Determination of lithium in human serum by electrothermal atomic absorption spectrometry

An efficient method was developed for the determination of nanogram levels of lithium in biological samples. Serum samples from human subjects from southeastern Spain, treated or not treated with lithium carbonate, were analyzed by electrothermal atomic absorption spectrometry. The samples were previously treated with a matrix modifier consisting of 0.1% Triton X-100 and injected through a graphite tube with L'vov platform. The Li concentrations measured by the procedure described for the 3 certified reference samples used were not significantly different (p > 0.05) than certified levels. Sample recoveries and variability during several days, with coefficients of variation from 4.00 to 14.8%, demonstrated the reliability and accuracy of this technique. Mean Li concentration determined in the serum of individuals with psychiatric disorders treated with Li (n = 117, 5.077 +/- 1.795 microg Li/mL) was significantly higher (p < 0.001) than that in individuals not treated with Li (n = 24, 1.902 +/- 2.054 ng Li/mL).     

Intramolecular "Aryl-metal chelate ring" pi,pi-interactions as structural evidence for metalloaromaticity in (aromatic alpha,alpha'-diimine)-copper(II) chelates: molecular and crystal structure of aqua(1,10-phenanthroline)(2-benzylmalonato)copper(II) three-hydrate

By reaction of Cu(2)CO(3)(OH)(2), 2-benzylmalonic acid (H(2)Bzmal), and 1,10-phenanthroline (phen), [Cu(Bzmal)(phen)(H(2)O)] x 3H(2)O (compound 1) has been obtained and characterized by thermal, spectral, magnetic, and X-ray diffraction methods. The molecular structure of 1 is remarkably similar to that of [Cu(Bzmal)(bipy)(H(2)O)] x 2H(2)O (compound 2, bipy = 2,2'-bipyridine). In both complexes, the aryl(Bzmal) ring produces an unexpected pi,pi-stacking interaction with the Cu(II)-(aromatic alpha,alpha'-diimine) chelate ring, at an average distance d(pi)(-)(pi) of 3.40 A, involving roughly parallel and smoothly slipped rings. This insight is discussed as new structural evidence for metalloaromaticity of Cu(II)-(aromatic alpha,alpha'-diimine) chelate rings. Interestingly, 1 recognizes itself by a weak intermolecular pi,pi-stacking interaction between aryl(Bzmal) ligands to give pairs of complex molecules. In contrast, there is an intermolecular pyridyl-pyridyl pi,pi-stacking interaction also forming pairs of complex molecules in 2.     

Automation of the gas analysis of14C-labelled compounds utilizing a piston-type counter tube

In this paper an automatic apparatus designed for the radioactivity measurement of¹⁴C-labelled organic compounds in the gaseous phase is described. The labelled organic compounds are combusted in a mixture of argon and oxygen. After combustion the oxygen content of the gas is eliminated by passing it through a copper packing. The water and heteroelements present are also removed and the radioactive carbon dioxide gas is swept by argon carrier gas into a piston-type counter tube. In the counter tube the piston forming a dividing wall moves forward in accordance with the rate of combustion and sweeping, and thus sucks the gases leaving the combustion tube into the effective tube volume. The anode wire is carried by a reel located in the piston and a spring device ensures its stretched state. At the end of the sweeping period methane is fed into the counter tube and the activity of the argon—methane—carbon dioxide mixture is measured in the limited proportional region. Manual and automatic operation is possible. The piston-type counter tube provides possibility for strandardization by means of extrapolation and for measurement of absolute activities.     

Synthesis and characterization of new di- and tri-nuclear cyano-bridged bis(dioximato)cobalt(III) complexes

Summary Several new neutral and cationic di- and tri-nuclear cyano-bridged bis(dioximato)cobalt(III) complexes have been synthesized and characterized (dioximato = dimethylglyoximato or diphenylglyoximato). These compounds are obtained through substitution of labile axial ligands by the nitrogen of the cyano-group in [Co(dioximato)₂(CN)₂]^– or [LCo(dioximato)₂(CN)] (L = H₂O, NH₃, or py). In the first case, the existence of only one band in the CN-stretching region of the i.r. spectrum at 2190–2200 cm^–1 is indicative of a trinuclear compound, while the presence of a second band at 2140 cm^–1 attributable to a terminal cyano-group indicates a dinuclear structure. In the presence of water, aquation of axial positions may take place at the same time as bridge formation, whereas the use of a non-aqueous solvent allows the preparation of complexes with pyridine or NH₃.     

