Novel Heptamethine 3H-Indocyanines and their Spectral Properties

Novel heptamethine 3H-indocyanine dyes are synthesized and embedded into a matrix of silica gel derived from tetraethoxysilicane. The photophysical properties of these near infrared dyes in various solvents and in SiO2 sol gel were investigated. The results show that the dyes containing cyclohexenylene bridge and N-(p-carboxy)benzyl groups have better photostability and longer absorption wavelength than those containing linear heptamethine bridge and/or N-(5-carboxy)pentanyl groups. The absorption maxima of these dyes are in reverse proportion to the polarity of the solvents. The microenvironment of the dyes in SiO2 sol-gel characters medium polarity (between methanol and DMF) according to the absorption maxima.     

Nested Genetic Algorithm for Resolving Overlapped Spectral Bands

Resolvingoverlappedpeaksisamainproblemencounteredinal1alyzingspectraanddataprocessing.OptimizationmethodshavebeenusedforresoIvingoverlappedbands.Geneticalgorithrns(GAs)arenumericaloptin1izationmethodsbasedontheconceptsofgeneticsandnaturalselection.Therefore,GAspossessebetternonlinearparalleIandseIfadaptiveproperties'.Inthiswork,anestedgenetica1gorithm(NGA),includinggeneticparameterleveIandgeneticimplementedleveI,wasdescribedandappliedforresolvingsimulatedunresolvedbands.Figurelshowsthelo…     

Synthesis and Spectral Properties of Novel Water-soluble Near-infrared Fluorescent Indocyanines

Two fluorescent pentamethine and a squarylium indocyanines containing at least one p-carboxybenzyl group on N atoms in the heterocyclic rings were synthesized. They had good water solubility and photostability. Their maximum absorption and maximum emission were 600-700 nm in water. When it was anchored onto nanostructured TiO2 electrode, compared with in water, the squaraine showed double absorption peaks (one blue shifted and another red shifted) and absorption intensity of the red shift peak increased with the increase of the time of irradiation. The intensity of the blue one decreased simultaneously. We proposed that the presence of two electronic charge forms of squaraine anchored on the TiO2 film might be the reason.     

Spectral Properties of Extracted Complexes of MetalPicrates with Crown Ethers

The investigation on UV-visible spectra of species formed by extracting some metal picrates with benzo-15-crown-5(B15C5) and dibenzo-18-crown-6(DB18C6) verified that there are some interactions of picrate anion with K , Na and rare earth ions in loaded organic phase. By the study of the charge transfer band and absorption spectra of picrate anion, it can be determined whether an ion pair has been formed and either a 1 : 1 contact ion pair or a 1 : 2 crown-separated ion pair involved in organic phase can be distinguished for an ion-pair extraction.     

Electrospray Ionization Mass Spectral Characteristics of Polyamide Containing 1,4,7,10-Tetraazacyclododecane

The study of the fragmentations of the protonated molecular species[M H]~ and selected fragment ions al-lowed proposals for the main fragmentation pathways of the title compound.In order to better understand the frag-mentation pathways,the MS~3 and MS~4 spectra of the title compound were obtained.The main fragmentation path-ways occur by the cleavage of the C-CO bonds between N-methylpyrrole and carbonyl groups,CO-NH amidebonds,NH-C bonds between the NH groups and the N-methylpyrrole rings,and N-C bonds in1,4,7,10-tetraazacyclododecane.Electrospray ionization was proven to be a good method for the structural charac-terization and identification of this kind of compound.     

Spectral Studies on the Interaction between Mercuric Ion and ApoCopC

The interaction between mercuric ion and apoCopC in the absence or presence of cupric ion was investigated through difference UV spectra in Hepes buffer （10 mmol·L^-1） at pH 7.4. The results suggest that mercuric ion can bind to C- and N-terminal binding sites of apoCopC, and the conditional binding constants were calculated to be kN=（6.79± 1.12）× 10^6 mol^-1·L and kc=（3.06±0.05）× 10^5 mol^-1·L. Using urea as a chemical agent, the conformational stabilities of apoCopC and HgN^2＋ -CopC-Hgc^2＋ were monitored by fluorescence spectrum in Hepes buffer （50 mmol·L^-1） at pH 7.4. The free energy of stabilization is （14.69±0.85） and （16.66±0.55） kJ.mol^-1, respectively. HgN^2＋ -CopC-Hgc^2＋ is more stable than apoCopC.     

