Sensitized near-IR luminescence of lanthanide complexes based on push-pull diketone derivatives

Abstract

Lanthanide complexes with two push-pull diketone derivatives as sensitizers have been developed as synthons for near-infrared emitting materials. The ligand substituents consist of a carbazole moiety with hole-transport properties and an aromatic or heteroaromatic unit. According to quantitative NMR analysis and complementary HPLC experiments, the diketones are predominantly in their enolic form in polar solvents such as THF and MeCN at room temperature. The preferred cis-enol form contributes strongly to the binding of lanthanide ions (Ln = Nd, Gd, Er). The resulting tris(diketonate) ternary complexes with terpyridine (Ln = Nd, Er) display sizeable near-IR emission with long luminescence lifetimes.

Investigation on the Synthesis and Photocatalytic Property of Uranyl Complexes of the β-Diketonates Biscatecholamide Ligand

“…The resonance signals of the methylene protons of the major species isomers showed four peaks at 5.18 (dd, J = 23.8, 12.1 Hz, 2H, -CH 2 -), 4.78 (d, J = 11.9 Hz, 2H, -CH 2 -), 4.00 (t, J = 12.0 Hz, 2H, -CH 2 -), and 3.63 (d, J = 14.2 Hz, 2H, -CH 2 -). And the active methylene of -diketonates shows [20,[28][29][30]. It confirmed that oxygen atom of -diketonate did not bind to uranyl ion, also indicated by the FTIR spectra analysis.…”

Visible-light sensitized luminescent europium(iii)-β-diketonate complexes: bioprobes for cellular imaging

“…The carbazole moiety displays unique advantages for application in optoelectronic devices because of inexpensive starting material, good chemical stability, and being tailored with a wide variety of functional groups to tune the optical and electrical properties. [76][77][78][79][80][81][82][83] As a consequence, carbazole-containing β-diketones and their corresponding Eu 3+ complexes have been extensively studied and it was concluded that Eu 3+ complexes with these kinds of β-diketonates containing 1′,3′-dioxobutyl linked at the 3-and 6-positions failed to extend their excitation band to the visible region. On the other hand, the introduction of 1′,3′-dioxobutyl linked at the 2-and 7-positions in a carbazole ring leads to a longer π-conjugation length, which results in a bathochromic shift in the excitation band.…”

Photophysical properties of metal complexes

“…211 Nd(III) and Er(III) complexes of ''push-pull'' b-diketonate ligands with carbazole and naphthalene or thienothiophene substituents exhibit ILCT states, the energy from which sensitises NIR emission from the lanthanide. 212 The complex [{Eu(tta) 3 } 2 (m-2,2 0 -bipyrimidine)] (tta = 2-thenoyltrifluoromethane-sulfonato) yields white electroluminescent OLED emission through exciplex formation with the host matrix of the device. 213 Dinuclear lanthanide complexes (Gd, Eu) comprising DO3A domains with a piperazine-based bridge show modulated visible luminescence with quenching and changes to the hypersensitive emission bands for Eu(II) emission in the presence of Cu 2+ and Hg 2+ ions respectively.…”