154 research outputs found
Ligand Exchange Triggered Photosensitizers â BodipyâTagged NHCâMetal Complexes for Conversion of ÂłOâ to ÂčOâ
A new imidazolium salt 3â
HI with 8âBodipy as one Nâaryl substituent was synthesized from 8âchloroâBodipy and imidazole followed by alkylation with iPrI. NHCâmetal complexes [CuCl(3)], [AuCl(3)], [Pd(allyl)Cl(3)] and [MCl(cod)(3)] and [MCl(CO)â(3)] (M=Rh, Ir) were synthesized and the Xâray crystal structure of [IrCl(CO)â(3)] determined. The donation of NHC 3 was determined via IR (Îœ(CO) and cyclic voltammetry (Ir(I/II) redox potential). The photosensitizing properties of the complexes for the generation of ÂčOâ were quantified observing singlet oxygen quantum yield of up to Ίs.o.=0.63. [IrCl(cod)(3)] displays poor Ίs.o.=0.09, but, following a simple ligand exchange reaction of cod by two CO [IrCl(CO)â(3)], a pronounced increase to Ίs.o.=0.63 is observed
Facile Synthesis of TriptyceneâAzolium Salts and NHCâMetal Complexes
The cycloaddition reactions of eleven substituted anthracenes with nosylated quinone imines provides a convenient route to the respective triptycenes. Following reâaromatization, selective Oâbutylation and cleavage of the nosylâgroup the respective triptycene anilines are obtained, which are converted into the respective imidazolium salts according to established procedures. Deprotonation of the imidazolium salts provide new triptyceneâNHCâmetal complexes (M=AuCl, RhCl(cod), IrCl(cod), RhCl(CO)â, IrCl(CO)â, PdIâ(py), PtClâ(py), Pd(allyl)Cl) with unusual ligand sterics
Spontaneous emission of an atom in front of a mirror
Motivated by a recent experiment [J. Eschner {\it et al.}, Nature {\bf 413},
495 (2001)], we now present a theoretical study on the fluorescence of an atom
in front of a mirror. On the assumption that the presence of the distant mirror
and a lens imposes boundary conditions on the electric field in a plane close
to the atom, we derive the intensities of the emitted light as a function of an
effective atom-mirror distance. The results obtained are in good agreement with
the experimental findings.Comment: 8 pages, 6 figures, revised version, references adde
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