Spectral characterization ofβ-Cyclodextrin : Triton X-100 complexes

The spectral characteristics of the surfactant, Triton X-100, in the absence and presence of-cyclodextrin have been examined. The fluorescence of Triton X-100 is concentration dependent and is markedly enhanced in the presence of-cyclodextrin. Analysis of the variations in the excitation-emission profiles of the surfactant with concentration suggests excimer emission at concentrations above the critical micelle concentration (CMC). Nuclear magnetic resonance (NMR) spectroscopy suggests that the phenyl group is included inside the CD cavity while a portion of the ethylene oxide chain extends outside the cavity. Benesi-Hildebrand type equations were derived to determine the stoichiometry and to estimate the formation constant of the CD: S_f complex.     

Preparation and Spectral Characterization of 3-Benzyl-6-aryl-1,2,4-triazolothiadiazoles

Introduction1 ,2 ,4- Triazolo[3,4- b][1 ,3,4]thiadiazoles arecondensed heterocyclic compounds having wide-ranging application.They combine the propertiesof triazoles[1] and thiadiazoles[2 ] ,as a result,someof them show antimicrobial,antiinflammatory,fungicidal,antiviral,inhibiting plant pathogenicbacteria,herbicidal,plant- growth regulating,andother activities[3— 5] .Attaching an active methyleneto the fused heterocycle maybe change itsbioactivity.Moreover,hydrogens in the methylenebetween t…     

Spectral Characteristics of LiSrBO3：Tb^3＋ Green Phosphor

LiSrBO3:Tb3+ green phosphor was synthesized by means of a solid state reaction and its spectral characteristics were studied. The emission spectrum of LiSrBO3:Tb3+ consists of four major bands at 486, 544, 595 and 620 nm under the excitation of near ultraviolet irradiation, which are originated from the 5D4→7F6, 5D4→7F5, 5D4→7F4 and 5D4→7F3 characteristic transitions of Tb3+, respectively. Monitored at 544 nm, the excitation spectrum of the phosphor extends from 220 nm to 390 nm, with the excitation peaks c...     

Spectral and complex-forming properties of β-bromo-substituted porphyrins in N,N-dimethylformamide

Contributions of structural and electronic effects to the reactivity and chromophore properties of tetrapyrrole macrocycles modified by bromine atoms were revealed on the basis of the kinetic data on the complex formation of 2-bromo-5,10,15,20-tetraphenylporphyrin, 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin, and 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin with zinc(II) and copper(II) acetates in N,N-dimethylformamide, and also by measuring spectral characteristics of porphyrin ligands and zinc and copper porphyrinates.     

Spectral Differences of the Molecule-ion Adducts of β-Cyclodextrin and Lithium Carbonate

A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin (β-CD) was detected by ¹H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate (Li₂CO₃) to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li₂CO₃ and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li₂CO₃ to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.     

Spectral properties and structures of supramolecular complexes of naphthylpyridine with β-cyclodextrin

The electronic absorption and fluorescence spectra of 4-(2-naphthyl)pyridine (1) and N-methyl-4-(2-naphthyl)pyridinium perchlorate (2 ⁺·ClO₄ ^–) were studied in aqueous solutions in the absence and presence of -cyclodextrin (-CD). In aqueous solutions and organic solvents in the presence of water or H⁺ ions, compound 1 exhibits intense fluorescence with a maximum at 21 270 cm^–1, and its quantum yield in an aqueous solution is 0.9±0.09. The same fluorescence spectrum was detected for an aqueous solution of 2 ⁺·ClO₄ ^–. In an aqueous solution, compound 1 and -CD form stable fluorescing supramolecular 2:2 complexes, whose structure was calculated by the quantum-chemical MNDO/PM3 method. The formation of these complexes induces a hypsochromic shift of the fluorescence maximum of 1 by 5000 cm^–1. The stability constant of the complex is 2·10³ L mol^–1. A decrease in the pH results in the formation of a protonated form of 1(1·H⁺) and destruction of the complex, thus favoring the escape of the substrate from the -CD cavity. The quantum-chemical calculations showed that the insertion of 1 into the -CD cavity is thermodynamically more favorable than hydration; on the contrary, the formation of 1·H⁺ increases dramatically the hydration energy, which promotes the escape of 1·H⁺ from the -CD cavity; cation 2 ⁺ does not form a complex with -CD; in the thermodynamically most favorable 2:2 complex, the naphthalene fragments of two molecules 1 are parallel to each other in a broad section of the -CD dimer constructed according to the head-to-head type.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2420–2425, November, 2004.     

