Recent Submissions

  • Side Chain Redistribution as a Strategy to Boost Organic Electrochemical Transistor Performance and Stability

    Moser, Maximilian; Hidalgo, Tania Cecilia; Surgailis, Jokubas; Gladisch, Johannes; Ghosh, Sarbani; Sheelamanthula, Rajendar; Thiburce, Quentin; Giovannitti, Alexander; Salleo, Alberto; Gasparini, Nicola; Wadsworth, Andrew; Zozoulenko, Igor; Berggren, Magnus; Stavrinidou, Eleni; Inal, Sahika; McCulloch, Iain (Advanced Materials, Wiley, 2020-08-05) [Article]
    A series of glycolated polythiophenes for use in organic electrochemical transistors (OECTs) is designed and synthesized, differing in the distribution of their ethylene glycol chains that are tethered to the conjugated backbone. While side chain redistribution does not have a significant impact on the optoelectronic properties of the polymers, this molecular engineering strategy strongly impacts the water uptake achieved in the polymers. By careful optimization of the water uptake in the polymer films, OECTs with unprecedented steady-state performances in terms of [μC*] and current retentions up to 98% over 700 electrochemical switching cycles are developed.
  • From Capsule to Helix: Guest-Induced Superstructures of Chiral Macrocycle Crystals

    Dey, Avishek; Chand, Santanu; Alimi, Lukman Olawale; Ghosh, Munmun; Cavallo, Luigi; Khashab, Niveen M. (Journal of the American Chemical Society, American Chemical Society (ACS), 2020-08-01) [Article]
    The prediction, control, understanding and elucidation of phase transition from gel to crystal is in high demand for the de-velopment of various functional materials with macroscopic properties. Here, we show a detailed and systematic description of the self-assembly process of enantiopure trianglimine macrocyclic host from gel to single crystals. This proceeds via an unprecedented formation of capsule-like or right-handed helix superstructures as metastable products, depending on the nature of the guest molecule. Mesitylene promotes the formation of capsule-like superstructures; whereas, toluene results in the formation of helices as intermediates during the course of crystallization. Single crystal results demonstrate that the crystals obtained via the direct self-assembly from the gel phase are different from the crystals obtained from the stepwise assembly of the intermediate superstructures. Hence, investigating the phase-transition superstructures that self-assemble through the process of crystallization can unravel new molecular ordering with unexplored host-guest interactions. Such understanding will provide further tools to control hierarchical assemblies at the molecular level and consequently design or dictate the properties of evolved materials.
  • Alternating Gyroid Network Structure in an ABC Miktoarm Terpolymer Comprised of Polystyrene and Two Polydienes

    Moschovas, Dimitrios; Manesi, Gkreti-Maria; Karydis-Messinis, Andreas; Zapsas, Georgios; Ntetsikas, Konstantinos; Zafeiropoulos, Nikolaos E.; Piryazev, Alexey A.; Thomas, Edwin L.; Hadjichristidis, Nikos; Ivanov, Dimitri A.; Avgeropoulos, Apostolos (Nanomaterials, MDPI AG, 2020-07-31) [Article]
    The synthesis, molecular and morphological characterization of a 3-miktoarm star terpolymer of polystyrene (PS, M¯n = 61.0 kg/mol), polybutadiene (PB, M¯n = 38.2 kg/mol) and polyisoprene (PI, M¯n = 29.2 kg/mol), corresponding to volume fractions (φ) of 0.46, 0.31 and 0.23 respectively, was studied. The major difference of the present material from previous ABC miktoarm stars (which is a star architecture bearing three different segments, all connected to a single junction point) with the same block components is the high 3,4-microstructure (55%) of the PI chains. The interaction parameter and the degree of polymerization of the two polydienes is sufficiently positive to create a three-phase microdomain structure as evidenced by differential scanning calorimetry and transmission electron microscopy (TEM). These results in combination with small-angle X-ray scattering (SAXS) and birefringence experiments suggest a cubic tricontinuous network structure, based on the I4132 space group never reported previously for such an architecture.
  • Room-Temperature Valley Polarization in Atomically Thin Semiconductors via Chalcogenide Alloying

