Diboraanthracene-Doped Polymer Systems for Colour-Tuneable Room-Temperature Organic Afterglow

Organic ultralong room temperature phosphorescence (RTP), or organic afterglow, is a unique phenomenon, gaining widespread attention due to its far-reaching application potential and fundamental interest. Here, two laterally expanded 9,10-dimesityl-dihydro-9,10-diboraanthracene (DBA) derivatives are demonstrated as excellent afterglow materials for red and blue-green light emission, which is traced back to persistent thermally activated delayed fluorescence and RTP. The lateral substitution of polycyclic DBA scaffold, together with weak transversal electron-donating mesityl groups, ensures the optimal molecular properties for (reverse) intersystem crossing and long-lived triplet states in a rigid poly(methyl methacrylate) matrix. The achieved afterglow emission quantum yields of up to 3 % and 15 %, afterglow lifetimes up to 0.8 s and 3.2 s and afterglow durations up to 5 s and 25 s (for red and blue-green emitters, respectively) are attributed to the properties of single molecules.     

Water inclusion as a trigger for modulation of anthracene arrangement and fluorescence emission of organic salt

An organic salt composed 9,10-bis(4-aminophenyl)anthracene and hypophosphorous acid emits yellow-green fluorescence in the crystalline state. The salt also gives water inclusion crystal which provides blue-green fluorescence. Single X-ray crystal studies revealed that water molecules induced the fluorescence change resulting from reaggregation of molecular packing.     

STUDIES ON SOME INTERMEDIATES AND PRODUCTS OF THE PHOTOREDUCTION OF 9,10-ANTHRAQUINONE *,†

Abstract— The mechanism of the photoreduction of 9,10-anthraquinone (AQ) in alcohol and hexane has been studied by flash photolysis. The fluorescence spectrum of the photoproduct, 9,10-dihydroxy anthracene shows a large shift between hexane and ethanol. The quantum yields of photoreduction for AQ are solvent-dependent, the reaction between the solvent radical and AQ determining the quantum yield.
The absorption spectrum of the 9,10-anthrasemiquinone (AQH.) has a long-wavelength absorption band with peaks at 631 and 678 nm. The second-order decay constants for AQH. were estimated to be 1.3 × 10⁹, 6.7 × 10⁸ and 2.0 × 10⁸ M ^-1 sec^-1 in ethanol, 2-propanol and ethylene glycol, respectively.
A long-wavelength absorption band was observed for 9,10-anthrasemiquinone radical anion, having peaks at 776 and 860 nm; epsi;_max= 1900 at 776 nm. This spectrum is compared with the spectra of 9,10-dihydroxy anthracene mono- and di-anions. The 9,10-anthrasemiquinone radical anion was found to photoreduce quantitatively to 9,10-dihydroxy anthracene mono-anion with a quantum yield of 0.1.     

蒽镁的某些化学反应

本文报道了蒽镁与O_2,H_2,C_2H_2,CO,CO_2,(CH_3)_2CO,C_2H_5Br的反应。其中,蒽镁与(CH_3)_2CO和C_2H_5Br的反应可以分别作为合成(9,10-二氢-9-蒽基)二甲基甲醇和9,10-二乙基-9,10-二氢蒽的简易方法。     

EXCITED SINGLET AND TRIPLET PRODUCTS GENERATED FROM OXIDATION OF THE -CO-CH- CONTAINING MOLECULES

Abstract— In a previous study. we found indirect chemiluminescence from air oxidation of various simple ketones in alkaline aprotic solvents containing 9,10-diphenylanthracene and 9,10-dibromoanthracene. By summarizing the experimental results. it was concluded that excited products. mainly in the triplet state. were generated from air oxidation of those simple compounds having a -CO-CH-group via dioxetane intermediates.
Recently. we have succeeded in observing an intense direct chemiluminescence due to the generation of the excited singlet product by the air oxidation of such anthracene derivatives having a -CO-CH-group as 9,10-diisobutyrylanthracene and related compounds. The finding lends strong support to the hypothesis that dioxetane or dioxetanone may be the critical intermediate to give fluorescent singlet products.     

