Recent Submissions

  • Mechanistic insights into photochemical nickel-catalyzed cross-couplings enabled by energy transfer

    Kancherla, Rajesh; Muralirajan, Krishnamoorthy; Maity, Bholanath; Karuthedath, Safakath; Kumar, Gadde Sathish; Laquai, Frédéric; Cavallo, Luigi; Rueping, Magnus (Nature Communications, Springer Science and Business Media LLC, 2022-05-18) [Article]
    Various methods that use a photocatalyst for electron transfer between an organic substrate and a transition metal catalyst have been established. While triplet sensitization of organic substrates via energy transfer from photocatalysts has been demonstrated, the sensitization of transition metal catalysts is still in its infancy. Here, we describe the selective alkylation of C(sp3)–H bonds via triplet sensitization of nickel catalytic intermediates with a thorough elucidation of its reaction mechanism. Exergonic Dexter energy transfer from an iridium photosensitizer promotes the nickel catalyst to the triplet state, thus enabling C–H functionalization via the release of bromine radical. Computational studies and transient absorption experiments support that the reaction proceeds via the formation of triplet states of the organometallic nickel catalyst by energy transfer.
  • Origin of active sites on silica-magnesia catalysts and control of reactive environment in the one-step ethanol-to-butadiene process

    Chung, Sang-Ho; Li, Teng; Shoinkhorova, Tuiana; Ramirez, Adrian; Mukhambetov, Ildar; Abou-Hamad, Edy; Shterk, Genrikh; Telalovic, Selvedin; Dikhtiarenko, Alla; Sirks, Bart; Lavrik, Polina; Tang, Xinqi; Weckhuysen, Bert M.; Bruijnincx, Pieter; Gascon, Jorge; Ruiz-Martinez, Javier (Research Square Platform LLC, 2022-05-18) [Preprint]
    Wet-kneaded silica–magnesia is a benchmark catalyst for the one–step ethanol-to-butadiene Lebedev process. Magnesium silicates, formed during wet-kneading, have been proposed as active sites responsible for butadiene formation, and their catalytic performance has been mainly explained by the variations in the ratio of acid and base sites. While the Lebedev process was developed in the 1930s, However, a detailed insight into how the peculiar, yet essential wet-kneading synthesis leads to the generation, location, and catalytic role of magnesium silicates has not been fully established. Here, we demonstrate that magnesium silicates formation occurs via dissolution of Si and Mg subunits from SiO2 and Mg(OH)2 precursors, initiated by the alkaline pH of the aqueous wet-kneading medium, followed by cross-deposition of the dissolved species on the precursor surfaces. Building on these new insights, two individual model systems (Mg/SiO2 and Si/MgO) were synthesized, representative of the constituents of the wet-kneaded silica–magnesia catalyst, by selective dissolution/deposition induced by pH alteration of the aqueous wet-kneading medium. Using these model catalysts, we demonstrate that the location of the magnesium silicates (i.e., Mg on SiO2 or Si on MgO) governs not only their chemical nature but also the ethanol adsorption configuration, which ultimately cause the catalyst material to be selective mainly for ethylene or butadiene. We demonstrate close proximity at the particle level of the of acid and basic sites is a prerequisite to promote the butadiene formation. The insights gained from the new structure–performance relationships that correlate catalytic activity with types and nature of magnesium silicates can offer new possibilities for the development of next generation Lebedev catalysts.
  • Photoactivated p-Doping of Organic Interlayer Enables Efficient Perovskite/Silicon Tandem Solar Cells

