4,4′-Dipyridyl and 2,2′-dipyridyl complexes of rare-earth perchlorates

4,4-Dipyridyl and 2,2-dipyridyl complexes of rare-earth perchlorates of the formulaLn(4-dipy)₈(ClO₄)₃HClO₄ · 4H₂O (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 4-dipy=4,4-dipyridyl) andLn(2-dipy)₃(ClO₄)₃ · 6H₂O (Ln=Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 2-dipy = 2,2-dipyridyl) have been synthesized. The IR spectra of these compounds and other physical properties are discussed.

---

4,4-Dipyridyl- und 2,2-Dipyridylkomplexe von Seltenerdmetallperchloraten

Zusammenfassung Es wurden 4,4-Dipyridylkomplexe des TypsLn(4-dipy)₈(ClO₄)₃HClO₄ · · 4 H₂O mitLn=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y und 2,2-Dipyridylkomplexe des TypsLn(2-dipy)₃(ClO₄)₃ · 6 H₂O mitLn=Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu und Y dargestellt. Die IR-Spektren und andere physikalische Eigenschaften werden diskutiert.

     

Effect of a Nickel Bipyridyl Complex on the Reduction of Organic Halides

Indirect reduction of 1-phenylethylbromide (I) and 1-(4-isobutylphenyl)ethylchloride (II) in a carbon dioxide atmosphere containing tris(2,2-bipyridyl)nickel tetrafluoroborate (BPN) is studied. In the reactions the BPN complex exhibits properties of a one-electron mediator and catalyzes radical generation from aryl halides, which mostly undergo dimerization. Electroreduction of I and II in the presence of -cyclodextrin and BPN yields biaryls with a low enanthioselectivity (1.5%), which may indicate generation of a small amount of inclusion complexes and dimerization of intermediate radicals in the hydrophobic cavity of -cyclodextrin.     

Synthesis of 4,4′-bis(4-aminophenoxy)benzophenone and polyimides based on this compound

Synthesis of 4,4-bis(4-aminophenoxy)benzophenone was performed starting from chloral. Various polyimides were obtained by reactions of 4,4 -bis(4-aminophenoxy)benzophenone with aromatic tetracarboxylic acid dianhydrides. Some of the polyimides obtained are crystalline compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 673–676, March, 1996.     

Flow-injection chemiluminescent determination of metoclopramide hydrochloride in pharmaceutical formulations and biological fluids using the [Ru(dipy)(3)(2+)]-permanganate system

A flow-injection (FI) methodology using (2,2′-dipyridyl) ruthenium(II) [Ru(dipy)₃²⁺] chemiluminescence (CL) was developed for the rapid and sensitive determination of metoclopramide hydrochloride. The method is based on the CL reaction of metoclopramide with Ru(dipy)₃²⁺ and KMnO₄ in a sulfuric acid medium. Under the optimum conditions, a calibration graph was obtained over the concentration range 0.005-3.5 μg ml⁻¹ with a limit of detection (S/N=2) of 1 ng ml⁻¹. The correlation coefficient was 0.99993 (n=8) with a relative standard deviation of 0.48% for 10 determinations of 1 μg ml⁻¹ of drug. The method was successfully applied to the determination of metoclopramide in pharmaceutical preparations and biological fluids after IP administration of 25 mg kg⁻¹ dose to rats. The elimination half-life was 2.5±0.4 h.     

Kinetics ofEDTA substitution of N,N′-ethylenedisalicylamidato cuprate(II) in alkaline media

Summary The kinetics ofEDTA reaction with N,N-ethylenedisalicylamidato cuprate(II) is followed at 30°C in borate buffer and is found to be first order in each reactant. The reaction ispH dependent and involves protonation of a deprotonated peptide nitrogen followed by nucleophilic attack byEDTA.

---

Kinetik derEDTA-Substitution von N,N-Ethylendisalizylamidatokupfer(II) in alkalischem Medium (Kurze Mitt.)

Zusammenfassung Die Kinetik derEDTA-Reaktion mit N,N-Ethylendisalizylamidatokupfer(II) wurde bei 30°C in Borat-Puffer verfolgt. Es wurde erste Ordnung bezüglich jedes Reaktanden festgestellt. DiepH-abhängige Reaktion beinhaltet die Protonierung eines deprotonierten Peptid-Stickstoffs, gefogt von einem nucleophilen Angriff einesEDTA-Moleküls.

