title: Carbonyl amine/Schiff base ligands in manganese complexes: theoretical study on the mechanism, capability of NO release.
abstract: A compound having the capability of releasing NO upon exposure to visible or near-infrared (vis or NIR) light could be a potential candidate for photodynamic therapy (PDT), which is significant for humans. Here, we investigated a series of Mn(II) complexes (a-d) based on density functional theory (DFT) to illuminate the mechanism of their behavior of releasing NO. Their structural, spectroscopic, and photodissociable properties were calculated by quantum theoretical methods to give a detailed and warranted explanation of the performance of releasing NO. The results indicate that, for a-d, releasing NO was attributed to the electron transfer from d(yz)/d(xz)(Mn) orbitals to π*(NO) orbitals at the second excited triplet state (T(2)). Importantly, we confirmed the finding in the experiment that d could release NO upon exposure to the NIR region and, thus, may be a best candidate for PDT in a-d. Therefore, to take d for example, the analyses of the potential energy curves (PECs) of difference states and electron density difference between the T(2) and the ground state (S(0)) were performed to further provide evidence of ligand dissociation and release of NO at the T(2) state. Finally, we hope that our discussion can provide assistance to understand the behavior of the release of NO and design novel photodissociable transition metal nitrosyls for PDT applications.
authors.affiliation: Institute of Functional Material Chemistry, Faculty of Chemistry,  Northeast Normal University , Changchun 130024, Jilin, People's Republic of China.
authors.forename: Weili
authors.initials: W
authors.lastname: Zheng
authors.forename: Shuixing
authors.initials: S
authors.lastname: Wu
authors.forename: Shanshan
authors.initials: S
authors.lastname: Zhao
authors.forename: Yun
authors.initials: Y
authors.lastname: Geng
authors.forename: Junling
authors.initials: J
authors.lastname: Jin
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Su
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fu
mesh_terms: D000588:Amines / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D006801:Humans; D008027:Light; D008345:Manganese / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009569:Nitric Oxide / Q000737:chemistry*; D055668:Photochemical Processes; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry*; D011789:Quantum Theory; D012545:Schiff Bases / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D000588:Amines; D017319:Photosensitizing Agents; D012545:Schiff Bases; D009569:Nitric Oxide; D008345:Manganese