- An unlikely DNA cleaving agent: A photo-active trinuclear Cu(II) complex based on hexaazatriphenylene
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This paper describes the synthesis of a trinuclear Cu(II) complex (4) containing a central 1,4,5,8,9,12-hexaazatriphenylene-hexacarboxylate (hat) core (3). Low, micromolar concentrations of the negatively charged parent ligand 3 and the neutral trinuclear complex 4 were found to photocleave negatively charged pUC19 plasmid DNA with high efficiency at neutral pH (350?nm, 50?min, 22?°C). The interactions of complex 4 with double-helical DNA were studied in detail. Scavenger and colorimetric assays pointed to the formation of Cu(I), superoxide anion radicals, hydrogen peroxide, and hydroxyl radicals during photocleavage reactions. UV–visible absorption, circular dichroism, DNA thermal denaturation, and fluorescence data suggested that the Cu(II) complex contacts double-stranded DNA in an external fashion. The persistent association of ligand 3 and complex 4 with Na(I) and/or other cations in aqueous solution might facilitate electrostatic DNA interactions.
- Williams, Dominique E.,Fischer, Christina M.,Kassai, Miki,Gude, Lourdes,Fernández, María-José,Lorente, Antonio,Grant, Kathryn B.
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- Anion-π recognition between [M(CN)6]3? complexes and HAT(CN)6: structural matching and electronic charge density modification
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Hexacyanidometalates (M = FeIII, CoIII) and multisite anion receptor HAT(CN)6 (1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile) recognize each other in acetonitrile solution and self-assemble into the novel molecular networks (PPh4)3[M(CN)6][HAT(CN)6] (M = Fe, 1; Co, 2) and (AsPh4)3[M(CN)6][HAT(CN)6]·2MeCN·H2O (M = Fe, 3; Co, 4). 1-4 contain the stacked columns {[M(CN)6]3?;[HAT(CN)6]}∞ separated by the organic cations. All of the M-C≡N vectors point collectively towards the centroids of pyrazine rings on neighboring HAT(CN)6 molecules, with Ncyanide?centroidpyrazine distances that are under 3 ?. The directional character and structural parameters of the new supramolecular synthons correspond to collective triple anion-π interactions between the CN? ligands of the metal complexes and the π-deficient areas of HAT(CN)6. Physicochemical characterisation (IR spectroscopy, UV-Vis spectroscopy, cyclic voltammetry) and dispersion-corrected DFT studies reveal the dominating charge-transfer (CT) and polarisation characters of the interactions. The electronic density flow occurs from the CN? ligands of [M(CN)6]3? to the HAT(CN)6 orbital systems and further, toward the peripheral-CN groups of HAT(CN)6. Solid-state DFT calculations determined the total interaction energy of HAT(CN)6 to be ca. ?125 kcal mol?1, which gives ca. ?15 kcal mol?1 per one CN??HAT(CN)6 contact after subtraction of the interaction with organic cations. The UV-Vis electronic absorption measurements prove that the intermolecular interactions persist in solution and suggest a 1?:?1 composition of the anion-π {[M(CN)6]3?;[HAT(CN)6]} chromophore, with the formation constant Kadd = (5.8 ± 6) × 102 dm3 mol?1 and the molar absorption coefficient εadd = 180 ± 9 cm?1 dm3 mol?1 at 600 nm, as estimated from concentration-dependent studies.
- Kobylarczyk, Jedrzej,Pinkowicz, Dawid,Srebro-Hooper, Monika,Hooper, James,Podgajny, Robert
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- Synthesis and mesomorphic behavior of a donor-acceptor-type hexaazatriphenylene
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(Chemical Equation Presented) A new donor-acceptor, 1,4,5,8,9,12- hexaazatriphenylene HATCNORn, is described. The synthesis of HATCNOR1 and HATCNOR6 is achieved by the regioselective displacement of 1,4,5,8,9,12-hexaazatriphenylene hexacarbonitrile (HATCN) with an alkoxy group. The X-ray analysis revealed self-assembly of HATCNOR 1 in the solid state. HATCNOR6 is the new difunctionalized hexaazatriphenylene discotic liquid crystal.
- Chang, Tsu-Hsin,Wu, Bi-Ru,Chiang, Michael Y.,Liao, Su-Chih,Ong, Chi Wi,Hsu, Hsiu-Fu,Lin, Shu-Yu
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- In Situ Doping Strategy for the Preparation of Conjugated Triazine Frameworks Displaying Efficient CO2 Capture Performance
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An in situ doping strategy has been developed for the generation of a novel family of hexaazatriphenylene-based conjugated triazine frameworks (CTFs) for efficient CO2 capture. The resulting task-specific materials exhibit an exceptionally high CO2 uptake capacity (up to 4.8 mmol g-1 at 297 K and 1 bar). The synergistic effects of ultrananoporosity and rich N/O codoped CO2-philic sites bestow the framework with the highest CO2 adsorption capacity among known porous organic polymers (POPs). This innovative approach not only enables superior CO2 separation performance but also provides tunable control of surface features on POPs, thereby affording control over bulk material properties. We anticipate this novel strategy will facilitate new possibilities for the rational design and synthesis of nanoporous materials for carbon capture.