    Liu, Sheng; Granados del Águila, Andrés; Liu, Xue; Zhu, Yihan; Han, Yu; Chaturvedi, Apoorva; Gong, Pu; Yu, Hongyi; Zhang, Hua; Yao, Wang; Xiong, Qihua (ACS Nano, American Chemical Society (ACS), 2020-07-31) [Article]
    Room-temperature manipulation and processing of information encoded in the electronic valley pseudospin and spin degrees of freedoms lie at the heart of the next technological quantum revolution. In atomically thin layers of transition-metal dichalcogenides (TMDs) with hexagonal lattices, valley-polarized excitations and valley quantum coherence can be generated by simply shining with adequately polarized light. In turn, the polarization states of light can induce topological Hall currents in the absence of an external magnetic field, which underlies the fundamental principle of opto-valleytronics devices. However, demonstration of optical generation of valley polarization at room temperature has remained challenging and not well understood. Here, we demonstrate control of strong valley polarization (valley quantum coherence) at room temperature of up to ∼50% (∼20%) by strategically designing Coulomb forces and spin−orbit interactions in atomically thin TMDs via chalcogenide alloying. We show that tailor making the carrier density and the relative order between optically active (bright) and forbidden (dark) states by key variations on the chalcogenide atom ratio allows full control of valley pseudospin dynamics. Our findings set a comprehensive approach for intrinsic and efficient manipulation of valley pseudospin and spin degree of freedom toward realistic opto-valleytronics devices.
  • Remarkable Influence of α-SnWO4 Exposed Facets on Its Photocatalytic Performance for H2 and O2 Evolution Reactions

    Harb, Moussab; Cavallo, Luigi; Basset, Jean-Marie (The Journal of Physical Chemistry C, American Chemical Society (ACS), 2020-07-31) [Article]
    A significant effect of the five major (121), (210), (111), (200), and (040) exposed facets obtained experimentally for orthorhombic α-SnWO4 material on its performance for photocatalytic water splitting is highlighted from a hybrid DFT-based comprehensive study. Their electronic, redox, and transport characteristics reveal significant anisotropic characters. The specific function of each surface in water oxidation and proton reduction is in direct relationship with the exposed W coordination number. Our study predicts the (210) facet as being the only possible good candidate for OER and HER upon surface modification, whereas the (200) facet is found a good candidate only for HER. The (121) facet is an acceptable candidate for both OER and HER and the (111) facet for HER only but less potentials than (210) and (200). The (040) facet is an unsuitable candidate neither for OER nor for HER. Interestingly, the proposed (001) facet is predicted to be the best candidate for HER. These results indicate the right direction to be followed for enhanced photocatalytic water splitting reactions based on a rational design of facet-oriented α-SnWO4 samples.
  • The hidden perils of lead in the lab: Guidelines for containing, monitoring and decontaminating lead in the context of perovskite research

    Salvador, Michael; Motter, Christopher E.; McCulloch, Iain (Chemistry of Materials, American Chemical Society (ACS), 2020-07-29) [Article]
    The metal lead is an integral part of mainstream perovskite solar cells. Lead-based compounds in the form of lead-based paint and lead-contaminated dust are known to potentially trigger long lasting health implications when exposure surpasses certain limits and lead is accumulated in the human body. Because it is not clear what the health implications are of lead that is processed in the context of perovskite research and no organization has published specific directives, we have established a set of instructions for lead safety in perovskite research labs. The instructions include best practices for handling, containing, monitoring and decontaminating lead-based materials. Importantly, it is shown that lead can be contained best by adopting strict cleaning and housekeeping protocols, while decontamination can be accomplished with conventional detergents. Reliable testing of contamination levels requires periodic chemical analysis such as ICP (inductively coupled plasma spectroscopy). Conversely, simple lead tests that are currently on the market can lead to misleading assessment. We further recommend periodic medical surveillance in the form blood lead level testing to ensure the well-being of lab users. The directives described here were established such that they can be easily adopted by any lab working on perovskite research.
  • Removal of Organic Micropollutants from Water by Macrocycle-Containing Covalent Polymer Networks.