    Zheng, Xiaopeng; Liu, Jiang; Liu, Tuo; Aydin, Erkan; Chen, Min; Yan, Wenbo; de Bastiani, Michele; Allen, Thomas; Yuan, Shuai; Kirmani, Ahmad R.; Baustert, Kyle N.; Salvador, Michael; Turedi, Bekir; Alsalloum, Abdullah Yousef; Almasabi, Khulud M.; Kotsovos, Konstantinos; Gereige, Issam; Liao, Liang-Sheng; Luther, Joseph; Graham, Kenneth R.; Mohammed, Omar F.; De Wolf, Stefaan; Bakr, Osman (ACS Energy Letters, American Chemical Society (ACS), 2022-05-17) [Article]
    Solution-processed organic semiconductor layers on rough surfaces tend to vary widely in thickness, significantly hindering charge extraction in relevant optoelectronic devices. Herein, we report the photoactivated p-doping of hole-transporting material (HTM) to enhance hole extraction for (textured) perovskite/silicon tandem solar cells, making the device performance less sensitive to the variation of hole transport layer thickness. We used the ionic compound 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate) (DPI-TPFB) as a p-type dopant in poly(triaryl amine) (PTAA), which we used as the HTM. We observed that light soaking DPI-TPFB-doped PTAA shows approximately 22 times higher conductivity compared with an undoped PTAA film, which translated into an improved fill factor (FF) for tandem solar cells. Our tandem solar cells achieved an ∼80% FF and 27.8% efficiency and operated at their maximum power point for 200 h without loss of performance, in addition to retaining ∼83% of initial performance over a month of operation in an outdoor environment.
  • Dehydrogenation of formic acid mediated by a Phosphorus–Nitrogen PN3P-manganese pincer complex: Catalytic performance and mechanistic insights

    Dutta, Indranil; Alobaid, Nasser A.; Menicucci, Fabio Lorenzo; Chakraborty, Priyanka; Guan, Chao; Han, Delong; Huang, Kuo-Wei (International Journal of Hydrogen Energy, Elsevier BV, 2022-05-16) [Article]
    The utilization of formic acid as a liquid organic hydrogen carrier has taken a vast interest lately because of several desirable properties. The state-of-the-art homogenous catalysts known for formic acid dehydrogenation are mainly based on noble metals such as iridium or ruthenium. 3d metals are considered to be an attractive alternative due to their abundance and low toxicity. Exploration of 3d metals has achieved exciting results mainly with iron-based catalysts; however, manganese has not received much attention, and only a few examples are available. Here we report a manganese complex [Mn(PN3P)(CO)2]Br containing a pincer backbone, as an efficient catalyst for formic acid dehydrogenation. Under the optimized condition, the complex afforded a TON of 15,200. To the best of our knowledge, this is considered one of the best TON achieved using a manganese-based complex with excellent selectivity. Mechanistic studies suggested that the imine arm participates in the formic acid activation/deprotonation step, emphasizing the importance of metal-ligand cooperativity during substrate activation to promote catalytic efficacy.
  • New cross-linked poly(methyl methacrylate): Synthesis, characterization, and inhibitory effects against selected bacteria and cancer cells

    Altowairki, Hanan; Basingab, Fatemah S.; Abdullah, Samaa T.; Hussein, Mahmoud A.; Hadjichristidis, Nikos; Alkayal, Nazeeha (Polymer Engineering & Science, Wiley, 2022-05-11) [Article]
    Novel cross-linked poly(methyl methacrylate) (PMMA) derivatives with different ratios of crosslinkers (2, 5, 10, 20, 30, 40, and 50 wt%) were synthesized using the condensation method between PMMA and bifunctional amino derivative cross-linkers, o-phenylenediamine (OPD), and m-phenylenediamine (MPD). The final products were tested for antibacterial and anticancer activities. Various techniques were used to characterize the cross-linked polymers. Fourier transform infrared (FTIR) spectroscopy was used to identify interactions between PMMA and diamine derivatives. The scanning electron microscope (SEM) images show that the smooth PMMA surface was totally changed after cross-linking. Thermogravimetric analysis (TGA) results show that when the percentage of cross-linked PMMA (C-PMMA) increased, the decomposition temperature at 25%, 50%, and 75% weight loss increased. C-PMMA/2% OPD, C-PMMA/20% OPD, and C-PMMA/20% MPD have an antibacterial effect on both Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) with an inhibitory zone ranged from 9 to 16 mm. In addition, C-PMMA/2% OPD showed anticancer activities, reducing the number of HepG2 cancer cells significantly. A positive correlation between the concentrations of the product and the reduction of HepG2 cells has been detectedr.
  • Nerve Network-Inspired Solid Polymer Electrolytes (NN-SPE) for Fast and Single-Ion Lithium Conduction

