TY - JOUR AB - Molecular recognition is at the heart of the noncovalent synthesis of supramolecular assemblies and, at higher length scales, supramolecular materials. In a recent publication in Nature, Stoddart and co-workers demonstrate that the formation of host-guest complexes can be catalyzed by one of the simplest possible catalysts: the electron. AU - Gemen, Julius AU - Klajn, Rafal ID - 13351 IS - 5 JF - Chem KW - Materials Chemistry KW - Biochemistry (medical) KW - General Chemical Engineering KW - Environmental Chemistry KW - Biochemistry KW - General Chemistry SN - 2451-9308 TI - Electron catalysis expands the supramolecular chemist’s toolbox VL - 8 ER - TY - JOUR AB - Confinement within molecular cages can dramatically modify the physicochemical properties of the encapsulated guest molecules, but such host-guest complexes have mainly been studied in a static context. Combining confinement effects with fast guest exchange kinetics could pave the way toward stimuli-responsive supramolecular systems—and ultimately materials—whose desired properties could be tailored “on demand” rapidly and reversibly. Here, we demonstrate rapid guest exchange between inclusion complexes of an open-window coordination cage that can simultaneously accommodate two guest molecules. Working with two types of guests, anthracene derivatives and BODIPY dyes, we show that the former can substantially modify the optical properties of the latter upon noncovalent heterodimer formation. We also studied the light-induced covalent dimerization of encapsulated anthracenes and found large effects of confinement on reaction rates. By coupling the photodimerization with the rapid guest exchange, we developed a new way to modulate fluorescence using external irradiation. AU - Gemen, Julius AU - Białek, Michał J. AU - Kazes, Miri AU - Shimon, Linda J.W. AU - Feller, Moran AU - Semenov, Sergey N. AU - Diskin-Posner, Yael AU - Oron, Dan AU - Klajn, Rafal ID - 13350 IS - 9 JF - Chem KW - Materials Chemistry KW - Biochemistry (medical) KW - General Chemical Engineering KW - Environmental Chemistry KW - Biochemistry KW - General Chemistry SN - 2451-9308 TI - Ternary host-guest complexes with rapid exchange kinetics and photoswitchable fluorescence VL - 8 ER - TY - JOUR AB - Thermoelectric technology requires synthesizing complex materials where not only the crystal structure but also other structural features such as defects, grain size and orientation, and interfaces must be controlled. To date, conventional solid-state techniques are unable to provide this level of control. Herein, we present a synthetic approach in which dense inorganic thermoelectric materials are produced by the consolidation of well-defined nanoparticle powders. The idea is that controlling the characteristics of the powder allows the chemical transformations that take place during consolidation to be guided, ultimately yielding inorganic solids with targeted features. Different from conventional methods, syntheses in solution can produce particles with unprecedented control over their size, shape, crystal structure, composition, and surface chemistry. However, to date, most works have focused only on the low-cost benefits of this strategy. In this perspective, we first cover the opportunities that solution processing of the powder offers, emphasizing the potential structural features that can be controlled by precisely engineering the inorganic core of the particle, the surface, and the organization of the particles before consolidation. We then discuss the challenges of this synthetic approach and more practical matters related to solution processing. Finally, we suggest some good practices for adequate knowledge transfer and improving reproducibility among different laboratories. AU - Fiedler, Christine AU - Kleinhanns, Tobias AU - Garcia, Maria AU - Lee, Seungho AU - Calcabrini, Mariano AU - Ibáñez, Maria ID - 12237 IS - 19 JF - Chemistry of Materials KW - Materials Chemistry KW - General Chemical Engineering KW - General Chemistry SN - 0897-4756 TI - Solution-processed inorganic thermoelectric materials: Opportunities and challenges VL - 34 ER - TY - JOUR AB - Mercury telluride (HgTe) thin films with a critical thickness of 6.5 nm are predicted to possess a gapless Dirac-like band structure. We report a comprehensive study on