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Showing papers by "J. Fraser Stoddart published in 2020"


Journal ArticleDOI
17 Apr 2020-Science
TL;DR: The simulation-motivated synthesis of ultraporous metal–organic frameworks (MOFs) based on metal trinuclear clusters, namely, NU-1501-M (M = Al or Fe), achieves high gravimetric and volumetric uptake and delivery of methane and hydrogen and exhibits one of the best deliverable hydrogen capacities.
Abstract: A huge challenge facing scientists is the development of adsorbent materials that exhibit ultrahigh porosity but maintain balance between gravimetric and volumetric surface areas for the onboard storage of hydrogen and methane gas—alternatives to conventional fossil fuels. Here we report the simulation-motivated synthesis of ultraporous metal–organic frameworks (MOFs) based on metal trinuclear clusters, namely, NU-1501-M (M = Al or Fe). Relative to other ultraporous MOFs, NU-1501-Al exhibits concurrently a high gravimetric Brunauer−Emmett−Teller (BET) area of 7310 m2 g−1 and a volumetric BET area of 2060 m2 cm−3 while satisfying the four BET consistency criteria. The high porosity and surface area of this MOF yielded impressive gravimetric and volumetric storage performances for hydrogen and methane: NU-1501-Al surpasses the gravimetric methane storage U.S. Department of Energy target (0.5 g g−1) with an uptake of 0.66 g g−1 [262 cm3 (standard temperature and pressure, STP) cm−3] at 100 bar/270 K and a 5- to 100-bar working capacity of 0.60 g g−1 [238 cm3 (STP) cm−3] at 270 K; it also shows one of the best deliverable hydrogen capacities (14.0 weight %, 46.2 g liter−1) under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar).

334 citations


Journal ArticleDOI
TL;DR: Findings suggest that the utilization of electron-active organic macrocycles, combined with the low interfacial resistance associated with the solvation of divalent carrier ions, is essential for the overall performance ofdivalent battery systems.
Abstract: Aqueous rechargeable zinc batteries (ZBs) have received considerable attention recently for large-scale energy storage systems in terms of rate performance, cost, and safety. Nevertheless, these ZBs still remain a subject for investigation, as researchers search for cathode materials enabling high performance. Among the various candidate cathode materials for ZBs, quinone compounds stand out as candidates because of their high specific capacity, sustainability, and low cost. Quinone-based cathodes, however, suffer from the critical limitation of undergoing dissolution during battery cycling, leading to a deterioration in battery life. To address this problem, we have introduced a redox-active triangular phenanthrenequinone-based macrocycle (PQ-Δ) with a rigid geometry and layered superstructure. Notably, we have confirmed that Zn2+ ions, together with H2O molecules, can be inserted into the PQ-Δ organic cathode, and, as a consequence, the interfacial resistance between the cathode and electrolytes is decreased effectively. Density functional theory calculations have revealed that the low interfacial resistance can be attributed mainly to decreasing the desolvation energy penalty as a result of the insertion of hydrated Zn2+ ions in the PQ-Δ cathode. The combined effects of the insertion of hydrated Zn2+ ions and the robust triangular structure of PQ-Δ serve to achieve a large reversible capacity of 210 mAh g-1 at a high current density of 150 mA g-1, along with an excellent cycle-life, that is, 99.9% retention after 500 cycles. These findings suggest that the utilization of electron-active organic macrocycles, combined with the low interfacial resistance associated with the solvation of divalent carrier ions, is essential for the overall performance of divalent battery systems.

192 citations


Journal ArticleDOI
13 Oct 2020
TL;DR: In this paper, a class of porous molecular materials that rely on the assembly of organic building blocks by means of hydrogen-bonding interactions to form a hydrogen-branched organic framework is defined.
Abstract: ConspectusHydrogen-bonded organic frameworks (HOFs) are a class of porous molecular materials that rely on the assembly of organic building blocks by means of hydrogen-bonding interactions to form ...

