- Highly selective turn-on probe for H2S with imaging applications in vitro and in vivo
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Hydrogen sulfide (H2S) is the third endogenous gaseous signaling molecule, and its distribution affects several biological processes. To clarify the roles of H2S in living systems, the exact determination of H2S in living cells in vivo has become an important issue. Herein, we report a novel pyrene-based fluorescent probe, PyN3, as a H2S turn-on sensor via reduction of azide to amine, which subsequently undergoes self-immolation through intramolecular 1,6-elimination of the p-aminobenzyl moiety, releasing 1-aminopyrene and leading to the recovery of fluorescence intensity. With its high sensitivity, good selectivity, and low cytotoxicity, PyN3 was able to recognize both exogenous and endogenously produced H2S in biological systems. In contrast to the traditional azide-based H2S probes, PyN3 shows efficient and effective selectivity to H2S at biological pH ranges. Because of these promising properties, PyN3 is an excellent probe for visualizing endogenous H2S in vitro and in vivo.
- Thirumalaivasan, Natesan,Venkatesan, Parthiban,Wu, Shu-Pao
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- Quantification of DNA and Protein Adducts of 1-Nitropyrene: Significantly Higher Levels of Protein than DNA Adducts in the Internal Organs of 1-Nitropyrene Exposed Rats
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1-Nitropyrene (1NP) level is closely associated with the mutagenicity of diesel exhaust and is being used as the marker molecule for diesel exhaust. Thus, quantitation of the exposure to 1NP may provide an efficient method for biomonitoring human exposure to diesel exhaust and risk assessment. Using ultra-performance liquid chromatography coupled with fluorescence or tandem mass spectrometric detection methods, we quantitated and compared in this study the DNA and protein adducts of 1NP in internal organs of 1NP-exposed rats. While previous studies using radioactivity-based detection methods were descriptive in nature and focused on the mutation-associated genetic materials, the results of our quantitative analysis showed, for the first time, a significantly higher concentration of the protein adduct than the DNA adduct in the tissue samples. The data also revealed higher in vivo stability of the protein adduct than that of the DNA adduct. Our results provide solid evidence that demonstrates that the protein adduct might be a more-sensitive dosimeter for 1-NP and, thus, diesel-exhaust exposure.
- Chan, Wan,Wong, Sum-Kok,Li, Weiwei
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- A new processable and fluorescent polydithienylpyrrole electrochrome with pyrene appendages
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A new hybrid compound, namely 1-(pyren-3-yl)-2,5-di(thiophen-2-yl)-1H- pyrrole (SNS-P), was polymerized via both chemical and electrochemical methods. Chemically obtained soluble polydithienylpyrrole (c-PSNS-P) bearing pyrene appendages is a homogeneous and uniform polymer with a number averaged molecular weight of 15,200 g/mol. The polymer exhibits both multi-electrochromic and fluorescent properties. Upon oxidation, the color of electrochemically obtained polymer (e-PSNS-P) changes from yellowish orange to greenish yellow and to green/blue and finally to blue. In addition, the polymer induces yellowish orange (564 nm) and bright orange emission (613 nm) in solution and solid states, respectively.
- Tirke?, Seha,Mersini, Jetmire,?zta?, Zahide,Algi, Melek Pamuk,Algi, Fatih,Cihaner, Atilla
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- 4-(Pyren-1-ylimino)methylphenol and its silylated derivative as chromogenic chemosensors highly selective for fluoride or cyanide
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Two novel compounds, 4-(pyren-1-ylimino)methylphenol and 4-[(triisopropylsilyl)oxy] phenylmethylenepyren-1-amine) were synthesized. Solutions of 4-(pyren-1-ylimino)methylphenol in dimethyl sulfoxide (DMSO) are colorless, but on addition of cyanide and fluoride they become colored due to the deprotonation of the chemosensor. The system is highly selective toward cyanide with the addition of water. This compound can be solubilized in water with addition of cetyltrimethylammonium bromide above its critical micellar concentration. The pKa of the compound in water was determined as 10.49 ± 0.02 and this value is lowered in micellar medium to 7.49 ± 0.02, which means that only cyanide is sufficiently basic to achieve the deprotonation of the compound. Solutions of 4-[(triisopropylsilyl)oxy]phenylmethylenepyren-1-amine) in DMSO are colorless, but they are colored in the presence of cyanide and fluoride and only cyanide could be detected in DMSO-water mixture. The nucleophilic attack of the anions on the silicon center of the compound releases colored 4-(pyren-1-ylimino)methylphenolate, enabling the detection of nucleophilic analytes.
