Viewing archived talks containing the keyword: 16
Speaker: Jeff Long (University of California, Berkeley)
Owing to their high surface areas, tunable pore dimensions, and adjustable surface functionality, metal-organic frameworks (MOFs) can offer advantages for a variety of gas storage and gas separation applications.Â In an effort to help curb greenhouse gas emissions from power plants, we are developing new MOFs for use as solid adsorbents in post- and pre-combustion CO2 capture, and for the separation of O2 from air, as required for oxy-fuel combustion.1Â In particular, MOFs with open metal cation sites or diamine-functionalized surfaces are demonstrated to provide high selectivities and working capacities for the adsorption of CO2 over N2 under dry flue gas conditions.2Â Multicomponent adsorption measurements further show compounds of the latter type to be effective in the presence of water,3 while calorimetry and temperature swing cycling data reveal a low regeneration energy compared to aqueous amine solutions.4Â MOFs with open metal sites, such as Mg2(dobdc) (dobdc4â€“ = 2,5-dioxido-1,4- benzenedicarboxylate), are highly effective in the removal of CO2 under conditions relevant to H2 production, including in the presence of CH4 impurities.5Â Redox-active Fe2+ sites in the isostructural compound Fe2(dobdc) allow the selective adsorption of O2 over N2 via an electron transfer mechanism.6Â The same material is demonstrated to be effective at 45 Â°C for the fractionation of mixtures of C1 and C2 hydrocarbons, and for the high-purity separation of ethylene/ethane and propylene/propane mixtures.7Â Finally, it will be shown that certain structural features possible within MOFs, but not in zeolites, can enable the fractionation of hexane isomers according to the degree of branching or octane number.8
1.Â Â Â Â Â Sumida, K.; Rogow, D. L.; Mason, J. A.; McDonald, T. M.; Bloch, E. D.; Herm, Z. R.; Bae, T.-H.; Long, J. R. Chem. Rev. 2012, 112, 724.
2.Â Â Â Â Â McDonald, T. M.; Lee, W. R.; Mason, J. A.; Wiers, B. M.; Hong, C. S.; Long, J. R. J. Am. Chem. Soc. 2012, 134, 7056.
3.Â Â Â Â Â Mason, J. A.; McDonald, T. M.; Bae, T.-H.; Bachman, J. E.; Sumida, K.; Dutton, J. J.; Kaye, S. S.; Long, J. R. J. Am. Chem. Soc. 2015, 137, 4787.
4.Â Â Â Â Â McDonald, T. M.; Mason, J. A.; Kong, X.; Bloch, E. D.; Gygi, D.; Dani, A.; CrocellÃ , V.; Giordano, F.; Odoh, S.; Drisdell, W.; Vlaisavljevich, B.; Dzubak, A. L.; Poloni, R.; Schnell, S. K.; Planas, N.; Kyuho, L.; Pascal, T.; Prendergast, D.; Neaton, J. B.; Smit, B.; Kortright, J. B.; Gagliardi, L.; Bordiga, S.; Reimer, J. A.; Long, J. R. Nature 2015, 519, 303.
5.Â Â Â Â Â Herm, Z. R.; Swisher, J. A.; Smit, B.; Krishna, R.; Long, J. R. J. Am. Chem. Soc. 2011, 133, 5664.
6.Â Â Â Â Â Bloch, E. D.; Murray, L. J.; Queen, W. L.; Maximoff, S. N.; Chavan, S.; Bigi, J. P.; Krishna, R.; Peterson, V. K.; Grandjean, F.; Long, G. J.; Smit, B.; Bordiga, S.; Brown, C. M.; Long, J. R. J. Am. Chem. Soc. 2011, 133, 14814.
7.Â Â Â Â Â Bloch, E. D.; Queen, W. L.; Krishna, R.; Zadrozny, J. M.; Brown, C. M.; Long, J. R. Science 2012, 335, 1606.