    Li, Zhen; Guo, Dong; Li, Fan; Hou, Guangjin; Liu, Xiaowei; Li, Chunyang; Cao, Li; Wei, Ruicong; Zhou, Zongyao; Lai, Zhiping (Energy Storage Materials, Elsevier BV, 2022-05-04) [Article]
    The low lithium-ion conductivity is current the bottleneck in developing solid-state electrolytes (SSEs) that are expected to be a key component in the next generation of lithium batteries. Inspired by the high connectivity of the biological nerve network, we designed a mimic architecture inside a polymer electrolyte to provide fast lithium-ion pathways. Detailed experimental and simulation studies revealed that the mimic nerve network could efficiently form the bi-continuous structure at very low percolation threshold, and rendered an unprecedentedly non-linear increment by order of magnitudes in the lithium-ion conductivity, with a superior lithium-ion conductivity up to 0.12 mS•cm−1, transference number up to 0.974 and robust mechanical strength of 10.3 MPa. When applied in lithium metal batteries, good rate and cycling performance were achieved at both room and elevated temperatures.
  • Plasmonic Nb2CTx MXene-MAPbI3 Heterostructure for Self-Powered Visible-NIR Photodiodes

    Liu, Zhixiong; El Demellawi, Jehad K.; Bakr, Osman; Ooi, Boon S.; Alshareef, Husam N. (ACS Nano, American Chemical Society (ACS), 2022-05-01) [Article]
    The ability of MXenes to efficiently absorb light is greatly enriched by the surface plasmons oscillating at their two-dimensional (2D) surfaces. Thus far, MXenes have shown impressive plasmonic absorptions spanning the visible and infrared (IR) regimes. However, their potential use in IR optoelectronic applications, including photodiodes, has been marginally investigated. Besides, their relatively low resistivity has limited their use as photosensing materials due to their intrinsic high dark current. Herein, heterostructures made of methylammonium lead triiodide (MAPbI3) perovskite and niobium carbide (Nb2CTx) MXene are prepared with a matching band structure and exploited for self-powered visible-near IR (NIR) photodiodes. Using MAPbI3 has expanded the operation range of the MAPbI3/Nb2CTx photodiode to the visible regime while suppressing the relatively large dark current of the NIR-absorbing Nb2CTx. In consequence, the fabricated MAPbI3/Nb2CTx photodiode has responded linearly to white light illumination with a responsivity of 0.25 A/W and a temporal photoresponse of <4.5 μs. Furthermore, when illuminated by NIR laser (1064 nm), our photodiode demonstrates a higher on/off ratio (∼103) and faster response times (<30 ms) compared to that of planar Nb2CTx-only detectors (<2 and 20 s, respectively). The performed space-charge-limited current (SCLC) and capacitance measurements reveal that such an efficient and enhanced charge transfer depends on the coordinate bonding between the surface groups of the MXene and the undercoordinated Pb2+ ions of the MAPbI3 at the passivated MAPbI3/Nb2CTx interface.
  • Hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene over NiMo supported on yolk-shell silica catalysts with adjustable shell thickness and yolk size