    Sessler, Jonathan L; Ji, Xiaofan; Wang, Hu; Wang, Hongyu; Zhao, Tian; Page, Zachariah A; Khashab, Niveen M. (Angewandte Chemie (International ed. in English), Wiley, 2020-07-28) [Article]
    Access to clean drinking water is a recognized societal need that touches on the health and livelihood of millions of people worldwide. This is providing an incentive to develop new water-treatment technologies. Traditional technologies, while widespread, are usually inefficient at removing organic pollutants from sewage or so-called grey water. Macrocycle-containing covalent polymer networks have begun to attract attention in the context of water treatment owing to the inherent stability provided by the polymer backbones and their ability to capture micropollutant guests as the result of tunable macrocycle-based host-guest interactions. In this minireview, we summarize recent advances (from 2016 to mid-2020) involving the removal of organic micropollutants from water using macrocycle-containing covalent polymer networks. An overview of future challenges within this subfield is also provided.
  • Methanol as the Hydrogen Source in the Selective Transfer Hydrogenation of Alkynes Enabled by a Manganese Pincer Complex

    Sklyaruk, Jan; Zubar, Viktoriia; Borghs, Jannik C.; Rueping, Magnus (Organic Letters, American Chemical Society (ACS), 2020-07-28) [Article]
    The first base metal-catalyzed transfer hydrogenation of alkynes with methanol is described. An air and moisture stable manganese pincer complex catalyzes the reduction of a variety of different alkynes to the corresponding (Z)-olefins in high yields. The reaction is stereo- and chemoselective and scalable.
  • Light-Harvesting Two-Photon-Absorbing Polymers

    Goswami, Subhadip; Cekli, Seda; Alarousu, Erkki; Winkel, Russell W.; Younus, Muhammad; Mohammed, Omar F.; Schanze, Kirk (Macromolecules, American Chemical Society (ACS), 2020-07-24) [Article]
    A series of atactic polystyrene-based polymers was synthesized that contains grafted π-conjugated organic and organometallic chromophores to investigate two-photon light-harvesting properties. The polymers feature 4-(diphenylamino)fluorene (DPAF) and Pt−DPAF as π-conjugated units which are known to be moderately efficient two-photon absorption (2PA) chromophores. The polymers were synthesized by reversible addition−fragmentation transfer (RAFT) polymerization of 4-chloromethylstyrene, and following substitution of Cl by N3, the DPAF and Pt−DPAF chromophores were grafted onto the polymer via the coppercatalyzed azide−alkyne click reaction. The loading of Pt−DPAF units in the polymers was varied from 0 to 20% by varying the feed ratio in the click reactions. With an increase in the Pt−DPAF content, the fluorescence quantum yield from the DPAF singlet excited state decreases and fluorescence is replaced by phosphorescence characteristic of the Pt−DPAF units at 530 nm. The emission lifetime and ultrafast transient absorption spectroscopy confirm that rapid and efficient singlet energy transfer occurs from DPAF to DPAF− Pt. Excitation of the polymers with 100 fs, near-infrared pulses gives rise to upconverted emission, and the observed emission spectra are similar to those under one-photon excitation. The results indicate that the DPAF units effectively function as 2-photon absorption light-harvesting units, transferring the excitation to the Pt−DPAF units where intersystem crossing occurs efficiently. Taken together, the results point the way to development of novel polymer-based optical power-limiting materials for ultrashort and long optical pulses.
  • Model-Based Design of Graphite-Compatible Electrolytes in Potassium-Ion Batteries

