A new chiral anthracene for the asymmetric Diels-Alder/retro-Diels-Alder sequence

(-)-(R)-9-(1,2-Dimethoxyethyl)anthracene (8) is successfully employed as a chiral template in the Diels-Alder/retro-Diels-Alder sequence for the preparation of alpha,beta-unsaturated lactams. The cycloadditions proceed with complete diastereoselectivity, and regioselectivity in subsequent transformations of the carbonyl groups is also excellent. Flash vacuum pyrolysis accomplishes the cycloreversion.     

Fused-seven-ring anthracene derivative with two sulfur bridges for high performance red organic light-emitting diodes

A fused-seven-ring anthracene derivative with two sulfur bridges, benzobisthioxanthene (BTA), was synthesized, facilely. OLEDs employing BTA as the emitter exhibited bright (maximum 40,752 cd m(-2)) and efficient red emission (CIE, x = 0.64, y = 0.36) with a luminous efficiency of 4.4 cd A(-1).     

Semi-metallic single-component crystal of soluble La@C82 derivative with high electron mobility

We prepared an organic conductor crystal having extremely high electron mobility, in which the adamantylidene (Ad) derivative of La@C(82) (an endohedral metallofullerene known as a n-type semiconductor) is aligned in an orderly fashion. The single-component crystal exhibits high electron mobility of μ > 10 cm(2) V(-1) s(-1) along the c axis under normal temperatures and pressures in the atmosphere, as shown by flash-photolysis time-resolved microwave conductivity (TRMC) measurements, which are the highest of reported organic conductors measured by TRMC. According to density functional calculations, the single crystal of La@C(82)Ad is semi-metallic, with a small band gap of 0.005 eV.     

DSC Investigation on anthracene derivative photodimers

Anthracene derivative dimers reveal a thermal monomerization at temperatures higher than the melting points of the corresponding monomers. Thermograms of these dimers are consisting of a broad endotherm followed by a small exotherm. A detailed investigation on 9-chloroanthracene dimer allowed to explain this peculiar behaviour.

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Zusammenfassung Dimere Anthracenderivate zeigen für Temperaturen, die höher als die Schmelzpunkte der entsprechenden Monomeren liegen, eine thermische Monomerisierung. Die beobachteten Thermogramme dieser Dimeren bestehen aus einem breiten endothermen Vorgang mit partieller überlappung eines anschliessenden schwach exothermen Vorgangs. Für 9-Chloroanthracen konnte sowohl mittels geeignet ausgeführter konsekutiver Scans als auch mit einer Modellmischung dieses eigenartige Verhalten erklÄrt werden.

     

Metal-organic framework from an anthracene derivative containing nanoscopic cages exhibiting high methane uptake

A microporous metal-organic framework, PCN-14, based on an anthracene derivative, 5,5'-(9,10-anthracenediyl)di-isophthalate (H4adip), was synthesized under solvothermal reaction conditions. X-ray single crystal analysis revealed that PCN-14 consists of nanoscopic cages suitable for gas storage. N2-adsorption studies of PCN-14 at 77 K reveal a Langmuir surface area of 2176 m2/g and a pore volume of 0.87 cm3/g. Methane adsorption studies at 290 K and 35 bar show that PCN-14 exhibits an absolute methane-adsorption capacity of 230 v/v, 28% higher than the DOE target (180 v/v) for methane storage.     

A new fluorescent as well as chromogenic chemosensor for anions based on an anthracene carbamate derivative

A new fluorescent as well as chromogenic anion sensor, 1,8-anthradiol bis(N-phenylcarbamate) 2, was synthesized. It exhibits new selective red-shifted absorption and fluorescence bands with F⁻ and AcO⁻, which could be attributed to the anthracene moiety directly involved in the bonding interaction with the anions.     

Catalytic asymmetric Michael addition with curcumin derivative

Catalytic asymmetric Michael additions with curcumin derivatives were achieved by a new series of tertiary amine-thiourea organocatalysts to afford the Michael adducts in high yields and excellent enantioselectivities.     

A new acridine derivative as a fluorescent chemosensor for zinc ions in an 100% aqueous solution: a comparison of binding property with anthracene derivative

A new acridine derivative was synthesized as a fluorescent chemosensor for Zn²⁺ in an 100% aqueous solution. Compound 1 displayed a selective CHEF (chelation enhanced fluorescence) effect with Zn²⁺, on the other hand, a similar anthracene derivative 2 did not display any significant change with the metal ions examined.     

Feasibility of higher-order differential ion mobility separations using new asymmetric waveforms

Technologies for separating and characterizing ions based on their transport properties in gases have been around for three decades. The early method of ion mobility spectrometry (IMS) distinguished ions by absolute mobility that depends on the collision cross section with buffer gas atoms. The more recent technique of field asymmetric waveform IMS (FAIMS) measures the difference between mobilities at high and low electric fields. Coupling IMS and FAIMS to soft ionization sources and mass spectrometry (MS) has greatly expanded their utility, enabling new applications in biomedical and nanomaterials research. Here, we show that time-dependent electric fields comprising more than two intensity levels could, in principle, effect an infinite number of distinct differential separations based on the higher-order terms of expression for ion mobility. These analyses could employ the hardware and operational procedures similar to those utilized in FAIMS. Methods up to the 4th or 5th order (where conventional IMS is 1st order and FAIMS is 2nd order) should be practical at field intensities accessible in ambient air, with still higher orders potentially achievable in insulating gases. Available experimental data suggest that higher-order separations should be largely orthogonal to each other and to FAIMS, IMS, and MS.     