    Yu, Ke; Kong, Weimin; Zhao, Zhen; Duan, Aijun; Kong, Lian; Wang, Xilong (Journal of Catalysis, Elsevier BV, 2022-04-27) [Article]
    Mesoporous yolk-shell silica spheres with different shell thicknesses and yolk sizes (YxSy) were synthesized by incubating mesostructured silica nanospheres with water. Al-modified YxSy-supported NiMo catalysts were prepared and applied to hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The shell thickness and yolk size have a large effect on the HDS activities. Among the as-made catalysts, NiMo/Al-Y30S13 catalyst with relatively low shell thickness (13 nm), yolk size (30 nm) and proper structural stability exhibit the highest activities for HDS of DBT and 4,6-DMDBT at the weight time of 1.39–13.76 g min mol−1, of which its DBT conversion at 1.39 g min mol−1 (50.4%) is 1.5 times as that of the reference NiMo/Al2O3 (33.6%), four times as that of NiMo/Al-Y83S28 (12.3%) and what's more, the HDS conversion of Al-Y30S13 could reach 99.5% at 13.76 g min mol−1 (about 2.5 ppm S remained). Its 4,6-DMDBT conversion at 1.39 g min mol−1 (27.1%) is almost 2 times as that over NiMo/Al2O3 (13.8%), and 2.7 times as that over NiMo/Al-Y83S28 (9.9%). Additionally, the 95.7% HDS conversion (about 16.6 ppm S remained) of Al-Y30S13 could be obtained at 13.76 g min mol−1. The good HDS performance of the NiMo/Al-Y30S13 catalyst could be derived from the synergistic effect of moderate shell thickness and relatively small yolk size, proper structural stability, appropriate acidity, moderate metal-support interaction (MSI), suitable dispersion and desirable stacking morphology of the Ni and Mo species. DBT HDS over the NiMo/Al-Y30S13 catalyst shows the lowest direct desulfurization (DDS)/hydrodesulfurization (HYD) ratio (2.70), demonstrating that the increase of HYD proportion could improve the ability of ultra-deep desulfurization of catalysts. 4,6-DMDBT HDS over the NiMo/Al-Y30S13 catalyst shows the highest selectivity of isomerization (ISO) route (69%), illustrating that the ISO route is the dominant pathway. Furthermore, the mechanisms of DBT and 4,6-DMDBT HDS are proposed over NiMo/Al-YxSy materials.
  • Comparison of Conventional and Two-Zone Fluidized Bed Reactors for Methanol to Olefins. Effect of Reaction Conditions and the Presence of Water in the Feed

    Zapater, Diego; Lasobras, Javier; Soler, Jaime; Herguido, Javier; Menéndez, Miguel (Industrial & Engineering Chemistry Research, American Chemical Society (ACS), 2022-04-26) [Article]
    The effect of water over the performance of the Methanol-to-Olefins process was studied in a conventional fluidized bed reactor (CFBR) and a two-zone fluidized bed reactor (TZFBR). Both of them contained the same SAPO-34-based catalyst, prepared by agglomeration with bentonite and alumina. In the first section of this paper, the performance was studied in the TZFBR for a wide range of temperatures (350–600 °C, ΔT = 50 °C), and two oxygen concentrations fed to the lower zone (7.5 and 10.8% for 500, 550, and 600 °C). In the second section, a comparison between the performance over the two previously mentioned reactors is presented, followed by a comparison between feeding water or not doing so to the TZFBR. Results showed that the TZFBR increased the initial yield to olefins and the production time of them, an effect that was increased by feeding a mixture of methanol–water (1:1 molar ratio) instead of pure methanol.
  • Plasmonic Titanium Nitride Tubes Decorated with Ru Nanoparticles as Photo-Thermal Catalyst for CO2 Methanation