DIFFERENTIAL EFFECT OF ULTRAVIOLET-B RADIATION ON CERTAIN METABOLIC PROCESSES IN A CHROMATICALLY ADAPTING Nostoc

The impact of UV-B radiation on growth, pigmentation and certain physiological processes has been studied in a N2-fixing chromatically adapting cyanobacterium, Nostoc spongiaeforme. A brownish form (phycoerythrin rich) was found to be more tolerant to UV-B than the blue-green (phycocyanin rich) form of N. spongiaeforme. Continuous exposure to UV-B (5.5 W m-2) for 90 min caused complete killing of the blue-green strain whereas the brown strain showed complete loss of survival after 180 min. Pigment content was more strongly inhibited in the blue-green strain than in the brown. Nitrogenase activity was completely abolished in both strains within 35 min of UV-B treatment. Restoration of nitrogenase occurred upon transfer to fluorescent or incandescent light after a lag of 5-6 h, suggesting fresh synthesis of nitrogenase. Unlike the above processes, in vivo nitrate reductase activity was stimulated by UV-B treatment, the degree of enhancement being significantly higher in the blue-green strain. Like the effect of UV-B on nitrogenase, 14CO2 uptake was also completely abolished by UV-B treatment in both strains. Our findings suggest that UV-B may produce a deleterious effect on several metabolic activities of cyanobacteria, especially in cells lacking phycoerythrin. Strains containing phycoerythrin appear to be more tolerant to UV-B, probably because of their inherent property of adapting to a variety of light qualities.     

THERMAL GENERATION OF ELECTRONICALLY EXCITED STATES BY α-PEROXYLACTONES: ACTIVATION PARAMETERS AND EXCITATION YIELDS AS A FUNCTION OF α-DEUTERATION*

Abstract— The kinetics and the direct, the 9,10-dibromo- (DBA) and the 9,10-diphenylanthracene- (DPA) enhanced chemiluminescence of tert-butyl α-peroxylactone 1, with and without α-deuteration, was investigated in order to probe the mechanism of direct chemiexcitation by these hyperenergetic molecules. The small secondary isotope effect on the rates and activation parameters suggests that a diradical mechanism is obtained. The partitioning of the diradical intermediate into excited vs ground state product and the yield of triplet excited product are moderately (ca. 5-fold) increased by α-deuteration, but the singlet yield is unaffected. A convenient and useful chemiluminescence method for the determination of fluorescence quantum yields has been developed.     

PHOTOTACTIC AND PHOTOKINETIC ACTION SPECTRA OF THE DIATOM NITZSCHIA COMMUNIS

Abstract— Three different types of photomotion reactions, photokinesis, photo-topotaxis and photo-phobotaxis, have been investigated in the diatom Nitzschia communis . In photokinesis the active light appears to be absorbed by the photosynthetic pigments. Apparently, the acceleration of movement by light is due to an additional ATP supply from photosynthetic phosphorylation, as it is the case in the blue-green algae of the genus Phormidium . On the other hand, no correlations exist between photo-phobotaxis and photosynthesis, because red light does not induce photo-phobotactic responses in N. communis . The phobotactic action spectrum resembles that one of photo-topotaxis. In the visible region only violet, blue and blue-green light is active in both the reactions. However, it is not yet clear whether or not the stimuli are mediated by the same photoreceptor, mainly because of the different sensitivity of both the reactions to u.v.     

Circular dichroism of 9,10-dihydrophenanthrene derivatives reveals both the absolute configuration and conformation: a novel approach to Mislow's helicity rule

The absolute configuration and the conformation of 9,10-trans-disubstituted 9,10-dihydrophenanthrenes, known chiral metabolites of phenanthrene-9,10-oxide, have been determined by circular dichroism. The absolute configuration assignment is based on the sign of the long-wavelength Cotton effect (A-band), which is conformation invariant and originates from benzylic chirality. This provides a new interpretation of the Mislow biphenyl-helicity rule for the case of the 9,10-dihydrophenanthrene chromophore. The sign of the B-band Cotton effect reflects the conformation of the biphenyl chromophore in 9,10-dihydrophenanthrenes. It is shown that the origin of chiroptical properties of 9,10-dihydrophenanthrenes is closely related to those of 5,6-trans-disubstituted 1,3-cyclohexadienes.     