- Buske, Jonatan L. O.,Nicoleti, Celso R.,Cavallaro, Aluisio A.,Machado, Vanderlei G.
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- 1,3-Bis(pyren-1-yliminomethyl)calix[4]arene as a selective fluorescent turn-on sensor for mercury(II) ion
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A novel calixarene-based diimine, 1,3-bis(pyren-1-yliminomethyl)calix[4]arene (5), serves as a turn-on-type fluorescent sensor, which selectively detects Hg2+ in THF/H2O (99:1, v/v) in the presence of various other metal ions. Such selectivity is not seen with half salen 1 derived from salicylaldehyde and 1-aminopyrene. 1H NMR analysis reveals that it is a chemodosimetric sensor based on its hydrolysis mediated by Hg2+ to release 1-aminopyrene molecules as fluorescent chromophores.
- Tanaka, Shinya,Hirasawa, Kengo,Watanabe, Kyohei,Hattori, Tetsutaro
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- Reduction of nitroaromatics by non-metal hydrazinolysis
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High temperature (160°C) can substitute for a metal catalyst in achieving the complete reduction of nitroaromatic compounds to corresponding amines by hydrazine.
- Abdel-Baky,Zhuang,Giese
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- A new pyrene-based Schiff-base: A selective colorimetric and fluorescent chemosensor for detection of Cu(II) and Fe(III)
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A new receptor 1 was prepared, for the detection of Cu2+ and Fe3+ in solutions as a colorimetric and fluorescent sensor, respectively. Receptor 1 shows highly selective and sensitive recognition toward Cu2+ and Fe3+ by naked eye UV-Vis and fluorescent color changes in aqueous solution (DMSO/H2O = 8/2, v/v), respectively. The sensitivity toward Cu2+ or Fe3+ was not interfered with by the presence of other metal ions such as Mg2+, Cd2+, Ag+, Zn2+, Ni2+, Co2+, Mn 2+, Cr3+, Ca2+, Na+, Pb 2+, K+, Fe2+, Li+ and Hg 2+ ions. Receptor 1 can be used for semi-quantitative recognition of Cu2+ ions at ppm level. The fluorescence microscopy experiments showed that the receptor is efficient for detection of Fe3+ in vitro, developing a good image of the biological organelles.
- Bhorge, Yeshwant Ramchandra,Tsai, Haw-Tyng,Huang, Keh-Feng,Pape, Albert J.,Janaki, Sudhakar Narasimha,Yen, Yao-Pin
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- Preparation and characterization of pyrene modified uridine derivatives as potential electron donors in RNA
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Charge transfer across double stranded DNA was observed for the first time about 20 years ago, and ever since it has been the subject of a large number of studies. RNA has been hardly investigated in this regard, which not least is due to the lack of suitably functionalized ribonucleotide building blocks to serve as electron sources upon incorporation into oligoribonucleotides. We have synthesized two uridine derivatives carrying pyrene or dimethylaminopyrene linked to C5 of the nucleobase. The key to successful synthesis was the adaptation of Suzuki-Miyaura conditions to the coupling of the pyrene moiety with the ribonucleoside. Final decoration of the pyrenylated nucleosides with standard 5′-O- and 2′-O-protecting groups and subsequent 3′-O-phosphitylation delivered the building blocks for incorporation into RNA. Spectroscopic analysis of the two pyrenylated uridines and of the accordingly modified oligonucleotides showed that in particular the dimethyaminopyrene functionalized nucleoside is a promising candidate as an electron source for RNA charge transport studies.
