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1.
Formation of N‐Heterocyclic Carbenes by Tautomerization of Mesomeric Betaines: Cyclic Boron Adducts and Palladium Complexes From 2‐(Imidazolium‐1‐yl)phenolates
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Ming Liu Dr. Martin Nieger Prof. Dr. Eike G. Hübner Prof. Dr. Andreas Schmidt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5416-5424
2‐(Imidazolium‐1‐yl)phenolates are conjugated heterocyclic mesomeric betaines in tautomeric equilibrium with the corresponding N‐heterocyclic carbenes (NHCs), 3‐(2‐hydroxyphenyl)‐imidazol‐2‐ylidenes. The carbene tautomers can be trapped as thiones (X‐ray analysis). Moreover, bis(triphenylphosphine)palladium(II) dichloride in THF trapped the carbene tautomer as a palladium complex without participation of the phenolate group (X‐ray analysis). The corresponding anionic NHCs, 2‐phenolate‐substituted imidazol‐2‐ylidenes, can be trapped by triethylborane or triphenylborane to form 4,4‐diethyl‐ or 4,4‐diphenyl‐4H‐benzo[e]imidazo[2,1‐c][1,4,2]oxaza‐borininium‐4‐ides, respectively (two X‐ray analyses). These tricyclic systems are the first representatives of a new heterocyclic ring system. The results of DFT calculations concerning the HOMO/LUMO profiles and partial charges are also presented. 相似文献
2.
Masala S Ahmed T Bergvall C Westerholm R 《Analytical and bioanalytical chemistry》2011,401(10):3305-3315
The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) with molecular masses of 252, 276, 278, 300, and 302 Da
from standard reference material diesel particulate matter (SRM 2975) has been investigated using accelerated solvent extraction
(ASE) with dichloromethane, toluene, methanol, and mixtures of toluene and methanol. Extraction of SRM 2975 using toluene/methanol
(9:1, v/v) at maximum instrumental settings (200 °C, 20.7 MPa, and five extraction cycles) with 30-min extraction times resulted in
the following elevations of the measured concentration when compared with the certified and reference concentrations reported
by the National Institute of Standards and Technology (NIST): benzo[b]fluoranthene, 46%; benzo[k]fluoranthene, 137%; benzo[e]pyrene, 103%; benzo[a]pyrene, 1,570%; perylene, 37%; indeno[1,2,3-cd]pyrene, 41%; benzo[ghi]perylene, 163%; and coronene, 361%. The concentrations of the following PAHs were comparable to the reference values assigned
by NIST: indeno[1,2,3-cd]fluoranthene, dibenz[a,h]anthracene, and picene. The measured concentration of dibenzo[a,e]-pyrene was lower than the information value reported by the NIST. The measured concentrations of other highly carcinogenic
PAHs (dibenzo[a,l]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene) in SRM 2975 are also reported. Comparison of measurements using the optimized ASE method and using similar conditions
to those applied by the NIST for the assignment of PAH concentrations in SRM 2975 indicated that the higher values obtained
in the present study were associated with more complete extraction of PAHs from the diesel particulate material. Re-extraction
of the particulate samples demonstrated that the deuterated internal standards were more readily recovered than the native
PAHs, which may explain the lower values reported by the NIST. The analytical results obtained in the study demonstrated that
the efficient extraction of PAHs from SRM 2975 is a critical requirement for the accurate determination of PAHs with high
molecular masses in this standard reference material and that the optimization of extraction conditions is essential to avoid
underestimation of the PAH concentrations. The requirement is especially relevant to the human carcinogen benzo[a]pyrene, which is commonly used as an indicator of the carcinogenic risk presented by PAH mixtures. 相似文献
3.