Preparation of a new FerroPHOS derivative for palladium-catalyzed asymmetric allylic alkylations

A new C₂-symmetric only cylindrically chiral FerroPHOS derivative possessing (1-methoxy-1-methyl)ethyl substituents was prepared and applied to the palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenylprop-2-en-1-yl acetate. Both high catalytic activity (up to 500 turnovers) and enantioselectivity (e.e.'s of up to 96.3%) were attained in reactions using the new diphosphine ligand.     

A new crown ether annelated tetrathiafulvalene derivative with anthracene moiety as a sensor for Li and O2

A new crown ether annulated tetrathiafulvalene derivative with an anthracene moiety is shown to act as a dual-functional sensor for Li⁺ and ¹O₂, which may be useful in information processing at the molecular level.     

Tuning the DNA binding modes of an anthracene derivative with salt

The DNA binding properties of an anthracene derivative with substituents at the 9 and 10 positions, carrying four positive charges, are examined in calorimetric, spectroscopic and photocleavage studies. Isothermal titration calorimetric data indicated exothermic binding of the ligand to calf thymus DNA with a binding constant of (1.4 ± 0.5) × 10⁵ M⁻¹ and this value is much greater than binding of similar monocationic derivatives. The values for the other binding parameters were, ΔH = −3.5 ± 0.4 kcal/mol; ΔS = 11.6 ± 1.6 cal/mol K, and a binding site size of ∼4 base pairs. Absorption spectral studies indicated small, but significant red shifts in the vibronic bands, and ∼70% of hypochromism. The binding plots indicated bi-phasic binding of the ligand. At higher ionic strengths, the red shifts in the absorption spectra were abolished but significant hypochromism persisted.Excitation and sensitized fluorescence spectral studies indicated weak energy transfer from the DNA bases to the ligand. Further more, energy transfer was reduced substantially at higher ionic strengths. Strong induced circular dichroism bands are noted, in the 300–400 nm region, and these are most likely dominated by the contributions from the groove bound form as well as the intercalated chromophore. Helix melting studies indicated improvement in the helix stability, and substantial increase in the melting temperature (ΔT_m > 17 °C). Differential scanning calorimetric data, on the other hand, indicated only minor improvements in the thermodynamic parameters. Irradiation of a mixture of the ligand (2 μM) and supercoiled pUC18 DNA (20 μM, @374 nm) resulted in the efficient formation of nicked circular DNA (>90%) in an hour. The data indicated at least two distinct binding modes, and one of these persisted at high ionic strengths (375 mM NaCl). Substitution at 9 and 10 positions of the anthracene ring system with positively charged residues resulted in multiple binding modes, and these are resolvable in ionic strength studies.     

A structurally simple l-proline derivative promotes the asymmetric allylation of aldehydes with tribromoallyltin

An asymmetric allylation of aldehydes with the allyltin tribromide was achieved using the l-proline derivative as a chiral promoter in dichloromethane in the presence of a Lewis base. Various optically active homoallylic alcohols were obtained in high yields with moderate enatioselectivities of up to 62% ee.     

High-field asymmetric waveform ion mobility spectrometry: a new tool for mass spectrometry

High-field asymmetric waveform ion mobility spectrometry (FAIMS) is a new technology for ion separation at atmospheric pressure. This review introduces the reader to FAIMS, covering topics ranging from the fundamentals and extraction of physical parameters from the raw data, to applications of FAIMS extending from homeland security to environmental analysis to proteomics. The investigation of FAIMS as an ion pre-processing tool for mass spectrometry is in its infancy, but reports in the literature illustrate that FAIMS separates isobaric ions including diastereoisomers, separates isotopes, reduces background ions by isolating ions of interest, and simplifies spectra of complex mixtures by dividing the mixture into a series of simpler subsets of ions. Applications ranging from quantitative analysis of inorganic and organometallic compounds, to studies of the conformers of intact proteins, have been reported. This review is a launching point for further exploration of FAIMS.     

A new amidrazone derivative with anti­mycobacterial activity

Of a series of pyridine‐2‐carboxamidrazone derivatives with activity against mycobacteria, the N¹‐[4‐(1,1‐di­methyl­propyl)­benzyl­idene] derivative reported here, C₁₈H₂₂N₄, is one of the most active. The predicted E isomer about the C11=N12 double bond is confirmed and intramolecular hydrogen bonding involving both amino H atoms helps to keep the mol­ecule flat. The same donor and acceptor atoms also form intermolecular hydrogen bonds.     

A new asymmetric organocatalytic nitrocyclopropanation reaction

Using 5-(pyrrolidin-2-yl)-1H-tetrazole as an organic catalyst, the nitrocyclopropanation of 2-cyclohexen-1-one has been achieved, proceeding in high yield and with good enantioselective control.     

A new asymmetric synthesis of trans-hydroisoquinolones

[reaction: see text]. A convenient enantioselective synthesis of trans-hydroisoquinolones is described. This synthesis capitalizes on the ready availability of enantioenriched 2-substituted cyclohexenols by exploiting the asymmetry of an allylic carbon-oxygen sigma bond to control carbon-carbon bond formation in pinacol-terminated cyclizations of N-acyliminium cations.