André K. Eckhardt
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View article: Enhanced Resolution in EPR Spectroscopy Using <i>para</i> ‐Hydrogen Matrices
Enhanced Resolution in EPR Spectroscopy Using <i>para</i> ‐Hydrogen Matrices Open
We developed a matrix isolation experiment utilizing a closed‐cycle helium cryostat, which operates at 2.5 K and enables electron paramagnetic resonance (EPR) measurements in solid para ‐hydrogen ( p ‐H 2 ) matrices. The EPR spectra of the…
View article: EPR Spectroscopy in para-Hydrogen Matrices
EPR Spectroscopy in para-Hydrogen Matrices Open
We developed a matrix isolation experiment utilizing a closed-cycle helium cryostat, which operates at 2.5 K and enables electron paramagnetic resonance (EPR) measurements in solid para-hydrogen (p-H2) matrices. The EPR spectra of the pers…
View article: Photochemical Generation and Characterization of Alanine Imine: A Key Intermediate in Prebiotic Amino Acid Formation
Photochemical Generation and Characterization of Alanine Imine: A Key Intermediate in Prebiotic Amino Acid Formation Open
Simple imino acids have received sparse consideration as reactive intermediates in the formation of amino acids under prebiotic or astrochemical conditions. Under cryogenic matrix isolation conditions 2-azidopropionic acid decomposes after…
View article: Formation of hydrogen trioxide (HOOOH) in extraterrestrial ice analogs and its role as an oxidizer in prebiotic chemistry
Formation of hydrogen trioxide (HOOOH) in extraterrestrial ice analogs and its role as an oxidizer in prebiotic chemistry Open
The formation and characterization of hydrogen trioxide have fascinated scientists for more than a century, due to its role as a prototype model for oxygen-chain bonding and as a key transient in antibody-catalyzed oxidation reactions rele…
View article: A Combined Crossed Molecular Beam and Theoretical Investigation of the Elementary Reaction of Tricarbon (C<sub>3</sub>(X<sup>1</sup>Σ<sub>g</sub><sup>+</sup>)) with Diacetylene (C<sub>4</sub>H<sub>2</sub>(X<sup>1</sup>Σ<sub>g</sub><sup>+</sup>)): Gas Phase Formation of the Heptatriynylidyne Radical (<i>l</i>-C<sub>7</sub>H(X<sup>2</sup>Π))
A Combined Crossed Molecular Beam and Theoretical Investigation of the Elementary Reaction of Tricarbon (C<sub>3</sub>(X<sup>1</sup>Σ<sub>g</sub><sup>+</sup>)) with Diacetylene (C<sub>4</sub>H<sub>2</sub>(X<sup>1</sup>Σ<sub>g</sub><sup>+</sup>)): Gas Phase Formation of the Heptatriynylidyne Radical (<i>l</i>-C<sub>7</sub>H(X<sup>2</sup>Π)) Open
An elucidation of the underlying formation pathways to acyclic hydrocarbons such as polyynes (CnH2), cumulenes (CnH2), and linear resonantly stabilized linear radicals (l-CnH) is indispensable to understand the hydrocarbon chemistry in ext…
View article: Generation and UV-photolysis of N-methyleneformamide
Generation and UV-photolysis of N-methyleneformamide Open
Simple imines have been detected in space and are considered as building blocks to larger heteroaromatic, cyclic and biological relevant compounds. Herein we revisited the formation of the simplest acylimine, namely N-methyleneformamide, b…
View article: H-Tunneling Rotamerization in Glycine Imine
H-Tunneling Rotamerization in Glycine Imine Open
Quantum mechanical tunneling governs chemical reactivity at cryogenic temperatures. Here we present the near-infrared (NIR) light-induced generation of a higher energy conformer of glycine imine and its H-tunneling CO bond rotamerization i…
View article: H-Tunneling Rotamerization in Glycine Imine
H-Tunneling Rotamerization in Glycine Imine Open
Quantum mechanical tunneling governs chemical reactivity at cryogenic temperatures. Here we present the near-infrared (NIR) light-induced generation of a higher energy conformer of glycine imine and its H-tunneling CO bond rotamerization i…
View article: Binding the Power of Cycloaddition and Cross-Coupling in a Single Mechanism: An Unexpected Bending Journey to Radical Chemistry of Butadiynyl with Conjugated Dienes
Binding the Power of Cycloaddition and Cross-Coupling in a Single Mechanism: An Unexpected Bending Journey to Radical Chemistry of Butadiynyl with Conjugated Dienes Open
What if an experiment could combine the power of cycloaddition and cross-coupling with the in situ formation of an aromatic molecule in a single collision? Crossed molecular beam experiments augmented with electronic structure and statisti…
View article: Interstellar formation of 1,2-propanediol (CH <sub>3</sub> CH(OH)CH <sub>2</sub> OH) and 1,2-ethenediol (HOCHCHOH)—key precursors to sugars and sugar derivatives
Interstellar formation of 1,2-propanediol (CH <sub>3</sub> CH(OH)CH <sub>2</sub> OH) and 1,2-ethenediol (HOCHCHOH)—key precursors to sugars and sugar derivatives Open
This study reveals viable abiotic routes of the three-carbon deoxysugar alcohol 1,2-propanediol (CH 3 CH(OH)CH 2 OH) and enol 1,2-ethenediol (HOCHCHOH)—a critical intermediate in the formose reaction—in interstellar analog ices.
