Syntheses in the field of 5-nitro-2-furylpolyalkenals and 5-nitro-2-furylpolyalkenones

A series of, -bis(5-nitro-2-furyl)poryalkenones has been synthesized by the condensation of 5-nitro-2-furylalkenones with 5-nitrofuran aldehydes in acetic acid (concentrated sulfuric acid catalyst). In the , -bis(5-nitro-2-furyl)polyalkenone series, the keto group acts as a partial insulator of conjugation, which is shown most clearly in the case of 1,3-bis(5-nitro-2-furyl)prop-2-en-1-one and 1,5-bis(5-nitro-2-furyl)-penta-2,4-dien-1-one, i.e. compounds having the keto group directly linked to a 5-nitrofuran ring. The electronic spectra of the semicarbazones of the, -bis(5-nitro-2-furyl)polyalkenones exhibit a stronger disturbing effect of the conjugation in the molecule than in the case of the ketones, which may be connected with a disturbance of coplanarity. In a number of cases, the infrared spectra of the, -bis(5-nitro-2-furyl)polyalkenones exhibit splitting of the symmetrical and antisymmetrical vibrations of the nitro group.For part VII, see [1].Preliminary results of the present investigation were given for the first time at the 2-nd All-union Scientific Conference on the Chemistry of Furan Compounds, Saratov, 23–26 January, 1962, see [2].     

Some rules forS(-2k) dipole sums?

Stieltjes conditions and the ratio test provide necessary but not sufficient conditions onS(-2k) dipole sums. If the dipole sums are accurate the associated [n, n –1] Padé approximant provides a better representation of (), the frequency-dependent dipole polarizability, than a truncated series expression and, in addition, should bound () below. It is shown how constraints on the dipole sums effect the form of the [2,1] Padé approximant and an additional constraint is derived that ensures the analyticity of the approximant on 0 < ₁. There then follows a discussion of the reliability of available literature dipole sum values for small molecules containing H, C, N and O.     

Peroxidase oxidations of hydroquinone and p-cresol in AOT reversed micelles

The enzymatic activities of horseradish peroxidase solubilized in reversed micelles of bis(2-ethylhexyl)sodium sulfosuccinate formed in octane at various _o values ( _o=[H₂O]/[AOT]) were investigated by studying the catalytic oxidation of hydroquinone and p-cresol. These enzymatic reactions obeyed Michaelis-Menten kinetics. The turnover number of the enzymatic reaction of hydroquinone solubilized in the water pool increased with a decrease in _o value. On the other hand, the dependence of the turnover number of the enzymatic reaction of p-cresol solubilized in octane on the _o value was similar to that in the case of hydroquinone, although even at higher _o values the turnover number was smaller than that in water. Furthermore, it was suggested by spectrophotometric and circular dichroism measurements that the conformational change of enzyme induced the change in enzymatic activity.     

MO-Berechnungen an Heterocyclen, 1. Mitt.: Die Anwendung verschiedener SCα-Techniken auf pyrrol-und pyridinartige Heterocyclen

Zusammenfassung Die Untersuchungen beschäftigen sich mit der Anwendbarkeit verschiedener SC-LCAO-MO-Verfahren inHückelscher Näherung (SC-HMO) auf Heterocyclen.Die vorliegende Arbeit untersucht den Einfluß der Iterationsbeziehungen zwischen _r undq _r nach der - und -Technik an pyrrol-und pyridinartigen Verbindungen. Durch Variation von als auch des Korrekturparametersh _y für das Coulombintegral _y des Heteroatoms y läßt sich der Einfluß dieser Größen auf verschiedene MO-Daten bestimmen. Die Bedeutung der beiden SC-Verfahren für einige MO-Daten wird diskutiert.

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Our work deals with the applicability of different SC LCAO MO methods in theHückel approximation (SC HMO) on heterocycles.This paper examines the influence of the iteration relations between _r andq _r with the -and -technique on pyrrole- and pyridine-like compounds. By variation of andh _y — the correction parameter for theCoulomb integral _y of the heteroatom y — the influence of these magnitudes on MO quantities can be determined. The importance of the two SC-methods for some MO quantities is discussed.

