- Exploiting excited-state aromaticity to design highly stable singlet fission materials
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Singlet fission, the process of forming two triplet excitons from one singlet exciton, is a characteristic reserved for only a handful of organic molecules due to the atypical energetic requirement for low energy excited triplet states. The predominant strategy for achieving such a trait is by increasing ground state diradical character; however, this greatly reduces ambient stability. Herein, we exploit Baird's rule of excited state aromaticity to manipulate the singlet-triplet energy gap and create novel singlet fission candidates. We achieve this through the inclusion of a [4n] 5-membered heterocycle, whose electronic resonance promotes aromaticity in the triplet state, stabilizing its energy relative to the singlet excited state. Using this theory, we design a family of derivatives of indolonaphthyridine thiophene (INDT) with highly tunable excited state energies. Not only do we access novel singlet fission materials, they also exhibit excellent ambient stability, imparted due to the delocalized nature of the triplet excited state. Spin-coated films retained up to 85% activity after several weeks of exposure to oxygen and light, while analogous films of TIPS-pentacene showed full degradation after 4 days, showcasing the excellent stability of this class of singlet fission scaffold. Extension of our theoretical analysis to almost ten thousand candidates reveals an unprecedented degree of tunability and several thousand potential fission-capable candidates, while clearly demonstrating the relationship between triplet aromaticity and singlet-triplet energy gap, confirming this novel strategy for manipulating the exchange energy in organic materials.
- Fallon, Kealan J.,Budden, Peter,Salvadori, Enrico,Ganose, Alex M.,Savory, Christopher N.,Eyre, Lissa,Dowland, Simon,Ai, Qianxiang,Goodlett, Stephen,Risko, Chad,Scanlon, David O.,Kay, Christopher W. M.,Rao, Akshay,Friend, Richard H.,Musser, Andrew J.,Bronstein, Hugo
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- STRUCTURE OF TYRIVERDIN, THE IMMEDIATE PRECURSOR OF TYRIAN PURPLE
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Stereoisomeric tyriverdins A and B were isolated from Thais clavigera.The former, which is identical with tyriverdin isolated by Baker, was confirmed by 13C-NMR spectrum to be 2,2'-bis(methylthio)-6,6'-dibromo-2,2'-diindoxyl.None of these compounds are detected in the gastropod, suggesting that they are formed during the isolation process probably from tyrindoxyl sulfate, a genuine constituent.
- Fujise, Yutaka,Miwa, Katsuyuki,Ito, Sho
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- Synthesis and properties of indigo based donor-acceptor conjugated polymers
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Indigo is for the first time used as a building block to construct polymer semiconductors for organic thin film transistors (OTFTs). Two donor-acceptor polymers using indigo as the acceptor and bithiophene as the donor are synthesized via Stille coupling polymerization. Two types of acyl groups, 2-hexldecanoyl (for polymer P1) and 2-octyldodecanoyl (for polymer P2), are utilized as solubilizing side chains. These polymers possess very deep highest-occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, due to the strong electron accepting capability of the indigo moiety. In OTFT devices, characteristic n-type semiconductor performance with electron mobility of up to ~10-3 cm2 V-1 s-1 is observed.
- Guo, Chang,Sun, Bin,Quinn, Jesse,Yan, Zhuangqing,Li, Yuning
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- Indigo-Based Acceptor Type Small Molecules: Synthesis, Electrochemical and Optoelectronic Characterizations
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In this paper, we report design and synthesis of novel low bandgap small molecules, indigo-benzimidazole (Tyr-3) and indigo-schiff base (Tyr-4) type acceptors. In these structures, tert-butoxycarbonyl (t-BOC) group has been attached to indigo nitrogen ato
- Saltan, G?zde Murat,K?ymaz, Deniz Aykut,Zafer, Ceylan,Din?alp, Haluk
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- Air-stable organic semiconductors based on 6,6′-dithienylindigo and polymers thereof
