Synthesis of functionalized nitrogen-containing polycyclic aromatic hydrocarbons and other prebiotic compounds in impacting glycine solutions

Abstract

Impacting glycine mixtures could have resulted in the shock synthesis of NPAHs and other prebiotic compounds.

Mechanochemical synthesis of glycine oligomers in a virtual rotational diamond anvil cell

“…In the case of V-RDAC simulations, one route to develop DFTB parameter sets tuned for shearing conditions would be to force-match the DFTB repulsive potential in eqn (1) to forces from a V-RDAC simulation performed at a DFT level of theory. 23,24,75 Iterative renement schemes that use DFTB-based QMD as a driver to sample new congurations for which one obtains forces from DFT-level single-point calculations is another promising path towards a semi-automated DFTB model development cycle.…”

“…37 Simulations modeling impacting glycine-water mixtures have shown that even higher pressures and temperatures (48 GPa, 3000 K) can drive the formation larger oligomeric structures that spontaneously rearrange into polyaromatic molecules upon adiabatic expansion. 24 Polymerization of dry glycine to form dimers up to 10-mers have also been observed under more modest static pressures ranging from 5-100 MPa at elevated temperatures (423 K) over time frames of 1-32 days. 17 Elevated temperatures appear necessary to drive oligomerization in pure glycine under hydrostatic conditions as Hinton et al showed that crystalline a-glycine is largely unreactive at room temperature when compressed up to 50 GPa based on Raman spectroscopy and Xray diffraction measurements.…”

“…[12][13][14][15][16][17][18][19][20][21][22][23][24] Theories put forth to explain how glycine forms and reacts under prebiotic conditions to make larger oligomeric structures include thermal cycling at submarine hydrothermal vents, 14,15,18,19 alternating between wet and dry environments, 13 electron irradiation, 25 and impact events. 16,22,24,[26][27][28] Tidal or tectonic shearing forces within the interiors of planets and moons such as Europa, Enceladus, Triton, and Pluto have also been considered as general drivers of chemistry where subsurface oceans interact with a rocky oor. [29][30][31][32] Mechanochemistry can arise during impact events or geological compressive shear scenarios through short-lived deformed or compressive states.…”

“…53 Atomistic modeling approaches such as semiempirical quantum-based molecular dynamics (QMD) using density functional tight binding [54][55][56] (DFTB) can accurately predict chemistry under extreme conditions. 24,36,44,[57][58][59][60] Using QMD offers a powerful route to perform computer "experiments" that can help selectively target and interpret more expensive and labor-intensive laboratory experiments. The DFTB method is derived from density functional theory 61,62 (DFT) and offers a competitive balance between computational accuracy and expense that allows for the practical generation of nanoseconds worth of QMD trajectory.…”

Organic Molecules: Is It Possible to Distinguish Aromatics from Aliphatics Collected by Space Missions in High Speed Impacts?

“…For example, once created, the protein forming amino acid glycine has to do something more to form life. It has been pointed out that, if glycine formed on a comet and was delivered to Earth via an impact event, then the energy delivered in that impact may drive further reactions [17]. Therefore, you start with one piece of knowledge, then have to add another, and another, following a path, which may or may not be the right one in terms of the origin of life.…”