Fragmentation Pathways of Diaminomaleonitrile: Automated Discovery and High-Level Energetics Under Laser-Driven Conditions.

We investigate the fragmentation chemistry of 2,3-diaminomaleonitrile (DAMN), a key hydrogen cyanide (HCN) tetramer in prebiotic synthesis, aiming to reproduce products observed in laser ablation experiments under interstellar medium (ISM)-relevant energetics. Using automated reaction discovery (AutoMeKin) with PM7/MOPAC explorations, we generate candidate minima and transition states that are refined at M08HX/6-31+G(d, p) and validated by Hessians; final energetics are obtained from DLPNO-CCSD(T)/cc-pVTZ single points corrected with DFT scaled zero-point energies. The resulting network recovers experimentally reported products like malononitrile, Z-C-cyanomethanimine, and radical pairs leading to aminoacetonitrile in the presence of H atoms and rationalizes their relative accessibility via low- to moderate-barrier pathways. Together, these results reconcile laser ablation outcomes with first-principles kinetics and may help to guide future laboratory and observational searches.