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Herein we report on the synthesis and properties of 6,6′-dithienylindigo (DTI), as well as its solubilized N,N′-di(tert-butoxy carbonyl) derivative (tBOC-DTI). tBOC-DTI can be electropolymerized and thermally interconverted into films of poly(DTI). Thin films of DTI afford quasi-reversible 2-electron reduction and oxidation electrochemistry, and demonstrate ambipolar charge transport in organic field-effect transistors with a hole mobility of up to 0.11 cm2 V-1 s-1 and an electron mobility of up to 0.08 cm2 V-1 s-1. Operation of the p-channel shows excellent air stability, with minimal degradation over a 60 day stressing study. Poly(DTI) can be reversibly oxidized and reduced over hundreds of cycles while remaining immobilized on the working electrode surface, and additionally shows a pronounced photoconductivity response in a diode device geometry. This work shows the potential of extended indigo derivatives for organic electronic applications, demonstrating impressive stability under ambient conditions. This journal is
- G?owacki,Apaydin,Bozkurt,Monkowius,Demirak,Tordin,Himmelsbach,Schwarzinger,Burian,Lechner,Demitri,Voss,Sariciftci
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- Tyrian purple precursors in the egg masses of the Australian muricid, Dicathais orbita: A possible defensive role
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We report a putative defensive role for the precursors of Tyrian purple in the egg masses of the Australian muricid, Dicathais orbita. The fresh egg masses contain a high proportion of tyrindoleninone, which reacts to form tyriverdin and subsequently Tyrian purple and 6-bromoisatin as the eggs develop and the larvae hatch. Antimicrobial testing revealed that tyrindoleninone is toxic to both marine and human pathogens at a concentration of 1 mg/ml. Tyriverdin inhibits the growth of two marine pathogens, as well as the yeast Candida albicans at 0.001 mg/ml and was effectively bacteriostatic at 0.0005 mg/ml against three human pathogenic bacteria. Tyriverdin did not appear to significantly lyse the microbial cells. 6-Bromoisatin has mild antimicrobial properties, whereas Tyrian purple exhibited no significant activity. The antimicrobial properties of these compounds and changes in their presence during egg development correlates with ripening in the egg masses of D. orbita. This is the first report of the chemical ripening of eggs in a marine environment.
- Benkendorff, Kirsten,Bremner, John B.,Davis, Andrew R.
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- An indigo-based polymer bearing thermocleavable side chains for n-type organic thin film transistors
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A new n-type semiconducting polymer based on indigo having thermocleavable tert-butoxycarbonyl (t-Boc) groups was synthesized and used as an active layer in organic thin film transistors (OTFTs). Twisting of the polymer main chain due to the presence of the bulky t-Boc groups renders this indigo-based polymer highly soluble. A post-deposition thermal treatment at a temperature above 170 °C could remove the t-Boc groups to retrieve the highly coplanar geometry of the unsubstituted indigo units. The thermally annealed polymer semiconductor films at 200 °C showed an electron mobility of up to ~6 × 10-3 cm2 V-1 s-1 in OTFTs, which is a 5-fold increase compared to that of the indigo-based polymers reported previously due to the retrieved high backbone coplanarity. This journal is
- Guo, Chang,Quinn, Jesse,Sun, Bin,Li, Yuning
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- Design of indigo derivatives as environment-friendly organic semiconductors for sustainable organic electronics
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We report the synthesis and systematic investigation of nine different indigo derivatives as promising materials for sustainable organic electronics. It has been shown that chemical design allows one to tune optoelectronic properties of indigoids as well
- Klimovich,Leshanskaya,Troyanov,Anokhin,Novikov,Piryazev,Ivanov,Dremova,Troshin
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- A tunable synthesis of indigoids: Targeting indirubin through temperature
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The spontaneous conversion of 3-indoxyl to indigo is a well-established process used to produce indigo dyes. It was recently shown that some indoles, when reacted with molybdenum hexacarbonyl and cumyl peroxide, proceed through an indoxyl intermediate to produce significant amounts of indirubin through a competing mechanism. Modulation of this system to lower temperatures allows for careful tuning, leading to selective production of indirubins in a general process. A systematic assay of indoles show that electron deficient indoles work well when substituted at the 5 and 7 positions. In contrast, 6-substituted electron rich indoles give the best results whereas halogeno indoles work well in all cases. This process shows broad functional group tolerance for generally reactive carbonyl-containing compounds such as aldehydes and carboxylic acids. This journal is
- Cheek, Joshua T.,Horner, John S.,Kaller, Kaylie S.,Kinsey, Ally L.,Shriver, James A.,Sterrenberg, Summer R.,Van Vors, Madison K.,Wang, Katelyn R.