    Zhang, Jiao; Cao, Zhen; Zhou, Lin; Liu, Gang; Park, Geon-Tae; Cavallo, Luigi; Wang, Limin; Alshareef, Husam N.; Sun, Yang-Kook; Ming, Jun (ACS Energy Letters, American Chemical Society (ACS), 2020-07-24) [Article]
    Potassium-ion batteries (KIBs) are attractive alternatives to lithium-ion batteries (LIBs) because of their lower cost and global potassium sustainability. However, designing compatible electrolytes with graphite anode remains challenging. This is because the electrolyte decomposition and/or graphite exfoliation (due to K+–solvent co-insertion) always exist, which is much harder to overcome compared to the case of LIBs because of the higher activities of K+. Herein, we report a general principle to design compatible electrolytes with the graphite anode, where the K+ can be reversibly (de)intercalated. We find that the electrolyte composition is critical to determining the graphite performance, which can be tuned by the kind of solvent, anion, additives, and concentration. We present a new interfacial model to understand the variation in performance (i.e., K+ (de)intercalation or K+–solvent co-insertion or decomposition). Our model is distinctly different from the solid electrolyte interphase interpretation. This work offers new opportunities to design high-performance KIBs and potassium-ion sulfur batteries. Particularly, we present new guideline to design electrolytes for KIBs and other advanced mobile (ion) batteries.
  • Thermally Induced Formation of HF4TCNQ- in F4TCNQ-Doped Regioregular P3HT

    Watts, Kristen E; Neelamraju, Bharati; Moser, Maximilian; McCulloch, Iain; Ratcliff, Erin L.; Pemberton, Jeanne E (The Journal of Physical Chemistry Letters, American Chemical Society (ACS), 2020-07-23) [Article]
    The prototypical system for understanding doping in solution-processed organic electronics has been poly(3-hexylthiophene) (P3HT) p-doped with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). Multiple charge transfer states, defined by the fraction of electron transfer to F4TCNQ, are known to coexist and are dependent on polymer molecular weight, crystallinity, and processing. Less well understood is the loss of conductivity after thermal annealing of these materials. Specifically, in thermoelectrics, F4TCNQ-doped regioregular (rr) P3HT exhibits significant conductivity losses at temperatures lower than other thiophene-based polymers. Through detailed spectroscopic investigation of progressively heated P3HT films co-processed with F4TCNQ, we demonstrate that this diminished conductivity is due to formation of the non-chromophoric, weak dopant HF4TCNQ-. This species is likely formed through hydrogen abstraction from the alpha aliphatic carbon of the hexyl chain at the 3-position of thiophene rings of rr-P3HT. This reaction is eliminated for polymers with ethylene glycol-containing side chains, which retain conductivity at higher operating temperatures. In total, these results provide a critical materials design guideline for organic electronics.
  • Recycling Borate Complex for Synthesis of Polycarbonate Polyols: Towards an Environmentally Friendly and Cost-Effective Process.

    Gnanou, Yves; Patil, Naganath; Bhoopathi, Senthil; Chidara, Vamshi Krishna; Hadjichristidis, Nikos; Feng, Xiaoshuang (ChemSusChem, Wiley, 2020-07-22) [Article]
    In this investigation, we unveil a metal-free process that warrants the synthesis of poly(propylene carbonate) (PPC) diols/polyols by copolymerization of carbon dioxide (CO 2 ) with propylene epoxide (PO) under environmentally-friendly, and cost-effective conditions; this process implies the recycling of triethylborane (TEB) and of ammonium salts that both enter in the composition of the initiators used to copolymerize CO 2 and PO. In complement to the above approach, a polymeric support poly(diallyl dimethylammonium chloride) (PDADMAC), was synthesized and modified to carry ammonium carboxylate salts along its chain; the prepared polymeric initiator was utilized to copolymerize CO 2 with PO under heterogeneous conditions. Not only were the polymerization results similar to the samples obtained under homogeneous conditions, but the polymer substrate could easily be recovered by simple filtration. The integrity of the polycarbonate diols/polyols, the recycling process were followed by 1 H, 11 B NMR, GPC, and MALDI-TOF.
  • Noncovalent Supramolecular Diblock Copolymers: Synthesis and Microphase Separation