《Journal of heterocyclic chemistry》2017,54(2):1514-1521
A new method for the preparation of 2‐substituted 6‐chloro‐2,7‐dihydro‐3H‐dibenzo[de ,h ]cynnoline‐3,7‐diones has been developed. The compounds have been obtained in an original three‐step procedure comprising the oxidation of 1‐methyl‐9,10‐anthraquinones with periodate or permanganate/brominating reagent systems, cyclization to 6‐chloro‐2,7‐dihydro‐3H‐dibenzo[de ,h ]cynnoline‐3,7‐dione, and selective alkylation thereof. The selected processes were applied in the efficient scale‐up of specific 2,6‐substituted 2,7‐dihydro‐3H‐dibenz[de ,h ]cinnolin‐3,7‐dione derivatives, currently being investigated pre‐clinically as anticancer agents. 相似文献
4.
Dijana Pei Ivana Ozimec Landek Mladen Meraep Milan Mesia 《Journal of heterocyclic chemistry》2006,43(3):749-754
5.
Shanpeng Wen Weidong Cheng Pengfei Li Shiyu Yao Bin Xu Hui Li Yajun Gao Zilong Wang Wenjing Tian 《Journal of polymer science. Part A, Polymer chemistry》2012,50(18):3758-3766
Three donor–acceptor (D–A) 1,3‐di(thien‐2‐yl)thieno [3,4‐c]pyrrole‐4,6‐dione‐based copolymers, poly{9,9‐dioctylfluorene‐2,7‐diyl‐alt‐1,3‐bis(4‐hexylthien‐2‐yl)‐5‐octylthieno[3,4‐c]pyrrole‐4,6‐dione}, poly{N‐(1‐octylnonyl)carbazole‐2,7‐diyl‐alt‐1,3‐bis(4‐hexylthien‐2‐yl)‐5‐octylthieno[3,4‐c]pyrrole‐4,6‐dione}, and poly {4,8‐bis(2‐ethylhexyloxyl) benzo[1,2‐b:3,4‐b′]dithiophene‐alt‐1,3‐bis(4‐hexylthien‐2‐yl)‐5‐octylthieno[3,4‐c] pyrrole‐4,6‐dione} were synthesized by Suzuki or Stille coupling reaction. By changing the donor segment, the bandgaps and energy levels of these copolymers could be finely tuned. Cyclic voltammetric study shows that the highest occupied molecular orbital (HOMO) energy levels of the three copolymers are deep‐lying, which implies that these copolymers have good stability in the air and the relatively low HOMO energy level assures a higher open‐circuit potential when they are used in photovoltaic cells. Bulk‐heterojunction photovoltaic cells were fabricated with these polymers as the donors and PC71BM as the acceptor. The cells based on the three copolymers exhibited power conversion efficiencies of 0.22, 0.74, and 3.11% with large open‐circuit potential of 1.01, 0.99, and 0.90 V under one sun of AM 1.5 solar simulator illumination (100 mW/cm2). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
6.
Teddy Salim Swarnalatha Bomma Andrew C. Grimsdale Yeng Ming Lam 《Journal of polymer science. Part A, Polymer chemistry》2012,50(2):250-260
Four new polymers containing a benzo[c]thiophene‐N‐dodecyl‐4,5‐dicarboxylic imide (DIITN) unit including the homopolymer and three donor–acceptor copolymers were designed, synthesized, and characterized. For these copolymers, DIITN unit with low bandgap was selected as an electron acceptor, whereas 5,5′‐(2,7‐bisthiophen‐2‐yl)‐9‐(2‐decyltetradecyl)‐9H‐carbazole), 5,5′‐(3,3′‐di‐n‐octylsilylene‐2,2′‐bithiophene), and 5,5′‐(2,7‐bisthiophen‐2‐yl‐9,9‐bisoctyl‐9H‐fluoren‐7‐yl) were chosen as the electron donor units to tune the highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) levels of the copolymers for better light harvesting. These polymers exhibit extended absorption in the visible and near‐infrared range and are soluble in common organic solvents. The relative low lying HOMO of these polymers promises good air stability and high open‐circuit voltage (Voc) for photovoltaic application. Bulk heterojunction solar cells were fabricated by blending the copolymers with [6,6]‐phenyl‐C61‐butyric acid methyl ester or [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM). The best power conversion efficiency of 1.6% was achieved under simulated sunlight AM 1.5G (100 mW/cm2) from solar cells containing 20 wt % of the fluorene copolymer poly[5,5′‐(2,7‐bisthiophen‐2‐yl‐9,9‐bisoctyl‐9H‐fluoren‐7‐yl)‐alt‐2,9‐(benzo[c]thiophene‐N‐dodecyl‐4,5‐dicarboxylic imide)] and 80 wt % of PC71BM with a high open‐circuit voltage (Voc) of 0.84 V. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
7.
