scholarly journals Structure and Orientation of Molecular Wires Embedded in Ultrathin Silica Membrane for Artificial Photosynthesis Elucidated by Polarized FT-IRRAS

2019 ◽  
Vol 123 (31) ◽  
pp. 18905-18913 ◽  
Author(s):  
Georgios Katsoukis ◽  
Won Jun Jo ◽  
Heinz Frei
Keyword(s):  
Artificial Photosynthesis ◽  
Molecular Wires ◽  
Silica Membrane

(Invited) Driving Metal Oxide Water Oxidation Catalyst By Visible Light Absorber Separated By an Ultrathin Proton Conducting Silica Membrane with Embedded Molecular Wires

2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1845-1845
Author(s):  
Heinz Frei
Keyword(s):  
Charge Transfer ◽  
Metal Oxide ◽  
Visible Light ◽  
Water Oxidation ◽  
Oxide Catalyst ◽  
Molecular Wires ◽  
Core Shell ◽  
Molecular Wire ◽  
Silica Membrane ◽  
Light Absorber

We are developing nanoscale photosynthetic assemblies for coupling the catalysis for CO2 reduction with the H2O oxidation half reaction, taking an inorganic molecular approach that utilizes heterobinuclear units such as ZrOCoII as light absorber coupled to metal oxide catalyst. Artificial nanoscale photosystems are inspired by natural photosynthesis, the only existing technology for producing energy-dense chemicals on the terawatt scale, which has as key design feature the closing of the cycle of water oxidation and formation of primary reduction intermediates on the shortest possible length scale, the nanometer scale, while separating the incompatible redox environments by an ultrathin membrane. To accomplish the photocatalytic cycle of CO2 reduction by H2O under membrane separation, we are exploring a Co oxide – silica core-shell nanotube geometry.1-3 The inside surface of the Co oxide nanotube core provides the catalytic sites for H2O oxidation, which are separated from light absorber and sites of CO2 reduction on the outside by an ultrathin (2 nm) dense phase silica layer. The latter functions as proton conducting, O2 impermeable membrane.4 Tight, molecular-level control of charge transfer between light absorber and Co oxide nanotube catalyst is accomplished by oligo-para(phenylene vinylene) molecules with 3 aryl units embedded in the silica shell.5 This approach addresses the requirements of robustness and tunability of the electronic properties of the photosystem components with the objective of converting the maximum fraction of the solar photon energy into chemical energy of the fuel.6 The core-shell nanotube geometry offers the opportunity of assembling macroscale arrays of enormous numbers of nanotubes, each operating as independent photosynthetic unit while at the same time providing separation of evolving O2 and reduced CO2 products on all length scales from nano to centimeters.3 Detailed characterization of charge transfer between light absorber and Co oxide catalyst across the silica membrane was investigated by transient optical absorption spectroscopy and photoelectro-chemical methods using nanotube, spherical, or planar morphology depending on the type of experiment. Ultrafast optical monitoring allowed us to detect transient positive charge (hole) on the silica embedded molecular wire and revealed very efficient, 255 ps transfer to the Co oxide catalyst.7 Short circuit current measurements upon visible light sensitized hole injection using sensitizers with different redox potentials showed that charge transfer is controlled by the HOMO and LUMO energetics of the silica embedded wire molecules.4,5 Synthetic methods were developed for the accurate selection of embedded molecular wire loading and tuning of the concentration. Electron transfer processes of visible light excited ZrOCo or TiOCo light absorbers coupled to silica embedded wires and Co oxide catalyst are being explored by transient optical spectroscopy and photoelectrochemical methods, and will be the main topic of the presentation.8 Time permitting, recent application of ultrathin silica membrane with embedded molecular wires for separating incompatible catalytic environments of electronically coupled inorganic and microbial components will also be discussed.9 [1] Kim, W.; Edri, E.; Frei, H. Acc. Chem. Res. 49, 1634 (2016) [2] Kim, W.; McClure, B. A.; Edri, E.; Frei, H. Chem. Soc. Rev. 45, 3221 (2016) [3] Edri, E.; Aloni, S.; Frei, H., ACS Nano, submitted [4] Yuan, G.; Agiral, A.; Pellet, N.; Kim, W.; Frei, H. Faraday Discuss. 176, 233 (2014) [5] Edri, E.; Frei, H. J. Phys. Chem. C 119, 28326 (2015) [6] Frei, H. Curr. Opin. Electrochem. 2, 128 (2017) [7] Edri, E.; Cooper, J. K.; Sharp, I. D.; Guldi, D. M.; Frei, H. J. Am. Chem. Soc. 139, 5458 (2017) [8] Katsoukis, G.; Frei, H., to be submitted [9] Cornejo, J. A.; Sheng, H.; Edri, E.; Ajo-Franklin, C.; Frei, H., submitted

Endgroup and Sidechain Functionalization of Surface-Initiated ROMP Thin Films: Progress Towards ROMP-Based Molecular Wires

2018 ◽  
Author(s):  
Nicholas Marshall
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Cyclic Voltammetry ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Ring Opening ◽  
Molecular Wires ◽  
Metathesis Polymerization ◽  
Cross Metathesis ◽  
Active Ester

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.<br>

scholarly journals Describing chain-like assembly of ethoxygroup-functionalized organic molecules on Au(111) using high-throughput simulations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lokamani ◽  
Jeffrey Kelling ◽  
Robin Ohmann ◽  
Jörg Meyer ◽  
Tim Kühne ◽  
...  
Keyword(s):  
High Throughput ◽  
Energy Function ◽  
Organic Molecules ◽  
Molecular Wires ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Intermolecular Interaction Energy ◽  
One Dimensional ◽  
Coverage Density ◽  
Clustering Approach

AbstractDue to the low corrugation of the Au(111) surface, 1,4-bis(phenylethynyl)-2,5-bis(ethoxy)benzene (PEEB) molecules can form quasi interlocked lateral patterns, which are observed in scanning tunneling microscopy experiments at low temperatures. We demonstrate a multi-dimensional clustering approach to quantify the anisotropic pair-wise interaction of molecules and explain these patterns. We perform high-throughput calculations to evaluate an energy function, which incorporates the adsorption energy of single PEEB molecules on the metal surface and the intermolecular interaction energy of a pair of PEEB molecules. The analysis of the energy function reveals, that, depending on coverage density, specific types of pattern are preferred which can potentially be exploited to form one-dimensional molecular wires on Au(111).

scholarly journals Electric and magnetic properties of cobalt, copper and nickel organometallic complexes for molecular wires

2021 ◽  
Author(s):  
Rehab I. Yousef ◽  
Naglaa F.H. Mahmoud ◽  
Fouad I. El-Hosiny ◽  
Fritz E. Kühn ◽  
Ghada Bassioni
Keyword(s):  
Magnetic Properties ◽  
Molecular Wires ◽  
Organometallic Complexes ◽  
Cobalt Copper

Density functional theory studies of Nb–benzene and Nb–borazine sandwich clusters and molecular wires

2012 ◽  
Vol 45 (2) ◽  
pp. 025102 ◽  
Author(s):  
Zhi Yang ◽  
Xuguang Liu ◽  
Shaoding Liu ◽  
Yongzhen Yang ◽  
Xiuyan Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Molecular Wires ◽  
Functional Theory
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