    Mateo, Diego; Navarro, Juan Carlos; Khan, Il Son; Ruiz-Martinez, Javier; Gascon, Jorge (Molecules, MDPI AG, 2022-04-22) [Article]
    Photo-thermal catalysis has recently emerged as a viable strategy to produce solar fuels or chemicals using sunlight. In particular, nanostructures featuring localized surface plasmon resonance (LSPR) hold great promise as photo-thermal catalysts given their ability to convert light into heat. In this regard, traditional plasmonic materials include gold (Au) or silver (Ag), but in the last years, transition metal nitrides have been proposed as a cost-efficient alternative. Herein, we demonstrate that titanium nitride (TiN) tubes derived from the nitridation of TiO2 precursor display excellent light absorption properties thanks to their intense LSPR band in the visible–IR regions. Upon deposition of Ru nanoparticles (NPs), Ru-TiN tubes exhibit high activity towards the photo-thermal CO2 reduction reaction, achieving remarkable methane (CH4) production rates up to 1200 mmol g−1 h−1. Mechanistic studies suggest that the reaction pathway is dominated by thermal effects thanks to the effective light-to-heat conversion of Ru-TiN tubes. This work will serve as a basis for future research on new plasmonic structures for photo-thermal applications in catalysis.
  • Co–Fe–B Nanochain Electrocatalysts for Oxygen Evolution at High Current Density

    Patil, Komal; Babar, Pravin Tukaram; Li, Xue; Karade, Vijay; Kim, Sugil; Jang, Su Young; Bhoite, Pravin; Kim, Jin Hyeok (ACS Applied Nano Materials, American Chemical Society (ACS), 2022-04-19) [Article]
    Constructing earth-abundant, robust, and cheap-to-make electrode materials for the oxygen evolution reaction (OER) is crucial for the practical application of hydrogen energy. In this work, we prepare amorphous cobalt iron boride (Co–Fe–B) nanochains on a nickel foam (labeled as Co–Fe–B/NF) via one-pot sodium borohydride reduction of Co2+ and Fe2+ at room temperature and use them to boost the performance of OER. The as-prepared Co–Fe–B nanochains exhibit promising catalytic activity with low overpotentials of 270 and 280 mV at higher current densities of 50 and 100 mA cm–2, respectively, and a much lower Tafel slope of 36 mV dec–1 for OER. In addition, the Co–Fe–B shows excellent stability for more than 50 h at a high current density of 100 mA cm–2. The satisfactory electrocatalytic performance is mainly due to the synergy between the metal ions (Co and Fe) and plentiful catalytically active sites of the one-dimensional chain-like structure, which improves the atom utilization efficiency
  • Installation of synergistic binding sites onto porous organic polymers for efficient removal of perfluorooctanoic acid

    Liu, Xiongli; Zhu, Changjia; Yin, Jun; Li, Jixin; Zhang, Zhiyuan; Li, Jinli; Shui, Feng; You, Zifeng; Shi, Zhan; Li, Baiyan; Bu, Xian-He; Nafady, Ayman; Ma, Shengqian (Nature communications, Springer Science and Business Media LLC, 2022-04-19) [Article]
    Herein, we report a strategy to construct highly efficient perfluorooctanoic acid (PFOA) adsorbents by installing synergistic electrostatic/hydrophobic sites onto porous organic polymers (POPs). The constructed model material of PAF-1-NDMB (NDMB = N,N-dimethyl-butylamine) demonstrates an exceptionally high PFOA uptake capacity over 2000 mg g−1, which is 14.8 times enhancement compared with its parent material of PAF-1. And it is 32.0 and 24.1 times higher than benchmark materials of DFB-CDP (β-cyclodextrin (β-CD)-based polymer network) and activated carbon under the same conditions. Furthermore, PAF-1-NDMB exhibits the highest k2 value of 24,000 g mg−1 h−1 among all reported PFOA sorbents. And it can remove 99.99% PFOA from 1000 ppb to <70 ppt within 2 min, which is lower than the advisory level of Environmental Protection Agency of United States. This work thus not only provides a generic approach for constructing PFOA adsorbents, but also develops POPs as a platform for PFOA capture
  • Unravelling the key factors in the chlorine-promoted epoxidation of ethylene over a silver-copper oxide nanocatalyst