《Journal of heterocyclic chemistry》2017,54(3):2022-2028
A variety of substituted benzo[g ]quinoline‐5,10‐dione derivatives were synthesized via one‐pot three‐component reaction of 2‐hydroxynaphthalene‐1,4‐dione, aromatic aldehydes, and (E )‐3‐aminobut‐2‐enoates using carbonaceous material as the heterocyclic catalyst. This procedure is simple and efficient owing to short reaction times, easy work‐up, and recovery of heterogeneous catalyst. This procedure develops an efficient and promising synthetic method to construction of the benzo[g ]quinoline‐5,10‐dione skeleton. 相似文献
8.
Hiroki Uoyama Kil Suk Kim Dr. Kenji Kuroki Jae‐Yoon Shin Dr. Toshi Nagata Dr. Tetsuo Okujima Dr. Hiroko Yamada Dr. Noboru Ono Prof. Dongho Kim Prof. Hidemitsu Uno Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(13):4063-4074
Tetrameric porphyrin formation of 2‐hydroxymethylpyrrole fused with porphyrins through a bicyclo[2.2.2]octadiene unit gave bicyclo[2.2.2]octadiene‐fused porphyrin pentamers. Thermal conversion of the pentamers gave fully π‐conjugated cruciform porphyrin pentamers fused with benzene units in quantitative yields. UV/Vis spectra of fully π‐conjugated porphyrin pentamers showed one very strong Q absorption and were quite different from those of usual porphyrins. From TD‐DFT calculations, the HOMO level is 0.49 eV higher than the HOMO?1 level. The LUMO and LUMO+1 levels are very close and are lower by more than 0.27 eV than those of other unoccupied MOs. The strong Q absorption was interpreted as two mutually orthogonal single‐electron transitions (683 nm: 86 %, HOMO→LUMO; 680 nm: 86 %, HOMO→LUMO+1). The two‐photon absorption (TPA) cross section value (σ(2)) of the benzene‐fused porphyrin pentamer was estimated to be 3900 GM at 1500 nm, which is strongly correlated with a cruciform molecular structure with multidirectional π‐conjugation pathways. 相似文献
9.
Chaolumen Hiroki Enno Dr. Michihisa Murata Prof. Dr. Atsushi Wakamiya Prof. Dr. Yasujiro Murata 《化学:亚洲杂志》2014,9(11):3136-3140
Perylene bisimides (PBIs) are fascinating dyes with various potential applications. To study the effects of introducing a dibenzo‐fused structure to the perylene moiety, π‐extended PBI derivatives with a dibenzo‐fused structure at both of the a and f bonds were synthesized. The twisted structure was characterized by X‐ray crystal structure analysis. In the cyclic voltammograms, the dibenzo[a,f]‐fused PBI showed a reversible oxidation wave at much less positive potential, relative to a dibenzo[a,o]‐fused PBI derivative. These data indicated that two ring fusions at both sides of a naphthalene moiety, which construct a tetracene core, effectively raise the HOMO level compared to fusion of one ring at each naphthalene moiety (two anthracene cores). The dibenzo[a,f]‐fused PBI derivative showed an absorption band at 735 nm with a shoulder band reaching 900 nm. 相似文献
10.