- Frommer, Jennifer,Karg, Beatrice,Weisz, Klaus,Müller, Sabine
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- Uncovering the true mechanism of optical detection of HSO4 - in water by Schiff-base receptors - Hydrolysis vs. hydrogen bonding
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The mechanism of optical detection of HSO4- in aqueous medium by Schiff-base receptors has previously been proposed to depend on selective hydrogen-bond interactions. Here, we clearly demonstrate for the first time that the acidic na
- Kumar, Virendra,Kumar, Ajit,Diwan, Uzra,Upadhyay
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- Assembly of plasmid DNA with pyrene-amines cationic amphiphiles into nanoparticles and their visible lysosome localization
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In this study, we constructed a visible model for drug/gene dual delivery. Firstly, we prepared a series of pyrene fluorophore bearing cationic amphiphiles (Py-amines), which could be further employed as amphiphilic gene carriers and antitumor polyamine drug models. Then, the Py-amines fluorescent amphiphiles were utilized to bind/load plasmid DNA via electrostatic interactions to form nano-sized particles in aqueous solution. The average size, zeta potential and morphology of the self-assembled Py-amines/pDNA complexes were found to be largely dependent on the molecular structures of Py-amines amphiphiles. Moreover, the Py-amines and their pDNA complexes showed an evident cell proliferation inhibition capability in H1299 (human lung cancer) cells. Notably, the lysosomal localization of the Py-amines/pDNA complexes could be directly visualized using fluorescence microscopy in vitro. In summary, this current study could provide new and visible approach to design polyamine-based anti-tumor drug/plasmid DNA dual delivery systems, which could facilitate a greater understanding of the intracellular trafficking/localization of polyamine-based cationic gene/drug payloads.
- Sheng, Ruilong,An, Feifei,Wang, Zhao,Li, Mingrui,Cao, Amin
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- Intramolecular excimer fluorescence from folded ground state rotamers of N,N′dimethyl-N,N′-dipyrenylurea protophanes
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The molecular structure, absorption, and fluorescence spectra of N,N′-dimethyl-N,N′-di-1-pyrenylurea and N,N′ -dimethyl-N,N′-di-2-pyrenylurea have been investigated and compared to the properties of N,N,N′-trimethyl-N′-pyrenylurea model compounds. Di-1-pyrenylurea exists as a mixture of folded (E,E) syn- and anti-rotamers that interconvert via flipping of one of the pyrene rings to an unfolded (E,Z) rotamer geometry. The symmetric di-2-pyrenylurea exists as a single folded (E,E) conformation which is in equilibrium with a less-stable, unfolded (E,Z) rotamer. The absorption and fluorescence spectra of the dipyrenylureas at 77 K in a rigid glass are similar to those of monopyrenylurea model compounds. However, in fluid solution, the dipyrenylureas exhibit excimer fluorescence and very weak monomer fluorescence which have identical decay times. This behavior is attributed to fast rotational equilibrium between folded rotamers which exhibit excimer fluorescence and unfolded rotamers which exhibit monomer fluorescence. The behavior of the dipyrenylureas is compared with that of other systems that form intramolecular pyrene excimers and diarylureas.
- Lewis, Frederick D.,Kurth, Todd L.
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- Tuning of n- and p-type reduced graphene oxide transistors with the same molecular backbone
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Play the field: A field-effect transistor using reduced graphene oxides was prepared through the reduction of graphene oxides connected between two electrodes. The use of pyrene with an electron-withdrawing group and an electron-donating group showed the p- and n-doping effects, respectively, while the pyrene backbone with no electron-withdrawing or -donating groups showed no doping effect.
- Lee, Junghyun,Hwang, Eunhee,Lee, Eunkyo,Seo, Sohyeon,Lee, Hyoyoung
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- Preparation method of aminopyrene compound
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The invention relates to a preparation method of an aminopyrene compound. The method includes the steps of: in the presence of a copper catalyst and alkali, subjecting a halogen substituted pyrene derivative and tert-butyl carbamate to heating reaction in a mixed solvent of PEG and water to obtain the aminopyrene compound. The raw materials, catalyst and solvent adopted by the invention are cheapand easily available. The method provided by the invention has the advantages of simple operation, high conversion efficiency and easy mass production. The amino protecting group is removed in the Ullmann coupling reaction system in the reaction process, and can be directly converted to aminopyrene without additional protecting group removal step.
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Paragraph 0048; 0049
(2019/10/29)
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- Cobalt-Catalyzed Direct Carbonylative Synthesis of Free (NH)-Benzo[ cd]indol-2(1 H)-ones from Naphthylamides
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A cobalt-catalyzed C-H carbonylation of naphthylamides for the synthesis of benzo[cd]indol-2(1H)-one scaffolds has been developed. The reaction employs a traceless directing group and uses benzene-1,3,5-triyl triormate as the CO source, affording various free (NH)-benzo[cd]indol-2(1H)-ones in moderate to high yields (up to 88%). Using this protocol, the total synthesis of BET bromodomain inhibitors A and B was accomplished as well.
