Stereoselective and temporally controlled supramolecular polymerizations are ubiquitous in nature and are desirable attributes for the design of chiral, well-defined functional materials. Kinetically controlled, living supramolecular polymerization (LSP) has emerged recently for the synthesis of supramolecular polymers with controlled length and narrow dispersity. On the other hand, stringent design requirements for chiral-discriminating monomers precludes the stereoselective control of the supramolecular polymer structure. Herein, a synergetic stereo-and structural control of supramolecular polymerization by the realization of an unprecedented stereoselective seed-induced LSP is reported. Homochiral and seeded growth is demonstrated with bischromophoric naphthalene diimide (NDI) enantiomers with a chiral binaphthyl amine core, exhibiting strong self-recognition abilities and pathway complexity.
Chiral organic phosphors with circularly polarized room-temperature phosphorescence (CPP) provide new prospects to the realm of circularly polarized luminescence (CPL) materials, owing to the long-lived triplet states and persistent emission. Although several molecular designs show efficient room-temperature phosphorescence (RTP), realization of ambient organic CPP remains a formidable challenge. Herein, we introduce a chiral bischromophoric phosphor design to realize ambient CPP emission by appending molecular phosphors to a chiral diaminocyclohexane core. Thus, solution-processable polymer films of the trans-1,2-diaminocyclohexane (DAC) chiral cores with heavy-atom substituted pyromellitic diimide phosphors, exhibits one of the most efficient exclusive CPP emissions with high phosphorescence quantum yield ( � 18 % in air and � 46 % under vacuum) and significant luminescence dissymmetry factor (j g lum j � 4.0 × 10 À 3 ).
Bioinspired, kinetically controlled seeded growth has been recently shown to provide length, dispersity, and sequence control on the primary structure of dynamic supramolecular polymers. However, command over the molecular organization at all hierarchical levels for the modulation of higher order structures of supramolecular polymers remains a formidable task. In this context, a surface-catalyzed secondary nucleation process, which plays an important role in the autocatalytic generation of amyloid fibrils and also during the chiral crystallization of small monomers, offers exciting possibilities for topology control in synthetic macromolecular systems by introducing secondary growth pathways compared to the usual primary nucleation−elongation process. However, mechanistic insights into the molecular determinants and driving forces for the secondary nucleation event in synthetic systems are not yet realized. Herein, we attempt to fill this dearth by showing an unprecedented molecular chirality control on the primary and secondary nucleation events in seed-induced supramolecular polymerization. Comprehensive kinetic experiments using in situ spectroscopic probing of the temporal changes of the monomer organization during the growth process provide a unique study to characterize the primary and secondary nucleation events in a supramolecular polymerization process. Kinetic analyses along with various microscopic studies further reveal the remarkable effect of stereoselective nucleation and seeding events on the (micro)structural aspects of the resulting multicomponent supramolecular polymers.
Mechanistic understanding and the control of molecular self-assembly at all hierarchical levels remain grand challenges in supramolecular chemistry. Functional realization of dynamic supramolecular materials especially requires programmed assembly at higher levels of molecular organization. Herein, we report an unprecedented molecular control on the fibrous network topology of supramolecular hydrogels and their resulting macroscopic properties by biasing assembly pathways of higher-order structures. The surface-catalyzed secondary nucleation process, a well-known mechanism in amyloid fibrilization and chiral crystallization of small molecules, is introduced as a non-covalent strategy to induce physical cross-links and bundling of supramolecular fibers, which influences the microstructure of gel networks and subsequent mechanical properties of hydrogels. In addition, seed-induced instantaneous gelation is realized in the kinetically controlled self-assembled system under this study, and more importantly, the extent of secondary nucleation events and network topology is manipulated by the concentration of seeds.
We develop a self-consistent, Gravitoelectromagnetic (GEM) formulation of a slowly rotating, self-gravitating and dilute Bose-Einstein condensate (BEC), intended for astrophysical applications in the context of dark matter halos. GEM self-consistently incorporates the effects of frame dragging to lowest order in v/c via the Gravitomagnetic field. BEC dark matter has attracted attention as an alternative to Cold dark matter (CDM) and Warm dark matter (WDM) for some time now. The BEC is described by the Gross-Pitaevskii-Poisson (GPP) equation with an arbitrary potential allowing for either attractive or repulsive interactions. Owing to the difficulty in obtaining exact solutions to the GEM equations of motion without drastic approximations, we employ the variational method to examine the conditions under which rotating condensates, stable against gravitational collapse, may form in models with attractive and repulsive quartic interactions. We also describe the approximate dynamics of an imploding and rotating condensate by employing a collective coordinate description in terms of the condensate radius. *
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