Dr. Shern‐Long Lee Min‐Jie Huang Prof. Chun‐hsien Chen Cheng‐I Wang Prof. Rai‐Shung Liu 《化学:亚洲杂志》2011,6(5):1181-1187
In this scanning‐tunneling‐microscopy/spectroscopy study (STM/STS), samples of isolated and close‐packed dibenzo[g,p]chrysene (DBC), a nonplanar polyaromatic compound, are used as model systems to demonstrate the effect of intermolecular interactions on the electronic structures. For dropcast films, DBC molecules adopt an edge‐on orientation in a close‐packed structure on graphite. Isolated DBC molecules are prepared on graphite from a DBC‐coated STM tip by a ca. 7 V/10 μs pulse. STS spectra for both isolated‐ and close‐packed DBC molecules exhibit diode‐like I–V curves in which the latter shows a turn‐on voltage (0.47 V) smaller than that of the former (0.91 V). The diode‐like behaviors are attributed to the more‐facile tunneling of electrons through the HOMO of DBC than through the LUMO. The reduced turn‐on voltage for the films is ascribed to the diminished HOMO–LUMO gap based on the results of DFT (density functional theory) simulations for the energy‐level couplings of π‐stacked DBC molecules. 相似文献
11.
This review presents a survey of synthetic methods and reaction mechanism of the dibenzo[d,f][1,3] dioxepine derivatives. Furthermore, the influence of the substituent groups in 6,6′‐position of dibenzo[d,f][1,3] dioxepine on their conformation is explored. The functional dibenzo[d,f][1,3] dioxepine synthetically versatiles substrate, as they can be used for synthesis of a large variety of π‐conjugated oligomer and polymer containing heterocyclic compounds, such as dibromination dibenzo[d,f][1,3] dioxepine derivative as a raw material of synthesis for organic semiconductor polymers. The synthetic and fluorescent property of π‐conjugated polymers basic on dibenzo[d,f][1,3] dioxepine also is explored. J. Heterocyclic Chem., (2012). 相似文献
12.
Diastereoselective Synthesis of (Z)‐6‐(2‐Oxo‐1,2‐dihydro‐3H‐indol‐3‐ylidene)‐3,3a,9,9a‐tetrahydroimidazo[4,5‐e]thiazolo[3,2‐b]‐1,2,4‐triazin‐2,7(1H,6H)‐diones
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Galina A. Gazieva Ekaterina A. Shishkova Ludmila B. Kulikova Natal'ya G. Kolotyrkina Natal'ya V. Sigay Angelina N. Kravchenko 《Journal of heterocyclic chemistry》2014,51(4):921-926
Two efficient and diastereoselective procedures for the synthesis of (Z)‐6‐(2‐oxo‐1,2‐dihydro‐3H‐indol‐3‐ylidene)‐3,3a,9,9a‐tetrahydroimidazo[4,5‐e]thiazolo[3,2‐b]‐1,2,4‐triazin‐2,7(1H,6H)‐diones by aldol‐crotonic condensation of 1,3‐dimethyl‐3a,9a‐diphenyl‐3,3a,9,9a‐tetrahydroimidazo[4,5‐e]thiazolo[3,2‐b]‐1,2,4‐triazin‐2,7(1H,6H)‐dione with isatins under acidic or basic catalysis are reported. Isomerization in (Z)‐7‐(1‐allyl‐2‐oxo‐1,2‐dihydro‐3H‐indol‐3‐ylidene)‐1,3‐dimethyl‐3a,9a‐diphenyl‐1,3a,4,9a‐tetrahydroimidazo[4,5‐e]thiazolo[2,3‐c]‐1,2,4‐triazin‐2,8(3H,7H)‐dione was observed under basic conditions. 相似文献
13.
New Mansonone analogues of 9‐substitued benzo[de]chromene‐7,8‐dione 5b–e and 5‐benzyl‐9‐substitued benzo[de]chromene‐7,8‐dione 6a–e were prepared through a modified route. The first step involved a bulky base t‐butylamine mediated regioselective deacetylation of 2‐substituted‐1,4‐naphth‐diyl diacetate, resulting in obtaining of monoacetate 4‐acetate 2 in high yield. The mechanism of cyclization, debenzylation, and oxidation for the formation of 5a–e and 6a–e were discussed. The cytotoxicity of the prepared compounds 5 and 6 were comparable with naturally occurring Mansonone F. 相似文献
14.
