Progress in chemistry over the past four decades has generated a variety of porous materials for removing iodine-a radioactive emission accompanying nuclear fission. However, most studies are still based on the notion that entangled pores together with specific binding sites are essential for iodine capture. Here, an unraveled physical picture of iodine capture that overturns the preconception by exploring 1D channeled porous materials is disclosed. 2D covalent organic frameworks are constructed in a way so that they are free of interpenetration and binding sites but consist of 1D open channels. As verified with different channels shaping from hexagonal to tetragonal and trigonal and ranging from micropores to mesopores, all the 1D channels enable a full access to iodine, generalizing a new paradigm that the pore volume determines the uptake capacity. These results are of fundamental importance to understanding iodine uptake and designing materials to treat coagulative toxic vapors.

wileyonlinelibrary.comnanorods, [ 6,7 ] carbon nanotubes (CNTs), [ 8,9 ] graphene, [ 10,11 ] etc.), have been investigated and developed. Accompany with the development of stimulus-responsive materials, various types of external stimulus, including electric, [ 12,13 ] heat, [14][15][16] light, [ 17,18 ] magnetic, [19][20][21] chemical stimulus, [ 22 ] pneumatic stimulus, [ 23 ] and so forth, have been successfully employed to develop biomimetic or bio-inspired microrobotic systems applying in microjets, [ 16 ] microgrippers, [ 24,25 ] drilling of tissues, [ 26 ] drug and cell delivery, [ 27,28 ] fi xing cancer cells, [ 29 ] artifi cial muscles, [ 30 ] and some other smart microstructures.Because of their ability in wireless/ remote control, low noise, localized driven ability rather than whole-fi eld driven, [ 31 ] light-driven microrobots have attracted more and more attention in novel microbio-robots or micro-motors for biological use. For example, for the minimally invasive medicine applications, the microrobots must exhibit locomotion and controlled interaction with their environment, which should be able to reach a targeted area under the direct supervision and control of an external user. Due to its excellent penetration ability in biological tissues (can be over several centimeters [ 32 ] ), near infrared (nIR) light provides a promising approach to remotely actuate the microrobots in bodies, which may fi nd applications in the development of novel micro-bio-robots or biomimetic micro-motors in vivo and in vitro.Graphene, due to its excellent electrical and thermal conductivity, high surface area, and high fl exibility, has been employed to perform various actuation based on graphene polymeric nanocomposites, that is, stimulated by electrical, [ 33,34 ] electrochemical, [ 11,35 ] and optical energy. [ 10 ] Because of its photothermal effect and high thermal conductivity, graphene and its composites show promising photoresponsive properties. Panchapakesan [ 31 ] reported a large light-induced reversible and elastic response of graphene nanoplatelets (GNPs) polymer composites which is composited with GNPs and polydimethylsiloxane (PDMS), and developed a two-axis submicrometer resolution positioning stage. Wu [ 36 ] developed a bimorph confi guration which was constituted with chemically modifi ed polye thylene (PE) fi lms and a mixture of large-area graphene-chitosan, behaving as a transparent soft actuator that expanded under nIR irradiation. Wang [ 37 ] developed light-driven hand-shape Biomimetic microsystems, which can be driven by various stimuli, are an emerging fi eld in micro/nano-technology and nano-medicine. In this study, a soft and fast-response robotic platform, constituted by PDMS/graphenenanoplatelets composited layer (PDMS/GNPs) and pristine PDMS layer, is presented. Due to the differences in coeffi cient of thermal expansion and Young's modulus of the two layers, the bilayer platform can be driven to bend to the PDMS/GNPs side by light irradiation. The robotic platform (1 mm in width and 7 m...

