Facile synthesis of an ambient stable pyreno[4,5-b]pyrrole monoanion and pyreno[4,5-b:9,10-b′]dipyrrole dianion: from serendipity to design

The stability of singly or multiply negatively charged π-conjugated organic compounds is greatly influenced by their electronic delocalization. Herein, we report a strategic methodology for isolation of a mysterious compound. The isolated compounds, a pyreno[4,5-b]pyrrole monoanion and pyreno[4,5-b:9,10-b′]dipyrrole dianion, were highly stable under ambient conditions due to high delocalization of the negative charge over multiple electron deficient C N groups and pyrene π-scaffolds and allowed purification by column chromatography. To our knowledge, this is the first report on TCNE type reductive condensation of malononitrile involving pyrene di- and tetraone and formation of pyrenopyrrole. All compounds were characterized by spectroscopic methods and X-ray crystallography. A UV-vis spectroscopic study shows an intense low energy absorption band with a large absorption coefficient (ε).

An ambient stable pyreno[4,5-b]pyrrole monoanion and pyreno[4,5-b:9,10-b′]dipyrrole dianion have been isolated and characterized, showing a low energy intense absorption band with the absorption coefficient reaching 7.1 × 10⁴ dm³ mol⁻¹ cm⁻¹.     

Synthesis and aggregational behavior of acidic proteinoid

Polypeptide-based acidic proteinoid containing L -glutamic acid and L -aspartic acid in excess and five other neutral and basic amino acids in minor proportions have been synthesized and found that it forms organized aggregates in an aqueous solution. The proteinoid aggregate has been characterized using ¹³C-NMR, IR, and fluorescence spectroscopic techniques. The c.m.c. of the proteinoid has been determined by conductometric and pH metric methods. The aggregation studies were carried out at different temperatures and varying ionic strengths of the medium. The phase transition of the proteinoid aggregate has been determined using the fluorescence absorbance method. The aggregation behavior is shown to be dependent on the pH of the solution. This was also supported by conductivity measurements. Using methylene blue as a model drug, the drug delivery property of the proteinoid micelles were studied in acidic (pH 4.5) and neutral (pH 7.4) mediums. Using biphasic model thermochemical parameters, ΔG, ΔH, ΔS, and ΔC_p have been evaluated. © 1996 John Wiley & Sons, Inc.     

Design and synthesis of interpenetrating polymer networks for second-order nonlinear optics

There has been a tremendous recent interest in the development of second-order nonlinear optical (NLO) polymeric materials for photonic applications. However, a major drawback of second-order NLO polymers that prevents them from being used in device applications is the instability of their electric field induced dipolar alignment. The randomization of the dipole orientation leads to the decay of second-order optical nonlinearities. Numerous efforts have been made to increase the stability of the second-order NLO properties of polymers. The search for new approaches to develop NLO polymers with optimal properties has been an active research area since the past decade. A novel approach, combining the hybrid properties of high glass transition temperatures, extensively extensively crosslinked networks and permanent entanglements, based on interpenetrating polymer networks (IPN) is introduced to develop stable second-order NLO materials. Two types of IPN systems are prepared and their properties are investigated. The designing criteria and the rationale for the selection of polymers are discussed. The IPN samples show excellent temporal stability at elevated temperatures. Long-term stability of the optical nonlinearity at 100°C has been observed in these materials. Temporal stability of the NLO properties of these IPNs is synergistically enhanced. Relaxation behavior of the optical nonlinearity of an IPN system has been studied and compared with that of a typical guest/host system. The improved temporal stability of the second-order NLO properties of this IPN system is a result of the combination of the high rigidity of the polymer backbones, crosslinked matrices and permanent entanglements of the polymer networks. A slight modification of the chemical structure resulted in an improvement of the optical quality of the sample.     

