Possible Chemical Pathways leading to Life's Building Blocks:

[beecee]

https://phys.org/news/2018-03-chemical-sleuthing-unravels-path-life.html

Chemical sleuthing unravels possible path to forming life's building blocks in space

March 5, 2018, Lawrence Berkeley National Laboratory

Scientists have used lab experiments to retrace the chemical steps leading to the creation of complex hydrocarbons in space, showing pathways to forming 2-D carbon-based nanostructures in a mix of heated gases.
 

The latest study, which featured experiments at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), could help explain the presence of pyrene, which is a chemical compound known as a polycyclic aromatic hydrocarbon, and similar compounds in some meteorites.

A team of scientists, including researchers from Berkeley Lab and UC Berkeley, participated in the study, published March 5 in the Nature Astronomy journal. The study was led by scientists at the University of Hawaii at Manoa and also involved theoretical chemists at Florida International University.

"This is how we believe some of the first carbon-based structures evolved in the universe," said Musahid Ahmed, a scientist in Berkeley Lab's Chemical Sciences Division who joined other team members to perform experiments at Berkeley Lab's Advanced Light Source (ALS).

Read more at: https://phys.org/news/2018-03-chemical-sleuthing-unravels-path-life.html#jCp

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the paper:

https://www.nature.com/articles/s41550-018-0399-y

Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures

 

Abstract:

For the past decades, the hydrogen-abstraction/acetylene-addition (HACA) mechanism has been instrumental in attempting to untangle the origin of polycyclic aromatic hydrocarbons (PAHs) as identified in carbonaceous meteorites such as Allende and Murchison. However, the fundamental reaction mechanisms leading to the synthesis of PAHs beyond phenanthrene (C14H10) are still unknown. By exploring the reaction of the 4-phenanthrenyl radical (C14H9•) with acetylene (C2H2) under conditions prevalent in carbon-rich circumstellar environments, we show evidence of a facile, isomer-selective formation of pyrene (C16H10). Along with the hydrogen-abstraction/vinylacetylene-addition (HAVA) mechanism, molecular mass growth processes from pyrene may lead through systematic ring expansions not only to more complex PAHs, but ultimately to 2D graphene-type structures. These fundamental reaction mechanisms are crucial to facilitate an understanding of the origin and evolution of the molecular universe and, in particular, of carbon in our Galaxy.