124688-03-5Relevant academic research and scientific papers
From Photoinduced Supramolecular Polymerization to Responsive Organogels
Xu, Fan,Pfeifer, Lukas,Crespi, Stefano,Leung, Franco King-Chi,Stuart, Marc C. A.,Wezenberg, Sander J.,Feringa, Ben L.
supporting information, p. 5990 - 5997 (2021/05/06)
Controlling supramolecular polymerization by external stimuli holds great potential toward the development of responsive soft materials and manipulating self-assembly at the nanoscale. Photochemical switching offers the prospect of regulating the structure and properties of systems in a noninvasive and reversible manner with spatial and temporal control. In addition, this approach will enhance our understanding of supramolecular polymerization mechanisms; however, the control of molecular assembly by light remains challenging. Here we present photoresponsive stiff-stilbene-based bis-urea monomers whose trans isomers readily form supramolecular polymers in a wide range of organic solvents, enabling fast light-triggered depolymerization-polymerization and reversible gel formation. Due to the stability of the cis isomers and the high photostationary states (PSS) of the cis-trans isomerization, precise control over supramolecular polymerization and in situ gelation could be achieved with short response times. A detailed study on the temperature-dependent and photoinduced supramolecular polymerization in organic solvents revealed a kinetically controlled nucleation-elongation mechanism. By application of a Volta phase plate to enhance the phase-contrast method in cryo-EM, unprecedented for nonaqueous solutions, uniform nanofibers were observed in organic solvents.
Force-reactivity property of a single monomer is sufficient to predict the micromechanical behavior of its polymer
Akbulatov, Sergey,Tian, Yancong,Boulatov, Roman
supporting information; experimental part, p. 7620 - 7623 (2012/06/30)
We demonstrate an accurate prediction of the micromechanical behavior of a single chain of cyclopropanated polybutadiene, which is governed by rapid isomerization of the cyclopropane moieties at ~1.2 nN, from the force-rate correlation of this reaction measured in a small series of increasingly strained macrocycles. The data demonstrate that a single physical quantity, force, uniquely defines the dynamics across length scales from >100 to 1 nm and that strain imposed through molecular design and that imposed by micromanipulation techniques have equivalent effects on the kinetics of a chemical reaction. This represents a new method of screening potential monomers for applications in stress-responsive materials that could also facilitate atomistic interpretations of single-molecule force experiments.
W(CO)6-Mediated Desulfurdimerization of Dithioketals. Evidence for a Thione Intermediate
Yeung, Lam Lung,Yip, Yu Chi,Luh, Tien-Yau
, p. 1874 - 1881 (2007/10/02)
Upon treatment with W(CO)6, dithioketals undergo desulfurdimerization to give the corresponding dimeric olefins in good to excellent yields.The mechanism of this the newly discovered reaction has been investigated.Thioketones have been isolated from the reactions of highly crowded dithioketals.The mechanism for the formation of thioketones has been shown to occur via a new type of radical fragmentation process of dithiolane.Thermolysis of 2,2-dimethylindan-1-yl 2-thiophenoxyethyl sulfide in the presence of tert-butyl adamantane-1-peroxycarboxylate (a typical radical initiator) has been studied for comparison.Thioketones react with W(CO)6, giving dimeric olefins and/or undergoing carbene-like insertion reactions.
