三羟基荧光酮试剂的量子化学计算和性能的讨论

应用Hückel分子轨道法计算了15种三羟基荧光酮试剂分子的π电荷密度分布,确定了三羟基荧光酮分子中3个羟基离解的顺序、金属离子的配合位置和螯合物的结构。进一步讨论了取代基和反应介质对此类试剂分析性能的影响。     

Heterostructure Ag@WO3-x Composites with High Selectivity for Breaking Azo-bond

The heterostructure Ag@WO_3-x(x=0.1 or 1) composites with high selectivity for breaking azo-bond were obtained by in situ reduction of Ag₂WO₄. The crystal structure and morphology of Ag@WO_3-x were characterized by X-ray powder diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM). The residue solution of methyl orange(MO) after degradation was tested by gas chromatograph mass spectrometer (GCMS) to analyze the exact components. The results indicate that the products after degradation are N, N-dimethylaniline, N, N-dimethyl-p-phenylenediamine and sulfanilic acid. This is caused by specific breaking of azo-bond in MO. The azo-bond breaking of MO by Ag@WO_3-x could occur in dark without any light illumination. Therefore, we proposed a possible mechanism for this azo-bond breaking reaction based on the reaction condition and results.     

Theoretical Analysis on Magnetic Properties of Conjugated Organic Molecules Containing Borepin

Theoretical study about the magnetic properties of conjugated organic molecules containing borepin with π current density was carried out. 1-(2,4,6-Trimethylphenyl)borepin moiety is the center and other different groups are situated on the both β sides, which are named molecules 1-12 as theoretical model in order to establish the relationship between aromaticity and geometry variation of borepin. The optimized molecular structures of molecules 1-12 are almost keeping planar and the C2-C3 bond length of borepin turns longer from molecule 1 to molecule 12. Different borepin-annulated ring could change the conjugated effect of π-electron between borepin and these borepin-annulated rings. Moreover, the molecule presents antiaromaticity, in other words, the molecule became unstable when the C2-C3 bond length of borepin extended more than ca. 0.1417 nm. But the β position fragment and substituent groups of borepin are not affected in this case, they are still steady. However, the central borepin ring current is counteracted by symmetrical overlap of it with affiliated borepin-annulated ring current. Hence, the central borepin ring breaking would be liable to occur. These molecules have higher vertical ionization potentials(VIPs) and lower vertical electron affinities(VEAs), which suggests that these molecules could easily exist in anionic form.     

Triarylborane π-electron systems with intramolecular charge-transfer transitions

The incorporation of B element into π-conjugated system is an efficient strategy to tune the steric and electronic structure and thus optoelectronic properties of π-electron systems.The vacant p orbital on the tricoordinate B center makes it exhibit several electronic and steric features,such as electron-accepting ability through p-π~* conjugation,the high Lewis acidity to coordinate with Lewis bases,as well as the steric bulk arising from the aryl substituent on the B center to get enough kinetic stability.As a result,the boryl group is a very unique electron acceptor.When an electron-donating amino group is present,the triarylboranes would display intense intramolecular charge transfer transitions,which lead to interesting optoelectronic properties and great utilities.This short review summarizes the recent progress in π-electron systems,which contain both B and N elements and thus display intramolecular charge-transfer transitions.The triarylboranes are introduced based on their structural features,including the linear π-system with boryl and amino groups at the terminal positions,the lateral borylsubstituted π-system with amino groups at the terminal positions,the biphenyl π-system with an amino and a boryl groups at o,o'-positions,nonconjugated U- and V-shaped π-system,macrocylcic π-system with B and N embedded in the ring,B,N-bridged ladder-type π-system,as well as the polycyclicπ-system with B embedded in the center.     

Simulating the Degradation of Odor Precursors in Primary and Waste-Activated Sludge During Anaerobic Digestion

Degradation of known odor precursors in sludge during anaerobic digestion was systematically studied and simulated using the Anaerobic Digestion Model Number 1 (ADM1). The degradation of various protein fractions (particulate, soluble, and bound), volatile fatty acids (VFAs), lipids, and amino acids of primary sludge (PS) and waste-activated sludge (WAS) were monitored during anaerobic digestion. The degradation kinetic constants of the odor precursors namely, protein, lipid, and VFAs were determined. Relationships between degradations of protein fractions and volatile suspended solid were established; a strong relationship between bound protein, a major odor precursor, and volatile suspended solid degradation was found. No statistically significant difference in bound protein reduction was observed between PS and WAS. ADM1 was successfully used to simulate the lab scale continuous anaerobic digestion; model results with optimized parameters showed good agreement with the experimental data for methane production and several other sludge parameters including odor precursors such as lipids, VFAs, and proteins.     