139 citations


Journal ArticleDOI
TL;DR: A semi- artificial system - containing an immobilized enzyme, formate dehydrogenase, in a light harvesting scaffold - is reported for the conversion of CO2 to formic acid using white light, demonstrating of a feasible pathway for solar-driven carbon fixation.
Abstract: Protection of enzymes with synthetic materials is a viable strategy to stabilize, and hence to retain, the reactivity of these highly active biomolecules in non-native environments. Active syntheti...

139 citations


Journal ArticleDOI
12 Jun 2020-Science
TL;DR: The assembly line–like emergence of polyrotaxanes with increasingly higher energies is reported by harnessing artificial molecular pumps to deliver rings in pairs by cyclical redox-driven processes, which leads to the precise incorporation of two, four, six, eight, and 10 rings carrying 8+, 16+, 24+, 32+, and 40+ charges, respectively, onto hexacationic polymer dumbbells.
Abstract: Mechanically interlocked molecules are likely candidates for the design and synthesis of artificial molecular machines. Although polyrotaxanes have already found niche applications in exotic materials with specialized mechanical properties, efficient synthetic protocols to produce them with precise numbers of rings encircling their polymer dumbbells are still lacking. We report the assembly line–like emergence of poly[n]rotaxanes with increasingly higher energies by harnessing artificial molecular pumps to deliver rings in pairs by cyclical redox-driven processes. This programmable strategy leads to the precise incorporation of two, four, six, eight, and 10 rings carrying 8+, 16+, 24+, 32+, and 40+ charges, respectively, onto hexacationic polymer dumbbells. This strategy depends precisely on the number of redox cycles applied chemically or electrochemically, in both stepwise and one-pot manners.

115 citations


Journal ArticleDOI
TL;DR: A porphyrin-based porous polymer with selective binding shows remarkable selectivity and a reductive mechanism, a combination which makes for record-high recycling of precious metals––particularly gold––from e-waste.
Abstract: Urban mining of precious metals from electronic waste, such as printed circuit boards (PCB), is not yet feasible because of the lengthy isolation process, health risks, and environmental impact Although porous polymers are particularly effective toward the capture of metal contaminants, those with porphyrin linkers have not yet been considered for precious metal recovery, despite their potential Here, we report a porous porphyrin polymer that captures precious metals quantitatively from PCB leachate even in the presence of 63 elements from the Periodic Table The nanoporous polymer is synthesized in two steps from widely available monomers without the need for costly catalysts and can be scaled up without loss of activity Through a reductive capture mechanism, gold is recovered with 10 times the theoretical limit, reaching a record 162 g/g With 99% uptake taking place in the first 30 min, the metal adsorbed to the porous polymer can be desorbed rapidly and reused for repetitive batches Density functional theory (DFT) calculations indicate that energetically favorable multinuclear-Au binding enhances adsorption as clusters, leading to rapid capture, while Pt capture remains predominantly at single porphyrin sites

95 citations


Journal ArticleDOI
TL;DR: The heterogeneous photocatalytic activities of both the parent POP and its derivative for the detoxification of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES), have been examined and the results show significant enhancement in the generation of the singlet oxygen (1O2).
Abstract: Designing new materials for the effective detoxification of chemical warfare agents (CWAs) is of current interest given the recent use of CWAs. Although halogenated boron-dipyrromethene derivatives (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene or BDP or BODIPY) at the 2 and 6 positions have been extensively explored as efficient photosensitizers for generating singlet oxygen (1O2) in homogeneous media, their utilization in the design of porous organic polymers (POPs) has remained elusive due to the difficulty of controlling polymerization processes through cross-coupling synthesis pathways. Our approach to overcome these difficulties and prepare halogenated BODIPY-based porous organic polymers (X-BDP-POP where X = Br or I) represents an attractive alternative through post-synthesis modification (PSM) of the parent hydrogenated polymer. Upon synthesis of both the parent polymer, H-BDP-POP, and its post-synthetically modified derivatives, Br-BDP-POP and I-BDP-POP, the BET surface areas of all POPs have been measured and found to be 640, 430, and 400 m2·g-1, respectively. In addition, the insertion of heavy halogen atoms at the 2 and 6 positions of the BODIPY unit leads to the quenching of fluorescence (both polymer and solution-phase monomer forms) and the enhancement of phosphorescence (particularly for the iodo versions of the polymers and monomers), as a result of efficient intersystem crossing. The heterogeneous photocatalytic activities of both the parent POP and its derivatives for the detoxification of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES), have been examined; the results show a significant enhancement in the generation of singlet oxygen (1O2). Both the bromination and iodination of H-BDP-POP served to shorten by 5-fold of the time needed for the selective and catalytic photo-oxidation of CEES to 2-chloroethyl ethyl sulfoxide (CEESO).