Biochemical synthesis of water soluble polyanilines: Poly(p-aminobenzoic acid)

This report describes the synthesis of a water soluble polyaniline through a biochemical synthetic route. The oxidative free radical coupling mechanism for the synthesis of poly(p-aminobenzoic acid) is catalyzed by horseradish peroxidase in the presence of hydrogen peroxide. The resulting polymer is electrochemically active and undergoes reversible redox reactions. The polymer as synthesized is self doped and undergoes undoping in alkaline or ammonia solutions.     

Unravelling the Helianthus tuberosus L. (Jerusalem Artichoke,Kiku-Imo) Tuber Proteome by Label-Free Quantitative Proteomics

The present research investigates the tuber proteome of the ‘medicinal’ plant Jerusalem artichoke (abbreviated as JA) (Helianthus tuberosus L.) using a high-throughput proteomics technique. Although JA has been historically known to the Native Americans, it was introduced to Europe in the late 19th century and later spread to Japan (referred to as ‘kiku-imo’) as a folk remedy for diabetes. Genboku Takahashi research group has been working on the cultivation and utilization of kiku-imo tuber as a traditional/alternative medicine in daily life and researched on the lowering of blood sugar level, HbA1c, etc., in human subjects (unpublished data). Understanding the protein components of the tuber may shed light on its healing properties, especially related to diabetes. Using three commercially processed JA tuber products (dried powder and dried chips) we performed total protein extraction on the powdered samples using a label-free quantitate proteomic approach (mass spectrometry) and catalogued for the first time a comprehensive protein list for the JA tuber. A total of 2967 protein groups were identified, statistically analyzed, and further categorized into different protein classes using bioinformatics techniques. We discussed the association of these proteins to health and disease regulatory metabolism. Data are available via ProteomeXchange with identifier PXD030744.     