8.Â Â Â Â Â Herm, Z. R.; Wiers, B. M.; Mason, J. A.; van Baten, J. M.; Hudson, M. R.; Zajdel, P.; Brown, C. M.; Masciocchi, N.; Krishna, R.; Long, J. R. Science 2013, 340, 960.
On: November 15, 2016 From: 13h30 To: 14h30View talk
Speaker: Guido Clever (Dortmund)
Multifunctional and Stimuli-responsive Coordination Cages G. H. Clever * Department of Chemistry and Chemical Biology, TU Dortmund University, Germany guido.clever@tu -dortmund.de Banana -shaped bis-monodentate ligands react with Pd(II) cations to coordination compounds with a broad range of topologies from small Pd 2L4 cages, their interpenetrated dimers, rings of various size up to large Pd 24L48 spheres. 1 We introduce stimuli-responsive behaviour triggered by small molecules or light leading to the modulation of guest affinity 2 or complete structural reorganization (Figure a). 3 Interpenetrated double cages consisting of donor and acceptor moieties were shown to undergo light-induced charge separation but suffer from a lack of control over stoichiometry and stereochemistry (Figure b). 4 Therefore, we recently started to apply principles of geometric shape complementarity to control the structure and composition of heteroleptic cages (Figure c). 5 On the other hand, circularly polarized luminescence (CPL) was observed for chiral Pt(II) complexes (Figure d). 6 Advanced self -assembly strategies will enable the targeted synthesis of supra-molecular systems and materials with increasing structural and functional complexity. Figure 1 Light -responsive coordination cages and chiral organometallic luminophors 1. Reviews: a) M. Han, D. M. Engelhard, G. H. Clever, Chem. Soc. Rev. 2014, 43, 1848; b) M. Frank, M. D. Johnstone, G. H. Clever, Chem. Eur. J. 2016 , 22 , 14104. Recent examples: c) W. M. Bloch, J. J. Holstein, B. Dittrich, W. Hiller, G. H. Clever, Angew. Chem. Int. Ed. 2018, 57, 5534; d) R. Zhu, I. Regeni, J. J. Holstein, B. Dittrich, M. Simon, S. Prévost, M. Gradzielski, G. H. Clever, Angew. Chem. Int. Ed. 2018 , DOI: 10.1002/ani e.201806047. 2. a) S. Löffler, J. Lübben, L. Krause, D. Stalke, B. Dittrich, G. H. Clever, J. Am. Chem. Soc. 2015, 137, 1060; b) M. Han, R. Michel, B. He, Y. -S. Chen, D. Stalke, M. John, G. H. Clever, Angew. Chem. Int. Ed. 2013 , 52 , 1319. 3. a) R. Zhu, J. Lübben, B. Dittrich, G. H. Clever, Angew. Chem. Int. Ed. 2015, 54, 2796; b) M. Han, Y. Luo, B. Damaschke, L. Gómez, X. Ribas, A. Jose, P. Peretzki, M. Seibt, G. H. Clever, Angew. Chem. Int. Ed. 2016, 55 , 445 . 4. M. Frank, J. Ahrens, I. Bejenke, M. Krick, D. Schwarzer, G. H. Clever, J. Am. Chem. Soc. 2016 , 138 , 8279. 5. a) W. M. Bloch, Y. Abe, J. J. Holstein, C. M. Wandtke, B. Dittrich, G. H. Clever, J. Am. Chem. Soc. 2016, 138, 13750; b) W. M. Bloch, J. J. Holstein, W. Hiller, G. H. Clever, Angew. Chem. Int. Ed. 2017 , 56 , 8285. 6. T. R. Schulte, J. J. Holstein, L. Krause, R. Michel, D. Stalke, E. Sakuda, K. Umakoshi, G. Longhi, S. Abbate, G. H. Clever, J. Am. Chem. Soc. 2017 , 139 , 6863.