    Urbiztondo, Miguel; Ramirez, Adrian; Hueso, Jose L; Santamaria, Jesus; Ruiz-Salvador, A Rabdel; Hamad, Said (Nanoscale, Royal Society of Chemistry (RSC), 2022-04-19) [Article]
    Ethylene oxide is one of the most important raw materials in the chemical industry, with an annual production close to 35 million metric tons. Despite its importance, to date, no metal has been found that can compete with the original silver bulk material catalyst discovered in 1931. Recently, a few copper and copper–silver based nanostructures have demonstrated remarkable selectivity and activity, especially when coupled with an industrial chlorine promoter. The present work evaluates the mechanistic role of chlorine as an active promoter of the selective oxidation of ethylene to ethylene oxide in the presence of a silver–copper oxide hybrid nanocatalyst (AgCuO). Experimental kinetic studies combined with density functional theory (DFT) calculations provide insight into the influence that Ag/CuO-supported chlorine atoms have over the ethylene epoxidation reaction. Remarkably, the typically described indirect route via the formation of an oxametallacycle (OMC) is also accompanied by a direct route. Furthermore, the presence of chlorine seems to facilitate a more favorable adsorption energy for ethylene oxide (EO) than for acetaldehyde (AA), the main reaction by-product. As a result, complete oxidation of EO can be further prevented in the presence of this AgCuO hybrid heteronanostructure.
  • Enantioselective Au(I)/Au(III) Redox Catalysis Enabled by Chiral (P,N)-Ligands

    Chintawar, Chetan C.; Bhoyare, Vivek W.; Mane, Manoj Vasisht; Patil, Nitin T. (Journal of the American Chemical Society, American Chemical Society (ACS), 2022-04-18) [Article]
    Presented herein is the first report of enantioselective Au(I)/Au(III) redox catalysis, enabled by a newly designed hemilabile chiral (P,N)-ligand (ChetPhos). The potential of this concept has been demonstrated by the development of enantioselective 1,2-oxyarylation and 1,2-aminoarylation of alkenes which provided direct access to the medicinally relevant 3-oxy- and 3-aminochromans (up to 88% yield and 99% ee). DFT studies were carried out to unravel the enantiodetermining step, which revealed that the stronger trans influence of phosphorus allows selective positioning of the substrate in the C2-symmetric chiral environment present around nitrogen, imparting a high level of enantioselectivity
  • A zirconium(IV)-based metal–organic framework modified with ruthenium and palladium nanoparticles: synthesis and catalytic performance for selective hydrogenation of furfural to furfuryl alcohol

    Lestari, Witri Wahyu; Suharbiansah, Rujito S.R.; Larasati, Larasati; Rahmawati, Fitria; Arrozi, Ubed S.F.; Durini, Sara; Rohman, Fadli; Iskandar, Riza; Hey-Hawkins, Evamarie (Chemical Papers, Springer Science and Business Media LLC, 2022-04-16) [Article]
    The conversion of biomass into sustainable biofuel is achievable through biorefinery. In this regard, the selective hydrogenation of furfural to furfuryl alcohol, 2-methylfuran, and tetrahydrofurfuryl alcohol has attracted a great interest. This research aims to prepare an active and selective catalyst for hydrogenation of furfural in liquid phase. To achieve this objective, we employed a water-stable zirconium(IV)-based metal–organic framework (MOF) [Zr6O4(OH)4(BTC)2(CH3COO)6] (Zr–BTC) (BTC = benzene-1,3,5-tricarboxylate) and modified it with Ru and Pd to form Ru/Zr–BTC and Pd/Zr–BTC. The diffractograms of Zr–BTC modified with Ru and Pd metal fit well with the diffractogram of the pristine Zr–BTC, indicating that the presence of Ru and Pd in Zr–BTC does not change the Zr–BTC structure. This is further confirmed by FTIR spectra. The obtained materials showed type I adsorption isotherms, thus the material can be classified as microporous. The presence of Pd/Ru metal on the surface and in the pores of Zr–BTC decreases the total pore volume and BET surface area. Electron microscopy (SEM and TEM) analysis further confirmed that the Pd and Ru were successfully encapsulated in Zr–BTC. Ru/Zr–BTC and Pd/Zr–BTC showed excellent performance in the catalytic liquid-phase hydrogenation reaction of furfural to furfuryl alcohol with conversion of 99.4% and 98.4% for Ru/Zr–BTC and Pd/Zr–BTC, respectively, and selectivity to furfuryl alcohol (FA) up to 100% for both catalysts
  • Interface Engineering of Bi-Fluorescence Molecules for High-Performance Data Encryption and Ultralow UV-Light Detection