A series of iridium‐ and rhodium‐based hexanuclear organometallic cages containing 2,5‐dichloro‐3,6‐dihydroxy‐1,4‐benzoquinone, 9,10‐dihydroxy‐1,4‐anthraquinone, and 6,11‐dihydroxynaphthacene‐5,12‐dione ligands were synthesized from the self‐assembly of the corresponding molecular “clips” and 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine ligands in good yields. These organometallic cages can form inclusion systems with a wide variety of π‐donor substrates, including coronene, pyrene, [Pt(acac)2], and hexamethoxytriphenylene. The 1:1 complexation of the resulting supramolecular assemblies was confirmed by 1H NMR spectroscopy. Large complexation shifts (Δδ>1 ppm) were observed in the 1H NMR spectra of guests in the presence of cage [Cp*6M6(μ‐DHNA)3(tpt)2](OTf)6 ( 6a ; M=Ir, tpt=2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine). The formation of discrete 1:1 donor–acceptor complexes, pyrene ?6 b (M=Rh), coronene ?6 a , coronene ?6 b , and [Pt(acac)2] ?6 a was confirmed by their single‐crystal X‐ray analyses. In these systems, the most important driving force for the formation of guest–host complexes is clearly the donor–acceptor π???π stacking interaction, including charge‐transfer interactions between the electron‐donating and electron‐accepting aromatic components. These structures provide compelling evidence for the existence of strong attractive forces between the electron‐deficient triazine core and electron‐rich guest. The results presented here may provide useful guidance for designing artificial receptors for functional biomolecules. 相似文献
15.
Serife O. Hacioglu Sinem Toksabay Merve Sendur Levent Toppare 《Journal of polymer science. Part A, Polymer chemistry》2014,52(4):537-544
In this study, a series of benzotriazole (BTz) and triphenylamine (TPA)‐based random copolymers; poly4‐(5‐(2‐dodecyl‐7‐methyl‐2H‐benzo[d][1,2,3]triazol‐4‐yl)thiophen‐2‐yl)‐N‐(4‐(5‐methylthiophen‐2‐yl)phenyl)‐N‐phenylaniline ( P1 ), poly4′‐(2‐dodecyl‐7‐methyl‐2H‐benzo[d][1,2,3]triazol‐4‐yl)‐N‐(4′‐methyl‐[1,1′‐biphenyl]‐4‐yl)‐N‐phenyl‐[1,1′‐biphenyl]‐4‐amine ( P2 ), and poly4‐(5′‐(2‐dodecyl‐7‐(5‐methylthiophen‐2‐yl)?2H‐benzo[d][1,2,3]triazol‐4‐yl)‐[2,2′‐bithiophen]‐5‐yl)‐N‐(4‐(5‐methylthiophen‐2‐yl)phenyl)‐N‐phenylaniline ( P3 ) were synthesized to investigate the effect of TPA unit and π‐bridges on electrochemical and spectroelectrochemical properties of corresponding polymers. The synthesis was carried out via Stille coupling for P1 , P3 , and Suzuki coupling for P2 . Electrochemical and spectral results showed that P1 has an ambipolar character, in other words it is both p‐type and n‐type dopable, whereas P2 and P3 have only p‐doping property. Effect of different π‐bridges and TPA unit on the HOMO and LUMO energy levels, switching time, and optical contrast were discussed. All polymers are promising materials for electrochromic devices. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 537–544 相似文献
16.
Vincent Remusat Thierry Terme Armand Gellis Pascal Rathelot Patrice Vanelle 《Journal of heterocyclic chemistry》2004,41(2):221-225
A new heterocyclic bioreductive bis‐alkylating agent, 2,3‐bis(chloromethyl)benzo[g]quinoxaline‐5,10‐dione, was prepared in a four‐steps synthesis. It was shown to react under electron transfer conditions with 2‐nitropropane anion by an bis‐SRN1 mechanism to give three C‐alkylation products in excellent yields. Extension of this bis‐SRN1 reaction to various nitronate or malonate anions and S‐centered anions led to a new class of potentially active benzo[g]quinoxaline‐5,10‐dione derivatives. 相似文献
17.
