Eller S, Trettenbrein B, Oberhuber D, Strabler C, Gutmann R, van der Veer WE, Ruetz M, Kopacka H, Obendorf D, Brüggeller P. Oxidative quenching within photosensitizer-acceptor dyads based on
bis(bidentate) phosphine-connected osmium(II) bipyridyl light absorbers and reactive metal sites.
INORG CHEM COMMUN 2013;
23:41-45. [PMID:
23471298 PMCID:
PMC3587338 DOI:
10.1016/j.inoche.2012.06.001]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 06/03/2012] [Indexed: 11/25/2022]
Abstract
For the first time oxidative quenching of OsP2N4 chromophores by reactive PtII or PdII sites containing cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) is directly observed despite the presence of a saturated cyclobutane backbone “bridge”. This dramatic effect is measured as a sudden temperature-dependent onset of a reduction in phosphorescence lifetime in [Os(bpy)2(dppcb)MCl2](SbF6)2 (M = Pt, 1; Pd, 2). The appearance of this additional energy release is not detectable in [Os(bpy)2(dppcbO2)](PF6)2 (3), where dppcbO2 is cis, trans, cis-1,2-bis(diphenylphosphinoyl)-3,4-bis(diphenylphosphino)cyclobutane. Obviously, the square-planar metal centers in 1 and 2 are responsible for this effect. In line with these observations, the emission quantum yields at room temperature for 1 and 2 are drastically reduced compared with 3. Since this luminescence quenching implies strong intramolecular interaction between the OsII excited states and the acceptor sites and depends on the metal⋯metal distances, also the single crystal X-ray structures of 1–3 are given.
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