68 citations


Journal ArticleDOI
06 Aug 2020-Chem
TL;DR: This review discusses the emergence of pumps, both natural and crafted through the ages, focusing on recent advances toward the design and synthesis of artificial molecular pumps (AMPs) that are capable of creating local concentrations of rings on collecting chains.

59 citations


Journal ArticleDOI
TL;DR: The quadrangle-shaped co-crystal constitutes a unique material that exhibits two-photon absorption and near-infrared emission simultaneously and holds considerable promise for the future design and synthesis of more advanced optical materials.
Abstract: Two-photon excited near-infrared fluorescence materials have garnered considerable attention because of their superior optical penetration, higher spatial resolution, and lower optical scattering compared with other optical materials. Herein, a convenient and efficient supramolecular approach is used to synthesize a two-photon excited near-infrared emissive co-crystalline material. A naphthalenediimide-based triangular macrocycle and coronene form selectively two co-crystals. The triangle-shaped co-crystal emits deep-red fluorescence, while the quadrangle-shaped co-crystal displays deep-red and near-infrared emission centered on 668 nm, which represents a 162 nm red-shift compared with its precursors. Benefiting from intermolecular charge transfer interactions, the two co-crystals possess higher calculated two-photon absorption cross-sections than those of their individual constituents. Their two-photon absorption bands reach into the NIR-II region of the electromagnetic spectrum. The quadrangle-shaped co-crystal constitutes a unique material that exhibits two-photon absorption and near-infrared emission simultaneously. This co-crystallization strategy holds considerable promise for the future design and synthesis of more advanced optical materials. Two-photon excited near-infrared fluorescence materials have garnered considerable attention because of their superior optical properties compared with other optical materials. Here, the authors use a convenient and efficient supramolecular approach to synthesize a two-photon excited near-infrared emissive co-crystalline material.

54 citations


Journal ArticleDOI
TL;DR: The design, synthesis, and operation of an AMP incorporating a photocleavable stopper that allows for the use of orthogonal stimuli is reported, which may find application in the fabrication of molecular transporting systems with on-demand functions.
Abstract: The ability to control the relative motions of component parts in molecules is essential for the development of molecular nanotechnology. The advent of mechanically interlocked molecules (MIMs) has...

41 citations


Journal ArticleDOI
TL;DR: The search for a fresh approach to obtain exciplex PL from permanent structures by incorporating anthracene moieties into pyridinium-containing mechanically interlocked molecules (MIMs) was sought and live-cell imaging performed in MIAPaCa-2 prostate cancer cells confirmed that the catenaneexciplex emission can be detected at micromolar concentrations.
Abstract: Collisional intermolecular interactions between excited states form short-lived dimers and complexes that lead to the emergence of excimer/exciplex emission of lower energy, a phenomenon which must...