     

Reaction of the dimethoxyaminyl radical with tertiary nitrosoalkanes as a method for the preparation of N-alkyl-N′-methoxydiazene N-oxides

The reaction of the dimethoxyaminyl radical with functionally substituted nitrosoalkanes (2) in a 2:1 ratio at 20°C gives the corresponding N-alkyl-N-methoxydiazene N-oxides (3) as a single isomer in preparative yields.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2443–2445, October, 1992.     

Aromatische Spirane, 23. Mitt.: Darstellung von unsymmetrisch substituierten Dimethyl-2,2′-Spirobiindan-1,1′-dionen

Summary Both spirodiketones7 and8 were obtained as a mixture (56:44) by treatment of dicarbonic acid5 with polyphosphoric acid (PPA).5 was accessible from dimethylester3, synthesized byretro-Claisen reaction between1 and2. In the same way,30 was obtainedvia 27. The preparation of the pure spiro compounds7 and8, resp., was achieved by aldol reaction between9 and10 or9 and16, resp. Short treatment of the resulting compounds11 and17 with diazomethane yielded the methylbenzoates12 and18. Prolonged reaction (several hours) gave the pyrazole compounds14 and19, resp., which were also obtained (several days) from phthalides14 and20. The latter were formed from the benzylidene compounds11 and17, resp., by heating.11 and17 (after hydrogenation to15a and21a) were cyclized either withPPA or thermically to the spiro compounds7 and8. The main product20 was cyclized thermically to8 after reduction with zinc to a mixture of21a and8 (20:75).

     

A simple optimization strategy based on Rs-minimum and information theory of chromatography

Summary A simple optimization method based on the well-known Rs-minimum method and on the information theory of FUMI Φ is proposed. Resolution (Rs), peak area and height (or width) are the only parameters necessary for the calculation of the information Φ and information flow ϑ. The most precise analysis can be selected as the chromatogram having maximal ϑ. Mobile phase composition, column length, flow rate, detection wavelength, amount of internal standard, etc. can be optimized by this method.     

X-ray and IR spectroscopic studies of specific intermolecular interactions inN′-substituted isonicotinohydrazides

_N-Thenylidene- andN-(o-nitrobenzylidene)hydrazides of isonicotinic acid have been studied by X-ray structural analysis and IR spectroscopy. In the crystalline state, these molecules are linked through intermolecular N—H ... Np_y hydrogen bonds. Carbonyl groups are not involved in intermolecular hydrogen bonds. However, it was found that the C=O group participates in an attractive interaction with the sulfur atom of the thiophene group. The energy of this interaction is comparable with the energies of intermolecular C=O ... H—N hydrogen bonds in amides.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 896–900, April, 1996.     

Simple test system for single molecule recognition force microscopy

We have established an easy-to-use test system for detecting receptor-ligand interactions on the single molecule level using atomic force microscopy (AFM). For this, avidin-biotin, probably the best characterized receptor-ligand pair, was chosen. AFM sensors were prepared containing tethered biotin molecules at sufficiently low surface concentrations appropriate for single molecule studies. A biotin tether, consisting of a 6 nm poly(ethylene glycol) (PEG) chain and a functional succinimide group at the other end, was newly synthesized and covalently coupled to amine-functionalized AFM tips. In particular, PEG₈₀₀ diamine was glutarylated, the mono-adduct NH₂-PEG-COOH was isolated by ion exchange chromatography and reacted with biotin succinimidylester to give biotin-PEG-COOH which was then activated as N-hydroxysuccinimide (NHS) ester to give the biotin-PEG-NHS conjugate which was coupled to the aminofunctionalized AFM tip. The motional freedom provided by PEG allows for free rotation of the biotin molecule on the AFM sensor and for specific binding to avidin which had been adsorbed to mica surfaces via electrostatic interactions. Specific avidin-biotin recognition events were discriminated from nonspecific tip-mica adhesion by their typical unbinding force (∼40 pN at 1.4 nN/s loading rate), unbinding length (<13 nm), the characteristic nonlinear force-distance relation of the PEG linker, and by specific block with excess of free d-biotin. The convenience of the test system allowed to evaluate, and compare, different methods and conditions of tip aminofunctionalization with respect to specific binding and nonspecific adhesion. It is concluded that this system is well suited as calibration or start-up kit for single molecule recognition force microscopy.