Stephen H. Dempsey

Polyethylene conversion to mevalonate via catalyst-free autoxidation and bioconversion

Brandon L. Frey, Ross Eaglesfield, Ciaran W. Lahive, Jeremy R. Bussard et autres

Hybrid chemical and biological processes are promising strategies to valorize recalcitrant plastic waste streams by generating soluble oxygenates that can be biologically converted into a single product. Here, we show that acetic acid-mediated autoxidation in the absence of metal catalysts can deconstruct …

us, kr (code pays fourni par la source)

Charge-enhanced pyridyl trifluoroborate organocatalysts: crystal structures and reactivity

Alex Lovstedt, Stephen H. Dempsey, Steven R. Kass

The crystal structures of eleven 3- and 4-pyridyl borate salts with a variety of cations are reported. These are potassium trifluoro(pyridin-3/4-yl)borate, K + ·C 5 H 4 BF 3 N − , 1 and 2 (as the monohydrate), tetrabutylammonium trifluoro(pyridin-3/4-yl)borate, C 16 …

us (code pays fourni par la source)

Acetolysis for epoxy-amine carbon fibre-reinforced polymer recycling

Ciaran W. Lahive, Stephen H. Dempsey, Sydney E Reiber, Ajinkya Pal et autres

us, gb (code pays fourni par la source)

Process innovations to enable viable enzymatic poly(ethylene terephthalate) recycling

Natasha P. Murphy, Stephen H. Dempsey, Jason S. DesVeaux, Taylor Uekert et autres

us, gb (code pays fourni par la source)

Electrostatically Enhanced 3- and 4-Pyridyl Borate Salt Nucleophiles and Bases

Alex Lovstedt, Stephen H. Dempsey, Steven R. Kass

Work in our group has shown the addition of a positively charged center dramatically increases the activity of Brønsted acid organocatalysts in non-polar media.1,2 Following on this, we set out to determine if the addition of a negatively charged center would increase …

us (code pays fourni par la source)

Anion-Activated Bases and Nucleophiles Characterized by Photoelectron Spectroscopy

Stephen H. Dempsey, Wenjin Cao, Xue‐Bin Wang, Steven R. Kass

Negative ion photoelectron spectra at 20 K along with ab initio [CCSD(T)] and M06-2X density functional theory calculations are reported for a series of six basic and nucleophilic pyridine derivatives with an anionic substituent [i.e., 3- and 4-PyrBX 3 –, where X …

us (code pays fourni par la source)

Electrostatically Enhanced 3- and 4-Pyridyl Borate Salt Nucleophiles and Bases

Stephen H. Dempsey, Alex Lovstedt, Steven R. Kass

A variety of electrostatically enhanced 3- and 4-pyridylborate salt catalysts are reported and show significant improvement over an activated noncharged neutral control compound. Their nucleophilicity in a stoichiometric S N 2 reaction and catalytic performance in a urethane synthesis are evaluated along …

us (code pays fourni par la source)

CCDC 2247331: Experimental Crystal Structure Determination

Stephen H. Dempsey, Alex Lovstedt, Steven R. Kass

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, …

CCDC 2247332: Experimental Crystal Structure Determination

Stephen H. Dempsey, Alex Lovstedt, Steven R. Kass

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, …

Structure determination of a bis[4-(di- n -butylamino)phenyl](pyridin-3-yl)borane tetramer highlighting a unique geometric conformation of the core 16-membered ring

Alex Lovstedt, Stephen H. Dempsey, Steven R. Kass

The tetramer of bis(4-di- n -butylaminophenyl)(pyridin-3-yl)borane [systematic name: 2λ 4 ,4λ 4 ,6λ 4 ,8λ 4 -tetrabora-1,3,5,7(1,3)-tetrapyridinacyclooctaphane-1 1 ,3 1 ,5 1 ,7 1 -tetrakis(ylium)], C 132 H 192 B 4 N 12 , was synthesized unexpectedly and crystallized. Its structure contains …

us (code pays fourni par la source)

Liberating the Anion: Evaluating Weakly Coordinating Cations

Stephen H. Dempsey, Steven R. Kass

A series of commonly used weakly coordinating cations (WCCs) including tetraalkylammonium, bis(triphenylphosphine)iminium (PPN), P2 and P5 phosphazenium, and tetraphenylphosphonium ions were investigated along with five additional tetraarylphosphonium ions [Ar = 4-Me, 4- t -Bu, 3,5-Me 2, 4-Me 2 N, and 3,5-(MeO) 2 …

us (code pays fourni par la source)

Facile syntheses of functionalized toll-like receptor 7 agonists

Babatope Akinbobuyi, Matthew R. Byrd, Charles Chang, Mysa Nguyen et autres

us (code pays fourni par la source)