- Ying, Jun,Fu, Lu-Yang,Zhong, Guoqiang,Wu, Xiao-Feng
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supporting information
p. 5694 - 5698
(2019/07/08)
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- Diphenylpyrenylamine-functionalized polypeptides: Secondary structures, aggregation-induced emission, and carbon nanotube dispersibility
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In this study we prepared - through ring-opening polymerization of γ-benzyl-l-glutamate N-carboxyanhydride (BLG-NCA) initiated by N,N-di(4-aminophenyl)-1-aminopyrene (pyrene-DPA-2NH2) - poly(γ-benzyl-l-glutamate) (PBLG) polymers with various degrees of polymerization (DP), each featuring a di(4-aminophenyl)pyrenylamine (DPA) luminophore on the main backbone. The secondary structures of these pyrene-DPA-PBLG polypeptides were investigated using Fourier transform infrared spectroscopy and wide-angle X-ray diffraction, revealing that the polypeptides with DPs of less than 19 were mixtures of α-helical and β-sheet conformations, whereas the α-helical structures were preferred for longer chains. Interestingly, pyrene-DPA-2NH2 exhibited weak photoluminescence (PL), yet the emission of the pyrene-DPA-PBLG polypeptides was 16-fold stronger, suggesting that attaching PBLG chains to pyrene-DPA-2NH2 turned on a radiative pathway for the non-fluorescent molecule. Furthermore, pyrene-DPA-2NH2 exhibited aggregation-caused quenching; in contrast, after incorporation into the PBLG segments with rigid-rod conformations, the resulting pyrene-DPA-PBLG polypeptides displayed aggregation-induced emission. Transmission electron microscopy revealed that mixing these polypeptides with multiwalled carbon nanotubes (MWCNTs) in DMF led to the formation of extremely dispersible pyrene-DPA-PBLG/MWCNT composites. The fabrication of MWCNT composites with such biocompatible polymers should lead to bio-inspired carbon nanostructures with useful biomedical applications.
- El-Mahdy, Ahmed F. M.,Kuo, Shiao-Wei
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p. 15266 - 15281
(2018/05/04)
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- Multifunctional polybenzoxazine nanocomposites containing photoresponsive azobenzene units, catalytic carboxylic acid groups, and pyrene units capable of dispersing carbon nanotubes
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In this study, we synthesized a new multifunctional benzoxazine monomer Azo-COOH-Py BZ - featuring an azobenzene unit, a carboxylic acid group, and a pyrene moiety - through the reaction of 4-(4-hydroxyphenylazo)benzoic acid (Azo-COOH), paraformaldehyde, and aminopyrene (Py-NH2) in 1,4-dioxane. Fourier transform infrared (FTIR) spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy confirmed the structure of this new monomer. Using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and FTIR spectroscopy, we monitored the curing behavior of Azo-COOH-Py BZ leading to the formation of poly(Azo-COOH-Py BZ); we found that the carboxylic acid and azobenzene units acted as catalysts for the ring opening reaction of the benzoxazine unit. The pyrene moiety of Azo-COOH-Py BZ enhanced the dispersibility of carbon nanotubes (CNTs) in THF, leading to the formation of highly dispersible Azo-COOH-Py BZ/CNT nanocomposites stabilized through π-π stacking of the pyrene and CNT units, as detected through fluorescence emission spectroscopy. We also used DSC and TGA to examine the curing behavior of Azo-COOH-Py BZ/CNTs to form poly(Azopy-COOH-Py BZ)/CNTs nanocomposites. Interestingly, DSC profiles revealed that the maximum exothermic peak representing the ring opening polymerization of the benzoxazine unit of Azo-COOH-Py BZ shifted to much lower temperature upon increasing the content of single-walled CNTs (SWCNTs) or multiwalled CNTs (MWCNTs), suggesting that the CNTs acted as catalysts for the ring opening reaction of the benzoxazine. In addition, the curing temperatures for the SWCNT composites were lower than those for the MWCNT composites, suggesting that the SWCNTs were dispersed better than the MWCNTs in their composites and that the thermal stability of the SWCNT nanocomposites was higher than that of the MWCNT nanocomposites. The combination of photoresponsive azobenzene units, carboxylic acid groups, and CNTs enhanced the thermal stability and char yields of the polybenzoxazine matrixes, as determined through TGA analyses.
