Viewing archived talks containing the keyword: 22
Speaker: Prof Dan Nocera (Harvard)
The artificial leaf accomplishes a solar fuels process that captures the elements of photosynthesis – the splitting of water to hydrogen and oxygen using light, from neutral water, at atmospheric pressure and room temperature. These conditions are met owing to the development of water splitting catalysts of the elements of Mn, Co and Ni that are self-healing; the design principles for self-healing catalysis will be presented. The self-healing catalysts are coated on a silicon wafer in a buried junction configuration, which enables light harvesting and charge separation to be coupled to catalysis under simple conditions. We have advanced the design of the artificial leaf by utilizing the hydrogen from the artificial leaf and combining it with carbon dioxide to make liquid fuels. Using the tools of synthetic biology, a bio-engineered bacterium has been developed to convert carbon dioxide, along with the hydrogen produced from the artificial leaf, into biomass and fusel alcohols. This hybrid microbial | artificial leaf system scrubs 180 grams of CO2 from air, equivalent to 230,000 liters of air per 1 kWh of electricity. Coupling this hybrid device to existing photovoltaic systems leads to unprecedented solar-to-biomass (10.7%) and solar-to-liquid fuels (6.2%) yields, which greatly exceeding natural photosynthetic systems.
On: May 30, 2016 From: 16h00 To: 17h00View talk
Speaker: E W Meijer (Eindhoven University of Technology)
The intriguing prospects of molecular electronics, nanotechnology, biomaterials, and the aim to close the gap between synthetic and biological molecular systems are important ingredients to study the cooperative action of molecules in the self-assembly towards functional supramolecular systems. The design and synthesis of well-defined supramolecular architectures requires a balanced choice between covalent synthesis and the self-assembly of the fragments prepared. The current self-assembly processes are primarily controlled by solvent, temperature or concentration. For synthetic chemists, the non-covalent synthesis of these supramolecular architectures is regarded as one of the most challenging objectives in science: How far can we push chemical self-assembly and can we get control over the kinetic instabilities of the non-covalent architectures made? How can we go from self-assembly to self-organization? Where the number of different components is increasing the complexity of the system is increasing as well. Mastering this complexity is a prerequisite to achieve the challenges in creating functional systems. In the lecture we illustrate our approach using a number of examples out of our own laboratories, with the aim to come to new strategies for multi-step non-covalent synthesis of functional supramolecular systems.
On: June 17, 2016 From: 15h30 To: 16h30View 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