Absorption spectra, photophysical properties, and redox behavior of ruthenium(II) polypyridine complexes containing accessory dipyrromethene-BF2 chromophores.

摘要: The six multichromophoric species 1-6, containing the potentially luminescent Ru(II) polypyridine subunits and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene fluorophores (dipyrromethene-BF(2) dyes, herein after called bodipy), have been prepared their absorption spectra, luminescence properties (both at room temperature in fluid solution 77 K rigid matrix), redox investigated (for structuralformulas of all compounds, see Figure 1). For comparison purposes, also same bodipy-based free ligands examined. Three (1-3) are based on Ru(bpy)(3)-type metal subunit, whereas 4-6 Ru(terpy)(2)-type subunit. Transient spectroscopy compounds has performed. spectra complexes show features that can be assigned to bodipy centers. In particular, lowest energy spin-allowed pi-pi* transition groups dominates visible region, peaking about 530 nm. All new exhibit a rich behavior, with reversible processes attributed specific sites, indicating small perturbation each center therefore highlighting supramolecular nature assemblies. Despite good separated components, 1-6 do not any temperature; however, transient evidences for them long-lived (microsecond time scale) excited state is formed, which identified as triplet state. Pump-probe suggests such formed from promptly (1)pi-pi* most cases by intervention charge-separated level. At K, except complex 1 fluorescence, although slightly shortened lifetime compared corresponding ligand(s), phosphorescence subunits. Phosphorescence had never reported literature best our knowledge: present we propose it an effective decay process thanks presence ruthenium heavy atom closely lying (3)MLCT