Disk-shaped Symmetric Hexa-substituted Triphenylene Derivatives: Synthesis,Physical Properties and Self-assembly

A series of triphenylene derivatives with six symmetric substituents was synthesized from hexabromotriphenylene. The synthesis was conducted by six-fold palladium-catalyzed Hagihara-Sonogashira cross- coupling reactions to yield the hexa-alkynyl substituted triphenylene derivatives of HTP1, HTP2, HTP3 and HTP4. The six symmetric substituents can not only endow the triphenylene the longer π-conjugated range, but also increase the solubility of the compounds. Their photophysical, electrochemical, thermal properties were investigated respectively. With the comparison of their properties, the structure-property relationships were established which demonstrated the influences of different substituents on the electronic nature and the mesomorphic phase of these disk-shaped molecules. In addition, with the scanning electron microscopy(SEM) and polarized optical microscopy(POM) characterization, the self-assembly behaviors of the compounds were also investigated.     

双甲基化大豆苷元磺酸盐的合成、晶体结构及活性研究

以大豆苷元为原料合成了强水溶性异黄酮类化合物7,4′-二甲氧基异黄酮-3′-磺酸钠(1)和7,4′-二甲氧基异黄酮-3′-磺酸铜(2).X射线单晶衍射分析表明,化合物1的分子组成为[Na(H₂O)₂](C₁₇H₁₃O₄SO₃),Na的配位数为6,且相邻钠离子以7,4′-二甲氧基异黄酮-3′-磺酸根氧原子桥连,与两个磺酸根的3个氧原子和1个S原子组成六元环,六元环通过Na-O配位键彼此稠合,在晶体结构中形成延伸的锯齿状聚合八面体配位钠离子链;这些钠离子链之间又通过配位水与配位水、磺酸根之间的氢键作用自组装成二维结构的超分子离子聚合物.化合物2的分子组成为[Cu(H₂O)₆](C₁₇H₁₃O₄SO₃)₂·8H₂O,Cu(Ⅱ)位于对称中心上.[Cu(H₂O)₆]²⁺,C₁₇H₁₃O₄SO^-₃和H₂O之间存在多种氢键;并且异黄酮环反平行排列存在π…π的堆积作用.氢键和π…π的堆积作用使化合物2自组装成三维结构的超分子.抗缺氧缺血活性试验结果表明,它们的抗缺氧缺血活性比大豆苷元的高.     

有机试剂结构与性质的研究(X)——偶氮苯衍生物结构与吸收光谱的研究

本文应用PPP-SCF-CI法计算了偶氮苯衍生物的结构,发现偶氮苯衍生物波长最大的吸收峰(相应于电子从基态向第一激发态跃迁)是分子内荷移光谱,这些吸收峰的计算值与实验值完全一致.此外,还根据PPP计算结果研究了取代基对吸收光谱的影响.     

Decolorization and partial degradation of selected azo dyes by methanogenic sludge

The toxicity potential and decolorization of three acid azo dyes (Acid Orange 6, Acid Orange 7, and Acid Orange 52) by methanogenic granular sludge from an anaerobic expanded granular sludge bed reactor was assayed. Complete bioreduction was found for all three azo dyes. Sulfanilic acid and 4-aminoresorcinol were detected from the decolorization of Acid Orange 6, sulfanilic acid and 1-amino-2-naphtol were detected from the reduction of Acid Orange 7, and sulfanilic acid and N,N-dimethyl-1,4-phenylenediamine (DMP) were found to be intermediates of Acid Orange 52 degradation. Sulfanilic acid and 1-amino-2-naphtol were persistent in the anaerobic conditions, whereas 4-aminoresorcinol was completely mineralized by anaerobic sludge and DMP was transformed into 1,4-phenylenediamine. Enrichment cultures obtained via consecutive passages on basal medium with only azo dye as a carbon and an energy source seemed to be morphologically heterogeneous. Baculiform and coccus cells were found when viewed under a light microscope. Cocci were joined in chains. Because anaerobic sludge contains sulfate-reducing bacteria and therefore may generate sulfide, azo dyes were tested for chemical decolorization by sulfide to compare rates of chemical and biologic reduction.     

Studies of the regioselective ring-opening–closing mode of functionally different thiazolidine type enaminones: en route to the synthesis of trithiaazapentalene derivatives

Trithiaazapentalene derivatives were prepared by the reaction of 2-alkylidene-4-oxothiazolidines with Lawesson's reagent. They are classified as two structurally different trithiaazapentalene compounds that have different contributions of monocyclic 1,2-dithiole and 1,2,4-dithiazole structures and degrees of aromaticity of the bicyclic trithiaazapentalene system. The electron-donating ability of substituents at the C(5) position of the trithiaazapentalene system is recognized as the main cause for changes in π-electron distribution. This is the first complete study of substituent effects on the structure of trithiapentalenes.     