gated and optically doped samples by magnetooptical spectroscopy in the THz range. The quasi-classical analysis of the cyclotron resonance allowed the mapping of the band dispersion of Dirac charge carriers in a broad range of electron and hole doping. A smooth transition through the charge neutrality point between Dirac holes and electrons was observed. An additional peak coming from a second type of holes with an almost density-independent mass of around 0.04m0 was detected in the hole-doping range and attributed to an asymmetric spin splitting of the Dirac cone. Spectroscopic evidence for disorder-induced band energy fluctuations could not be detected in present cyclotron resonance experiments. AU - Shuvaev, Alexey AU - Dziom, Uladzislau AU - Gospodarič, Jan AU - Novik, Elena G. AU - Dobretsova, Alena A. AU - Mikhailov, Nikolay N. AU - Kvon, Ze Don AU - Pimenov, Andrei ID - 12278 IS - 14 JF - Nanomaterials KW - General Materials Science KW - General Chemical Engineering SN - 2079-4991 TI - Band structure near the Dirac Point in HgTe quantum wells with critical thickness VL - 12 ER - TY - JOUR AB - Coulombic interactions can be used to assemble charged nanoparticles into higher-order structures, but the process requires oppositely charged partners that are similarly sized. The ability to mediate the assembly of such charged nanoparticles using structurally simple small molecules would greatly facilitate the fabrication of nanostructured materials and harnessing their applications in catalysis, sensing and photonics. Here we show that small molecules with as few as three electric charges can effectively induce attractive interactions between oppositely charged nanoparticles in water. These interactions can guide the assembly of charged nanoparticles into colloidal crystals of a quality previously only thought to result from their co-crystallization with oppositely charged nanoparticles of a similar size. Transient nanoparticle assemblies can be generated using positively charged nanoparticles and multiply charged anions that are enzymatically hydrolysed into mono- and/or dianions. Our findings demonstrate an approach for the facile fabrication, manipulation and further investigation of static and dynamic nanostructured materials in aqueous environments. AU - Bian, Tong AU - Gardin, Andrea AU - Gemen, Julius AU - Houben, Lothar AU - Perego, Claudio AU - Lee, Byeongdu AU - Elad, Nadav AU - Chu, Zonglin AU - Pavan, Giovanni M. AU - Klajn, Rafal ID - 13357 IS - 10 JF - Nature Chemistry KW - General Chemical Engineering KW - General Chemistry SN - 1755-4330 TI - Electrostatic co-assembly of nanoparticles with oppositely charged small molecules into static and dynamic superstructures VL - 13 ER - TY - JOUR AB - Dissipative self-assembly is ubiquitous in nature, where it gives rise to complex structures and functions such as self-healing, homeostasis, and camouflage. These phenomena are enabled by the continuous conversion of energy stored in chemical fuels, such as ATP. Over the past decade, an increasing number of synthetic chemically driven systems have been reported that mimic the features of their natural counterparts. At the same time, it has been shown that dissipative self-assembly can also be fueled by light; these optically fueled systems have been developed in parallel to the chemically fueled ones. In this perspective, we critically compare these two classes of systems. Despite the complementarity and fundamental differences between these two modes of dissipative self-assembly, our analysis reveals that multiple analogies exist between chemically and light-fueled systems. We hope that these considerations will facilitate further development of the field of dissipative self-assembly. AU - Weißenfels, Maren AU - Gemen, Julius AU - Klajn, Rafal ID - 13359 IS - 1 JF - Chem KW - Materials Chemistry KW - Biochemistry (medical) KW - General Chemical Engineering KW - Environmental Chemistry KW - Biochemistry KW - General Chemistry SN - 2451-9294 TI - Dissipative self-assembly: Fueling with chemicals versus light VL - 7 ER - TY - JOUR AB - The cost-effective conversion of low-grade heat into electricity using thermoelectric devices requires developing alternative materials and material processing technologies able to reduce the currently high device manufacturing costs. In