqueous solution and facilitates the distribution of EF1A1 to the membrane periphery and ruffles upon growth factor stimulation. Here, we report the structure of an N-terminal truncated DLC1 SAM domain (DLC1-SAM) and its urea-induced equilibrium unfolding investigated with various biophysical methods such as CD, fluorescence emission spectroscopy, and NMR. CD and tryptophan intrinsic fluorescence emission data imply that the unfolding of DLC1-SAM follows a simple two-state mechanism, yet the NMR data suggest the presence of at least one intermediate state. The intermediate cannot be detected by NMR, but it does not exist in large aggregates as shown by analytical ultracentrifugation experiments. Analysis of the free energy values for different residues shows that in the transition from the native state to non-native states the C-terminal helix is somewhat more stable than the other parts of the protein, whereas in the transition from the native and intermediate states to the denatured state, the stabilities of different residues are similar except for that of the region surrounding residues D37−F40 which has lower stability and is more readily denatured at high urea concentrations. Analysis of the midpoints of the transitions shows that the unfolding of the native state and formation of the denatured state are not cooperative and the unfolding of only a few residues seems to follow a two-state mechanism

(a) Structure, (b, c) integration, and (d, e) angle choice of Macau streets and lanes, drawn according to the 1780 base map.

Global variable radius = n; local variable radius = 500 m.</p