- Mohamed, Mohamed Gamal,Hsiao, Chi-Hui,Luo, Faliang,Dai, Lizong,Kuo, Shiao-Wei
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p. 45201 - 45212
(2015/06/02)
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- A ferrocene-pyrene based 'turn-on' chemodosimeter for Cr 3+-application in bioimaging
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Structurally simple, ferrocene-pyrene imine dyad 1 has been developed as a 'turn-on' chemodosimeter for Cr3+. The sensing event is based upon the hydrolysis of the imine functionality. Further, 1, which is also non-cytotoxic (100% cell viability), detects intracellular Cr3+ in the human breast cancer (MCF-7) cells.
- Kaur, Mandeep,Kaur, Paramjit,Dhuna, Vikram,Singh, Sukhdev,Singh, Kamaljit
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p. 5707 - 5712
(2014/04/03)
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- Tunable star-shaped triphenylamine fluorophores for fluorescence quenching detection and identification of nitro-aromatic explosives
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Triphenylamine-based fluorophores containing pyrene or corannulene show variable fluorescence quenching sensitivity toward nitro explosives. The most sensitive fluorophore is capable of detecting TNT on the ng cm-2 scale; the array is useful for identifying nitro aromatics.
- Niamnont, Nakorn,Kimpitak, Nattaporn,Wongravee, Kanet,Rashatasakhon, Paitoon,Baldridge, Kim K.,Siegel, Jay S.,Sukwattanasinitt, Mongkol
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p. 780 - 782
(2013/02/23)
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- A new class of heterogeneous platinum catalysts for the chemoselective hydrogenation of nitroarenes
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A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel.
- Pandarus, Valerica,Ciriminna, Rosaria,Beland, Francois,Pagliaro, Mario
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scheme or table
p. 1306 - 1316
(2011/06/25)
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- Recognition of anions by bis urea based fluorescent receptors
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Three bis urea based acyclic receptors with fixed spacer and varying size of substituents have been synthesized and their binding behavior with different anions are reported along with the selectivity of these receptors towards anions. The fluorescence quenching of the receptors 2 and 3 on binding with anions is also shown. The receptor 1 binds better with Y-shaped AcO-ion whereas receptor 3 binds well with Cl-ion.
- Goswami, Shyamaprosad,Jana, Subrata
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p. 399 - 405
(2011/04/12)
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- Fluorescent and electrochromic polyamides with pyrenylamine chromophore
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A series of novel polyamides with a pyrenylamine chromophore in the backbone were prepared from a newly synthesized diamine monomer, N,N-di(4-aminophenyl)-1-aminopyrene, and various dicarboxylic acids via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution-cast into tough and amorphous films. They had useful levels of thermal stability with glass-transition temperatures in the range of 246-326 °C and 10% weight loss temperatures in excess of 500 °C. The dilute NMP solutions of these polyamides exhibited fluorescence maxima around 522-544 nm with quantum yields up to 30.2%. These polyamides also showed remarkable fluorescence solvatochromism in various solvents. The polymer films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from the yellow neutral state to a purple oxidized state and to an orange reduced state. The anodically electrochromic films had high coloration efficiency (up to 172 cm2 C-1 at 834 nm) and good redox stability, which still retained a high electroactivity after long-term redox cycles.
- Kung, Yi-Chun,Hsiao, Sheng-Huei
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p. 5481 - 5492
(2011/08/10)
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- Pyrene-naftylamide bifluorophore for spectra-converting media
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New bifluorophore containing pyrene as an excitation energy donor and naphtylamide as an acceptor is synthesized and its optical properties are studied. It is founded that excitation spectrum of the bifluorophore is almost the sum of its constituents-pyrene and naftylamide. At the same time, in the luminescence spectrum there only the peak of acceptor luminescence is observed, which indicates the effective radiationless energy transfer from the donor to the acceptor. This is also proved by time resolved measurements of bifluorophore decay. The decay rate was calculated from decay curve and appear to be 0.25 hc-1. The same value obtained from the Foerster's theory is almost by an order as high. It indicates that Foerster's does not applicable in this particular case. Instead, we have to use the electron excitation density functions approach.