Journal ArticleDOI
TL;DR: The encapsulation of this extended tetracationic cyclophane by both one and two cucurbit[8]urils provides an incentive to design and synthesize more advanced supramolecular systems, as well as opening up a feasible approach toward achieving tunable multicolor photoluminescence with a single chromophore.
Abstract: One ring threaded by two other rings to form a non-intertwined ternary ring-in-rings motif is a challenging task in noncovalent synthesis. Constructing multicolor photoluminescence systems with tunable properties is also a fundamental research goal, which can lead to applications in multidimensional biological imaging, visual displays, and encryption materials. Herein, we describe the design and synthesis of binary and ternary ring-in-ring(s) complexes, based on an extended tetracationic cyclophane and cucurbit[8]uril. The formation of these complexes is accompanied by tunable multicolor fluorescence outputs. On mixing equimolar amounts of the cyclophane and cucurbit[8]uril, a 1:1 ring-in-ring complex is formed as a result of hydrophobic interactions associated with a favorable change in entropy. With the addition of another equivalent of cucurbit[8]uril, a 1:2 ring-in-rings complex is formed, facilitated by additional ion-dipole interactions involving the pyridinium units in the cyclophane and the carbonyl groups in cucurbit[8]uril. Because of the narrowing in the energy gaps of the cyclophane within the rigid hydrophobic cavities of cucurbit[8]urils, the binary and ternary ring-in-ring(s) complexes emit green and bright yellow fluorescence, respectively. A series of color-tunable emissions, such as sky blue, cyan, green, and yellow with increased fluorescence lifetimes, can be achieved by simply adding cucurbit[8]uril to an aqueous solution of the cyclophane. Notably, the smaller cyclobis(paraquat-p-phenylene), which contains the same p-xylylene linkers as the extended tetracationic cyclophane, does not form ring-in-ring(s) complexes with cucurbit[8]uril. The encapsulation of this extended tetracationic cyclophane by both one and two cucurbit[8]urils provides an incentive to design and synthesize more advanced supramolecular systems, as well as opening up a feasible approach toward achieving tunable multicolor photoluminescence with single chromophores.

Journal ArticleDOI
05 Feb 2020
TL;DR: The molecular design presented herein constitutes a proof-of-principle approach to charged intramolecular circuits that are desirable for quantum circuits and devices and boosts the total conductance of the two-channel circuit.
Abstract: Summary For neutral intramolecular circuits with two constitutionally identical branches, a maximum 4-fold increase in total conductance can be obtained according to constructive quantum interference (CQI). For charged intramolecular circuits, however, the strong electrostatic interactions entangle the quantum states of these two parallel pathways, thus introducing complicated transport behavior that warrants experimental investigation of the intramolecular circuit rules. Here, we report that a tetracationic cyclophane with parallel channels exhibits a 50-fold conductance enhancement compared with that of a single-channel control, an observation that supplements intramolecular circuit law in systems with strong Coulombic interactions. Flicker noise measurements and theoretical calculations show that strong electrostatic interactions between charged parallel channels—serving as the chemical gate to promote the effective conductance of each channel—and CQI boosts the total conductance of the two-channel circuit. The molecular design presented herein constitutes a proof-of-principle approach to charged intramolecular circuits that are desirable for quantum circuits and devices.

Journal ArticleDOI
TL;DR: The synthesis of a tricyclic octacationic cyclophane is reported, which exhibits complementary stereoelectronic binding towards a widely used fluorescent dye, perylene diimide, with picomolar affinity in water.
Abstract: The rational design of wholly synthetic receptors that bind active substrates with ultrahigh affinities is a challenging goal, especially in water. Here, we report the synthesis of a tricyclic octacationic cyclophane, which exhibits complementary stereoelectronic binding toward a widely used fluorescent dye, perylene diimide, with picomolar affinity in water. The ultrahigh binding affinity is sustained by a large and rigid hydrophobic binding surface, which provides a highly favorable enthalpy and a slightly positive entropy of complexation. The receptor–substrate complex shows significant improvement in optical properties, including red-shifted absorption and emission, turn-on fluorescence, and efficient energy transfer. An unusual single-excitation, dual-emission, imaging study of living cells was performed by taking advantage of a large pseudo-Stokes shift, produced by the efficient energy transfer.


