636-32-8Relevant academic research and scientific papers
Exceptional aggregation-induced emission from one totally planar molecule
Yuan, Ying-Xue,Wu, Bai-Xing,Xiong, Jia-Bin,Zhang, Hong-Chao,Hu, Ming,Zheng, Yan-Song
, (2019)
Planar molecules usually display aggregation-caused quenching (ACQ). Here, it was found that a completely planar organic compound, 5,7,12,14-tetraoxapentacene A-D-A triad with carbon-oxygen bonds, had no fluorescence in high polar solvents but emitted strong light in suspension and in solid state, showed typical AIE effect. One novel AIE mechanism was disclosed by molecular packing in crystal state. In addition, its exceptional AIE effect showed great potential applications in fluorescent thermometer and highly sensitive sensor for selective detection of nitrophenolic compounds. The detection limit for 2,4,6-trinitrophenol was low to 0.168 nM.
Conjugated polymers with large effective stokes shift: Benzobisdioxole- based poly(phenylene ethynylene)s
Dutta, Tanmoy,Woody, Kathy B.,Parkin, Sean R.,Watson, Mark D.,Gierschner, Johannes
, p. 17321 - 17327 (2009)
Phenyleneethynylene-based conjugated copolymers using benzo[1,2-d:4,5- d′]bis[1,3]dioxole (BDO) in the repeating unit are reported. The electronic structure of the BDO unit imparts a localized HOMO topology while the LUMO is delocalized over the polymer backbone, so that the lowest optical absorption band of the polymer has considerable intramolecular charge transfer character. This contrasts with published donor-acceptor polymers with localized LUMO and delocalized HOMO. The very large Stokes shifts of the monomers, which are due to the small oscillator strength of the lowest optical transition, are largely retained in the polymers as a result of covalently constrained dihedral angles in the substituents (not the backbone), as predicted/explained by calculations.
1,2,4,5-Bis-(1,4,7,10,13,16-Hexaoxahexadecamethylene)Benzene: Benzo-Bis-(18-Crown-6)
Schlotter, Jacobus J. H.,Mertens, Ingrid J. A.,Wageningen, Andre M. A. van,Mulders, Frederik P. J.,Zwikker, Jan W.,et al.
, p. 7255 - 7258 (1994)
1,2,4,5-Bis-(1,4,7,10,13,16-hexaoxahexadecamethylene)benzene (1) is prepared in an one-pot synthesis from 2,5-dihydroxy-1,4-benzoquinone (4) and 1,14-dibromo-3,6,9,12-tetraoxatetradecane (3) in 35percent yield.A study of its host-guest 1:1 and 1:2 alkali metal cation complexation reveals that the cations only interact with the aliphatic oxygen lone pairs, hence, leaving the ?-electron system intact.
Convenient syntheses, spectroscopic and structural characterisation of bi-functional boranes
Aldridge,Calder,Cunningham,Malik,Steed
, p. 188 - 194 (2000)
The first examples of bi-functional borane derivatives based around a 1,2,4,5-tetrasubstituted benzene framework are reported. Synthesis of ClBO2C6H2O2BCl (4) is accomplished in three steps (69% overall yield) through the intermediacy of the trimethylsilyl derivative 1,2,4,5-(Me3SiO)4C6H2 (3). The bis(borane) species HBO2C6X2O2BH (X=H, 7; X=Cl, 8) on the other hand, can be synthesised in a single step from substituted para-quinone precursors. Crystal structures are reported for compounds 3 and 4.