- Adadurov, Alexander F.,Gurkalenko, Yurii A.,Zhmurin, Piotr N.
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p. 315 - 320
(2011/10/18)
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- Hg2+-Induced hydrolysis-based selective fluorescent chemodosimeter
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A new chemodosimeter-based approach to the detection of Hg(II) ions is described, involving the analyte-induced fluorescence enhancement of iminopyrene derivatives. The chemical and photo-physical properties of the chemodosimetric irreversible reaction be
- Kim, Ja Hyung,Kim, Hyun Jung,Bae, Chang Wan,Park, Jun Won,Kim, Jong Seung,Lee, Joung Hae
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p. 170 - 178,9
(2020/09/14)
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- Study on the synthesis and molecular recognition of new receptors for selective complexation of carboxylic acids
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A new synthetic method based on the synthesis of unsymmetrical thioureas followed by double S-alkylation reaction by xylylene dibromides was used to obtain isothiouronium receptors. Their binding abilities to acetate, succinate and maleate anions were evaluated by UV-vis spectroscopic titrations in such solvents as water, acetonitrile, methanol and mixtures of acetonitrile/methanol (1:1, v/v). For simple receptor 4 with one isothiouronium group, no selectivity was observed in the complexation of the anions studied. Receptors (R) 5a-c with two thiouronium groups are able to form with all the anions studied (A) not only stable complexes of 1:1 stoichiometry but also other possessing structure of the type AnRm. The most reliable values of stability constants are for systems of the type maleate anion-receptor 5 and acetate-receptor 5b. However, the best selectivity in the mixed solvents is demonstrated by anion-5c system. The study indicates also that particularly 5c is preferred as a chemosensor for the maleate anion. The obtained results suggest that subtle changes in the receptor structure lead to different binding modes towards anions.
- Or?owska, Maja,Mroczkiewicz, Micha?,Guzow, Katarzyna,Ostaszewski, Ryszard,K?onkowski, Andrzej M.
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experimental part
p. 2486 - 2491
(2010/06/14)
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- Interactions of new synthesized fluorescent cationic amphiphiles bearing pyrene hydrophobe with plasmid DNA: Binding affinities, aggregation and intracellular uptake
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In this work, we prepared a novel series of cationic amphiphiles denoted as the Py-cations (Py-Gly, Py-Ala, Py-Cap, Py-G1-Lys and Py-G 2-Lys) bearing fluorescent pyrene and various hydrocarbon linkers between the pyrene hydrophobe and cationic block. Employing these new cationic amphiphiles with pyrene as the fluorescent probe, the interactions between these Py-cations and plasmid DNA (pDNA) in distilled water and 0.1M PBS buffer solution have been explored by means of UV-vis and fluorescent spectrometers, and ethidium bromide dye displacement and agarose-gel retardant assays were also implemented to evaluate their pDNA binding affinities in aqueous solution. Furthermore, the average sizes and morphologies of self-assembled Py-cation/ pDNA lipoplex aggregates were examined by dynamic laser light scattering (DLS) and atomic force microscopy (AFM). It was found that these fluorescent cationic amphiphiles showed blue fluorescence emission of pyrene probe at λ=340 nm in distilled water while their interactions with pDNA led to new strong green emission at λ=490 nm, and this may be due to the stacking of pyrene and new formation of excimers via the rigid pDNA templated self-assembly. It was also revealed that the binding between new Py-cations and pDNA in aqueous solution was strongly influenced by the Py-cation hydrophobicity, charges of the cation and the presence of electrolytes.With respect to the Py-cation/pDNA aggregate morphologies, very interesting 1-D hybrid nanofibers were predominantly observed by AFM for the Py-Cap/pDNA aggregates. In addition, utilizing a COS-7 cell-line, in-vitro cellular uptakes of new cationic amphiphiles with pyrene probe were studied and visualized by fluorescent microscopy. As a result, this may provide a new approach to investigate the interactions between synthetic cationic lipids and nucleic acids, and pave an alternative clue to design new organic gene delivery carriers.