    Wang, Jian-Xin; Gutiérrez-Arzaluz, Luis; Yin, Jun; Maity, Partha; Zhou, Yang; Chen, Cailing; Han, Yu; Bakr, Osman; Eddaoudi, Mohamed; Mohammed, Omar F. (Advanced Optical Materials, Wiley, 2022-04-14) [Article]
    It is extremely difficult if not impossible to effectively and precisely regulate the luminescence of organic chromophores from different electronic excited states through external stimuli for use in light-conversion devices. This is mainly due to the difficulty in breaking Kasha's rule by large energy separation and stabilization of different emissive electronic excited states. Here, the authors address this great challenge in a single experiment by expanding the utility of a monounsaturated omega-9 fatty acid (oleic acid) capped with organic chromophores as a new and efficient luminescent regulator. More specifically, the authors have successfully promoted the use of oleic acid as an efficient and reversible switch that can precisely regulate chromophore luminescence. These time-resolved absorption and luminescence experiments, along with density functional theory calculations have clearly demonstrated that ultrafast electron transfer from oleic acid to the difluoroboron β-diketonate (DFBK) chromophores efficiently blocks the intramolecular charge transfer process of DFBK chromophores, and activates the locally excited state luminescence, leading to different emission colors from different electronic excited states for ultralow UV-light detection and high-performance data encryption.
  • Heteroleptic Copper(I) complexes of bipyridine glycoluril and phosphine ligands: Photophysical and computational studies

    Jadhav, Amita N.; Singh, Sushma B.; Mane, Manoj Vasisht; Kumbhar, Avinash S. (Inorganica Chimica Acta, Elsevier BV, 2022-04-13) [Article]
    A series of heteroleptic copper(I) complexes of the type [Cu(bpg)(P–P)]PF6 (1–4) have been synthesized where bpg = [4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f] [1,10]-phenanthroline-6,13-dione] and P–P are phosphine derived ancillary ligands (triphenyl phosphine (PPh3), 1,2 bis(diphenylphosphino)ethane (dppe), bis[(2-diphenylphosphino)phenyl]ether (POP) and 1,3 bis(diphenylphosphino)propane (dppp)). All copper(I)-phosphine complexes were thoroughly characterized by elemental analyses, IR, 1H NMR, 13C NMR, 31P NMR and ESI-MS, UV–visible, emission spectroscopy and DFT calculations. The crystal structure of 1 contains two Cu(I) molecules in asymmetric unit which localizes in distorted tetrahedral geometry with N2P2 coordination core. The UV–visible spectra indicated that ancillary phosphine ligands significantly affect the MLCT band of the copper(I) complexes. The bands in the UV–visible spectra fit well with the TD-DFT calculations and are assigned to the contribution of HOMO-2 → LUMO, HOMO-1 → LUMO and HOMO → LUMO orbitals. These Cu(I) complexes exhibit green emission in CH2Cl2 at room temperature with emission wavelengths at 545–572 nm. Cyclic voltammetric data revealed that steric hindrance of diphosphine ligands affected the oxidation potential of Cu(I) complexes
  • Wide-field-of-view Perovskite Quantum-dots Fibers Array for Easing Pointing, Acquisition and Tracking in Underwater Wireless Optical Communication

