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Full-Text Articles in Physical Sciences and Mathematics
Gram Scale Synthesis Of The C(1)-C(9) Fragment Of Amphidinolide C, Nicholas A Morra, Brian L Pagenkopf
Gram Scale Synthesis Of The C(1)-C(9) Fragment Of Amphidinolide C, Nicholas A Morra, Brian L Pagenkopf
Chemistry Publications
An allylic cis-epoxide prepared by Sharpless asymmetric epoxidation was transformed in 9 steps and 41% overall yield to the cyclization precursor 4 via a key one carbon homologation. Cobalt catalyzed aerobic oxidative cyclization of 4 gave the trans-THF in 94% yield at gram scale. Subsequent manipulations, including a Still-Gennari olefination, Sharpless asymmetric dihydroxylation, Corey-Fuchs alkynylation and Kazmaier hydrostannylation provided the fully functionalized C(1)-C(9) fragment 2 suitable for cross coupling. The sequence is readily scalable and provides gram quantities of 2
Plasmon-Mediated Drilling In Thin Metallic Nanostructures, M. Tabatabaei, A. Sangar, N. Kazemi-Zanjani, P. Torchio, A. Merlen, Francois Lagugne-Labarthet
Plasmon-Mediated Drilling In Thin Metallic Nanostructures, M. Tabatabaei, A. Sangar, N. Kazemi-Zanjani, P. Torchio, A. Merlen, Francois Lagugne-Labarthet
Chemistry Publications
Tetrahedral nanopyramids made of silver and gold over ITO/glass surfaces are fabricated. Our protocol is based on nanosphere lithography (NSL) with the deposition of thicker metal layers. After removing the microspheres used in the NSL process, an array of metallic tetrahedral nanostructures of ~350-400 nm height is formed. The reported procedure avoids the use of any stabilizing surfactant molecules that are generally necessary to segregate the individual particles onto surfaces. We focus here on the optical and the physical properties of these plasmonic surfaces using near-field spectroscopy in conjunction with finite difference time domain (FDTD) modeling of the electric field. …
Hydration Of The Pyrimidine Radical Cation And Stepwise Solvation Of Protonated Pyrimidine With Water, Methanol, And Acetonitrile, Ahmed M. Hamid, Pramod Sharma, M. Samy El-Shall, Rifaat Hilal, Shaaban Elroby, Saadullah G. Aziz, Abdulrahman O. Alyoubi
Hydration Of The Pyrimidine Radical Cation And Stepwise Solvation Of Protonated Pyrimidine With Water, Methanol, And Acetonitrile, Ahmed M. Hamid, Pramod Sharma, M. Samy El-Shall, Rifaat Hilal, Shaaban Elroby, Saadullah G. Aziz, Abdulrahman O. Alyoubi
Chemistry Publications
Equilibrium thermochemical measurements using an ion mobility drift cell technique have been utilized to investigate the binding energies and entropy changes associated with the stepwise hydration of the biologically significant ions pyrimidine radical cation and protonated pyrimidine. The binding energy of the hydrated pyrimidine radical cation is weaker than that of the proton-bound dimer pyrimidineH+(H2O) consistent with the formation of a weak carbon-based CHδ+··OH2 hydrogen bond (11.9 kcal/mol) and a stronger NH+··OH2 hydrogen bond (15.6 kcal/mol), respectively. Other proton-bound dimers such as pyrimidineH+(CH3OH) and pyrimidineH+(CH3CN) exhibit higher binding energies (18.2 kcal/mol and 22.8 kcal/mol, respectively) due to the higher proton …
Dynamics At A Janus Interface, M. Von Domaros, D. Bratko, B. Kirchner, A. Luzar
Dynamics At A Janus Interface, M. Von Domaros, D. Bratko, B. Kirchner, A. Luzar
Chemistry Publications
Electric field effects on water interfacial properties abound, ranging from electrochemical cells to nanofluidic devices to membrane ion channels. On the nanoscale, spontaneous orientational polarization of water couples with field alignment, resulting in an asymmetric wetting behavior of opposing surfacesa field-induced analogue of a chemically generated Janus interface. Using atomistic simulations, we uncover a new and significant field polarity (sign) dependence of the dipolar- orientation polarization dynamics in the hydration layer. Applying electric fields across a nanoparticle, or a nanopore, can lead to close to 2 orders of magnitude difference in response times of water polarization at opposite surfaces. Typical …