The Synthesis of Carboxylate Rich Alicyclic Molecules for the Investigation of the Chemical Space of Dissolved Organic Matter

Dissolved Organic Matter (DOM) is a vast and complex chemical mixture that plays a key role as a mediator of the global carbon cycle. Fundamental understanding of the source and fate of oceanic organic matter is limited due to poor definition of the key molecular contributors to DOM, which limits accurate sample analysis and prediction of the Earth’s carbon cycle. Previous work has attempted to define the chemical space of DOM through a variety of chromatographic and spectral techniques. However, modern preparative and analytical methods are unable to isolate molecules from DOM, and so previously proposed structures are based solely on the mixture’s aggregate properties, and cannot accurately describe any true individual molecular component. To overcome this limitation, we have synthesized a series of compounds representative of Carboxylate Rich Alicyclic Molecules (CRAM), a molecular class hypothesized to exist as a major contributor to DOM. Key characteristic features of the analytical data of these synthetic CRAMs are consistent with marine DOM, reinforcing the hypothesis that CRAMs are present within aged environmental samples. This new approach ultimately provides access to purified molecules that can be used in previously inaccessible experiments to test the many unproven hypotheses surrounding the ever-enigmatic DOM.