Sensitization of lanthanide luminescence by two different Pt → Ln energy transfer pathways in PtLn3 heterotetranuclear complexes with 5-ethynyl-2,2′-bipyridine†
Abstract
Reactions of Cbpy) with Pt(bpy)Cl2 (
C–C
Cbpy)Cl2 (bpyC
C–C
Cbpy =
Cbpy)2 (1) and Pt(bpyC
C–C
Cbpy)(C
Cbpy)2 (5), respectively. Incorporating Ln(hfac)3(H2O)2 (hfac = hexafluoroacetylacetone) with 1 or 5 gave the corresponding PtLn2 (Ln = Nd (2), Eu (3), Yb (4)) or PtLn3 arrays (Ln = Nd (6), Eu (7), Gd (8), Yb (9)). With excitation at 360 ≤ λex ≤ 480 nm, which is the MLCT absorption region of the Pt(2,2′-bipyridyl)(acetylide)2
Cbpy–Ln (Pt⋯Ln = 8.6 Å) array, energy transfer transmitted across the Pt–bpyC
C–C
Cbpy–Ln (Pt⋯Ln = 13.3 Å) array is less efficient owing to the much longer Pt⋯Ln separation in the latter.