Journal ArticleDOI
TL;DR: This approach could pave the way for the development of new stimuli-responsive materials based on mechanically interlocked molecules for future electro-optical applications, such as sensors, molecular memories, and molecular logic gates.
Abstract: We report how the nanoconfined environment, introduced by the mechanical bonds within an electrochemically switchable bistable [2]rotaxane, controls the rotation of a fluorescent molecular rotor, namely, an 8-phenyl-substituted boron dipyrromethene (BODIPY). The electrochemical switching of the bistable [2]rotaxane induces changes in the ground-state coconformation and in the corresponding excited-state properties of the BODIPY rotor. In the starting redox state, when no external potential is applied, the cyclobis(paraquat-p-phenylene) (CBPQT4+) ring component encircles the tetrathiafulvalene (TTF) unit on the dumbbell component, leaving the BODIPY rotor unhindered and exhibiting low fluorescence. Upon oxidation of the TTF unit to a TTF2+ dication, the CBPQT4+ ring is forced toward the molecular rotor, leading to an increased energy barrier for the excited state to rotate the rotor into the state with a high nonradiative rate constant, resulting in an overall 3.4-fold fluorescence enhancement. On the other hand, when the solvent polarity is high enough to stabilize the excited charge-transfer state between the BODIPY rotor and the CBPQT4+ ring, movement of the ring toward the BODIPY rotor produces an unexpectedly strong fluorescence signal decrease as the result of photoinduced electron transfer from the BODIPY rotor to the CBPQT4+ ring. The nanoconfinement effect introduced by mechanical bonding can effectively lead to modulation of the physicochemical properties as observed in this bistable [2]rotaxane. On account of the straightforward synthetic strategy and the facile modulation of switchable electrochromic behavior, our approach could pave the way for the development of new stimuli-responsive materials based on mechanically interlocked molecules for future electro-optical applications, such as sensors, molecular memories, and molecular logic gates.

Journal ArticleDOI
TL;DR: A laboratory-scale gold recovery protocol, aligned with an attractive strategy for the practical recovery of gold, was established based on the highly efficient co-precipitation of CB[6]·HAuCl4.
Abstract: Developing an extremely efficient and highly selective process for gold recovery is urgently desired for maintaining a sustainable ecological environment. Herein, we report a highly efficient gold-...

Journal ArticleDOI
TL;DR: The single crystal structure of a highly ordered polycationic polymer (polyelectrolyte) and its proton conductivity is described, which endows the polymer with potential applications as a robust proton-conducting material.
Abstract: The efficient preparation of single-crystalline ionic polymers and fundamental understanding of their structure–property relationships at the molecular level remains a challenge in chemistry and ma...

Journal ArticleDOI
TL;DR: This work examines in the context of recent artificial molecular pumps, the kinetics and thermodynamics of both light or externally driven pumps on the one hand and pumps driven by chemical catalysis on the other, and uses cycle kinetics developed by Terrell Hill in the analysis of energy driven pumping.
Abstract: A major goal in the design of synthetic molecular machines is the creation of pumps that can use the input of energy to transport material from a reservoir at low chemical potential to a different reservoir at higher chemical potential, thereby forming and maintaining a chemical potential gradient. Such pumps are ubiquitous in biology. Some, including the Ca+2-ATPase of the sarcoplasmic reticulum, and the (Na+,K+)-ATPase found in the membranes of almost all cells, use energy from ATP hydrolysis to accomplish this task. Others, such as bacteriorhodopsin, use energy from light. Here, we examine in the context of recent artificial molecular pumps, the kinetics and thermodynamics of both light or externally driven pumps on the one hand and pumps driven by chemical catalysis on the other. We show that even for formally similar mechanisms there is a tremendous difference in the design principles for these two classes of pumps, where the former can function as energy ratchets, and the latter must operate as information ratchets. This difference arises because, unlike optically or externally driven pumps, the transition constants for pumps in which the required energy is provided by catalysis of a chemical reaction obey the principle of microscopic reversibility. We use cycle kinetics developed by Terrell Hill in the analysis of energy driven pumping. This approach is based on the trajectory thermodynamics of Onsager and Machlup. The recent “stochastic thermodynamic” approach is shown to be fundamentally flawed and to lead to incorrect predictions regarding the behavior of molecular machines driven by catalysis of an exergonic chemical reaction.