this direction, thermoelectric materials that do not rely on rare or toxic elements such as tellurium or lead need to be produced using high-throughput technologies not involving high temperatures and long processes. Bi2Se3 is an obvious possible Te-free alternative to Bi2Te3 for ambient temperature thermoelectric applications, but its performance is still low for practical applications, and additional efforts toward finding proper dopants are required. Here, we report a scalable method to produce Bi2Se3 nanosheets at low synthesis temperatures. We studied the influence of different dopants on the thermoelectric properties of this material. Among the elements tested, we demonstrated that Sn doping resulted in the best performance. Sn incorporation resulted in a significant improvement to the Bi2Se3 Seebeck coefficient and a reduction in the thermal conductivity in the direction of the hot-press axis, resulting in an overall 60% improvement in the thermoelectric figure of merit of Bi2Se3. AU - Li, Mengyao AU - Zhang, Yu AU - Zhang, Ting AU - Zuo, Yong AU - Xiao, Ke AU - Arbiol, Jordi AU - Llorca, Jordi AU - Liu, Yu AU - Cabot, Andreu ID - 10858 IS - 7 JF - Nanomaterials KW - General Materials Science KW - General Chemical Engineering SN - 2079-4991 TI - Enhanced thermoelectric performance of n-type Bi2Se3 nanosheets through Sn doping VL - 11 ER - TY - JOUR AB - Aprotic alkali metal–O2 batteries face two major obstacles to their chemistry occurring efficiently, the insulating nature of the formed alkali superoxides/peroxides and parasitic reactions that are caused by the highly reactive singlet oxygen (1O2). Redox mediators are recognized to be key for improving rechargeability. However, it is unclear how they affect 1O2 formation, which hinders strategies for their improvement. Here we clarify the mechanism of mediated peroxide and superoxide oxidation and thus explain how redox mediators either enhance or suppress 1O2 formation. We show that charging commences with peroxide oxidation to a superoxide intermediate and that redox potentials above ~3.5 V versus Li/Li+ drive 1O2 evolution from superoxide oxidation, while disproportionation always generates some 1O2. We find that 1O2 suppression requires oxidation to be faster than the generation of 1O2 from disproportionation. Oxidation rates decrease with growing driving force following Marcus inverted-region behaviour, establishing a region of maximum rate. AU - Petit, Yann K. AU - Mourad, Eléonore AU - Prehal, Christian AU - Leypold, Christian AU - Windischbacher, Andreas AU - Mijailovic, Daniel AU - Slugovc, Christian AU - Borisov, Sergey M. AU - Zojer, Egbert AU - Brutti, Sergio AU - Fontaine, Olivier AU - Freunberger, Stefan Alexander ID - 9250 IS - 5 JF - Nature Chemistry KW - General Chemistry KW - General Chemical Engineering SN - 1755-4330 TI - Mechanism of mediated alkali peroxide oxidation and triplet versus singlet oxygen formation VL - 13 ER - TY - JOUR AB - Oligomeric species populated during the aggregation of the Aβ42 peptide have been identified as potent cytotoxins linked to Alzheimer’s disease, but the fundamental molecular pathways that control their dynamics have yet to be elucidated. By developing a general approach that combines theory, experiment and simulation, we reveal, in molecular detail, the mechanisms of Aβ42 oligomer dynamics during amyloid fibril formation. Even though all mature amyloid fibrils must originate as oligomers, we found that most Aβ42 oligomers dissociate into their monomeric precursors without forming new fibrils. Only a minority of oligomers converts into fibrillar structures. Moreover, the heterogeneous ensemble of oligomeric species interconverts on timescales comparable to those of aggregation. Our results identify fundamentally new steps that could be targeted by therapeutic interventions designed to combat protein misfolding diseases. AU - Michaels, Thomas C. T. AU - Šarić, Anđela AU - Curk, Samo AU - Bernfur, Katja AU - Arosio, Paolo AU - Meisl, Georg AU - Dear, Alexander J. AU - Cohen, Samuel I. A. AU - Dobson, Christopher M. AU - Vendruscolo, Michele AU - Linse, Sara AU - Knowles, Tuomas P. J. ID - 10351 IS - 5 JF - Nature Chemistry KW - general chemical engineering KW - general chemistry SN - 1755-4330 TI - Dynamics of oligomer populations formed during the aggregation