Guest–Host Interactions in Hofmann-Td-type Aniline Clathrates: IR Spectral Study

Synthesis and IR spectra of novel Hofmann-T _d -type aniline clathrates, M(NH₃)₂Zn(CN)₄· 2C₆H₅NH₂ (M = Zn or Cd) are reported for the first time. All the vibrational modes of aniline are characterised. The shifts in _a (NH₂) and _s (NH₂) reveal hydrogen bonding between the NH₂ group of aniline and the cyanide group of the host lattice to be stronger than in Hofmann-type aniline clathrates. However, the out of plane deformation mode of aniline indicates absence of hydrogen bonding between ammonia and the -cloud of the aniline ring. The related aniline clathrates with bridging Cd(CN)₄ M(NH₃)₂Cd(CN)₄· 2C₆H₅NH₂ (M=Zn or Cd), exhibit similar behaviour.     

Spectral and Electrochemical Investigation of Intercalations of Adrenaline and CT－DNA

A strong interaction between double stranded calf-thymus DNA (ds-DNA) and adrenaline in solution, but no interaction between single stranded calf-thymus DNA (ss-DNA) and adrenaline was observed by the use of UV-visible spectroscopy and voltammetric techniques. It is suggested that the interaction leads to an intercalation of adrenaline molecules into the groove of ds-DNA and the formation of ds-DNA (adrenallne)n complex. The binding site size of the interaction of adrenaline with CT-DNA in nucleotide phosphate [ NP] has been determined as 25. The interaction of different concentration adrenaline with DNA modified GCE shows that the DNA modified GCE can be a good tool to detect lower concentration adrenaline.     

A New Nanogold-Labeled Immunoresonance Scattering Spectral Probe for Determination of Trace IgG

A kind of 9 nm gold nanoparticles was prepared with the trisodium citrate and used to label goat anti-human IgG to obtain an IgG immunoresonance scattering spectral probe. In pH 5.8 buffer solution and in the presence of polyethylene glycol （PEG）, the immune reaction between gold-labeled goat anti-human IgG and IgG took place, and the resonance scattering intensity at 580 nm （I580nm） was enhanced greatly. The enhanced intensity AIRS is pro- portional to the IgG concentration from 1.3 to 1.5 X 10^3 ng.mL^-1, with a detection limit of 0.78 ng.mL ^-1. This assay showed high sensitivity and good selectivity for quantitative determination of IgG in human serum, with satisfactory results.     

Syntheses,Spectral Characterization of the Nickel（ Ⅱ）Compplexes of

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"Tables of Spectral Data for Structure Determination of Organic Compounds"

《有机化合物结构确定用光谱数据表》第2版(英文)由德国施普林格出版社于1989年出版。该书以表格和框图的形式给出了大量化合物的~(13)C-核磁共振波谱、红外光谱、质谱及电子激发光谱数据,为有机化合物结构的确定提供了重要依据。可供有机化学分析化学专业人员参考。本书已由世界图书出版公司购得重印权,将在     

Study of Spectral Character of Alkali Metals Using Microwave Plasma Torch Simultaneous Spectrometer

IntroductionIn the past decades, alkali metals were widely ap-plied in many fields, such as applied catalysis[1,2],surface science[3,4], and molecular biology[5]. Micro-wave plasma torch(MPT), developed and improved byYu and coworkers[6,7], is a novel dev…     

Solute–Solvent Interactions of Methyl Violet in Different Solvents on Spectral Data

Spectroscopic studies of Methyl violet in protic (water, methanol, ethanol, isopropanol and n-butanol) and aprotic solvents (acetone, DMF) were carried out. UV-Visible absorption spectra of Methyl violet in protic solvents showed a hypsochromic shift, as the solvent polarity was changed from less polar to more polar, while a bathochromic shift was observed for aprotic solvents. Transition energy of Methyl violet in different solvents was correlated with solvatochromic parameters to study solute–solvents interactions. The Kamlet–Taft, Catalan and unified scale models were applied to investigate interactions between Methyl violet and solvents. The best agreement is found for the Catalan model.