- Zhu, Xiang,Tian, Chengcheng,Veith, Gabriel M.,Abney, Carter W.,Dehaudt, Jérémy,Dai, Sheng
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- Mechanochemically Assisted Synthesis of Hexaazatriphenylenehexacarbonitrile
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1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HAT CN) was synthesized mechanochemically at room temperature. The coupling of hexaketocyclohexane and diaminomaleonitrile was conducted in 10 min by vibratory ball milling. The effects of milling parameters, acids, dehydrating agents, and liquid-assisted grinding were rationalized. With 67%, the yield of this mechanochemical approach exceeds that of state-of-the-art wet-chemical syntheses while being superior with respect to time-, resource-, and energy-efficiency as quantified via green metrics.
- Pickhardt, Wilm,Wohlgemuth, Maximilian,Gr?tz, Sven,Borchardt, Lars
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- Constructing a self-assembling C3-symmetric covalently linked (fused) donor-acceptor-type molecule containing a hexaazatriphenylene core
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A C3-symmetric covalently linked (fused) molecule, HAT-IPN, comprising a 13 fused ring system was synthesized by a condensation-cyclisation reaction between hexaazatriphenylenehexacarboxylic acid trisanhydride and 4,5-diamino-1,2-dioctyloxybenzene. This fused system exhibits ambipolar behaviour due to an n-type HAT-core at the center and three outer p-type fused dialkoxybenzimidazole moieties, which is confirmed by cyclic voltammetry. The self-assembling nature of this disc-shaped donor-acceptor type system is evident in13C NMR spectroscopy, dynamic light scattering studies, differential scanning calorimetry and atomic force microscopy (AFM) images, which illustrate the formation of the one-dimensional aggregates both in solution and in the film state; indicating its potential as an active component in organic electronic devices.
- Bhanvadia, Viraj J.,Patel, Arun L.,Zade, Sanjio S.
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- Template- and Metal-Free Synthesis of Nitrogen-Rich Nanoporous “Noble” Carbon Materials by Direct Pyrolysis of a Preorganized Hexaazatriphenylene Precursor
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The targeted thermal condensation of a hexaazatriphenylene-based precursor leads to porous and oxidation-resistant (“noble”) carbons. Simple condensation of the pre-aligned molecular precursor produces nitrogen-rich carbons with C2N-type stoichiometry. Despite the absence of any porogen and metal species involved in the synthesis, the specific surface areas of the molecular carbons reach up to 1000 m2 g?1 due to the significant microporosity of the materials. The content and type of nitrogen species is controllable by the carbonization temperature whilst porosity remains largely unaffected at the same time. The resulting noble carbons are distinguished by a highly polarizable micropore structure and have thus high adsorption affinity towards molecules such as H2O and CO2. This molecular precursor approach opens new possibilities for the synthesis of porous noble carbons under molecular control, providing access to the special physical properties of the C2N structure and extending the known spectrum of classical porous carbons.
- Walczak, Ralf,Kurpil, Bogdan,Savateev, Aleksandr,Heil, Tobias,Schmidt, Johannes,Qin, Qing,Antonietti, Markus,Oschatz, Martin
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- Improved synthesis of 1,4,5,8,9,12-hexaazatriphenylenehexacarboxylic acid
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The synthesis of hexaazatriphenylene (HAT) derivatives, including the title compound, have been reported previously. However, due to problems with purity, low yields and expensive solvents, their potential utility has yet to be fully realized. We now report the improved synthesis of HAT derivatives in good yields, high purity, and without the use of expensive solvents.
- Rademacher,Kanakarajan,Czarnik
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- Nitrogen-rich microporous carbon materials for high-performance membrane capacitive deionization
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Novel two-dimensional carbon nitride hexagonal-like sheets were fabricated from thermal condensation, which uses hexaazatriphenylene-based precursor prepared microporous and oxidation resistant carbons materials (HAT-CN). The results show that the as-prepared HAT-CN is the first electrode utilized in capacitive deionization, due to the rich heteroatom and border-group content, as well as the potential collaborative effect of C and N atoms, displaying the quick ion diffusion and strong charge transfer performance. Additionally, the capacitive deionization performance of HAT-CN is improved by the synergistic contribution of a large accessible surface area, large pore volume, and high graphitization. The electrode of HAT-CN was carbonized at 550 °C which display an excellent specific capacitance of 179.2 F g?1 in 1-M NaCl solution at a scan rate of 5 mV s?1. Subsequently, a high salt adsorption capacity of 24.66 mg g?1 was attained for an applied voltage of 1.2 V in 500 mg L?1 NaCl solution, showing good cyclic stability at 30 cycles. Considering those excellent properties of the prepared HAT-CN, the capacitive deionization electrode should be an ideal candidate for high-performance deionization application.