蓝藻与神府煤共成浆性的研究

考察了预处理方法对含水蓝藻表观黏度的影响,以及蓝藻对神府煤浆成浆浓度、流变性和静态稳定性的影响。结果表明,采用添加化学药剂、高速搅拌、加热等方法对含水蓝藻进行预处理,可以使表观黏度从72mPa·s降低到21.8mPa·s(剪切速率100s^-1)。蓝藻结构受到破坏是表观黏度降低的主要原因。含水蓝藻表观黏度的降低有利于蓝藻煤浆成浆浓度的提高。当添加水质量与含水蓝藻质量比为1∶1时,蓝藻煤浆的成浆浓度达到60%。蓝藻的加入提高了神府煤浆的稳定性,使稳定性从4h提高到72h以上。蓝藻煤浆为假塑性流体,剪切变稀。     

蒽醌衍生物在不同酸度溶液中的吸收光谱

蒽醌类化合物是一类古老的染料,对光和热非常稳定.某些蒽醌化合物还具有稳定的非晶态和晶态结构,在一定条件下可以进行相互转换,这种材料对强光具有非线性,有潜在的应用背景^[1].为此我们设计合成了两种新的蒽醌类化合物,测试了它们在溶液中的吸收光谱,研究了溶液酸碱性对吸收光谱的影响.     

一类以双酚A为连接链的电子给体—受体体系的合成及分子内电子转移反应研究

本文合成了一类以9,10-二甲氧基蒽为给体,双酚A为连接链连接不同受体的电子给体受体新体系,通过稳态荧光光谱及时间分辨荧光光谱研究了它们的光致电子转移反应,并通过测定氧化还原电位,计算出各电子给个受体体系电子转移反应的自由能变化。结果表明,在这一类体系中,光致电子转移速率常数与自由能变化关系符合Rehm-Weller关系式。     

PORPHYRIN-LIPOSOME INTERACTIONS: INFLUENCE OF THE PHYSICO-CHEMICAL PROPERTIES OF THE PHOSPHOLIPID BILAYER

Abstract— The quenching of the fluorescence emitted by hematoporphyrin incorporated into unilamellar liposomes of dipalmitoyl-phosphatidylcholine and dimyristoyl-phosphatidylcholine, was studied by using methylviologen, 9,10-anthraquinone-2,6-disulfonate and 9,10-anthraquinone-2-sulfonate as quenchers, in order to assess how the distribution of the porphyrin and the interaction mode of the various quenchers with the porphyrin is affected by the physico-chemical properties of the vesicles. The results obtained indicate that, below the critical temperature for the phase transition of the lipids, hematoporphyrin is preferentially distributed in the outer lipid monolayer of liposomes of dipalmitoyl-phosphatidylcholine while most hematoporphyrin molecules are located in the inner monolayer in liposomes of dimyristoyl-phosphatidylcholine. This distribution is only slightly changed when the external mean radius of liposomes increases from 26 to 50 nm. The rise of temperature above the critical value for the liquid-gel phase transition causes a shift of the hematoporphyrin molecules toward the inner phospholipid monolayer. This shift is more pronounced in liposomes of dimyristoyl-phosphatidylcholine. Studies on model systems, i.e. neutral and ionic micelles, indicate that methylviologen and anthra-quinone-type quenchers drastically differ in their interaction mechanism with hematoporphyrin. In particular, methylviologen is the only quencher which can discriminate different hematoporphyrin populations in liposomes of dimyristoyl-phosphatidylcholine and dipalmitoyl-phosphatidylcholine in both the liquid and gel phase. Anthraquinone-type quenchers interact with both hematoporphyrin populations when the lipids are in the gel phase. When the lipids are in a fluid state, the quenching occurs only on the external hematoporphyrin population in liposomes of dipalmitoyl-phosphatidylcho-line while in liposomes of dimyristoyl-phosphatidylcholine no discrimination is observed. The influence of the liposomal structure at different temperatures and of the length of the hydrocarbon chains is discussed.     

INFLUENCE OF AN SiO2/CYCLOHEXANE INTERFACE ON THE PHOTOCHEMISTRY OF ANTHRACENE

We have investigated the effect of added Si0₂ on the photochemistry of anthracene, 1, in cyclohexane. Adsorption of 1 onto the Si0₂ surface from cyclohexane follows a Freundlich adsorption isotherm indicating interactions between 1 and the surface over a distribution of adsorption sites. In the absence of oxygen, addition of Si0₂ to a cyclohexane solution of 1 leads to a significant increase in the rate of photolysis without a large concomitant change in product identity. The 9,10-photodimer of 1 is the major product under oxygen-deficient conditions. In the presence of oxygen, added Si0₂ has dramatic effects on both the photoproduct distribution and the kinetics of photodecomposition. The complicated mixture of oxygenated products formed from photolysis in oxygen-containing slurries is proposed to arise from thermal decomposition of a single primary photoproduct, anthracene-9,10-endo-peroxide. The polarity/polarizability of the Si0₂/cyclohexane interface is considered to be a major factor influencing the rate of photolysis in the oxygenated Si0₂/cyclohexane slurries.     

