Quantum chemical design and analysis of photoactive CO-Releasing materials using heterocyclic Moieties

This research investigates the development of advanced photoactive CO-releasing materials using heterocyclic structures. We designed a series of heterocyclic molecules to examine their electronic properties, electron density, metal-CO interactions, and CO-release efficiency in both ground and excited states. Quantum chemical and QTAIM analyses revealed a strong affinity between Mn(CO)₃ (charged species) and substrates with heterocycles like pyridine, pyraza, 1,2,3-triaza, thioaza, and imidaza in ground state geometries, with weakened CO binding to Mn in excited states, indicating CO release. AIMALL studies showed increased electron density of Mn^…N and decreased Mn…C[dbnd]O in excited states compared to ground states. Additionally, Mn^…C distances of the carbonyl groups elongated by 4.6 % to 8.5 % in excited states, suggesting progress towards CO release upon excitation. These findings highlight the potential of the newly designed molecules for future CO-releasing materials.