| 1. |
- dos Santos, John Marques, et al.
(författare)
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Color tuning of multi-resonant thermally activated delayed fluorescence emitters based on fully fused polycyclic amine/carbonyl frameworks
- 2023
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Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry. - 2050-7526 .- 2050-7534. ; 11:24, s. 8263-8273
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Tidskriftsartikel (refereegranskat)abstract
- Two novel π-extended amine/carbonyl-based multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters have been designed and synthesized. The two emitters are isomeric, composed of nine fused rings and show green-yellow emission. Sym-DiDiKTa and Asym-DiDiKTa possess tert-butyl groups distributed in a symmetrical and asymmetrical fashion, respectively, which significantly impact the single-crystal packing structure. The two compounds possess similar singlet-triplet energy gaps, ΔEST, of around 0.23 eV, narrowband emission characterized by a full-width at half-maximum, FWHM, of 29 nm and a photoluminescence quantum yield, ΦPL, of 70% and 53% for the symmetric and asymmetric counterparts, respectively, in toluene. Investigation in OLEDs demonstrated that the devices with Sym-DiDiKTa and Asym-DiDiKTa displayed electroluminescence maxima of 543 and 544 nm, and maximum external quantum efficiencies (EQEmax) of 9.8% and 10.5%, respectively. The maximum EQE was further improved to 19.9% by employing a hyperfluorescence strategy. We further present the first example of a neutral MR-TADF emitter incorporated in a LEC device where Sym-DiDiKTa acts as the emitter. The LEC shows a λEL at 551 nm and FWHM of 60 nm with luminance of 300 cd m−2 and a fast turn-on time of less than 2 s to 100 cd m−2
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| 2. |
- Lawrence, Samuel R., et al.
(författare)
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Hydrocarbon-soluble, hexaanionic fulleride complexes of magnesium
- 2019
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Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 10:46, s. 10755-10764
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Tidskriftsartikel (refereegranskat)abstract
- The reaction of the magnesium(i) complexes [{((Ar)nacnac)Mg}(2)], ((Ar)nacnac = HC(MeCNAr)(2), Ar = Dip (2,6-iPr(2)C(6)H(3)), Dep (2,6-Et2C6H3), Mes (2,4,6-Me3C6H2), Xyl (2,6-Me2C6H3)) with fullerene C-60 afforded a series of hydrocarbon-soluble fulleride complexes [{((Ar)nacnac)Mg}(n)C-60], predominantly with n = 6, 4 and 2. C-13{H-1} NMR spectroscopic studies show both similarities (n = 6) and differences (n = 4, 2) to previously characterised examples of fulleride complexes and materials with electropositive metal ions. The molecular structures of [{((Ar)nacnac)Mg}(n)C-60] with n = 6, 4 and 2 can be described as inverse coordination complexes of n [((Ar)nacnac)Mg](+) ions with C-60(n-) anions showing predominantly ionic metal-ligand interactions, and include the first well-defined and soluble complexes of the C-60(6-) ion. Experimental studies show the flexible ionic nature of the {((Ar)nacnac)Mg}+MIDLINE HORIZONTAL ELLIPSISC606- coordination bonds. DFT calculations on the model complex [{((Me)nacnac)Mg}(6)C-60] ((Me)nacnac = HC(MeCNMe)(2)) support the formulation as an ionic complex with a central C-60(6-) anion and comparable frontier orbitals to C-60(6-) with a small HOMO-LUMO gap. The reduction of C-60 to its hexaanion gives an indication about the reducing strength of dimagnesium(i) complexes.
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| 3. |
- Tyumentsev, Mikhail S, 1988, et al.
(författare)
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Crystal structure and identification of resonance forms of diethyl 2-(3-oxoiso-1,3-dihydrobenzo-furan-1-ylidene)malonate
- 2017
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Ingår i: Acta Crystallographica Section E: Crystallographic Communications. - 2056-9890. ; 73:10, s. 1576-1579
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Tidskriftsartikel (refereegranskat)abstract
- The reaction of diethyl malonate with phthaloyl chloride in acetonitrile in the presence of triethylamine and magnesium chloride results in the formation of the title compound, diethyl 2-(3-oxo-1,3-dihydro-2-benzofuran-1-ylidene)propanedioate, C15H14O6. One of the ester groups of the diethyl malonate fragment is almost coplanar with the isobenzofuran unit, while the plane of the other group is perpendicular to it [dihedral angles = 5.45 (3) and 83.30 (3)degrees, respectively]. The C-C and C-O distances both in the heterocyclic furan ring and the diethyl malonate fragment are indicative of the dipolar delocalization occurring within the isobenzofuran unit. This delocalization is likely to be responsible for the unusual intermolecular O center dot center dot center dot O contact [2.756 (2) angstrom], established between the O atom of the furan ring and the carbonyl O atom of the diethyl malonate fragment. In the crystal, weak C-H center dot center dot center dot O interactions are observed, which link the molecules into [100] chains.
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