折叠型双银配合物电子结构与相关性质

在密度泛函B3LYP/LanL2DZ的水平上,对具有π-π弱相互作用调控的折叠型银配合物Ag₂(MPTQ)₂²⁺进行计算研究。探讨该配合物的电子结构、成键特征、π-π弱相互作用机理、电荷布居及其相关性质。计算结果表明,Ag…Ag之间存在弱的直接相互作用,HOMO主要布居在配体中芳香环的σ-p轨道、S的σ-p轨道及与S相连的C12的S轨道上,LUMO主要布居在配体中芳香环的π^*-p轨道上,基态电子光谱主要是配体中的n→π^*跃迁产生的电荷转移光谱。论文还讨论了分子间π-π弱相互作用的本质及活性部位等。计算结果能较好地解释实验现象与规律。     

以主族元素为桥的梯形化合物的光电性质

梯形化合物具有大的平面π共轭结构, 不会产生构象扭曲, 可以有效增加π共轭长度, 因而表现出非常好的光电性质. 将主族元素引入到梯形化合物骨架中作为桥接单元不仅可以固定其结构而且由于主族元素和π共轭骨架之间的轨道相互作用, 可以实现对这类化合物光电性质的调节. 采用密度泛函理论对一系列主族元素桥的梯形化合物的结构和光电性质进行了理论研究, 从而可更好地理解和预测这类化合物的性质. 研究发现, 这类化合物的电子结构可以通过引入主族元素进行调节. 由于具有更大的π共轭程度, 四主族元素桥化合物的吸收与双主族元素桥化合物相比有明显的红移, 而且荧光寿命较短. 另外, 通过计算离子化势(IPs)、电子亲和能(EAs)和重组能(λ)考察了这类化合物的电子和空穴注入及传输性质. 研究发现, 四主族元素桥化合物表现出更强的电子和空穴注入能力.     

Solid-state Synthesis of Aryl and Vinyl of Ferrocene Derivatives via Wittig Reaction

Organometallic structure possessing extensively conjugated π-electron system are an interesting class of potentially highly nonlinear molecular blocks and photoactive semiconductor^[1,2]. The title compounds were synthesized following Wittig reaction or palladium-catalyzed reaction of olefines and iodoferrocene, which proceed in solution and refluxing^[3]. However, there are always some disadvantages such as long reaction time, difficult work-up and low yield. Herein we report a free-solvent synthesis of aryl and vinyl ferrocene derivatives. As shown in the table, the phosphoning salt (1mol),NaOH (1.5mol) and formylferrocene (1mol) were mixed by grinding at room temperature to 65℃ in dry state to give the corresponding title compounds in 60-90% yield. The reaction was usually completed within a few minutes. The product thus obtained is mainly E-isomer. It could be emphasized that solid-state Wittig reaction is fast, cleaner and efficient.     

Aerobic and anaerobic microbial degradation of poly-beta-hydroxybutyrate produced by Azotobacter chroococcum

Food industry wastewater served as a carbon source for the synthesis of poly-β-hydroxybutyrate (PHB) by Azotobacter chroococcum. The content of polymer in bacterial cells grown on the raw materials reached 75%. PHB films were degraded under aerobic, microaerobic, and anaerobic conditions in the presence and absence of nitrate by microbial populations of soil, sludges from anaerobic and nitrifying/denitrifying reactors, and sediment from a sludge deposit site. Changes in molecular mass, crystallinity, and mechanical properties of PHB were studied. Anaerobic degradation was accompanied by acetate formation, which was the main intermediate utilized by denitrifying bacteria or methanogenic archaea. On a decrease in temperature from 20 to 5° C in the presence of nitrate, the rate of PHB degradation was 7.3 times lower. Under anaerobic conditions and in the absence of nitrate, no PHB degradation was observed, even at 11°C. The enrichment cultures of denitrifying bacteria obtained from soil and anaerobic sludge degraded PHB films for a short time (3–7 d). The dominant species in the enrichment culture from soil were Pseudomonas fluorescens and Pseudomonas stutzeri. The rate of PHB degradation by the enrichment cultures depended on the polymer molecular weight, which reduced with time during biodegradation.     

