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Full-Text Articles in Chemistry

An Assessment Of Computational Methods For Calculating Accurate Structures And Energies Of Bio-Relevant Polysulfur/Selenium-Containing Compounds, Sahar Nikoo, Paul Meister, John Hayward, James Gauld Dec 2018

An Assessment Of Computational Methods For Calculating Accurate Structures And Energies Of Bio-Relevant Polysulfur/Selenium-Containing Compounds, Sahar Nikoo, Paul Meister, John Hayward, James Gauld

Chemistry and Biochemistry Publications

The heavier chalcogens sulfur and selenium are important in organic and inorganic chemistry, and the role of such chalcogens in biological systems has recently gained more attention. Sulfur and, to a lesser extent selenium, are involved in diverse reactions from redox signaling to antioxidant activity and are considered essential nutrients. We investigated the ability of the DFT functionals (B3LYP, B3PW91, ωB97XD, M06-2X, and M08-HX) relative to electron correlation methods MP2 and QCISD to produce reliable and accurate structures as well as thermochemical data for sulfur/selenium-containing systems. Bond lengths, proton affinities (PA), gas phase basicities (GPB), chalcogen–chalcogen bond dissociation enthalpies (BDE), …


Comparison Between Tetrel Bonded Complexes Stabilized By Σ And Π Hole Interactions, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner Jun 2018

Comparison Between Tetrel Bonded Complexes Stabilized By Σ And Π Hole Interactions, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The σ-hole tetrel bonds formed by a tetravalent molecule are compared with those involving a π-hole above the tetrel atom in a trivalent bonding situation. The former are modeled by TH4, TH3F, and TH2F2 (T = Si, Ge, Sn) and the latter by TH2=CH2, THF=CH2, and TF2=CH2, all paired with NH3 as Lewis base. The latter π-bonded complexes are considerably more strongly bound, despite the near equivalence of the σ and π-hole intensities. The larger binding energies of the π-dimers are attributed to greater electrostatic attraction and orbital interaction. Each progressive replacement of H by F increases the strength of …


Progress Toward Synthetically Simplified Natural Anticancer Peptide, David W. Kastner, Steven L. Castle Mar 2018

Progress Toward Synthetically Simplified Natural Anticancer Peptide, David W. Kastner, Steven L. Castle

Library/Life Sciences Undergraduate Poster Competition 2018

Yaku’amide A was isolated in late 2010 from the deep-sea sponge Ceratopsion sp. and exhibits potent inhibitory activity against 39 human cancer cell lines via a potentially novel mode of action. However, the total synthesis requires many steps and produces low yields. In this study, we determined two simpler YA analogues that may retain its anticancer properties and can be synthesized in larger quantities. The analogues replace dehydroisoleucine with either dehydroethylnorvaline or dehydrovaline.