of Alzheimer’s Aβ42 peptide VL - 12 ER - TY - JOUR AB - Gadolinium silicide (Gd5Si4) nanoparticles are an interesting class of materials due to their high magnetization, low Curie temperature, low toxicity in biological environments and their multifunctional properties. We report the magnetic and magnetothermal properties of gadolinium silicide (Gd5Si4) nanoparticles prepared by surfactant-assisted ball milling of arc melted bulk ingots of the compound. Using different milling times and speeds, a wide range of crystallite sizes (13–43 nm) could be produced and a reduction in Curie temperature (TC) from 340 K to 317 K was achieved, making these nanoparticles suitable for self-controlled magnetic hyperthermia applications. The magnetothermal effect was measured in applied AC magnetic fields of amplitude 164–239 Oe and frequencies 163–519 kHz. All particles showed magnetic heating with a strong dependence of the specific absorption rate (SAR) on the average crystallite size. The highest SAR of 3.7 W g−1 was measured for 43 nm sized nanoparticles of Gd5Si4. The high SAR and low TC, (within the therapeutic range for magnetothermal therapy) makes the Gd5Si4 behave like self-regulating heat switches that would be suitable for self-controlled magnetic hyperthermia applications after biocompatibility and cytotoxicity tests. AU - Nauman, Muhammad AU - Alnasir, Muhammad Hisham AU - Hamayun, Muhammad Asif AU - Wang, YiXu AU - Shatruk, Michael AU - Manzoor, Sadia ID - 9067 IS - 47 JF - RSC Advances KW - General Chemistry KW - General Chemical Engineering SN - 2046-2069 TI - Size-dependent magnetic and magnetothermal properties of gadolinium silicide nanoparticles VL - 10 ER - TY - JOUR AB - Glioblastoma is the most malignant cancer in the brain and currently incurable. It is urgent to identify effective targets for this lethal disease. Inhibition of such targets should suppress the growth of cancer cells and, ideally also precancerous cells for early prevention, but minimally affect their normal counterparts. Using genetic mouse models with neural stem cells (NSCs) or oligodendrocyte precursor cells (OPCs) as the cells‐of‐origin/mutation, it is shown that the susceptibility of cells within the development hierarchy of glioma to the knockout of insulin‐like growth factor I receptor (IGF1R) is determined not only by their oncogenic states, but also by their cell identities/states. Knockout of IGF1R selectively disrupts the growth of mutant and transformed, but not normal OPCs, or NSCs. The desirable outcome of IGF1R knockout on cell growth requires the mutant cells to commit to the OPC identity regardless of its development hierarchical status. At the molecular level, oncogenic mutations reprogram the cellular network of OPCs and force them to depend more on IGF1R for their growth. A new‐generation brain‐penetrable, orally available IGF1R inhibitor harnessing tumor OPCs in the brain is also developed. The findings reveal the cellular window of IGF1R targeting and establish IGF1R as an effective target for the prevention and treatment of glioblastoma. AU - Tian, Anhao AU - Kang, Bo AU - Li, Baizhou AU - Qiu, Biying AU - Jiang, Wenhong AU - Shao, Fangjie AU - Gao, Qingqing AU - Liu, Rui AU - Cai, Chengwei AU - Jing, Rui AU - Wang, Wei AU - Chen, Pengxiang AU - Liang, Qinghui AU - Bao, Lili AU - Man, Jianghong AU - Wang, Yan AU - Shi, Yu AU - Li, Jin AU - Yang, Minmin AU - Wang, Lisha AU - Zhang, Jianmin AU - Hippenmeyer, Simon AU - Zhu, Junming AU - Bian, Xiuwu AU - Wang, Ying‐Jie AU - Liu, Chong ID - 8592 IS - 21 JF - Advanced Science KW - General Engineering KW - General Physics and Astronomy KW - General Materials Science KW - Medicine (miscellaneous) KW - General Chemical Engineering KW - Biochemistry KW - Genetics and Molecular Biology (miscellaneous) SN - 2198-3844 TI - Oncogenic state and cell identity combinatorially dictate the susceptibility of cells within glioma development hierarchy to IGF1R targeting VL - 7 ER - TY - JOUR AB - Diamondoid nanoporous crystals represent a synthetically challenging class of materials that typically have been obtained from tetrahedral building blocks. In this issue of Chem, Stoddart and coworkers demonstrate that it is possible to generate diamondoid frameworks from a hexacationic building block lacking a tetrahedral symmetry. These results highlight