- Sheng, Ruilong,Luo, Ting,Zhu, Yingdan,Li, Hui,Cao, Amin
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body text
p. 974 - 982
(2011/11/29)
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- Synthesis and antitumour activity of pyrene-linked pyrrolo [2,1-c][1,4]benzodiazepine hybrids
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Pyrene-linked pyrrolobenzodiazepine hybrids have been synthesized that exhibit potential anticancer activity in a number of human tumour cell lines. These hybrids also exhibit much enhanced DNA-binding ability in comparison to the parent pyrrolobenzodiazepine ring system (DC-81).
- Kamal, Ahmed,Ramesh,Srinivas,Ramulu
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p. 471 - 474
(2007/10/03)
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- Pyrene-derived novel one- and two-component organogelators
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A new class of alkyl-chainappended pyrene derivatives 4 - 14 were synthesized and evaluated for their gelation abilities. Depending on the nature of the linking group, these compounds gelated a number of organic solvents, either in the presence or in the absence of the acceptor molecule 2,4,7-trinitrofluorenone (TNF). Compounds with ester, ether, or alkyl linkages gelated a number of hydroxylic and hydrocarbon solvents by means of a charge-transfer interaction with TNF, while compounds with amide, urethane and urea linkers formed gels on their own in a variety of solvents by means of π-π stacking and hydrogen-bonding interactions. The X-ray crystal structure of urethane (S)-12 showed hydrogen-bonding and stacking features, as suggested by the model. The gels obtained were investigated by spectroscopic and electron microscopic techniques which provided structural insights.
- Babu,Sangeetha,Vijaykumar,Maitra, Uday,Rissanen, Kari,Raju
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p. 1922 - 1932
(2007/10/03)
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- Polycyclic aromatic compounds as anticancer agents: Structure-activity relationships of chrysene and pyrene derivatives
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A large number of diamides and diamines were synthesized using 6-amino chrysene and 1-amino pyrene as starting materials. A structure-activity study with cis-platinum as internal control against animal and human tumor lines was carried out in vitro. This study indicated that the in vitro cytotoxicity toward these lines depends on the functionality present in the molecules. The diamino compounds were found to be more potent than the diamides, and these were equally active irrespective of the end heterocyclic group whereas the activity of the diamides was strongly dependent on the terminal unit. In general, the diamides containing chrysene as the chromophore were more active than those with a pyrene ring. The size of the end heterocyclic ring, along with the nature of the spacer connecting the polycyclic ring to the heterocyclic ring, seemed to affect the biological activity in certain stabilizing agens. This agent also demonstrated the stabilizing agents. This agent also demonstrated the capacity to produce differentiation in leukemia cells lines.
- Banik, Bimal K,Becker, Frederick F
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p. 593 - 605
(2007/10/03)
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- A facile reduction of aromatic nitro compounds to aromatic amines by samarium and iodine
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A simple method for the reduction of aromatic nitro compounds to aromatic amines was developed using samarium and catalytic amounts of iodine.
- Banik, Bimal K.,Mukhopadhyay, Chhanda,Venkatraman,Becker, Frederick F.
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p. 7243 - 7246
(2007/10/03)
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- Synthetic studies on 4,5-dihydro-3H-1,2,4-triazole-3,5-diones bearing fluorogenic residues at N-4
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A number of fluorescent 4,5-dihydro-3H-1,2,4-triazole-3,5-diones have been made. Intra-inter-electrophilic substitution by the triazoledione moiety on the activated naphthalene ring of 4-[6-(5-dimethylamino-1-naphthylsulfonamido)hexyl]-4,5-dihydro-3H-1,2,4- triazole-3,5-dione 4a3 leads to rapid decomposition. The dienophilicity of the triazoledione moiety in 4-pyren-1-yl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione 4d is dramatically lowered by steric shielding. Insertion of a three-carbon spacer unit into the latter compound, to give the 3-pyren-1-ylpropyl analogue 4e, affords a valuable fluorogenic reagent for the analysis of trace levels of 1,3-dienes. Powdered barium manganate is shown to be an excellent solid-phase oxidant for conversion of urazoles into 1,2,4-triazole-3,5-diones.
- Read, Gordon,Richardson, Nigel R.
