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When: Thursday, Sept 29, 6-9pm
Where: Eli's on Whitney, Hamden, Ct
Who: Dr. Nelu Grinberg
Title: Insights into Chromatographic Enantiomeric Recognition of Allenes with Cellulose Carbonate Stationary Phase
Bio: Dr. Nelu Grinberg is a Distinguished Research Fellow in the Chemical Development Department at Boehringer Ingelheim Pharmaceuticals in Ridgefield, CT, where he has worked for the past twelve years. Prior to this, he worked for sixteen years in the Analytical Department at Merck Research Laboratories in Rahway, NJ, where he was a Senior Research Fellow. He has authored and coauthored over 150 publications, including articles and book chapters. He is currently the Editor-in-Chief of the Journal of Liquid Chromatography and Related Technologies, Co-Editor of the Advances in Chromatography series, and Editor of the Chromatographic Science Series book series. He is also the only industrial chemist who has been a recipient of the Koltoff Fellowship of The Hebrew University of Jerusalem. Dr. Grinberg was the President of the Connecticut Separation Science Council, where he established a symposium in connection with the CSSC's Horvath Award. He has lectured on enantiomeric separation in Germany, Austria, Sweden, Israel, Hungary, Romania, Belgium, and at numerous universities in the United States. He has given short courses on the separation of enantiomers at a number of symposia in New Jersey, Israel, Croatia and Romania, and was an Adjunct Professor at Seton Hall University in New Jersey. Dr. Grinberg obtained his Ph.D. in Chemistry from the Technical University of lasi in Romania. He conducted post¬doctoral research with Professor Barry Karger at Northeastern University and with Professors Emmanuel Gil-Av and Abraham Patchornik at The Weizmann Institute of Science in Rehovot, Israel.
Abstract: Allenes are becoming highly sought building blocks for their ability to react with many different classes of substrates. They have three-carbon functional groups possessing a 1,2-diene moiety and serve as potential precursors in the synthesis of highly complex and strained target molecules of biological and industrial importance. Their unique reaction behavior where the reactivity is spread over three contiguous carbon atoms has been successfully applied to the field of pharmaceuticals, dyes, and polymers.
Enantiomeric separation of a chiral allene was achieved on a 3μm Cellulose Carbamate column (Chiracel OD-3) using heptane as a mobile phase. The base-line separation was obtained in under 5 minutes. Thermodynamic experiments revealed that the allene undergoes mixed interactions, with a van’t Hoff plot exhibiting an entropic interaction. To ascertain the types of interactions between the two enantiomers of the allene with the stationary phase we pursued vibrational circular dichroism (VCD), along with density functional theory (DFT) calculation. Experiments revealed changes in the VCD spectra of cellulose upon interaction with heptane. This talk will highlight the interactions between the cellulose stationary phase and the two enantiomers through, as observed through VCD spectroscopy and DFT calculation.