Fabrication of soft submicrospheres by sequential boronate esterification and their dynamic behavior
Nishiyabu, Ryuhei,Teraoka, Shiori,Matsushima, Yusuke,Kubo, Yuji
, p. 201 - 209 (2012)
Pyridine-assisted sequential boronate esterification of benzene- 1,4-diboronic acid and 1,2,4,5-tetrahydroxybenzene has induced hierarchical molecular self-assembly, and in turn producing well-defined submicrospheres. Spectroscopic analyses such as FE-SEM, TEM, DLS, NMR, XRD, and IR absorption spectroscopy indicates that the particles are composed of lamellar structures of sp2-hybridized trigonal planar poly(dioxaborole). The spontaneous self-organization is ascribable to reactive layerby- layer assembly through sequential boronate esterification of the diboronic acid and the tetrahydroxybenzene whereby initially formed oligo(dioxaborole) may provide a platform for further reactions, thus resulting in the production of submicrospheres. It is interesting to note that the dynamic covalent functionality as a result of the dioxaborole linkage induced a stimuli-responsive change in morphology by not only a pH switch but also the exchange reaction with pentaerythritol. Further, a selective saccharide-induced change in the submicrosphere morphology was observed through a simple exchange reaction of dynamic covalent boronate esters with saccharides in THF; the selective change in morphology is visually detected through the color change in the solution. These findings can provide a useful insight into the design of stimuli-responsive hierarchical architectures based on boron-containing dynamic covalent bond.
DBD dyes as fluorescence lifetime probes to study conformational changes in proteins
Wawrzinek, Robert,Ziomkowska, Joanna,Heuveling, Johanna,Mertens, Monique,Herrmann, Andreas,Schneider, Erwin,Wessig, Pablo
, p. 17349 - 17357 (2013)
Previously, [1,3]dioxolo[4,5-f][1,3]benzodioxole (DBD)-based fluorophores used as highly sensitive fluorescence lifetime probes reporting on their microenvironmental polarity have been described. Now, a new generation of DBD dyes has been developed. Although they are still sensitive to polarity, in contrast to the former DBD dyes, they have extraordinary spectroscopic properties even in aqueous surroundings. They are characterized by long fluorescence lifetimes (10-20 ns), large Stokes shifts (≈100 nm), high photostabilities, and high quantum yields (>0.56). Here, the spectroscopic properties and synthesis of functionalized derivatives for labeling biological targets are described. Furthermore, thio-reactive maleimido derivatives of both DBD generations show strong intramolecular fluorescence quenching. This mechanism has been investigated and is found to undergo a photoelectron transfer (PET) process. After reaction with a thiol group, this fluorescence quenching is prevented, indicating successful bonding. Being sensitive to their environmental polarity, these compounds have been used as powerful fluorescence lifetime probes for the investigation of conformational changes in the maltose ATP-binding cassette transporter through fluorescence lifetime spectroscopy. The differing tendencies of the fluorescence lifetime change for both DBD dye generations promote their combination as a powerful toolkit for studying microenvironments in proteins. Polarity probes: New fluorescent dyes based on the [1,3]dioxolo[4,5-f ][1,3]benzodioxole (DBD) skeleton were developed, with fluorescence lifetimes that exhibit a pronounced sensitivity to the polarity of the microenvironment. Several biocompatible derivatives were prepared, and their application was demonstrated with two biochemical examples (see figure; MBP=maltose binding protein).
[M2(μ-OH)2(DHBQ)3] (M = Zr, Hf) - Two New Isostructural Coordination Polymers based on the Unique M2O14 Inorganic Building Unit and 2,5-Dioxido-p-benzoquinone as Linker Molecule
Poschmann, Mirjam P. M.,Reinsch, Helge,Stock, Norbert
, p. 436 - 441 (2021)
Two new isostructural porous coordination polymers (CPs) were obtained under solvothermal reaction conditions using 2,5-dihydroxy-p-benzoquinone (H2DHBQ) or 1,2,4,5-tetrahydroxybenzene (H4THB) as linker molecule and Zr4+ or Hf4+ salts. Highly crystalline compounds with composition [M2(μ-OH)2(DHBQ)3]·xH2O (M = Zr4+ or Hf4+, x = 0–3.6/3.3) were found in a wide temperature range (120–200 °C) and a reaction time of 70 h. The crystal structures were determined ab initio from powder X-ray diffraction data and the oxidation state of the linker was confirmed spectroscopically. The dinuclear inorganic building unit M2O14 is new for Zr- and Hf-CPs. For both compounds a full characterization was carried out, i.e. crystal structure determination, spectroscopic measurements, elemental- and thermogravimetric analyses. [M2(OH)2(DHBQ)3] (M = Zr4+ or Hf4+) is stable up to 250 and 220 °C, respectively. Water sorption measurements proofed an uptake of 3.6 mol H2O per mol and 3.3 mol H2O per mol, respectively.