View article: Generation and UV-photolysis of <i>N</i>-methyleneformamide
Generation and UV-photolysis of <i>N</i>-methyleneformamide Open
N -Methyleneformamide is the simplest acylimine and was characterized under matrix isolation conditions at cryogenic temperatures by infrared and UV/Vis spectroscopy. The compound should be considered as a potential interstellar molecule.
View article: Gas-phase detection of oxirene
Gas-phase detection of oxirene Open
Oxirenes—highly strained 4π Hückel antiaromatic organics—have been recognized as key reactive intermediates in the Wolff rearrangement and in interstellar environments. Predicting short lifetimes and tendency toward ring opening, oxirenes …
View article: Prebiotic Synthesis and Isomerization in Interstellar Analog Ice: Glycinal, Acetamide, and Their Enol Tautomers
Prebiotic Synthesis and Isomerization in Interstellar Analog Ice: Glycinal, Acetamide, and Their Enol Tautomers Open
Glycinal (HCOCH 2 NH 2 ) and acetamide (CH 3 CONH 2 ) are simple molecular building blocks of biomolecules in prebiotic chemistry, though their origin on early Earth and formation in interstellar media remain a mystery. These molecules are…
View article: Prebiotic Synthesis and Isomerization in Interstellar Analog Ice: Glycinal, Acetamide, and Their Enol Tautomers
Prebiotic Synthesis and Isomerization in Interstellar Analog Ice: Glycinal, Acetamide, and Their Enol Tautomers Open
Glycinal (HCOCH 2 NH 2 ) and acetamide (CH 3 CONH 2 ) are simple molecular building blocks of biomolecules in prebiotic chemistry, though their origin on early Earth and formation in interstellar media remain a mystery. These molecules are…
View article: Glycine Imine—The Elusive <i>α</i>‐Imino Acid Intermediate in the Reductive Amination of Glyoxylic Acid
Glycine Imine—The Elusive <i>α</i>‐Imino Acid Intermediate in the Reductive Amination of Glyoxylic Acid Open
Simple unhindered aldimines tend to hydrolyze or oligomerize and are therefore spectroscopically not well characterized. Herein we report the formation and spectroscopic characterization of the simplest imino acid, namely glycine imine, by…
View article: A Mechanistic Study on the Formation of Acetone (CH<sub>3</sub>COCH<sub>3</sub>), Propanal (CH<sub>3</sub>CH<sub>2</sub>CHO), Propylene Oxide (c-CH<sub>3</sub>CHOCH<sub>2</sub>) along with Their Propenol Enols (CH<sub>3</sub>CHCHOH/CH<sub>3</sub>C(OH)CH<sub>2</sub>) in Interstellar Analog Ices
A Mechanistic Study on the Formation of Acetone (CH<sub>3</sub>COCH<sub>3</sub>), Propanal (CH<sub>3</sub>CH<sub>2</sub>CHO), Propylene Oxide (c-CH<sub>3</sub>CHOCH<sub>2</sub>) along with Their Propenol Enols (CH<sub>3</sub>CHCHOH/CH<sub>3</sub>C(OH)CH<sub>2</sub>) in Interstellar Analog Ices Open
Carbonyl-bearing complex organic molecules (COMs) in the interstellar medium (ISM) are of significant importance due to their role as potential precursors to biomolecules. Simple aldehydes and ketones like acetaldehyde, acetone, and propan…
View article: Equilibrating parent aminomercaptocarbene and CO<sub>2</sub> with 2-amino-2-thioxoacetic acid <i>via</i> heavy-atom quantum tunneling
Equilibrating parent aminomercaptocarbene and CO<sub>2</sub> with 2-amino-2-thioxoacetic acid <i>via</i> heavy-atom quantum tunneling Open
A novel heterosubstituted carbene spontaneously binds CO 2 in a tunneling reaction under cryogenic conditions.
View article: CCDC 2098667: Experimental Crystal Structure Determination
CCDC 2098667: Experimental Crystal Structure Determination Open
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 …
View article: CCDC 2098666: Experimental Crystal Structure Determination
CCDC 2098666: Experimental Crystal Structure Determination Open
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 …
View article: Formation of the elusive tetrahedral P <sub>3</sub> N molecule
Formation of the elusive tetrahedral P <sub>3</sub> N molecule Open
The tetrahedral 1,2,3-triphospha-4-azatricyclo [1.1.0.0 2,4 ] butane (P 3 N) molecule—an isovalent species of phosphorus (P 4 )—was prepared in low-temperature (5 K) phosphine-nitrogen ices and was identified in the gas phase through isome…
View article: CCDC 2098665: Experimental Crystal Structure Determination
CCDC 2098665: Experimental Crystal Structure Determination Open
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 …
View article: CCDC 2110927: Experimental Crystal Structure Determination
CCDC 2110927: Experimental Crystal Structure Determination Open
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 …