Journal ArticleDOI
TL;DR: The assembly of a kinetically trapped daisy chain polymer under redox control has been achieved with a self-complementary monomer using an energy ratchet mechanism, opening up opportunities for synthesizing mechanically interlocked polymers using molecular machines.
Abstract: The assembly of a kinetically trapped daisy chain polymer under redox control has been achieved with a self-complementary monomer using an energy ratchet mechanism. The monomer is composed of a mol...

Journal ArticleDOI
TL;DR: This organic counteranion co-assembly strategy opens up new routes for the construction of hybrid frameworks, which are inaccessible by existing de novo MOF assembly methodologies.
Abstract: A class of γ-cyclodextrin-containing hybrid frameworks (CD-HFs) has been synthesized, employing γ-cyclodextrin (γ-CD) as the primary building blocks, along with 4-methoxysalicylate (4-MS-) anions as the secondary building blocks. CD-HFs are constructed through the synergistic exploitation of coordinative, electrostatic, and dispersive forces. The syntheses have been carried out using an organic counteranion co-assembly strategy, which allows for the introduction of 4-MS-, in place of inorganic OH-, into the cationic γ-CD-containing metal-organic frameworks (CD-MOFs). Although the packing arrangement of the γ-CD tori in the solid-state superstructure of CD-HFs is identical to that of the previously reported CD-MOFs, CD-HFs crystallize with lower symmetry and in the cuboid space group P43212-when compared to CD-MOF-1, which has the cubic unit cell of I432 space group-on account of the chiral packing of the 4-MS- anions in the CD-HF superstructures. Importantly, CD-HFs have ultramicroporous apertures associated with the pore channels, a significant deviation from CD-MOF-1, as a consequence of the contribution from the 4-MS- anions, which serve as supramolecular baffles. In gas adsorption-desorption experiments, CD-HF-1 exhibits a Brunauer-Emmett-Teller (BET) surface area of 306 m2 g-1 for CO2 at 195 K, yet does not uptake N2 at 77 K, confirming the difference in porosity between CD-HF-1 and CD-MOF-1. Furthermore, the 4-MS- anions in CD-HF-1 can be exchanged with OH- anions, leading to an irreversible single-crystal to single-crystal transformation, with rearrangement of coordinated metal ions. Reversible transformations were also observed in CD-MOF-1 when OH- ions were exchanged for 4-MS- anions, with the space group changing from I432 to R32. This organic counteranion co-assembly strategy opens up new routes for the construction of hybrid frameworks, which are inaccessible by existing de novo MOF assembly methodologies.