    Bhaumik, Saibal; Ntetsikas, Konstantinos; Hadjichristidis, Nikos (Macromolecules, American Chemical Society (ACS), 2020-07-22) [Article]
    Supramolecular block copolymers (PS-DAT-sb-PI-Thy) were synthesized via noncovalent hydrogen bonding between well-defined thymine end-functionalized polyisoprene (PI-Thy) and diaminotriazine (DAT) end-functionalized polystyrene (PS-DAT). Three covalently linked block copolymers were also synthesized for comparison with the noncovalent supramolecular block copolymers. The complementary DAT/Thy interaction resulted in the microphase separation of the supramolecular block copolymer system. Detailed characterization of all functionalized homopolymers and block copolymers was carried out via proton nuclear magnetic resonance (1H NMR) spectroscopy, gel permeation chromatography, matrix-assisted laser desorption/ionizationtime of flight mass spectrometry, and differential scanning calorimetry. The self-assembly process of supramolecular block copolymers was evidenced by transmission electron microscopy. Small-angle X-ray scattering was also performed to study the microphase separation of supramolecular and covalently linked block copolymers. Comparison of microphase separation images of supramolecular block copolymers and the corresponding covalently linked analogues reveals differences in d-spacing and microdomain shape.
  • Ethylene Glycol-Based Side Chain Length Engineering in Polythiophenes and its Impact on Organic Electrochemical Transistor Performance

    Moser, Maximilian; Savagian, Lisa R.; Savva, Achilleas; Matta, Micaela; Ponder, James F.; Hidalgo, Tania Cecilia; ohayon, David; Hallani, Rawad; Reisjalali, Maryam; Troisi, Alessandro; Wadsworth, Andrew; Reynolds, John R.; Inal, Sahika; McCulloch, Iain (Chemistry of Materials, American Chemical Society (ACS), 2020-07-22) [Article]
    Replacing the alkyl side chains on conventional semiconducting polymers with ethylene glycol (EG)-based chains is a successful strategy in the molecular design of mixed conduction materials for bioelectronic devices, including organic electrochemical transistors (OECTs). Such polymers have demonstrated the capability to conduct both ionic and electronic charges and can offer superior performance compared to the most commonly used active material, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). While many research efforts have been dedicated to optimizing OECT performance through the engineering of the semiconducting polymers’ conjugated backbones, variation of the EG chain length has been investigated considerably less. In this work, a series of glycolated polythiophenes with pendant EG chains spanning two to six EG repeat units was synthesized and the electrochemical and structural characteristics of the resulting films were characterized by experimental means and molecular dynamics simulations. OECTs were fabricated and tested, and their performance showed a strong correlation to the the EG side chain length, thereby elucidating important structure−property guidelines for the molecular design of future channel materials. Specifically, a careful balance in the EG length must be struck during the design of EG-functionalized conjugated polymers for OECTs. While minimizing the EG side chain length appears to boost both the capacitive and charge carrier transport properties of the polymers, the chosen EG side chain length must be kept sufficiently long to induce solubility for processing, and allow for the necessary ion interactions with the conjugated polymer backbone.
  • Exciton and Charge Carrier Dynamics in Highly Crystalline PTQ10:IDIC Organic Solar Cells