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Mit 2 Abbildungen     

How electrons guard the space: shape optimization with probability distribution criteria

Efficient formulas for computing the probabilities of finding exactly electrons in an arbitrarily chosen volume ³ for Hartree–Fock wavefunctions are presented. These formulas allow the use of shape optimization techniques, such as level set methods, for optimizing with respect to various criteria involving such probabilities. The criterion defined as the difference between the Hartree–Fock and the independent-particle model probabilities of finding electrons in stresses the quantum effects due to the Pauli principle. We have implemented a 2D level set method for optimizing this criterion in order to study spatial separation of electron pairs in linear molecules. The method is described and the illustrative example of the BH molecule is reported.Contribution to the Jacopo Tomasi Honorary Issue     

Synthesis and properties of pyrimidinylalkylphosphonic acids

Conclusions Some esters of -(oxodihydro-N-pyrimidinyl)butyl- and -(oxodihydro-N-pyrimidinyi)pentylphosphonic acids, and also some diphenyl -(2,4-dioxo-6-methyl-1,2,3,4-tetrahydro-N-pyrimidinyl)alkyl phosphates, were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1397–1401, June, 1975.     

12-Tungstosilicic Acid (12-TSA) as a Tungsten Precursor in Alcoholic Solution for Deposition of xWO3(1 − x)SiO2 Thin Films (x ≤ 0.7) Exhibiting Electrochromic Coloration Ability

The preparation of stable alcoholic solution of tungstosilicic acid and silicon alkoxide, which can be used for xWO3 (1 – x)SiO2 thin film deposition by dipping, is described. After thermal treatment at temperatures 440 to 500°C in nitrogen films with x higher than 0.6 exhibit electrochromic coloration ability. After coloring the film by H+ imtercalation (by contact with an indium wire trough a drop of aqueous solution of H2SO4) the luminous transmittance (illuminant D65, wavelength range from 380 to 780 nm, summation at 10 nm intervals) of glass coated with 90 nm thick xWO3(1 – x)SiO2 thin film decreases from 71.7 to 28.6% and the IR reflection increases to over 30%. At the same time the surface resistance decreases from a few M/ to about 400/. The thermal decomposition of tungstosilic acid embedded in alkoxy-hydroxy-oxy-silicon matrix is investigated with DTA, TGA, XRD and FTIR spectroscopy.     

A General Analysis of Field-Based Molecular Similarity Indices

A formalism is presented that incorporates the entirety of all field-based molecular similarity indices of general form S _ij = _ij /h( _ii , _jj ), where the numerator is given by the inner product or overlap of field functions F _i and F _j corresponding to the ith and jth molecules, respectively, and the denominator is given by a suitable mean function of the self-similarities _ii and _jj . This family of similarity indices includes the index initially introduced by Carbó nearly twenty years ago, where h( _ii , _jj ) is taken to be the geometric mean of _ii and _jj , and the well-known indices due to Hodgkin and Richards, and Petke, where h( _ii , _jj ) is taken to be the arithmetic mean and maximum of _ii and _jj , respectively. Two new indices based upon the harmonic mean and minimum of _ii and _jj are also defined, and it is demonstrated that the entire set of field-based similarity indices can be generated from a one-parameter family of functions, called generalized means, through proper choice of the parameter value and suitable limiting procedures. Ordering and rigorous bounds for all of the indices are described as well as a number of inter-relationships among the indices. The generalization of field-based similarity indices, coupled with the relationships among indices that have been developed in the present work, place the basic theory of these indices on a more unified and mathematically rigorous footing that provides a foundation for a better understanding of the quantitative aspects of field-based molecular similarity.     

Laser Sintering of SnO2 : Sb Sol-Gel Coatings

Sb doped sol-gel SnO2 single layers (thickness 100 nm) were prepared from alcoholic solution and deposited via a dip coating process on fused silica substrates. The coatings have been sintered at a typical rate of 10–15 cm2/s by CO2 laser irradiation. The laser spot was scanned in one direction at a speed of 15,000 cm/s and the sample was moved in a perpendicular one at a speed up to 250 mm/s. The temperature of the topmost 10 m layer was monitored by a fast pyrometer (s resolution). The following properties of the coatings have been determined: the electrical resistivity , the carrier density n, and mobility , the structure, the thickness, the mesoscopic and micromorphology and the density. The sintering by CO2 laser radiation is mainly a thermal driven process. At T 500°C it allows to obtain coatings with a smaller resistivity (6.8×10–3 cm) than those produced by conventional furnace firing (el2.9×10–2 cm). The results are discussed in terms of particle size and packing density.     