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p. 5407 - 5414
(2022/03/01)
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- Indigoid dyes by group e monooxygenases: Mechanism and biocatalysis
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Since ancient times, people have been attracted by dyes and they were a symbol of power. Some of the oldest dyes are indigo and its derivative Tyrian purple, which were extracted from plants and snails, respectively. These 'indigoid dyes' were and still are used for coloration of textiles and as a food additive. Traditional Chinese medicine also knows indigoid dyes as pharmacologically active compounds and several studies support their effects. Further, they are interesting for future technologies like organic electronics. In these cases, especially the indigo derivatives are of interest but unfortunately hardly accessible by chemical synthesis. In recent decades, more and more enzymes have been discovered that are able to produce these indigoid dyes and therefore have gained attention from the scientific community. In this study, group E monooxygenases (styrene monooxygenase and indole monooxygenase) were used for the selective oxygenation of indole (derivatives). It was possible for the first time to show that the product of the enzymatic reaction is an epoxide. Further, we synthesized and extracted indigoid dyes and could show that there is only minor by-product formation (e.g. indirubin or isoindigo). Thus, group E monooxygenase can be an alternative biocatalyst for the biosynthesis of indigoid dyes.
- Heine, Thomas,Gro?mann, Carolin,Hofmann, Sarah,Tischler, Dirk
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p. 939 - 950
(2019/03/19)
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- High-Performance Ambipolar Polymers Based on Electron-Withdrawing Group Substituted Bay-Annulated Indigo
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For donor–acceptor conjugated polymers, it is an effective strategy to improve their electron mobilities by introducing electron-withdrawing groups (EWGs, such as F, Cl, or CF3) into the polymer backbone. However, the introduction of different EWGs always requires a different synthetic approach, leading to additional arduous work. Here, an effective two-step method is developed to obtain EWG substituted bay-annulated indigo (BAI) units. This method is effective to introduce various EWGs (F, Cl, or CF3) into BAI at different substituted positions. Based on this method, EWG substituted BAI acceptors, including 2FBAI, 2ClBAI, and 2CF3BAI, are reported for the first time. Furthermore, four polymers of PBAI-V, P2FBAI-V, P2ClBAI-V, and P4OBAI-V are developed. All the polymers show ambipolar transport properties. Particularly, P2ClBAI-V exhibits remarkable hole and electron mobilities of 4.04 and 1.46 cm2 V?1 s?1, respectively. These mobilities are among the highest values for BAI-based polymers.
- Yang, Jie,Jiang, Yaqian,Tu, Zeyi,Zhao, Zhiyuan,Chen, Jinyang,Yi, Zhengran,Li, Yifan,Wang, Shuai,Yi, Yuanping,Guo, Yunlong,Liu, Yunqi
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- Ambipolar organic phototransistors based on 6,6′-dibromoindigo
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Ambipolar organic phototransistors were fabricated using a natural pigment 6,6′-dibromoindigo (6-BrIG) as the active channel. These phototransistors yielded significantly enhanced currents upon light illumination with photoresponsivities and external quantum efficiencies as high as 10.3 A W-1 and 2437% for the n-channel, and 55.4 mA W-1 and 13.1% for the p-channel, respectively. In addition, simple inverter complementary circuits were fabricated by integrating two ambipolar phototransistors. Channel current was dependent on light intensity and voltage bias. This study provides a basis for an in-depth understanding of the optoelectronic characteristics of 6-BrIG, and introduces this material as an ecofriendly candidate for optoelectronic applications.
- Kim, Hyoeun,Kim, Gyoungsik,Song, Inho,Lee, Jungho,Abdullah, Hanum,Yang, Changduk,Oh, Joon Hak
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p. 14747 - 14752
(2018/04/30)
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- Bromo-substituted cibalackrot backbone, a versatile donor or acceptor main core for organic optoelectronic devices
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Cibalackrot (Ci-I), one of the latest highly conjugated compound possessing bis-lactam structure, was investigated with respect to their brominated derivatives in order to determine their suitable substitution points for the syntheses of new class of small molecules for optoelectronic devices. 7,14-Bis(4-bromophenyl) (Ci-II) and 3,10-dibromo (Ci-III) derivatives of cibalackrot possess moderately narrow band gaps of 2.15 and 2.09 eV, respectively. Notably, Ci-III dye exhibits more red-shifted ultraviolet–visible (UV–vis) absorption and fluorescence emission spectra as compared to that of Ci-II dye because Ci-III shows more prominent intramolecular charge transfer (ICT) complex than that of Ci-II dye. Electron mobilities of the order of 7.0 × 10?4 cm2/V and 3.1 × 10?4 cm2/V were measured using Ci-II and Ci-III as active layer, respectively. Charge transfer properties of the molecules were investigated in bulk heterojunction device configuration wherein Ci-III showed p-type behavior against n-type PCBM in photovoltaic device. Photovoltaic performance of Ci-III dye which was used as donor component is 20 times higher than that of the device in which this dye was used as acceptor.