Journal ArticleDOI
TL;DR: This research lays the solid foundation for the introduction of the structurally transformative tetracationic cyclophane into the realm of mechanically interlocked molecules and will provide a toolbox to construct and operate intelligent molecular machines.
Abstract: Synthetic macrocycles capable of undergoing allosteric regulation by responding to versatile external stimuli are the subject of increasing attention in supramolecular science. Herein, we report a structurally transformative tetracationic cyclophane containing two 3,6-bis(4-pyridyl)-l,2,4,5-tetrazine (4-bptz) units, which are linked together by two p-xylylene bridges. The cyclophane, which possesses modular redox states and structural post-modifications, can undergo two reversibly consecutive two-electron reductions, affording first its bisradical dicationic counterpart, and then subsequently the fully reduced species. Furthermore, one single-parent cyclophane can afford effectively three other new analogs through box-to-box cascade transformations, taking advantage of either reductions or an inverse electron-demand Diels-Alder (IEDDA) reaction. While all four new tetracationic cyclophanes adopt rigid and symmetric box-like conformations, their geometries in relation to size, shape, electronic properties, and binding affinities toward polycyclic aromatic hydrocarbons can be readily regulated. This structurally transformative tetracationic cyclophane performs a variety of new tasks as a result of structural post-modifications, thus serving as a toolbox for probing the radical properties and generating rapidly a range of structurally diverse cyclophanes by efficient divergent syntheses. This research lays a solid foundation for the introduction of the structurally transformative tetracationic cyclophane into the realm of mechanically interlocked molecules and will provide a toolbox to construct and operate intelligent molecular machines.

Journal ArticleDOI
TL;DR: A mixed-flow microfluidic printing approach to phase purity control, enabled by a printing blade design based on fluid flow simulations, that significantly elevates phase purity in bulk-heterojunction solar cells and thin-film transistors is reported.
Abstract: The rational creation of two-component conjugated polymer systems with high levels of phase purity in each component is challenging but crucial for realizing printed soft-matter electronics. Here, we report a mixed-flow microfluidic printing (MFMP) approach for two-component π-polymer systems that significantly elevates phase purity in bulk-heterojunction solar cells and thin-film transistors. MFMP integrates laminar and extensional flows using a specially microstructured shear blade, designed with fluid flow simulation tools to tune the flow patterns and induce shear, stretch, and pushout effects. This optimizes polymer conformation and semiconducting blend order as assessed by atomic force microscopy (AFM), transmission electron microscopy (TEM), grazing incidence wide-angle X-ray scattering (GIWAXS), resonant soft X-ray scattering (R-SoXS), photovoltaic response, and field effect mobility. For printed all-polymer (poly[(5,6-difluoro-2-octyl-2H-benzotriazole-4,7-diyl)-2,5-thiophenediyl[4,8-bis[5-(2-hexyldecyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl]) [J51]:(poly{[N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)}) [N2200]) solar cells, this approach enhances short-circuit currents and fill factors, with power conversion efficiency increasing from 5.20% for conventional blade coating to 7.80% for MFMP. Moreover, the performance of mixed polymer ambipolar [poly(3-hexylthiophene-2,5-diyl) (P3HT):N2200] and semiconducting:insulating polymer unipolar (N2200:polystyrene) transistors is similarly enhanced, underscoring versatility for two-component π-polymer systems. Mixed-flow designs offer modalities for achieving high-performance organic optoelectronics via innovative printing methodologies.

Journal ArticleDOI
TL;DR: Host-guest complexation-mediated supramolecular photon upconversion eliminates multiple issues in relation to the existing systems related to high working concentrations, high incident laser power, and low optical penetration depths.
Abstract: The phenomenon of photon upconversion, in which a system absorbs two or more photons of lower energy and emits a photon of higher energy, has been used in numerous applications, including non-destr...

Journal ArticleDOI
TL;DR: The encapsulation of free-base and zinc porphyrins by a tricyclic cyclophane receptor with subnanomolar binding affinities in water is reported, where their D/H exchange, protonation, and solvolysis under extremely acidic conditions are completely blocked.
Abstract: We report the encapsulation of free-base and zinc porphyrins by a tricyclic cyclophane receptor with subnanomolar binding affinities in water. The high affinities are sustained by the hydrophobic e...