    Cha, Hyojung; Zheng, Yizhen; Dong, Yifan; Lee, Hyun Hwi; Wu, Jiaying; Bristow, Helen; Zhang, Jiangbin; Lee, Harrison Ka Hin; Tsoi, Wing C.; Bakulin, Artem A.; McCulloch, Iain; Durrant, James R. (Advanced Energy Materials, Wiley, 2020-07-22) [Article]
    Herein the morphology and exciton/charge carrier dynamics in bulk heterojunctions (BHJs) of the donor polymer PTQ10 and molecular acceptor IDIC are investigated. PTQ10:IDIC BHJs are shown to be particularly promising for low cost organic solar cells (OSCs). It is found that both PTQ10 and IDIC show remarkably high crystallinity in optimized BHJs, with GIWAXS data indicating pi-pi stacking coherence lengths of up to 8 nm. Exciton-exciton annihilation studies indicate long exciton diffusion lengths for both neat materials (19 nm for PTQ10 and 9.5 nm for IDIC), enabling efficient exciton separation with half lives of 1 and 3 ps, despite the high degree of phase segregation in this blend. Transient absorption data indicate exciton separation leads to the formation of two spectrally distinct species, assigned to interfacial charge transfer (CT) states and separated charges. CT state decay is correlated with the appearance of additional separate charges, indicating relatively efficient CT state dissociation, attributed to the high crystallinity of this blend. The results emphasize the potential for high material crystallinity to enhance charge separation and collection in OSCs, but also that long exciton diffusion lengths are likely to be essential for efficient exciton separation in such high crystallinity devices.
  • Recent Progress on Microfine Design of Metal-Organic Frameworks: Structure Regulation and Gas Sorption and Separation.

    Li, Jiantang; Bhatt, Prashant M; Li, Jiyang; Eddaoudi, Mohamed; Liu, Yunling (Advanced materials (Deerfield Beach, Fla.), Wiley, 2020-07-17) [Article]
    Metal-organic frameworks (MOFs) have emerged as an important and unique class of functional crystalline hybrid porous materials in the past two decades. Due to their modular structures and adjustable pore system, such distinctive materials have exhibited remarkable prospects in key applications pertaining to adsorption such as gas storage, gas and liquid separations, and trace impurity removal. Evidently, gaining a better understanding of the structure-property relationship offers great potential for the enhancement of a given associated MOF property either by structural adjustments via isoreticular chemistry or by the design and construction of new MOF structures via the practice of reticular chemistry. Correspondingly, the application of isoreticular chemistry paves the way for the microfine design and structure regulation of presented MOFs. Explicitly, the microfine tuning is mainly based on known MOF platforms, focusing on the modification and/or functionalization of a precise part of the MOF structure or pore system, thus providing an effective approach to produce richer pore systems with enhanced performances from a limited number of MOF platforms. Here, the latest progress in this field is highlighted by emphasizing the differences and connections between various methods. Finally, the challenges together with prospects are also discussed.
  • Quest for Zeolite-like Supramolecular Assemblies: Self-Assembly of Metal-Organic Squares via Directed Hydrogen Bonding.

    Liu, Yunling; Li, Jiantang; Kan, Liang; Li, Jiyang; Eddaoudi, Mohamed (Angewandte Chemie (International ed. in English), Wiley, 2020-07-15) [Article]
    Our conceived approach based on the directed assembly of functional metal-organic squares (MOSs), 4-membered ring (4MR) building units, permitted the construction of two novel zeolite-like supramolecular assemblies (ZSAs), namely [Co 4 (ImDC) 4 (En) 4 ]·9H 2 O·1.5DMF ( ZSA-10 ) and [Co 4 (ImDC) 4 (En) 4 ]·7H 2 O ( ZSA-11 ) (H 3 ImDC = 4,5-imidazoledicarboxylic acid, En = ethylenediamine, DMF = N,N-dimethylformamide). The elected MOSs encompass both trans - and cis -coordinated nodes, offering complementary peripheral functional groups for their directed assembly into zeolite-like topologies via supramolecular hydrogen bonding interactions. Distinctly, ZSA-10 possesses the underling MER zeolite topology and is the only pure MER framework material (without any supporting templates) exhibiting permanent porosity up to now. ZSA-11 has the underlying ABW topology together with one type of narrow channel.
  • The role of noncovalent interactions in olefin polymerization catalysis: a further look to the fluorinated ligand effect