Planarity of ethylene/linear polyene analogues focused on π-electron holding ability of the components

Ethylene/polyene analogues composed of heavier group 14 elements, such as silicon and germanium, do not prefer a planar structure. In the repulsion dominant (RD) model of our previous study mainly focusing on the planarity of hexasilabenzene, it was demonstrated that electron repulsion promotes nonplanarization of heavy benzene analogues. In this study, we have investigated a correlation between intramolecular π-electron transfers (polarization effect) and planarity in various linear unsaturated compounds in order to deepen the RD model. Herein, it was revealed that the ability to hold π-electrons in the planar molecular structure is characteristic of each element. For example, carbon can hold more than one π-electron, whereas silicon and germanium cannot tolerate even one π-electron to keep the planar structure. Thus, π-accepting substituents on the heavy atom were found to make the heavy ethylenes and linear polyenes planar by controlling the number of π-electrons on each skeletal atom.     

芘基丁酸键合硅胶固定相对含π电子物质的高效液相色谱分离研究

通过芘基丁酸键合硅胶固定相对含π电子物质的分离研究, 考察了该固定相的色谱性能. 结果表明, 该固定相不仅具有疏水作用和电荷转移性能, 还具有很强的平面识别能力, 可很好地分离烷基苯、 稠环芳烃及取代硝基苯等各种含π电子物质， 且在pH 3.5～7.0 时化学稳定性能良好, 硅醇基效应得到了很好的抑制, 可有效地用于碱性化合物的分离分析.     

Influence of terminal substituents on the halide anion binding of foldamer-based receptors

Foldamers 1–4 incorporating different terminal substituents have been designed and synthesized for binding halide anions.~1H NMR titration experiments carried out in DMSO-d_6/CDCl_3(15/85, v/v)demonstrated that the short oligo (aryltriazole)s backbone 1 could not bind halide anions unless that amide H-bond donors were incorporated at the termini of the oligomer. Terminal substituents on oligo(aryltriazoleamide)s foldamers 2–4 display a considerable influence on the binding affinities of the foldamers for halide anions. Large steric hindrance of the terminal substituents was found to be unfavorable for binding halide anions, but aromatic π-π interactions between two terminal substituents are capable of stabilizing the conformation of foldamers thus giving rise to an enhancement in the binding strengths. However, the terminal substituents were found to hardly affect the binding selectivity in the studied cases.     

Spectral-luminescence properties and basicities of 2-(4-pyridyl)-5-(4-r-phenyl)oxazoles

The spectral-luminescence and acid-base properties of 2-(4-pyridyl)-5-(4-R-phenyl)oxazoles were studied. Significant -electron conjugation between the individual fragments exists in the molecules of these compounds in solutions at room temperature. Bathochromic and bathofluoric effects, which are particularly appreciable for electron-donor substituents, are observed when substituents R are introduced into the 5-phenyl ring. Ethanol solutions of the investigated compounds have high fluorescence quantum yields which, for some of them, are close to unity. Electron-donor substituents R increase the basicity of the pyridine nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 479–482, April, 1985.     

Electron beam pretreatment of sewage sludge before anaerobic digestion

The pretreatment of waste-activated sludge (WAS) by electron beam irradiation was studied in order to improve anaerobic sludge digestion. The irradiation dose of the electron beam was varied from 0.5 to 10 kGy. Batch and continuous-flow stirred tank reactors (CFSTRs) were operated to evaluate the effect of the electron beam pretreatment on anaerobic sludge digestion. Approximately 30–52% of the total chemical oxygen demand (COD) content of the WAS was solubilized within 24 h after electron beam irradiation. A large quantity of soluble COD, protein, and carbohydrates leached out from cell ruptures caused by the electron beam irradiation. Volatile fatty acids production from the irradiated sludge was approx 90% higher than that of the unirradiated sludge. The degradation of irradiated sewage sludge was described by two distinct first-order decay rates (k ₁ and k ₂). Most initial decay reaction accelerated within 10 d, with an average k ₁ of 0.06/d for sewage sludge irradiated at all dosages. The mean values for the long-term batch first-order decay coefficient (k ₂) were 0.025/d for irradiated sewage sludge and 0.007/d for unirradiated sludge. Volatile solids removal efficiency of the control reactor fed with unirradiated sewage sludge at a hydraulic retention time (HRT) of 20 d was almost the same as that of the CFSTRs fed with irradiated sludge at an HRT of 10 d. Therefore, disintegration of sewage sludge cells using electron beam pretreatment could reduce the reactor solid retention time by half.     

Studies on nitroenamines. Part III. Synthesis and spectral properties of 4-Acyl-1-arylimidazoles

The catalytic (C/Pd) hydrogenation of 3-arylamino-2-nitro-2-enones ( 1 ) in the presence of carboxylic ortho esters ( 2 ) affords 4-acyl-1-arylimidazoles ( 3 ) in yields (20–70%) which depend on the degree of substitution of the imidazole ring. The spectral properties of compounds 3 , and particularly the ¹³C-nmr spectra, reflect both the electronic and steric effects of the substituents on the π-electron delocalization and planarity of the bicyclic system.