- Bodipy dyes bearing oligo(ethylene glycol) groups on the meso-phenyl ring: Tuneable solid-state photoluminescence and highly efficient OLEDs
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Borondipyrromethene (Bodipy) dyes with strong solid-state photoluminescence are highly desirable for their applications in OLEDs. In this work, a series of meso-(4-R-C6H4)-substituted Bodipy dyes (R = H for B1; R = (OCH2CH2)nOCH2CH3, n = 0-3 for B2-B5, respectively) were prepared through an acid-catalyzed reaction. The flexible ether groups attached to the periphery of B2-B5 are expected to influence the molecular arrangement and intermolecular interactions in solid state. Crystallographic analysis of B1-B4 reveals that the meso-phenyl ring is almost orthogonal to the indacene plane. Intermolecular π-π interactions are observed in B1 but absent in B2-B4. As a consequence, the dye B1 is weakly emissive in solid state, while B2-B4 emit strongly in the red region with emission quantum yields of up to 0.33. The PMMA films doped with B2 show two separated emission peaks, and their relative intensity is concentration dependent, leading to the fluorescence color varying from greenish yellow to red as the concentrations successively increased from 5 to 80 wt%. The formation of dimers in the ground state is found to be responsible for the red emission in the condensed state. Efficient OLEDs were fabricated by doping 2 wt% B2-B4 as emitters and gave high luminance, current efficiency, and external quantum efficiency of up to 920 cd m-2, 8.00 cd A-1, and 2.15%, respectively. This journal is the Partner Organisations 2014.
- Liu, Cui-Lian,Chen, Yong,Shelar, Deepak P.,Li, Cong,Cheng, Gang,Fu, Wen-Fu
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supporting information
p. 5471 - 5478
(2014/07/08)
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- The effect of polyether terminal chains in the liquid crystalline behavior of ortho-palladated complexes
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A series of benzylideneanilines bearing terminal polyether chains, HL (HL = R-C6H4-CHN-C6H4-R′: R = OC8H17, R′ = O(CH2CH2O) 2C2H5; R = O(CH2CH 2O)2C2H5, R′ = OC 8H17; R = R′ = O(CH2CH2O) 2C2H5; R = OC12H25, R′ = O(CH2CH2O)3C2H 5; R = O(CH2CH2O)3C 2H5, R′ = OC12H25; R = R′ = O(CH2CH2O)3C2H 5) have been prepared. Their dinuclear, [Pd(μ-X)L]2 (X = OAc, Cl, Br, SC8), [Pd2(μ-SCn)(μ-X)L2] (X = OAc, Cl; n = 8, 2) and mononuclear orthopalladated derivatives, Pd(acac)L, Pd(Ala)L, are reported and their mesogenic properties are compared with those of the analogous compounds with alkoxy chains. In general a great lowering in the melting points is produced for all the products. The free ligands and the alanine complexes are not liquid crystals. The chloro-bridged complexes bearing alkoxy and short polyether chains (O(CH2CH2O) 2C2H5) show the larger improvement of mesogenic properties. Longer polyether chains (O(CH2CH2O) 3C2H5) result usually in a destabilization of the mesophases. If only polyether chains are present, the destabilization is important regardless of the chain length. The ability of these molecules as ionic extractants and transporters was qualitatively evaluated for the more propitious cis-dinuclear complexes, which in fact showed some extracting ability, modest but improved compared to the free ligands.
- Baena,Buey,Espinet,García-Prieto
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p. 998 - 1010
(2007/10/03)
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- MACROHETEROCYCLES. XLIII. SYNTHESIS OF (3N+1)-CROWN-n ETHERS
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The condensation of substituted bispropane-1,3-diols with di-p-tosyloxy derivatives of polyethyleneglycols gave the corresponding bis-(3n+1)-crown-n ethers.The products mostly form complexes of the "sandwich" type with the cations of alkali and alkaline-earth metals.
- Luk'yanenko, N. G.,Mel'nik, O. T.
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p. 1975 - 1983
(2007/10/02)
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