Synthesis and luminescent properties of platinum-containing polyynes with tetraacetylenic 9,9-dihexylfluorene units

Soluble platinum(II) polyyne polymers trans-{Pt-[P(C4H 8N)3]2(C ≡ C)2R(C ≡ C)2-}n and trans-{Pt-[P(C4-H3O) 3]2(C≡C)2R(C≡C)2-} n (R=9,9-dihexylfluorene-2,7-diyl) have been prepared in good yields by CuI-catalyzed polymerization involving the dehydrohalogenating coupling of trans-{PtCl2[P(C4H8N)3] 2} and trans-{PtCl2[P-(C4H3O) 3]2} with H(C≡C)2R(C≡C) 2H, respectively. We report the optical spectroscopy of these polyplatinaynes. The influence of the heavy metal atom in these metal alkynyl systems on the intersystem crossing rate and the spatial extent of lowest singlet and triplet excitons was systematically characterized. Our investigations indicate that the organic triplet emissions can be harvested by the heavy-atom effect which enables efficient intersystem crossing from the S1 singlet excited state to the T1 triplet excited state. KGaA.