- Din?alp, Haluk,Saltan, G?zde Murat,Zafer, Ceylan,K?ymaz, Deniz Aykut
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p. 512 - 520
(2018/09/14)
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- Nanowires of indigo and isoindigo-based molecules with thermally removable groups
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In this manuscript, indigo and isoindigo-based π-conjugated molecules with thermal removable tert-butoxycarbonyl (t-Boc) side groups were designed and synthesized. It was noted that the t-Boc side groups can be eliminated in nearly quantitative yields after thermal treatment at 200°C for 15 min, as confirmed by thermogravimetric analysis and Fourier transform infrared spectroscopy. From the thermal treated solution of isoindigo-based molecule DTIIC8C12 in the co-solvent of 1,2-dichlorobenzene/pyridine with volume ratio of 10/90, one-dimensional nanowires can be formed due to the hydrogen bonding assisted self-assembly. The afforded nanowires exhibited a moderate hole mobility of 1.3 × 10-3 cm2 V-1 s-1, as estimated from the organic field effect transistors. These observations illustrated that the utilization of thermal removable side chain functionalized conjugated polymers can be an effective strategy for developing conjugated polymers with impressive charge carrier transport.
- Liu, Chunchen,Xu, Wenzhan,Xue, Qifan,Cai, Ping,Ying, Lei,Huang, Fei,Cao, Yong
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- 6, 6'-dibromoindigo manufacturing method
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PROBLEM TO BE SOLVED: To provide a method for stably producing 6,6'-dibromoindigo at a high yield. SOLUTION: The method for producing 6,6'-dibromoindigo includes a process in which a base is added to a mixed liquid, which contains 4-bromo-2-nitrobenzaldehyde, acetone and water, to gain 6,6'-dibromoindigo. In this case, the pH of the mixed liquid is at least 12 and at most 14 immediately after the base addition. COPYRIGHT: (C)2013,JPOandINPIT
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Paragraph 0015; 0027-0029; 0034; 0036
(2016/12/16)
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- A simple, safe and efficient synthesis of Tyrian purple (6,6'-Dibromoindigo)
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6,6'-Dibromoindigo is a major component of the historic pigment Tyrian purple, arguably the most famous dye of antiquity. Over the last century, chemists have been interested in developing practical syntheses of the compound We describe herein a new, reasonably simple and efficient synthesis of Tyrian purple which opens the way to the production of large quantities of the dye with minimal hazards and at low cost.
- Wolk, Joel L.,Frimer, Aryeh A.
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experimental part
p. 5561 - 5580
(2010/12/20)
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- NMR spectroscopic study of the Murex trunculus dyeing process
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It is widely accepted that indigo dyes derived from Murex trunculus were used to produce the biblical dyes tekhelet and argaman. We describe a method of following the debromination of natural leucoindigos and their binding to wool using NMR spectroscopy. Debromination is observed prior to reaction with the wool and prior to oxidation. Binding to the wool is shown to occur prior to oxidation. NMR allows the dyeing process to be followed. This, in principle, could be used to correct problems during dyeing that would increase the reliability of the process. Copyright
- Hoffman, Rina C.,Zilber, Reut C.,Hoffman, Roy E.
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scheme or table
p. 892 - 895
(2011/09/16)
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- An improved synthetic procedure for 6,6′-dibromoindigo (Tyrian purple)
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Tyrian purple was the most precious dye of antiquity. We describe a simple synthetic procedure that yields the actual dye, 6,6′-dibromoindigo 1, in considerably improved overall yield and of analytical purity, also being amenable to scale-up.
- Imming,Imhof,Zentgraf
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p. 3721 - 3727
(2007/10/03)
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- Regioselective Bromine/Lithium Exchange in 2,5-Dibromo-1-nitrobenzene. - A Simple Synthesis of 4-Bromo-2-nitrobenzaldehyde and 6,6'-Dibromoindigo
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The reaction of phenyllithium with 2,5-dibromo-1-nitrobenzene (1) in tetrahydrofuran at -105 deg C leads to the lithium derivative 2 with high regioselectivity.By reaction with dimethylformamide 2 is converted into 4-bromo-2-nitrobenzaldehyde (3) in 92percent yield.The isomeric aldehyde 4 is not formed.With the same reaction sequence 2,4-dibromo-1-nitrobenzene (5) can be transformed into 5-bromo-2-nitrobenzaldehyde (6).From aldehyde 3 and nitromethane Tyrian purple (7) is easily accessible. - Keywords: Dibromonitrobenzenes; Bromine-lithium exchange; Formylation, regioselective; Indigo, 6,6'-dibromo-; Tyrian purple
- Voss, Gundula,Gerlach, Hans
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p. 1199 - 1202
(2007/10/02)
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