A field theoretical approach to calculate electronic Born-Oppenheimer coupling terms

In this paper we suggest to consider the spatial distribution of the Born-Oppenheimer nonadiabatic coupling terms as fields which are created by sources, located at degeneracy points, and which can be derived using the ordinary mathematical tools of field theory. It is shown that the curl-divergence equations as formed within a given Hilbert space [M. Baer, Chem. Phys. Lett. 35, 112 (1975)] can be converted into a set of inhomogeneous coupled Poisson equations which are solved for a given set of boundary conditions. The method is applied to the three-state Hilbert subspace of the H(3) system. The numerical results are compared with ab initio calculations for which a very encouraging fit is found.     

Nachweis isomerer Phenole und Nitroaniline,von Naphthylamin und Anilin

Zusammenfassung Die mit diazotiertem p-Nitranilin hergestellten Tetrazoverbindungen von Phenolderivaten geben mit Magnesium in alkalischem Mediumfarbige Komplexe. Die Farbe des Komplexes ist verschieden bei substituierten und nicht substituierten bzw. verschieden substituierten Phenolen. Damit kann man Phenol-, Kresol- und Chlorphenol-Isomere bzw. 2,4- und 2,6-Dichlorphenol unterscheiden.Beim Diazotieren von Nitranilin und Kuppeln mit Anilin entstehen. Indikatorsäuren; p-Nitranilin bildet die stärkste Indikatorsäure, m-Nitranilin die schwächste. Auf dieser Grundlage können alle drei Isomeren nebeneinander nachgewiesen werden. Außerdem bilden die aus p- und o-Nitranilin entstandenen Indikatoren mit Magnesium verschieden gefärbte Nitronsäurekomplexe, während m-Nitranilin, das zur Nitronsäuretautomerie nicht befähigt ist, keinen Komplex bildet.Naphthylamine geben mit diazotiertem p-Nitranilin in wäßrigem. Medium eine Indikatorbase, Anilin eine Indikatorsäure. In alkoholischem Medium führt-Naphthylamin bei Kupplung von diazotiertem p-Nitranilin zu einem amphoteren Säure-Base-Indikator, aber-Naphthylamin und Anilin zu Indikatorsäuren. Damit kann man Naphthylamin und Anilin nebeneinander nachweisen. Kuppelt man Phenyldiazoniumchlorid mit Naphthylamin, so erhält man mit-Naphthylamin eine starke Indikatorbase, mit- Naphthylamin eine schwache Indikatorbase. Auf der Basis dieser Indikatorwirkung kann man-Naphthylamin neben- Naphthylamin nachweisen.

---

Summary The tetrazo compounds of phenol derivatives prepared with diazotizedp-nitraniline yield colored complexes with magnesium in alkaline surroundings. The color of the complexes differs with substituted and non-substituted or variously substituted phenols. It is possible in this way to differentiate phenol, cresol and chlorophenol isomers, and also 2,4- and 2,6-dichlorophenol.Indicator acids result from diazotized nitraniline coupled with aniline;p-nitraniline yields the strongest indicator acid,m-nitraniline the weakest. With this information as a basis, all three isomers can be detected in the presence of each other. In addition, the indicators produced fromp- ando-nitraniline give nitronic acid complexes with magnesium that differ in color, whilem-nitraniline, which is not capable of nitronic acid tautomerism, forms no complex.Naphthylamines gives an indicator base in aqueous medium with diazotizedp-nitraniline, whereas aniline yields an indicator acid. In alcoholic medium, 1-naphthylamine on coupling with diazotizedp-nitraniline produces an amphoteric acid-base indicator, but 2-naphthylamine and aniline yield indicator acids. Naphthylamine and aniline can be detected in this way in the presence of each other. If phenyldiazonium chloride is coupled with naphthylamine, a strong indicator base is obtained with 1-naphthylamine, a weak indicator base with 2-naphthylamine. This indicator action is the basis of the detection of 1-naphthylamine in the presence of 2-naphthylamine.

