Distinct distribution of soluble N-heterocyclic compounds between CM and CR chondrites

Very complex mixtures of organic compounds occur in extraterrestrial materials such as carbonaceous meteorites. These intricate signatures of meteoritic organic matter can provide clues to elucidate chemical evolution processes in space. Previously, these complex organic molecules have not been well-resolved in primitive meteorites, so the formation mechanisms of extraterrestrial organics remain largely conjectural. In this study, the occurrence and abundance of soluble CHN organic compounds were examined in CM vs. CR meteorites to investigate possible chemical processes associated with the different parent bodies. Hydrogenated alkylpiperidines (C _n H _2n+1 N) are more abundant in the CR chondrite, in contrast to more abundant aromatic alkylpyridines (C _n H _2n-5 N) in the CM chondrites. Both alkylpyridines and alkylpiperidines are most likely synthesized from simple aldehydes and ammonia on meteorite parent bodies, but the differences between the distribution of N-cyclic compounds are consistent with different redox conditions of the parent bodies which influenced the organic molecular evolution processes in extraterrestrial materials.