Astrategy is presented for the synthesis of crystalline porous covalent organic frameworks via topology-templated polymerization. The template is based on imine-linked frameworks and their (001) facets seed the C = Cb ond formation reaction to constitute 2D sp 2 carbon-conjugated frameworks. This strategy is applicable to templates with different topologies,e nables designed synthesis of frameworks that cannot be prepared via direct polymerization, and creates as eries of sp 2 carbon frameworks with tetragonal, hexagonal, and kagome topologies.T he sp 2 carbon frameworks are highly luminescent even in the solid state and exhibit topologydependent p transmission and exciton migration;t hese key fundamental p functions are unique to sp 2 carbon-conjugated frameworks and cannot be accessible by imine-linked frameworks,a morphous analogues,a nd 1D conjugated polymers. These results demonstrate an unprecedented strategy for structural and functional designs of covalent organic frameworks.

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Pd-catalyzed cross-coupling reactions have achieved tremendous accomplishments in the past decades. However, C(sp 3 )-hybridized nucleophiles generally remain as challenging coupling partners due to their sluggish transmetalation compared to the C(sp 2 )-hybridized counterparts. While a single-electron-transfer-based strategy using C(sp 3 )hybridized nucleophiles had made significant progress recently, fewer breakthroughs have been made concerning the traditional two-electron mechanism involving C(sp 3 )hybridized nucleophiles. In this report, we present a series of unique alkyl carbagermatranes that were proven to be highly reactive in cross-coupling reactions with our newly developed electron-deficient phosphine ligands. Generally, secondary alkyl carbagermatranes show slightly lower, yet comparable activity to its Sn analogue. Meanwhile, primary alkyl carbagermatranes exhibit high activity, and they were also proved stable enough to be compatible with various reactions. Chiral secondary benzyl carbagermatrane gave the coupling product under base/additive-free conditions with its configuration fully inversed, suggesting that transmetalation was carried out in an "S E 2(open) Inv" pathway, which is consistent with Hiyama's previous observation. Notably, the cross-coupling of primary alkyl carbagermatranes could be performed under base/additivefree conditions with excellent functional group tolerance and therefore may have potentially important applications such as stapled peptide synthesis.

Germanium, a member of 14th group that falls between Si and Sn, has remained considerably ignored as a nucleophile for a long time. Compared with other forms of Ge-containing nucleophiles, germatranes are structure-defined, easily accessible, and stabilized nucleophilic fragments, but they fail to meet the need of high reactivity and facile introducing to organics. Herein, we report a modified structure of germatranes, whose cross-coupling reactivity is greatly improved. The structure can be easily constructed from inexpensive industrial GeO2, and corresponding Ge -Cl and Ge -H can also be obtained after facile transformations. Moreover, Ar- Ge can be effectively synthesized either from Grignard reagents or Pd-catalyzed germylation of aryl halides.

Bioinspired soft robotics have unique advantages in superior adaptability and complex motions for field exploration and interaction with humans. The mobility and output force, however, are still the critical challenges for many promising applications. It is attractive to develop “untethered” robotics to improve the mobility by getting rid of the external electrical or pneumatic tethers while achieving massive output stroke and force. Inspired by the creatures' movements induced by the multiplication of cells and asymmetric volume changes of the tissue, an untethered soft actuator composed of self‐contained liquids and super‐elastic chambers is proposed, and by remote stimuli (e.g., near‐infrared light), the capsuled liquids transit from liquid to vapor, giving rise to volume change in the corresponding chambers. Programmable motions, i.e., photophobia of artificial sunflower, can be realized, indicating a massive and linear driving stroke (up to 160% in elongation, 0.5 mm °C−1) and output force (14.5 N with 6 g self‐weight, 0.33 N °C−1). The untethered soft actuator suggests a feasible approach to develop smart, soft, and autonomous robotics and holds promise in fields ranging from surgery to rehabilitation and rescue.

Superconducting nanowire single photon detectors (SNSPDs) are a key enabling technology for optical quantum information science. In this paper we demonstrate a SNSPD fabricated on lithium niobate, an important material for high speed integrated photonic circuits. We report a system detection efficiency of 0.15% at a 1 kHz dark count rate with a maximum of ~1% close to the critical current at 1550 nm wavelength for a parallel wire SNSPD with front side illumination. There is clear scope for improving on this performance with further materials optimization. Detector integration with a lithium niobate optical waveguide is simulated, demonstrating the potential for high single photon detection efficiency in an integrated quantum optic circuit.