- Metal-Diamidobenzoquinone Frameworks via Post-Synthetic Linker Exchange
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Metal-organic frameworks with amidic linkers often exhibit exceptional physical properties, but, owing to their strong metal-nitrogen bonds, are exceedingly challenging to isolate through direct synthesis. Here, we report a route to access metal-diamidobenzoquinone frameworks from their dihydroxobenzoquinone counterparts via postsynthetic linker exchange. The parent compounds (Me2NH2)2[M2L3] (M = Zn, Mn; H2L = 2,5-dichloro-3,6-dihydroxo-1,4-benzoquinone) undergo linker exchange upon exposure to a solution of monodeprotonated 2,5-diamino-3,6-dibromo-1,4-benzoquinone or 2,5-diamino-3,6-dichloro-1,4-benzoquinone, proceeding through single-crystal-to-single-crystal reactions. The presence of both types of linker in the resulting frameworks is confirmed by a combination of NMR, Raman, and energy-dispersive X-ray (EDX) spectroscopies. Moreover, the extent of linker exchange in the Zn frameworks is quantified using 13C NMR spectroscopy, and spatially resolved EDX spectroscopy reveals the two types of linker to be homogeneously distributed within a crystal. Finally, we propose a tentative mechanism of linker exchange based on pKa measurements, considerations of framework solubility, and powder X-ray diffraction analysis. This work provides the first method to exchange organic linkers with different donor atoms in metal-organic frameworks and in doing so demonstrates exchange between linkers with donor atoms differing in acidity by a remarkable 11 units of pKa. Together, these results offer a potentially general synthetic strategy toward new materials with exotic metal-linker coordination modes.
- Liu, Lujia,Li, Liang,Ziebel, Michael E.,Harris, T. David
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- Organic compound, and organic electroluminescent device using same, and electronic device
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The invention relates to an organic compound with the structure shown as a formula 1, and belongs to the field of organic materials. In the formula 1, a ring A and a ring B are respectively and independently selected from unsubstituted aryl with the carbon atom number of 6-14 and unsubstituted heteroaryl with the carbon atom number of 5-12; Ar1, Ar2 and Ar3 are the same or different and are respectively and independently selected from substituted or unsubstituted alkyl with the carbon atom number of 1-20, substituted or unsubstituted aryl with the carbon atom number of 6-30, substituted or unsubstituted heteroaryl with the carbon atom number of 3-30 and substituted or unsubstituted cycloalkyl with the carbon atom number of 3-20; and L1, L2, L3, L4, L5 and L6 are respectively and independently selected from a single bond, a substituted or unsubstituted arylene with the carbon atom number of 6-30, and a substituted or unsubstituted heteroarylene with the carbon atom number of 3-30. When the organic compound is used as a light-emitting layer material of an electronic device, the light-emitting efficiency and the service life of the electronic device can be improved .
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Paragraph 0120-0123
(2021/06/12)
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- Organic compound, electronic component applying the same and electronic device
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The invention relates to an organic compound, an electronic component applying the same and an electronic device. The organic compound has a heterocyclic ring with a benzoxazole ring core as a parent structure, a benzoxazole series derivative molecule is
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Paragraph 0146-0149
(2021/07/17)
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- Tuning the optical and electronic properties of 4,8-disubstituted benzobisoxazoles via alkyne substitution
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In an effort to design new electron-deficient building blocks for the synthesis of conjugated materials, a series of new trans-benzobisoxazoles bearing halogen or alkynyl substituents at the 4,8-positions was synthesized. Additionally, the impact of these modifications on the optical and electronic properties was investigated. Theoretical calculations predicted that the incorporation of various alkynes can be used to tune the energy levels and band gaps of these small molecules. The targeted 4,8-disubstituted benzobisoxazoles were easily prepared in good yields using a two-step reaction sequence: Lewis acid catalyzed orthoester cyclization followed by Sonogashira cross-coupling. The experimentally determined HOMO values for these 4,8-disubstituted benzobisoxazoles ranged from -4.97 to -6.20 eV and showed reasonable correlation to the theoretically predicted values, with a percent deviation that ranged from 2.4-12.8%. However, the deviation between actual and predicted HOMO values was reduced to less than 3.5% when the theoretical values were extrapolated to the long-chain limit and compared to copolymers containing the 4,8-disubstituted benzobisoxazoles. Collectively, these results indicate that these 4,8-disubstituted trans-benzobisoxazoles can be used for the synthesis of new conjugated materials with electronic properties that are variable and predictable.
- Tlach, Brian C.,Tomlinson, Aimee L.,Bhuwalka, Achala,Jeffries-El, Malika
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experimental part
p. 8670 - 8681
(2011/12/22)
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- An efficient synthesis of 2,5-diamino-1,4-benzoquinone
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A novel and efficient synthesis of 2,5-diamino-1,4-benzoquinone is described. The reaction involves a palladium/charcoal hydrogenolysis as the key step and provides the desired product in only four steps and very good overall yield. Georg Thieme Verlag Stuttgart.
- Mereyala, Hari Babu,Chary, Mahankhali Venu,Kantevari, Srinivas
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p. 187 - 189
(2007/10/03)
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- Synthesis of 2,5-Disubstituted 3,6-Diamino-1,4-benzoquinones
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A general synthetic approach to a wide variety of 2,5-disubstituted 3,6-diamino-1,4-benzoquinones was developed.Bromanil was diaminated with ammonia, and adjacent NH2 and OH groups were protected as benzoxazoles by treatment with a carboxylic acid chloride followed by a polyphosphate ester cyclization-dehydration.The resulting 2,5-dibromobenzobis(oxazoles) were monolithiated by halogen-metal exchange with n-butyllithium and then reacted with a variety of electrophiles.The remaining bromide was replaced in a similar fashion.Alternatively the second bromide was replaced by reaction with ? allylnickel halide complexes.The benzoxazole protecting group could be hydrolyzed with zinc(II) chloride/HCl-aqueous ethanol under an inert atmostphere.Air oxidation of the resulting hydroquinone under neutral conditions gave the desired 2,5-disubstituted 3,6-diamino-1,4-benzoquinone in good to excellent overall yield.This method was used to synthesize precursors to the basic ring system of the mitomycin antineoplastic antibiotics.Acid hydrolysis of the benzoxazole protecting group under oxidizing conditions resulted in the production of 2,5-disubstituted 3,6-dihydroxy-1,4-benzoquinone.Methylation followed by reaction with ammonia gave the desired diaminoquinone.
- Hegedus, Louis S.,Odle, Roy R.,Winton, Peter M.,Weider, Paul R.
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p. 2607 - 2613
(2007/10/02)
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