On: November 28, 2018 From: 14h00 To: 15h00View talk
Using ab initio approaches to model, predict and understand the optical properties of organic and inorganic dyes - Joint Chemistry/Physics Colloquium
Speaker: Denis Jacquemin (Nantes)
Using ab initio approaches to model, predict and understand the optical properties of organic and inorganic dyes Denis Jacquemin Laboratoire CEISAM, UMR CNRS n°6230, Université de Nantes, 2, rue de la Houssinière, 44322 Nantes, Cedex 3, France. Denis.Jacquemin@univ -nantes.fr During this lecture, I will illustrate some of the successes and failures of Time-Dependent Density Functional Theory (TD -DFT) in simulating the properties of electronically excited -states, with a specific interest on structures of interest for dye chemistry. 1-2 Notably, I will discuss the importance of calculating vibronic effects to obtain accurate comparisons with experimental data, including 0 -0 energies and band shapes, and illustrate this aspect with several examples. 3 I will also present examples of applications of TD -DFT to real-life structures used in LEDs focussing on two examples: ESIPT -based organic dyes for white OLEDs 4 and inorganic complexes used in blue/green/red phosphors. 5 1 D. Jacquemin, C. Adamo, Chem. Soc. Rev., 2013, 42, 845 . 2 D. Jacquemin, C. Adamo, Top. Curr. Chem.. , 2016 , 368 , 345 . 3 F. Santoro, D. Jacquemin, Wires. Comput. Mol. Sci. 2016, 6, 460. 4 A. Steffen, K. Costuas, A. Bouccekkine, M. H. Thibault, A. Beeby, A. S. Batsanov, D. Jacquemin, A. Charaf -Eddin, J. F. Halet, T. D. Marder Inorg. Chem. , 2014 , 53 , 7055 . 5 E. Heyer, K. Benelhadj, S. Budzak, D. Jacquemin, J. Massue, G. Ulrich Chem. Eur. J ., 2017, 23, 7324 . 6 D W . Zhang, D. Jacquemin, Q. Peng, Z. Suhai, D. Escudero, J. Phys. Chem. C, 2018 , 122 , 6340 .
On: February 6, 2019 From: 14h00 To: 15h00View talk
Speaker: Prof Bruce Gibb (Tulane University)
Probing and harnessing the hydrophobic and Hofmeister Effect s A better understanding of how molecules interact in aqueous solutions has ramifications a cross the biosph ere, lithosphere, atmosphere, and hydrosphere . For example, aqueous solutions of dissolved organic molecul es and salts are central to all of biolo gy and biochemistry . Un surprisingly, documented studies of h ow organic solutes, dissolved sa lts, and water interact with each othe r arguably go back to at least the late 18 th Centur y with Franz Hoffmeister â€™s seminal work on protein solubility . However, to date no comprehensive atomistic model of the interactions between this trinity of solute, s alt, and water has been forthcoming. For some time now , our research has focused on building up an atomistic view point of aqueous supramolecular chemistry. In doing so we envis age not only being able to subtly engineer and contro l specific molecular inte ractions at the atomistic level to engender un usu al phenomena , but also apply this information to build ing a better understanding of bulk phenomena such as solubility . This presentation will focus on o ur recent stu dies into aqueous supramolecular interact ions uti liz ing deep -cavity cavitands as models . We will discuss how these interactions control the bulk prop erties of the hosts, and how they can b e harnessed to yield novel supramolecular containers that function as yoctoliter reaction vess els and tools for bringing about separation protocols. 1 References 1. (a) Jordan, J. H.; Gibb, C. L. D.; Wishard, A.; Pham, T.; Gibb, B. C., J. Am. Chem. Soc. 2018, 140 (11), 4092 -4099; (b) Hill yer, M. B.; Ga n, H.; Gibb, B. C., ChemPhysC hem 2018, 19 (18), 2285 -2289; (c) Sokkalingam, P.; Shraberg, J.; Rick, S. W.; Gibb, B. C., J. Am. Chem. Soc. 2016, 138 (1), 48 -51; (d) Wa ng, K.; Gibb, B. C., J. Org. Ch
On: February 19, 2019 From: 16h00 To: 16h30View talk