- Li, Danping,Ning, Xun-an,Huang, Yue,Li, Shengchuan
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- Discotic liquid crystals as electron carrier materials
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A series of five new hexaalkylthiohexaazatriphenylenes 2a-e has been synthesized. Their thermotropic behaviour has been investigated and compared with the corresponding series of hexaalkylthiotriphenylenes 1a-e and hexaalkylthiohexaazatrinaphthylenes 3a-e. Unexpectedly, hexaalkylthiohexaazatriphenylenes 2a-e, hexaalkylthiotriphenylenes 1d-e and hexaalkylthiohexaazatrinaphthylenes 3e, do not form columnar liquid crystalline mesophases.
- Roussel, Olivier,Kestemont, Gael,Tant, Julien,De Halleux, Veronique,Aspe, Rafael Gomez,Levin, Jeremy,Remacle, Adrienne,Gearba, Iona Raluca,Ivanov, Dimitri,Lehmann, Matthias,Geerts, Yves
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- Synthesis and Some Reactions of Hexaazatriphenylenehexacarbonitrile, a Hydrogen-Free Polyfunctional Heterocycle with D3h Symmetry
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In this paper, we report for the first time the synthesis of hexaazatriphenylenehexacarbonitrile, abbreviated HAT-hexacarbonitrile.This hydrogenless, symmetrically branched compound can be prepared in analytically pure form on a large scale by using commercially available starting materials.The conversions of HAT-hexacarbonitrile to the corresponding hexaamide, hexaacid, hexaester, and trianhydride derivatives were also accomplished.
- Kanakarajan, K.,Czarnik, Anthony W.
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- Different nature of the interactions between anions and HAT(CN) 6: From reversible anion-π complexes to irreversible electron-transfer processes (HAT(CN)6 = 1,4,5,8,9,12- hexaazatriphenylene)
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We report experimental evidence indicating that the nature of the interaction established between HAT(CN)6, a well-known strong electron acceptor aromatic compound, with mono-or polyatomic anions switches from the almost exclusive formation of reversible anion-π complexes, featuring a markedly charge transfer (CT) or formal electron-transfer (ET) character, to the quantitative and irreversible net production of the anion radical [HAT(CN)6]?- and the dianion [HAT(CN) 6]2- species. The preferred mode of interaction is dictated by the electron donor abilities of the interacting anion. Thus, weaker Lewis basic anions such as Br- or I- are prone to form mainly anion-π complexes. On the contrary, stronger Lewis basic F- or -OH anions display a net ET process. The ET process can be either thermal or photoinduced depending on the HOMO/LUMO energy difference between the electron donor (anion) and the electron acceptor (HAT(CN)6). These ET processes possibly involve the intermediacy of anion-π complexes having strong ET character and producing an ion-pair radical complex. We hypothesize that the irreversible dissociation of the pair of radicals forming the solvent-caged complex is caused by the reduced stability (high reactivity) of the radical resulting from the anion.
- Aragay, Gemma,Frontera, Antonio,Lloveras, Vega,Vidal-Gancedo, José,Ballester, Pablo
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- Ultrafast photoinduced electron transfer in face-to-face charge-transfer π-complexes of planar porphyrins and hexaazatriphenylene derivatives
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Charge-transfer (CT) π-complexes are formed between planar porphyrins and 1,4,5,8,9,12-hexaazatriphenylene (HAT) derivatives with large formation constants (e.g., 104 M-1), exhibiting broad CT absorption bands. The unusually large formation constants result from close face-to-face contact between two planar π-planes of porphyrins and HAT derivatives. The redox potentials of porphyrins and HAT derivatives measured by cyclic voltammetry indicate that porphyrins and HAT derivatives act as electron donors and acceptors, respectively. The formation of 1:1 CT complexes between porphyrins and HAT derivatives was examined by UV-vis, fluorescence and 1H NMR measurements in nonpolar solvents. The occurrence of unprecedented ultrafast photoinduced electron transfer from the porphyrin unit to the HAT unit in the CT π-complex was observed by femtosecond laser flash photolysis measurements. A highly linear aggregate composed of a planar porphyrin and an HAT derivative was observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM).
- Aoki, Toru,Sakai, Hayato,Ohkubo, Kei,Sakanoue, Tomo,Takenobu, Taishi,Fukuzumi, Shunichi,Hasobe, Taku
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p. 1498 - 1509
(2015/02/05)
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