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p. 167 - 174
(2007/10/03)
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- Determination of Nitro Polynuclear Aromatic Hydrocarbons in Air and Diesel Particulate Matter Using Liquid Chromatography with Electrochemical and Fluorescence Detection
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Three different approaches to the liquid chromatographic detection of nitro polynuclear aromatic hydrocarbons in air and diesel particulate extracts are presented, based on differential pulse (LCDPD) and amperometric (LCEC) electrochemical detection and fluorescence detection following on-line reduction to the amine (LCFI).The particulate extraction/fractionation procedure for each detection approach is discussed.The operational advantages of oxygen removal with a platinum oxygen scrubber ( all three types of detection), the use of modulated pulse detection, and wavele nght-programmed fluorescence detection are explored. 1-Nitropyrene is determined in Standard Reference Material (SRM) 1650 diesel particulate matter and in several other " round robin " samples by all three methods.Results are compared to those obtained by other techniques (gas chromatography/ mass spectrometry) and by other laboratories (LCFI).Additionally, 2-nitrofluorene, 9-nitroanthracene, 7-nitrobenzanthracene, and 6-nitrobenzopyrene are determined in SRM 1650 by LCFI.The detection limits for 1-nitropyrene (expressed as picograms) are 5200 (LCDPD), 60 (LCEC), and 10 (LCFI).
- MacCrehan, W. A.,May, W. E.,Yang, S. D.,Benner, B. A.
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p. 194 - 199
(2007/10/02)
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- PHOTOCHEMISTRY OF NAPHTHYL AND PYRENYL AZIDES: CHEMICAL PROPERTIES OF THE TRANSIENT INTERMEDIATES PROBED BY LASER SPECTROSCOPY
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The photochemistry of 1-naphthyl azide, 2-naphthyl azide, 1-pyrenyl azide, and 2-pyrenyl azide was examined in inert (benzene) and reactive (diethylamine) solvents.These studies employ a combination of product analysis, low-temperature spectroscopy, and laser-flash photolysis to reveal the chemical and physical properties of the highly reactive, short-lived intermediates formed in these reactions.In all cases two intermediates account for the observations.One of these is the triplet nitrene and the other is a ground-state singlet transient identified as an azirine.The relationship between these intermediates controls the chemical outcome of the reaction.
- Schrock, Alan A.,Schuster, Gary B.
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p. 5234 - 5240
(2007/10/02)
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- Preparation of Pure Isomers of Dinitropyrenes
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Isomers of dinitripyrenes (1,3-, 1,6-, and 1,8-dinitripyrenes) uncontamined by the other isomers were prepared from the corresponding diaminopyrenes by oxidation, or nucleophilic substitution with nitrite after diazotization.Keywords: dinitropyrene; 1,3-dinitropyrene; 1,6-dinitropyrene; 1,8-dinitropyrene; diaminopyrene; preparation of nitroarenes.
- Hashimoto, Yuichi,Shudo, Koichi
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p. 1992 - 1994
(2007/10/02)
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- Photosubstitution and photoreduction of pyrene and 1-halopyrenes
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Upon irradiation, pyrene reacts with cyanide to give 1-cyanopyrene and with amide to give 1-aminopyrene.With oxygen nucleophiles no reaction takes place.Irradiation of pyrene in the presence of diethyl malonate anion yields 4,5,9,10-tetrahydropyrene in high yield, probably via initial electron transfer to excited pyrene. 1-Fluoropyrene can be photosubstituted with oxygen nucleophiles, leading to 1-hydroxy- and 1-methoxy-pyrene, in contrast to 1-chloro- and 1-bromo-pyrene, which are converted into a mixture of pyrene and 4,5-dihydropyrene upon irradiation.
- Tintel, C.,Rietmeyer, F. J.,Cornelisse, J.
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p. 224 - 228
(2007/10/02)
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- Rabbit liver enzymes responsible for reduction of nitropolycyclic aromatic hydrocarbons
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The present paper is the first description of mammalian nitroreductases acting upon nitropolycyclic aromatic hydrocarbons. Rabbit liver microsomal and cytosolic fractions have ability to reduce 1-nitropyrene or 2-nitrofluorene to the corresponding amine under anaerobic conditions. The nitroreductase activity in the former fraction is mainly due to a cytochrome P-450 system and that in the latter fraction is due to aldehyde oxidase.
- Kitamura,Narai,Hayashi,Tatsumi
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p. 776 - 779
(2007/10/02)
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