The hydrogenation of 9,10-dimethylanthracene by hydridopentacarbonylmanganese(I). Evidence for a free-radical mechanism

The reaction of 9,10-dimethylanthracene with HMn(CO)₅ yields a nearly equimolar mixture of cis- and trans-9,10-dihydro-9,10-dimethylanthracene. The results of kinetic and isotropic tracer studies provide support for a free-radical mechanism in which the rate-determining step is the transfer of a hydrogen atom from HMn(CO)₅ to 9,10-dimethylanthracene.     

4,5-二芳基噁唑的光化学环化消除合成菲并[9,10-d]噁唑

具有异芪生色团结构的分子是有机光化学研究的重要对象^[1]。4,5-二芳基嗯唑(1)具有部分结构与异芪类似,本文对其分子内环化消除过程和产物进行了研究。     

SKIN OPTICS AND PHOTOTHERAPY OF JAUNDICE

Abstract The Kubelka–Munk theory of radiation transfer is applied to determine the influence of skin optical losses on the efficiency of phototherapy of jaundice. Using a multi-layer model of the skin the photon absorption rate of bilirubin molecules is calculated for spectrally Gaussian light sources and fluorescent lamps used in phototherapy. Light absorption and scattering processes in the skin layers shift the optimum value of the peak excitation wavelength from λ= 453 nm (absorption maximum of bilirubin in vitro ) to λ= 480 nm. This suggests the clinical investigation of narrow-spectrum lamps emitting in the blue-green region of the spectrum.     

Synthesis of Dialkyl 4-Ethoxy-2,5-dihydro-1-(9,10-dihydro-9,10-dioxoanthracen-1-yl)-5-oxo-1H-pyrrole2,3-dicarboxylates

Abstract

The reaction of ethyl 9,10-dihydro-9,10-dioxoanthracen-1-yl-carbamoyl-formate with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine leads to dialkyl 4-ethoxy-2,5-dihydro-1-(9,10-dihydro-9,10-dioxoanthracen-1-yl)-5-oxo-1H-pyrrole-2,3-dicarboxylates in fairly good yields. A dynamic NMR effect is observed as a result of restricted rotation around the single bond linking the anthraquinone moiety and the heterocyclic ring system, which is attributed to the interaction between the pyrrole residue and the peri C═O group.     

Syntheses and bioactivities of substituted 9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrones. Unusual reactivities with amines

A number of substituted 9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrones have been synthesized and their anticancer and antimalarial activities evaluated. A one-pot synthesis of 2,5,8-trimethoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4-dione (4) was achieved by heating a mixture of 1,4-dimethoxyanthracene, methoxyhydroquinone, silver oxide, and zinc iodide in toluene. Regioselective bromination of 4 and 2-methoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrone (7) with N-bromosuccinimide provided 2-bromo-3,5,8-trimethoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4-dione and 2-bromo-3-methoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrone (1), respectively. The reactions of 1 with aliphatic primary amines and secondary amines, respectively, produced different products, a result most likely attributed to the different basicities (or nucleophilicities) and steric effects of the two kinds of amines. The structure of the displacement product, 2-bromo-3-[2-(tert-butoxycarbonyl)ethylamino]-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrone, from the reaction of 1 with tert-butyl 3-aminopropanoate was unequivocally determined by a single-crystal X-ray analysis. IC(50) values of triptycene bisquinones for the inhibition of L1210 leukemia cell viability are in the 0.11-0.27 microM range and for the inhibition of Plasmodium falciparum 3D7 are in the 4.7-8.0 microM range.     

Reductive Activation of Arenes: XIII. Reaction with Butyl Bromide of Anionic Products Formed by Reduction of 9,10-Dicyanoanthracene with Potassium in Liquid Ammonia

Reduction of 9,10-dicyanoanthracene with one equivalent of metallic potassium in liquid ammonia at -33°C gives a product which almost does not react with butyl bromide. By contrast, the two-electron reduction product reacts with butyl bromide to form, depending on the reaction conditions and procedure for treatment of the reaction mixture, one of the three compounds: 10-butyl-9-cyanoanthracene, 10-butyl-10-cyano-9,10-dihydroanthracen-9-one, or 9,10-dibutyl-9,10-dicyano-9,10-dihydroanthracene. Relatively stable 10-butyl-9,10-dicyano-9,10-dihydro-9-anthryl anion was presumed to be a common precursor of these products.