---

Résumé Les composés tétrazoïques des dérivés phénoliques qui se forment avec lap-nitraniline diazotée, donnent avec le magnésium, en milieu alcalin, des complexes colorés. La couleur du complexe diffère suivant que les phénols sont substitués, non substitués ou différemment substitués. On peut ainsi distinguer le phénol, les crésols et les chlorophénols isomères, ainsi que les dichloro-2,4 et -2,6 phénols.En diazotant la nitraniline et en copulant avec l'aniline, des acides indicateurs prennent naissance, lap-nitraniline donnant l'acide indicateur le plus fort, lam-nitraniline le plus faible. En s'appuyant sur ce fait, on peut rechercher les trois isomères en présence les uns des autres. En outre, les indicateurs qui prennent naissance à partir de lap- et de l'o-nitraniline forment avec le magnésium différents complexes colorés acinitrés, alors que lam-nitraniline, qui n'est pas susceptible d'une tautomérie de l'acide nitronique, ne donne pas de complexe.Les naphtylamines donnent avec lap-nitraniline diazotée, en milieu aqueux, une base indicateur et l'aniline, un acide indicateur. En milieu alcoolique, l'-naphtylamine conduit par copulation de lap-nitraniline diazotée à un indicateur acide-base amphotère mais la-naphtylamine et l'aniline à des acides indicateurs. On peut ainsi rechercher la naphtylamine et l'aniline en présence l'une de l'autre. Si l'on copule le chlorure de phenyldiazonium avec la naphtylamine, on obtient avec la forme une base indicateur forte et avec la forme une base indicateur faible. En se fondant sur cette action d'indicateur, on peut rechercher l'-naphtylamine en présence de-naphtylamine.

     

Identification of a series of C25-C40 acyclic isoprenoid hydrocarbons in crude oils

The identification of acyclic isoprenoid hydrocarbons in organic extracts of geological samples and particularly in petroleum deserves a great interest from the biological origin of the sedimentary organic matter and the understanding of geochemical processes.     

Complex study of nickel skeleton catalysts: V. Study of novel non-pyrophoric nickel skeleton catalysts by derivatograph

The structure and properties of non-pyrophoric skeleton catalysts prepared from NiSi, NiAlSi, NiMg and NiZn alloys have been studied—apart from other thermal methods—by means of the derivatograph.Our experimental results have contributed to the explanation of the non-pyrophoric behaviour of these catalysts. We demonstrated that the desorption of the hydrogen content in our catalysts is not accompanied by the oxidation of active nickel. This oxidation takes place only at higher temperatures, above 200°C, at a rate proportional to the amount of active nickel.Other constituents of the catalysts (adsorbed water, hydroxide content) were also determined from the experimental data. The outstandingly high Mg(OH)₂ content of the NiMg catalyst indicates that its structure is dissimilar: Mg(OH)₂ also acts as support for the catalyst.     

Isotope gas analysis of tritium-labelled organic compounds based on pyrolytical decomposition

Summary A procedure has been developed for the activity measurement of tritium-labelled organic compounds in the gas phase. The organic compounds are pyrolysed in hydrogen carrier gas at 1150° and the decomposition products are swept through a carbon packing in accordance with the principle of the oxygen determination developed byUnterzaucher andBürger. The radioactive gas mixture obtained from the sample is swept by the hydrogen carrier gas flowing continuously through the reactor into a proportional counter tube, after the addition of propanebutane counter gas. By closure of the counter tube at a suitable moment, the radioactive gas is quantitatively trapped in the counter tube. The activity is measured in the limited proportional region. No memory effect occurs. The preparation of the sample requires 12 minutes; the relative standard deviation of analysis is <0.5%.

---

Zusammenfassung Ein Verfahren zur Aktivitätsbestimmung bei tritium-markierten organischen Verbindungen in der Gasphase wurde ausgearbeitet. Die organischen Substanzen werden in Wasserstoff als Trägergas bei 1150° pyrolysiert. Die Zersetzungsprodukte werden wie bei der Sauerstoffbestimmung nachUnterzaucher bzw.Bürger über eine Kohleschicht geleitet. Das radioaktive Gas-gemisch aus der Probe gelangt mit dem kontinuierlich strömenden Trägergas in ein Proportionalzählrohr, nachdem Propan-Butan-Zählgas zugesetzt wurde. Man schließt das Zählrohr im richtigen Augenblick, um das radioaktive Gas quantitativ zu erfassen. Die Aktivität wird im Proportionalbereich gemessen. Ein Memory-Effekt tritt nicht auf. Die Vorbereitung der Probe beansprucht 12 Minuten. Die relative Standardabweichung ist kleiner als 0,5%.

     

Saturated heterocycles, 162 [1]. synthesis and steric structures of 3,4-disubstituted 1,6,7,11b-tetrahydropyrimido[6,1-a]isoquinolin-2-ones

The reaction of 1-(hydrazidomethyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline 3 with aromatic aldehydes yield hydrazones 4a,b or pyrimido[6,1-a]isoquinolines 5a-c depending upon the proportions of the reagents. With ketones, 3 gives only hydrazones 4a-d and 7 , which can be transformed to pyrimidoisoquinolines 10a-e and 11 with aldehydes. The ring closures are stereospecific; the relative configurations were determined by DNOE measurements.