Synthesis of 5′-benzoyl-2′-hydroxychalcones and related flavonoid compounds

Summary 5 -Benzoyl-2 -hydroxychalcones were synthesized by the condensation of 5 -benzoyl-2 -hydroxyacetophenone with aromatic aldehydes in presence of an ethanolic solution of potassium hydroxide. Derivatives of 6-benzoylflavonoids were prepared from chalcones.     

Exact and approximate forms of the kinetic energy functional<Emphasis Type="Italic"> T</Emphasis><Subscript>s</Subscript>[ρ] for molecules obtained via local-scaling transformations

By means of a constructive procedure based on local-scaling transformations, we have obtained the following exact form for the noninteractive kinetic energy functional of general molecular systems: where (r) is the local-scaling transformation function, T _W[] is the von Weiszäcker term and ^l _N (r _l ) and ^l _N (r _l ) are the radial and angular enhancement factors, respectively, within an atomic domain _I. The terms ^C _N (r _l ) and ^C _N (r _l ) (where C stands for complement of I) contain all contributions to the radial and angular enhancement factors within _I coming from the tails of functions centered on nuclei outside _I. Also, in the context of an atoms-in-a-molecule approach, we discuss the construction of approximations to the kinetic energy enhancement factors appearing in the previous expression for T _s[]. Acknowledgement.The authors gratefully acknowledge support of this work by FONACIT of Venezuela through Group Project No. G-97000741.From the Proceedings of the 28th Congreso de Químicos Teóricos de Expresión Latina (QUITEL 2002)     

Wet Coating Deposition of ITO Coatings on Plastic Substrates

In₂O₃:Sn (ITO) transparent conducting coatings of high optical quality have been obtained on glass and several plastic substrates by spin and dip coating processes followed by a low temperature processing (T < 130°C). The sols are made of crystalline nanoparticles redispersable in an alcohol and modified by adding a binder to favour the coalescing of the particles and to allow the deposition of thick single layers (>400 nm). The smallest stable resistivity so far obtained is = 9 × 10^–2cm (sheet resistance of 1.6 k for a 570 nm thick single layer). The transparency in the visible range is high, T 87%, the abrasion resistance is in agreement with DIN 58-196-G10 and the hardness according to ASTM D 3363-92a is 1H. A spray process allows to obtain antiglare-conducting coatings with an adjustable gloss of 60 to 80 GU and an optical resolution >8 lines/mm.     

Research on pyrrolo[3,2-f]indolizines

3-(-Oxo--alkoxycarbonylalkyl)- and 3-benzoyl-substituted pyrroles undergo condensation with -unsubstituted pyrroles to give 6H-pyrrolo[3,2-f]indolizines that contain higher acid residues or a phenyl group in the 4 position of the heteroring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 777–780, June, 1977.See [1] for communication IV.     

Vacuum ultraviolet spectroscopic analysis of nitrogen in iron and steel with low-voltage condensed-spark discharge

Summary The determination of nitrogen in steels was investigated by low voltage condensed spark discharge and far ultraviolet vacuum spectroscopy. The excitation conditions were 1,000V, 193, 63 F and 50H in helium atmosphere of 700 mm Hg. Nitrogen contents from 20 ppm to 100 ppm in steel could be determined with the line pair of N I 1,745 Å/Fe I 1,876 Å or N I 1,742 Å/Fe I 1,876 Å.

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Zusammenfassung Zur Bestimmung von Stickstoff (20–100 ppm) in Stählen wurde eine UV-vakuumspektrometrische Methode mit Niederspannungs-Funkenentladung benutzt. Die Entladungsbedingungen waren: 1000 V, 193 , 63 F und 50 H, unter Heliumatmosphäre von 700 mm Hg; verwendet wurden die Linienpaare N I 1,745 Å/Fe I 1,876 Å oder N I 1,742 Å/ Fe I 1,876 Å.