    Kang, Chun Hong; Alkhazragi, Omar; Sinatra, Lutfan; Alshaibani, Sultan; Wang, Yue; Li, Kuang-Hui; Kong, Meiwei; Lutfullin, Marat; Bakr, Osman; Ng, Tien Khee; Ooi, Boon S. (IEEE, 2022-04-13) [Conference Paper]
    We demonstrated, for the first time, perovskite quantum-dots optical fibers array successfully eases the pointing, acquisition and tracking requirement facing visible-laser-based underwater wireless optical communication.
  • A Career in Catalysis: Jean-Marie M. Basset

    Astruc, Didier; Bertrand, Guy; Eddaoudi, Mohamed; Han, Yu; Huang, Kuo-Wei; Lercher, Johannes; Santini, Catherine; Takanabe, Kazuhiro; Taoufik, Mostafa; Cavallo, Luigi (ACS Catalysis, American Chemical Society (ACS), 2022-04-12) [Article]
    This account is to commemorate the retirement of Jean-Marie Basset from the KAUST Catalysis Center after a career spanning almost five decades. Jean-Marie has been a leading figure in the world of heterogeneous catalysis. Rather than studying supported catalysts through the traditional lens of surface science, he brought an approach of molecular organometallic chemistry to the field. In the process, Jean-Marie established the field of surface organometallic chemistry. During the first phase of his career, he pioneered ways to synthesize and characterize well-defined metal sites on oxide and metal surfaces. Through this work, the Basset group could establish structure–activity relationships on supported catalyst materials and also show that the rules known to govern the catalytic cycles of homogeneous catalysts could be employed to understand and enhance heterogeneous catalyst reactions. From this key insight, Jean-Marie developed the concept of heterogeneous catalysis by design, synthesizing surface organometallic fragments that were thought to form a part of the catalytic cycle. From this standpoint, the Basset group has improved the activity, selectivity, and sustainability of numerous known reactions and also discovered multiple reactions, including the Ziegler–Natta depolymerization, the metathesis of alkanes, the coupling of methane to ethane and hydrogen, the cleavage of alkanes by methane, the metathesis of imines, the metathetic cleavage of olefins to aldehydes by molecular oxygen, and the hydro-metathesis of olefins.
  • Metal–Organic Frameworks in Mixed-Matrix Membranes for High-Speed Visible-Light Communication

    Wang, Jian-Xin; Wang, Yue; Nadinov, Issatay; Yin, Jun; Gutierrez Arzaluz, Luis; Healing, George; Alkhazragi, Omar; Cheng, Youdong; Jia, Jiangtao; Alsadun, Norah Sadun; Kale, Vinayak Swamirao; Kang, Chun Hong; Ng, Tien Khee; Shekhah, Osama; Alshareef, Husam N.; Bakr, Osman; Eddaoudi, Mohamed; Ooi, Boon S.; Mohammed, Omar F. (Journal of the American Chemical Society, American Chemical Society (ACS), 2022-04-12) [Article]
    Mixed-matrix membranes (MMMs) based on luminescent metal-organic frameworks (MOFs) and emissive polymers with the combination of their unique advantages have great potential in separation science, sensing, and light-harvesting applications. Here, we demonstrate MMMs for the field of high-speed visible-light communication (VLC) using a very efficient energy transfer strategy at the interface between a MOF and an emissive polymer. Our steady-state and ultrafast time-resolved experiments, supported by high-level density functional theory calculations, revealed that efficient and ultrafast energy transfer from the luminescent MOF to the luminescent polymer can be achieved. The resultant MMMs exhibited an excellent modulation bandwidth of around 80 MHz, which is higher than those of most well-established color-converting phosphors commonly used for optical wireless communication. Interestingly, we found that the efficient energy transfer further improved the light communication data rate from 132 Mb/s of the pure polymer to 215 Mb/s of MMMs. This finding not only showcases the promise of the MMMs for high-speed VLC but also highlights the importance of an efficient and ultrafast energy transfer strategy for the advancement of data rates of optical wireless communication.

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