Bimanes (1,5-diazabicyclo[3.3.0]octadienediones): Laser activity in syn-bimanes

The conversion of 3-methyl-4-benzyl-4-chloro-2-pyrazolin-5-one 10b was catalyzed by a mixture of potassium fluoride and alumina to give syn-(methyl, benzyl)bimane 6 (62%) without detectable formation of the anti isomer, A6 [a 1 : 1 mixture (87%) of the isomers 6 and A6 was obtained when the catalyst was potassium carbonate]. In a similar reaction syn-(methyl,carboethoxymethyl)bimane 7 (15%) with the anti isomer A7 (36%) was obtained from 3-methyl-4-carboethoxymethyl-4-chloro-2-pyrazolin-5-one 10c . syn-(Methyl, β-acetoxyethyl)bimane 8 (70%) was obtained from 3-methyl-4-β-acetoxyethyl-4-chloro-2-pyrazolin-5-one 10d (potassium carbonate catalysis) and was converted by hydrolysis to syn-(methyl, β-hydroxyethyl)bimane 9 (40%). Acetyl nitrate (nitric acid in acetic anhydride) converted anti-(amino,hydrogen)bimane 11 to anti-(amino,nitro)bimane 15 (91%), anti-(methyl,hydrogen)bimane 13 to anti-(methyl,nitro)(methyl,hydrogen)bimane 16 (57%), and degraded syn-(methyl,hydrogen)bimane 12 to an intractable mixture. Treatment with trimethyl phosphite converted syn-(bromomethyl,methyl)bimane 17 to syn-(dimethoxyphosphinylmethyl,methyl)bimane 18 (78%) that was further converted to syn-(styryl,methyl)bimane 19 (29%) in a condensation reaction with benzaldehyde. Treatment with acryloyl chloride converted syn-(hydroxymethyl,methyl)bimane 20 to its acrylate ester 21 (22%). Stoichiometric bromination of syn-(methyl,methyl)bimane 1 gave a monobromo derivative that was converted in situ by treatment with potassium acetate to syn-(acetoxymethyl,methyl)(methyl,methyl)bimane 47 . N-Amino-μ-amino-syn-(methylene,methyl)bimane 24 (68%) was obtained from a reaction between the dibromide 17 and hydrazine. Derivatives of the hydrazine 24 included a perchlorate salt and a hydrazone 25 derived from acetone. Dehydrogenation of syn-(tetramethylene)bimane 26 by treatment with dichlorodicyanobenzoquinone (DDQ) gave syn-(benzo,tetramethylene)bimane 27 (58%) and syn-(benzo)bimane 28 (29%). Bromination of the bimane 26 gave a dibromide 29 (92%) that was also converted by treatment with DDQ to syn-(benzo)bimane 28 . Treatment with palladium (10%) on charcoal dehydrogenated 5, 6, 10, 11-tetrahydro-7H,9H-benz [6, 7] indazol [1, 2a]benz[g]indazol-7,9-dione 35 to syn-(α-naphtho)bimane 36 (71%). The bimane 35 was prepared from 1,2,3,4-tetrahydro-1-oxo-2-naphthoate 37 by stepwise treatment with hydrazine to give 1,2,4,5-tetrahydro-3H-benz[g]indazol-3-one 38 , followed by chlorine to give 3a-chloro-2,3a,4,5-tetrahydro-3H-benz[g]indazol-3-one 39 , and base. Dehydrogenation over palladium converted the indazolone 34 to 1H-benz[g] indazol-3-ol 36 . Helicity for the hexacyclic syn-(α-naphtho)bimane 36 was confirmed by an analysis based on molecular modeling. The relative efficiencies (RE) for laser activity in the spectral region 500–530 nm were obtained for 37 syn-bimanes by reference to coumarin 30 (RE 100): RE > 80 for syn-bimanes 3, 5, 18 , and μ-(dicarbomethoxy)methylene-syn-(methylene,methyl)bimane 22 : RE 20–80: for syn-bimanes 1,2,4,20,24,26 , and μ-thia-syn-(methylene,methyl)bimane 50 : and RE 0-20 for 26 syn-bimanes. The bimane dyes tended to be more photostable and more water-soluble than coumarin 30. The diphosphonate 18 in dioxane showed laser activity at 438 nm and in water at 514 nm. Presumably helicity, that was demonstrated by molecular modeling, brought about a low fluorescence intensity for syn-(α-naphtho)bimane 36 , Φ0.1, considerably lower than obtained for syn-(benzo)bimane 28 , Φ0.9.     

Dielectric properties of a hydrogen-bonded liquid-crystalline side-chain polymer

The dielectric properties of a hydrogen-bonded side-chain liquid-crystalline polysiloxane have been examined over wide ranges of frequency and temperature. This polymer has a side-chain mesogenic moiety consisting of a benzoic acid and a stilbazole. The observed dielectric loss curves contain a component from dipole reorientation of the hydrogen-bonded mesogenic group. It has been found to be possible that, using electrical and thermal treatments, such a polymer built through hydrogen bonding can align homeotropically.     

Semi-wet growth and characterization of multi-functional nano-engineered mixed metal oxides for industrial application

This review paper covers the low temperature wet growth of nano-engineered particles of ZnO-based mixed metal oxides, their growth mechanism, and characterization using X-ray diffraction, SEM, TEM and IR, UV–visible, and XPS spectral techniques. Main focus of this article is centered on low temperature semi-wet methods of synthesis that are suitable for large scale production of zinc oxide-based systems mixed with iron oxide, copper oxide, nickel oxide and cobalt oxide. These mixed metal oxides have broad industrial applications as catalyst, semiconductors, adsorbents, superconductors, electro-ceramics, and antifungal agents in addition to extensive applications in medicines. This paper discusses the low-cost and environment friendly synthesis of these mixed metal oxides, measurement of properties and applicability of these materials systems.     

Cerium vanadate/carbon nanotube hybrid composite nanostructures as a high-performance anode material for lithium-ion batteries

The pristine CeVO4 and CeVO4/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method.From the X-ray diffra...