Theoretical Investigation of Bimolecular Carbon Chain Growth Reactions in the Interstellar Media.

Detection of molecular anions in interstellar media implies that negatively charged species play a prominent role in astrochemical reactions. Among the observed species, carbon chain anions are important, as they can be precursors for the production of complex organic molecules. These anions can form either via direct electron attachment to the corresponding neutral species or through chain growth reactions of smaller anions, resulting in longer chains. In a recent study, crossed beam experiments coupled with velocity map imaging techniques were used to investigate the carbon chain growth reaction C2n- + C2H2 → C2n+2Hm- + H2-m (n = 1-3, m = 0,1). Products and branching ratios were established from experimental data. In the present work, electronic structure calculations and on-the-fly direct dynamics simulations were used to study these reactions. Energy profiles were investigated by using different density functional methods. Direct trajectory simulations were performed at the experimental collision energies using the B3LYP/6-31+G* level of theory. Trajectory analysis showed a variety of reaction pathways, and detailed atomic-level reaction mechanisms are presented.

NNN manganese complex-catalyzed α-alkylation of methyl ketones using alcohols: an experimental and computational study.

We present here a phosphine-free, quinoline-based pincer Mn catalyst for α-alkylation of methyl ketones using primary alcohols as alkyl surrogates. The C-C bond formation reaction proceeds via a hydrogen auto-transfer methodology. The sole by-product formed is water, rendering the protocol atom efficient. Electronic structure theory studies corroborated the proposed mechanism.

Reusable Supported Pyridine-Mediated Cascade Synthesis of trans-2,3-Dihydroindoles via In Situ-Generated N-Ylide.

Merrifield resin-anchored pyridines were prepared and applied as reusable mediators for trans-selective cascade synthesis of 2,3-dihydroindoles. The developed approach relied on in situ N-ylide formation followed by Michael substitution reactions. The cascade reaction was also carried out efficiently with simple pyridine. The products were further transformed into synthetically valuable compounds, and supported pyridine was reused for multiple cycles. Density functional theory calculations confirmed the trans-selectivity as the lower-energy pathway.