Pseudo-Octahedral Iron(II) Complexes with Near-Degenerate Charge Transfer and Ligand Field States at the Franck-Condon Geometry.

Increasing the metal-to-ligand charge transfer (MLCT) excited state lifetime of polypyridine iron(II) complexes can be achieved by lowering the ligand's π* orbital energy and by increasing the ligand field splitting. In the homo- and heteroleptic complexes [Fe(cpmp)2 ]2+ (12+ ) and [Fe(cpmp)(ddpd)]2+ (22+ ) with the tridentate ligands 6,2''-carboxypyridyl-2,2'-methylamine-pyridyl-pyridine (cpmp) and N,N'-dimethyl-N,N'-di-pyridin-2-ylpyridine-2,6-diamine (ddpd) two or one dipyridyl ketone moieties provide low energy π* acceptor orbitals. A good metal-ligand orbital overlap to increase the ligand field splitting is achieved by optimizing the octahedricity through CO and NMe units between the coordinating pyridines which enable the formation of six-membered chelate rings. The push-pull ligand cpmp provides intra-ligand and ligand-to-ligand charge transfer (ILCT, LL'CT) excited states in addition to MLCT excited states. Ground and excited state properties of 12+ and 22+ were accessed by X-ray diffraction analyses, resonance Raman spectroscopy, (spectro)electrochemistry, EPR spectroscopy, X-ray emission spectroscopy, static and time-resolved IR and UV/Vis/NIR absorption spectroscopy as well as quantum chemical calculations.

Photo-induced anti-inflammatory activities of chloro substituted subphthalocyanines on the mammalian macrophage in vitro.

In this study, a series of subphthalocyanines (SubPcs) derivatives were synthesized to generate unique immunomodulatory molecules that can be activated through photo-induction. Immunomodulatory agents have a great potential in medicine to manipulate the immune system according to our needs and prevent disease symptoms. Inflammation is one of these symptoms and macrophages play a crucial role in the generation of inflammatory responses. Being able to control the activity of these agents through photo-induction enables the fine tuning on their activities in a location specific and non-invasive manner with possibly minor side effects. Mammalian macrophages' pro-inflammatory activity was examined in the presence of our compounds as well as LPS as a danger mimic. These compounds exerted photo-induced anti-inflammatory activities on the macrophages. Number of Cl atoms was a defining factor in their photo-induced anti-inflammatory immunomodulatory efficiencies.