Elif Kose Unver Simge Tarkuc Yasemin Arslan Udum Cihangir Tanyeli Levent Toppare 《Journal of polymer science. Part A, Polymer chemistry》2010,48(8):1714-1720
A comparative investigation was undertaken for the electrosynthesis and electrochemical properties of three different electroactive polymers having a conjugated core building block, dibenzo[a,c]phenazine. A series of monomers has been synthesized as regards to thiophene based units; thiophene, 3‐hexyl thiophene, and 3,4‐ethylenedioxythiophene. The effects of different donor substituents on the polymers' electrochemical properties were examined by cyclic voltammetry. Introducing highly electron‐donating (ethylene dioxy) group to the monomer enables solubility while also lowering the oxidation potential. The planarity of the monomer unit enhances π‐stacking and consequently lowering the Eg from 2.4 eV (PHTP) to 1.7 (PTBP). Cyclic voltammetry and spectroelectrochemical measurements revealed that 2,7‐bis(4‐hexylthiophen‐2‐yl)dibenzo[a,c]phenazine (HTP) and 2,7‐bis(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐5‐yl)dibenzo[a,c]phenazine (TBP) possessed electrochromic behavior. The colorimetry analysis revealed that while PTBP have a color change from red to blue, PHTP has yellow color at neutral state and blue color at oxidized state. Hence the presence of the phenazine derivative as the acceptor unit causes a red shift in the polymers' absorption to have a blue color. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1714–1720, 2010 相似文献
18.
Natarajan Sampathkumar Arumugam Murugesh Subramaniam Parameswaran Rajendran 《Journal of heterocyclic chemistry》2016,53(3):924-928
The Vilsmeier Haack heterocyclization of 2‐aryl amino‐4‐phenyl quinolines quinoline yielded the hitherto unknown 5‐phenyl‐dibenzo[b,g][1,8]naphthyridines in quantitative yield. The synthesis of aryl amines was achieved by the action of anilines on 2‐chloro‐4‐phenyl quinoline, which in turn was sourced through the combes reaction of benzoyl acetanilides. 相似文献
19.
Masaya Toba Takuya Nakashima Tsuyoshi Kawai 《Journal of polymer science. Part A, Polymer chemistry》2011,49(8):1895-1906
Arylenevinylene‐based π‐conjugated polymers containing imidazolium cationic units in the main chain and their model compounds were synthesized and characterized in terms of optical and electrochemical properties. 9,9‐Bisoctylfluorene, 2,5‐bisdodecyloxybenzene, and 3‐dodecylthiophene were introduced as arylene units with different donor characteristics to evaluate the effect on the highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) gap energy. The UV–vis and fluorescence spectra of cationic polymers and model compounds with iodide counter anion exhibited a significant blue shift with respect to the parent neutral molecules. X‐ray single crystal analysis for model compounds revealed that the effective π‐conjugation length of cationic model compounds decreased compared to the neutral model compounds by means of twisted conformation directed by CH‐π interactions between N‐methyl groups of imidazolium and neighboring aryl units. The cyclic voltammetry measurement suggested the negative shift of LUMO levels by the conversion of imidazole to imidazolium, indicating the electron‐accepting characteristics of cationic imidazolium unit. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
20.
《Journal of heterocyclic chemistry》2017,54(3):2067-2070
Amidrazones reacted with benzo[b ]thiophene‐2,3‐dione at refluxing ethanol and catalyzed with trimethylamine to give 4‐aryl‐3‐phenyl‐1,2,4‐triazine‐5,6‐dione derivatives. The structure of the obtained products was proved by IR, mass, NMR spectra and elemental analyses. The reaction mechanism is also discussed. 相似文献