the great potential of self-assembly for rapidly transforming small molecules into structurally complex functional materials. AU - Białek, Michał J. AU - Klajn, Rafal ID - 13371 IS - 9 JF - Chem KW - Materials Chemistry KW - Biochemistry (medical) KW - General Chemical Engineering KW - Environmental Chemistry KW - Biochemistry KW - General Chemistry SN - 2451-9308 TI - Diamond grows up VL - 5 ER - TY - JOUR AB - Mapping free-energy landscapes has proved to be a powerful tool for studying reaction mechanisms. Many complex biomolecular assembly processes, however, have remained challenging to access using this approach, including the aggregation of peptides and proteins into amyloid fibrils implicated in a range of disorders. Here, we generalize the strategy used to probe free-energy landscapes in protein folding to determine the activation energies and entropies that characterize each of the molecular steps in the aggregation of the amyloid-β peptide (Aβ42), which is associated with Alzheimer’s disease. Our results reveal that interactions between monomeric Aβ42 and amyloid fibrils during fibril-dependent secondary nucleation fundamentally reverse the thermodynamic signature of this process relative to primary nucleation, even though both processes generate aggregates from soluble peptides. By mapping the energetic and entropic contributions along the reaction trajectories, we show that the catalytic efficiency of Aβ42 fibril surfaces results from the enthalpic stabilization of adsorbing peptides in conformations amenable to nucleation, resulting in a dramatic lowering of the activation energy for nucleation. AU - Cohen, Samuel I. A. AU - Cukalevski, Risto AU - Michaels, Thomas C. T. AU - Šarić, Anđela AU - Törnquist, Mattias AU - Vendruscolo, Michele AU - Dobson, Christopher M. AU - Buell, Alexander K. AU - Knowles, Tuomas P. J. AU - Linse, Sara ID - 10360 IS - 5 JF - Nature Chemistry KW - general chemical engineering KW - general chemistry SN - 1755-4330 TI - Distinct thermodynamic signatures of oligomer generation in the aggregation of the amyloid-β peptide VL - 10 ER - TY - JOUR AU - Roy, Soumendu AU - Roy, Sumit AU - Rao, Anish AU - Devatha, Gayathri AU - Pillai, Pramod P. ID - 15107 IS - 23 JF - Chemistry of Materials KW - Materials Chemistry KW - General Chemical Engineering KW - General Chemistry SN - 0897-4756 TI - Precise nanoparticle–reactant interaction outplays ligand poisoning in visible-light photocatalysis VL - 30 ER - TY - JOUR AB - Biological membranes have a central role in mediating the organization of membrane-curving proteins, a dynamic process that has proven to be challenging to probe experimentally. Using atomic force microscopy, we capture the hierarchically organized assemblies of Bin/amphiphysin/Rvs (BAR) proteins on supported lipid membranes. Their structure reveals distinct long linear aggregates of proteins, regularly spaced by up to 300 nm. Employing accurate free-energy calculations from large-scale coarse-grained computer simulations, we found that the membrane mediates the interaction among protein filaments as a combination of short- and long-ranged interactions. The long-ranged component acts at strikingly long distances, giving rise to a variety of micron-sized ordered patterns. This mechanism may contribute to the long-ranged spatiotemporal control of membrane remodeling by proteins in the cell. AU - Simunovic, Mijo AU - Šarić, Anđela AU - Henderson, J. Michael AU - Lee, Ka Yee C. AU - Voth, Gregory A. ID - 10369 IS - 12 JF - ACS Central Science KW - general chemical engineering KW - general chemistry SN - 2374-7943 TI - Long-range organization of membrane-curving proteins VL - 3 ER - TY - JOUR AB - Targeting protein–protein interactions has long been considered as a very difficult if impossible task, but over the past decade, front lines have moved. The number of successful examples is exponentially growing. This review presents a rapid overview of recent advances in this field considering the strengths and weaknesses of the small molecule approaches and alternative strategies such as the selection or design of artificial antibodies, peptides or peptidomimetics. AU - Bakail, May M AU - Ochsenbein, Francoise ID - 9019 IS - 1-2 JF - Comptes Rendus Chimie KW - General Chemistry KW - General Chemical Engineering SN - 1631-0748 TI - Targeting protein–protein interactions, a wide open field for drug design VL - 19 ER - TY - JOUR AB - The ability to guide the assembly of nanosized objects reversibly with external stimuli, in particular light, is of fundamental importance, and it contributes to the development of applications as diverse as nanofabrication and controlled drug delivery. However, all the systems described to date are based on nanoparticles (NPs) that are inherently photoresponsive, which makes their preparation cumbersome and can markedly hamper their performance. Here we describe a conceptually new methodology to assemble NPs reversibly using light that does not require the particles to be functionalized with light-responsive ligands. Our strategy is based on the use of a photoswitchable medium that responds to light in such a way that it modulates the interparticle interactions. NP assembly proceeds quantitatively and without apparent fatigue, both in solution and in gels. Exposing the gels to light in a spatially controlled manner allowed us to draw images that spontaneously disappeared after a specific period of time. AU - Kundu, Pintu K. AU - Samanta, Dipak AU - Leizrowice, Ron AU - Margulis, Baruch AU - Zhao, Hui AU - Börner, Martin AU - Udayabhaskararao, T. AU - Manna, Debasish AU - Klajn, Rafal ID - 13394 JF - Nature Chemistry KW - General Chemical Engineering KW - General Chemistry SN - 1755-4330 TI - Light-controlled self-assembly of non-photoresponsive nanoparticles VL - 7 ER - TY - JOUR AB - The immobilization of molecular switches onto inorganic supports has recently become a hot topic as it can give rise to novel hybrid materials in which the properties of the two components are mutually enhanced. Even more attractive is the concept of “transferring” the switchable characteristics of single layers of organic molecules onto the underlying inorganic components, rendering them responsive to external stimuli as well. Of the various molecular switches studied, azobenzene (AB) has arguably attracted most attention due to its simple molecular structure, and because its “trigger” (light) is a noninvasive one, it can be delivered instantaneously, and into a precise location. In order to fully realize its potential, however, it is necessary to immobilize AB onto solid supports. It is the goal of this manuscript to comprehensively yet concisely review such hybrid systems which comprise AB forming well-defined self-assembled monolayers (SAMs) on planar and curved (colloidal and nanoporous) inorganic surfaces. I discuss methods to immobilize AB derivatives onto surfaces, strategies to ensure efficient AB isomerization, ways to monitor the switching process, properties of these switchable hybrid materials, and, last but not least, their emerging applications. AU - Klajn, Rafal ID - 13409 IS - 12 JF - Pure and Applied Chemistry KW - General Chemical Engineering KW - General Chemistry SN - 0033-4545 TI - Immobilized azobenzenes for the construction of photoresponsive materials VL - 82 ER - TY - JOUR AB - Systems in which nanoscale components of different types can be captured and/or released from organic scaffolds provide a fertile basis for the construction of dynamic, exchangeable functional materials. In such heterogeneous systems, the components interact with one another by means of programmable, noncovalent bonding interactions. Herein, we describe polymers that capture and release functionalized nanoparticles selectively during redox-controlled aggregation and disaggregation, respectively. The interactions between the polymer and the NPs are mediated by the reversible formation of polypseudorotaxanes, and give rise to architectures ranging from short chains composed of few nanoparticles to extended networks of nanoparticles crosslinked by the polymer. In the latter case, the polymer/nanoparticle aggregates precipitate from solution such that the polymer acts as a selective ‘sponge’ for the capture/release of the nanoparticles of different types. AU - Klajn, Rafal AU - Olson, Mark A. AU - Wesson, Paul J. AU - Fang, Lei AU - Coskun, Ali AU - Trabolsi, Ali AU - Soh, Siowling AU - Stoddart, J. Fraser AU - Grzybowski, Bartosz A. ID - 13415 JF - Nature Chemistry KW - General Chemical Engineering KW - General Chemistry SN - 1755-4330 TI - Dynamic hook-and-eye nanoparticle sponges VL - 1 ER -