An indirect generation of 1D MII-2,5-dihydroxybenzoquinone coordination polymers, their structural rearrangements and generation of materials with a high affinity for H2, CO2 and CH4
Abrahams, Brendan F.,Dharma, A. David,Dyett, Brendan,Hudson, Timothy A.,Maynard-Casely, Helen,Kingsbury, Christopher J.,McCormick, Laura J.,Robson, Richard,Sutton, Ashley L.,White, Keith F.
, p. 1339 - 1344 (2016)
A series of solid-state structural transformations are found to accompany desolvation of relatively simple coordination polymers to yield materials that exhibit unexpected gas sorbing properties. Reaction of 1,2,4,5-tetrahydroxybenzene with MII salts (M = Mg, or Zn) in an alcohol/water solution in the presence of air affords cis-MII(C6H2O4-II)(H2O)2·2H2O·xROH, (M = Mg, or Zn), crankshaft-like chains in which the absolute configurations of the chiral metal centres follow the pattern ?Δ Δ Λ Λ Δ Δ Λ Λ?, and are hydrogen bonded together to generate spacious channels. When crystals of the crankshaft chain are air dried the crystals undergo a single crystal-to-powder rearrangement to form linear trans-MII(C6H2O4-II)(H2O)2 chains. Further dehydration yields microporous solids that reversibly sorb H2, CH4 and CO2 with high sorption enthalpies.
Adsorption and dehydrogenation of tetrahydroxybenzene on Cu(111)
Bebensee, Fabian,Svane, Katrine,Bombis, Christian,Masini, Federico,Klyatskaya, Svetlana,Besenbacher, Flemming,Ruben, Mario,Hammer, Bjork,Linderoth, Trolle
, p. 9308 - 9310 (2013)
Adsorption of tetrahydroxybenzene (THB) on Cu(111) and Au(111) surfaces is studied using a combination of STM, XPS, and DFT. THB is deposited intact, but on Cu(111) it undergoes gradual dehydrogenation of the hydroxyl groups as a function of substrate temperature, yielding a pure dihydroxy-benzoquinone phase at 370 K. Subtle changes to the adsorption structure upon dehydrogenation are explained from differences in molecule-surface bonding.
Synthesis of Boroxine and Dioxaborole Covalent Organic Frameworks via Transesterification and Metathesis of Pinacol Boronates
Hamzehpoor, Ehsan,Jonderian, Antranik,McCalla, Eric,Perepichka, Dmitrii F.
supporting information, p. 13274 - 13280 (2021/09/07)
Boroxine and dioxaborole are the first and some of the most studied synthons of covalent organic frameworks (COFs). Despite their wide application in the design of functional COFs over the last 15 years, their synthesis still relies on the original Yaghi's condensation of boronic acids (with itself or with polyfunctional catechols), some of which are difficult to prepare, poorly soluble, or unstable in the presence of water. Here, we propose a new synthetic approach to boroxine COFs (on the basis of the transesterification of pinacol aryl boronates (aryl-Bpins) with methyl boronic acid (MBA) and dioxaborole COFs (through the metathesis of pinacol boronates with MBA-protected catechols). The aryl-Bpin and MBA-protected catechols are easy to purify, highly soluble, and bench-stable. Furthermore, the kinetic analysis of the two model reactions reveals high reversibility (Keq ～1) and facile control over the equilibrium. Unlike the conventional condensation, which forms water as a byproduct, the byproduct of the metathesis (MBA pinacolate) allows for easy kinetic measurements of the COF formation by conventional 1H NMR. We show the generality of this approach by the synthesis of seven known boroxine/dioxaborole COFs whose crystallinity is better or equal to those reported by conventional condensation. We also apply metathesis polymerization to obtain two new COFs, Py4THB and B2HHTP, whose synthesis was previously precluded by the insolubility and hydrolytic instability, respectively, of the boronic acid precursors.