     

Indole derivatives. I.β-(3-indolyl) ketones

A number of -skatyl--substituted acetoacetic esters (ethyl, tert. -butyl, and benzyl) are prepared by treating gramine with sodium derivatives of -substituted acetoacetic esters. When ethyl -alkyl--skatylacetoacetates are heated with dilute alkali, they are split into indole and a substituted acetoacetic ester, while saponification with concentrated alcoholic alkali gives -substituted-(3-indolyl)propionic acids. 3-Skatyl-heptan-2-one can be obtained by pyrolysis of 3-skatyl-3-carbo-tert. -butoxyheptan-2-one, or by hydrogenolysis of 3-skatyl-3-carbobenzoxyheptan-2-one over a palladium catalyst. Alkylation of cycloheptanone and cyclohexanone enamines by gramine gives cyclic-(3-indolyl)ketones, viz., 2-skatylcyclopentanone and 2-skatylcyclohexanone.     

Superionic conductivity in (BEDT-TTF)AgXiY

We have synthesized the organic conductor (BEDT-TTF)Ag_XI_Y (X 1.8 and Y 2.9). This compound has, in addition to high electronic conductivity (_{300 k} 5–10 ^–1 · cm^–1), significant ionic conductivity connected with the motion of silver ions. The value of this ionic conductivity at room temperature is 10^{–3 –1} · cm^–1. The activation energy for diffusion of Ag ions is equal to 0.2 eV.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 247–249, March–April, 1989.     

Synthesis of coronands containing sulfonamide cores in the macrocycle

Sulfonamide coronands containing sulfonamide cores in the macrocycle are prepared by cyclization of 1,10-bis(5-nitro-2-chlorosulfonylphenyl)-1,4,7,10-tetraoxadecane with ,-diaminooligooxaalkanes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 677–679, May, 1989.     

Preparation of YSZ Coated AISI-Type 316L Stainless Steel by the Sol-Gel Coating Method and Its Corrosion Behavior in Molten Carbonate

The effect of heat-treatment conditions on the corrosion behavior of yttria stabilized zirconia (YSZ) coated AISI-type 316L stainless steels in molten carbonate are investigated. YSZ films on stainless steel were prepared by the sol-gel method. While the sample heat-treated at 800°C for 2 hours in air has an uneven surface microstructure with macrocracks, a YSZ coated sample heat-treated in argon has an even microstructure. The polarization resistance and corrosion rate of YSZ coated sample heat-treated in air were deteriorated from 6.948 cm² and 364.7 mpy (millimeter per year) to 3.291 cm² and 769.8 mpy, respectively, by the corrosion for 100 hours due to its poor surface microstructures. At the same experimental condition, meanwhile, those corrosion parameters of YSZ coated sample heat-treated in argon were 15.43 cm² and 164.2 mpy, respectively, and those were improved to 18.83 cm² and 134.6 mpy after the corrosion for 100 hours. This is attributed to the YSZ film with well developed surface microstructures. The concentration profiles of elements and X-ray diffractograms indicate that the oxide layer of YSZ coated sample heat-treated in argon had a triple layer structure composed of outer YSZ film, in between Fe₂O₃ layer, and inner chromium rich layer during corrosion.     

Nitration,amination, and halogenation of Di-O-methylphloracetophenone

Chlorination of the title compound gave 5- and 3-chloro-2-hydroxy-4,6-dimethoxyacetophenone. The nitration of its acetate, followed successively by reduction, diazotization, and reaction with cuprous chloride, gave the 3-substituted series, 2-acetoxy-4,6-dimethoxy-3-nitroacetophenone, 3-amino-2-hydroxy-4,6-dimethoxyacetophenone, and 3-chloro-2-hydroxy-4,6-methoxyacetophenone, respectively. The orientation of substituents in the products was proved. The amino and chloro members of the isomeric 5-substituted series were availablevia 2-hydroxy-4,6-dimethoxy-5-phenylazoacetophenone, the product of the reaction of the title compound with benzenediazonium chloride.

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Nitrierung, Aminierung und Halogenierung von Di-O-methylphloracetophenon

Zusammenfassung Chlorierung der Titelverbindung gab 5- und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Nitrierung des Acetats, gefolgt von Reduktion, Diazotierung und Reaktion mit CuCl ergab die 3-substituierte Reihe: 2-Acetoxy-4,6-dimethoxy-3-nitroacetophenon, 3-Amino-2-hydroxy-4,6-dimethoxyacetophenon und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Orientierung der Substituenten wird diskutiert. Die Amino- und Chlorderivate der isomeren 5-substituierten Reihe sind über 2-Hydroxy-4,6-dimethoxy-5-phenylacetophenon zugängig, dem Produkt der Reaktion der Titelverbindung mit Phenyldiazoniumchlorid.