Journal ArticleDOI
TL;DR: The homogeneous and heterogeneous photocatalytic activities of the TBP⊂ExBox4+ , for the elimination of a sulfur mustard simulant, has proved to be significantly more efficient than TBP and ExBox+4, confirming the importance of the newly formed excited-state manifold in T BP⊁ExBox 4+ for the population of the low-lying T1 state.
Abstract: Efficient heterogeneous photosensitizing materials require both large accessible surface areas and excitons of suitable energies and with well-defined spin structures. Confinement of the tetracationic cyclophane (ExBox4+ ) within a nonporous anionic polystyrene sulfonate (PSS) matrix leads to a surface area increase of up to 225 m2 g-1 in ExBox•PSS. Efficient intersystem crossing is achieved by combining the spin-orbit coupling associated to Br heavy atoms in 1,3,5,8-tetrabromopyrene (TBP), and the photoinduced electron transfer in a TBP⊂ExBox4+ supramolecular dyad. The TBP⊂ExBox4+ complex displays a charge transfer band at 450 nm and an exciplex emission at 520 nm, indicating the formation of new mixed-electronic states. The lowest triplet state (T1 , 1.89 eV) is localized on the TBP and is close in energy with the charge separated state (CT, 2.14 eV). The homogeneous and heterogeneous photocatalytic activities of the TBP⊂ExBox4+ , for the elimination of a sulfur mustard simulant, has proved to be significantly more efficient than TBP and ExBox+4 , confirming the importance of the newly formed excited-state manifold in TBP⊂ExBox4+ for the population of the low-lying T1 state. The high stability, facile preparation, and high performance of the TBP⊂ExBox•PSS nanocomposites augur well for the future development of new supramolecular heterogeneous photosensitizers using host-guest chemistry.

Journal ArticleDOI
TL;DR: Diversity leads to scientific excellence, the progress of science and, most importantly, it is simply the right thing to do.
Abstract: Valuing diversity leads to scientific excellence, the progress of science and, most importantly, it is simply the right thing to do. We must value diversity not only in words, but also in actions.

Journal ArticleDOI
TL;DR: A porphyrin-based suit[4]ane, which is composed of a p Morphyrin with four protruding ligands--called the limbs that are encompassed by a tricyclic octacationic cyclophane--is reported.
Abstract: Suitanes are two-component mechanically interlocked molecules in which one (torso) of the components, with several protruding limbs, is encompassed by another (suit) all-in-one component. This kind...

Journal ArticleDOI
TL;DR: A molecular tweezer is designed and synthesized that is able to encapsulate π-donors and also demonstrated a precise opening extension, revealing the opening of individual viologen tweezers with an unambiguous extension.
Abstract: Donor–acceptor (DA) π-interactions are weak attractive forces that are exploited widely in molecular and supramolecular chemistry. They have been characterized extensively by ensemble techniques, p...

Journal ArticleDOI
TL;DR: Flexible protruding limbs are sufficient for a suit[3]ane to remain mechanically stable even at high temperatures in solution, according to the results of the synthesis and characterization.
Abstract: Suitanes are a class of mechanically interlocked molecules (MIMs) that consist of two components: a body with limbs protruding outward and a suit that fits appropriately around it, so that there is no easy way for the suit to be removed from the body. Herein, we report the synthesis and characterization of a suit[3]ane, which contains a benzotrithiophene derivative (THBTT) with three protruding hexyl chains as the body and a 3-fold symmetric, extended pyridinium-based cage, namely, HexaCage6+, as the suit. Central to its realization is effective templation, provided by THBTT during cage formation, an observation that has been supported by the strong binding constant between benzotrithiophene (BTT) and the empty cage. The solid-state structure of the suit[3]ane reveals that the body is confined within the suit's cavity with its alkyl chains protruding outward through the orifices in the cage. Notably, such a seemingly unstable molecule, having three flexible alkyl chains as its only protruding limbs, does not dissociate after prolonged heating in CD3CN at 100 °C under pressure for 7 days. No evidence for guest exchange with the host was observed at this temperature in a 2:1 mixture of THBTT and HexaCage6+ in CD3CN. The results indicate that flexible protruding limbs are sufficient for a suit[3]ane to remain mechanically stable even at high temperatures in solution.