Synthesis and electronic spectroscopy of luminescent cyclometalated platinum-anthracenyl complexes

Dicyclometalated complexes syn- and anti-[Pt-2(L)(2)(PAnP-H-2)](OTf)(2) (Pt-2) are synthesized from reactions of 9,10-bis(diphenylphosphino)anthracene (PAnP) and Pt(L)(OTf)(2) (L = diphosphines, OTf = CF3SO3). Because of metal perturbation on the electronic structure of the anthracenyl ring, the B-1(2u)- <- (1)A(g) transition, which is forbidden in anthracene, is observed in the electronic spectra of Pt-2. The complexes display fluorescence arising from the ligand-centered S-1 excited state. No significant heavy atom effect is observed in the Pt-2 complexes. To understand the effect of the number of Pt ions on the extent of perturbation, a mononuclear analogue, [Pt(dppe)(PAn-H)]ClO4 (PAn = 9-diphenylphosphinoanthracene), is prepared and its spectroscopy studied.