    Falivene, Laura; Cavallo, Luigi; Talarico, Giovanni (Molecular Catalysis, Elsevier BV, 2020-07-14) [Article]
    The noncovalent interactions and remote ligand effects in catalysis have attracted a large attention in the last years. The rationalization of such interactions is tricky and often their role can be elucidated only with a detailed mechanistic study. Here we report the case of fluorinated ligand systems showing a very peculiar behavior in the catalysis of olefin polymerization. The results reported aim to clarify the origin of such behavior underlying the nature of the control of the fluorinated groups on the key steps of the polymerization. These insights can offer new cues to rationalize similar evidences in other reaction fields.
  • Quest for an optimal methane hydrates formation in the pores of hydrolytically stable MOFs

    Cuadrado-Collados, Carlos; Mouchaham, Georges; Daemen, Luke L.; Cheng, Yongqiang; Ramirez-Cuesta, Anibal J.; Aggarwal, Himanshu; Missyul, Alexander; Eddaoudi, Mohamed; Belmabkhout, Youssef; Silvestre-Albero, Joaquin (Journal of the American Chemical Society, American Chemical Society (ACS), 2020-07-11) [Article]
    Porous MOFs capable of storing relatively high amount of dry methane (CH4) in adsorbed phase are largely explored, however solid CH4 storage in confined pores of MOFs in the form of hydrates is yet to be discovered. Here we report a rational approach to form CH4 hydrates by taking advantage of the optimal pore confinement in relatively narrow cavities of hydrolytically stable MOFs. Unprecedentedly, we were able to isolate methane hydrate (MH) nanocrystals with a sI structure encapsulated inside MOF pores with an optimal cavity dimension. It was found, that confined nanocrystals require cavities slightly larger than the unit cell crystal size of MHs (1.2 nm), as exemplified in the experimental case study performed on Cr-soc-MOF-1 vs smaller cavities of Y-shp-MOF-5. Under these conditions, the excess amount of methane stored in the pores of Cr-soc-MOF-1 in the form of MH was found to be 50% larger than the corresponding dry adsorbed amount at 10 MPa. More importantly, the pressure gradient driving the CH4 storage/delivery process could be drastically reduced compared to the conventional CH4 adsorbed phase storage on the dry Cr-soc-MOF-1 (≤3 MPa vs. 10 MPa)
  • Topology Meets Reticular Chemistry for Chemical Separations: MOFs as a Case Study

    Bhatt, Prashant; Guillerm, Vincent; Datta, Shuvo Jit; Shkurenko, Aleksander; Eddaoudi, Mohamed (Chem, Elsevier BV, 2020-07-09) [Article]
    Chemical separations are of prime industrial importance; however, they consume a large portion of total industrial energy. Credibly, adsorbent-based separation methods offer the prospective to drastically lessen the energy demand of conventional energy-intensive separation processes. Prominently, a special class of porous materials, namely metal-organic frameworks (MOFs), are reasonably positioned to address various demanding separations in an energy-efficient manner. Out of a myriad of possible topologies for the construction of MOFs, face-transitive nets affording a sole type of window, preferably defined by three- or four-membered rings, can be regarded as ideal blueprints for the construction of MOFs for targeted separations. Intricate separations by MOFs based on some of these topologies are discussed, highlighting the effect of appropriate pore aperture and channel size with prerequisite functional groups on their separation performance. MOFs based on face-transitive nets offer great potential as effective fillers for the construction of practical mixed-matrix membranes (MMMs) with improved separation properties over conventional polymeric membranes.

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