On the second law of thermodynamics II. Inequalities for cyclic processes

Consequences of and relations among the classical statements of the second law of thermodynamics are derived for non-equilibrium thermodynamic systems not necessarily satisfying the first law. It is shown that each classical version of the second law implies one or two inequalities for cyclic processes which yield the Clausius inequality for cyclic processes if the first law holds. The inequalities for cyclic processes are derived by means of a general theorem stated and proved in the first part.The author wishes to express his deep thanks to Dr. Jan Kratochvíl for reading a previous draught of the paper and for discussing the topics dealt with in it.     

Diphosphacarborane analogues of ferrocene: the synthesis of two isomeric twelve-vertex closo-[(eta5-C5H5)FeP2CB8H9] complexes

The reaction of the Tl+ salt of the [nido-7,8,9-P2CB8H9]- anion (1-) with [CpFe(CO)2I](Cp =eta(5)-C5H5) in refluxing mesitylene for 12 h gives mixed-sandwich [1-Cp-closo-1,2,3,4-FeP2CB8H9] (2) (yield 63%). Reaction of the PPh4+ salt of the isomeric [nido-7,8,10-P2CB8H9]- anion 3- with [CpFe(CO)2I] in refluxing mesitylene gives [1-Cp-closo-1,2,3,5-FeP2CB8H9]4 (yield 56%), isomeric with 2. Compound 4 also results (yield 92%) from the sublimation of 2 under argon at ca. 350 degrees C. The constitution of all compounds is established by mass spectrometry, IR spectroscopy and multinuclear NMR spectroscopy (1H, 11B, 31P, and 13C; two-dimensional [11B-11B]-COSY, and 1H- 11B(selective)), further confirmed in the case of 4 by a single-crystal X-ray diffraction analysis.     

Synthesis of alpha-amino acids via asymmetric phase transfer-catalyzed alkylation of achiral nickel(II) complexes of glycine-derived Schiff bases

Achiral, diamagnetic Ni(II) complexes 1 and 3 have been synthesized from Ni(II) salts and the Schiff bases, generated from glycine and PBP (7) and PBA (11), respectively, in MeONa/MeOH solutions. The requisite carbonyl-derivatizing agents pyridine-2-carboxylic acid(2-benzoyl-phenyl)-amide 7 (PBP) and pyridine-2-carboxylic acid(2-formyl-phenyl)-amide 11 (PBA) were readily prepared from picolinic acid and o-aminobenzophenone or picolinic acid and methyl o-anthranilate, respectively. The structure of 1 was established by X-ray crystallography. Complexes 1 and 3 were found to undergo C-alkylation with alkyl halides under PTC conditions in the presence of beta-naphthol or benzyltriethylammonium bromide as catalysts to give mono- and bis-alkylated products, respectively. Decomposition of the complexes with aqueous HCl under mild conditions gave the required amino acids, and PBP and PBA were recovered. Alkylation of 1 with highly reactive alkyl halides, carried out under the PTC conditions in the presence of 10% mol of (S)- or (R)-2-hydroxy-2'-amino-1,1'-binaphthyl 31a (NOBIN) and/or its N-acyl derivatives and by (S)- or (R)-2-hydroxy-8'-amino-1,1'-binaphthyl 32a (iso-NOBIN) and its N-acyl derivatives, respectively, gave rise to alpha-amino acids with high enantioselectivities (90-98.5% ee) in good-to-excellent chemical yields at room temperature within several minutes. An unusually large positive nonlinear effect was observed in these reactions. The Michael addition of acrylic derivatives 37 to 1 was conducted under similar conditions with up to 96% ee. The (1)H NMR and IR spectra of a mixture of the sodium salt of NOBIN and 1 indicated formation of a complex between the two components. Implications of the association and self-association of NOBIN for the observed sense of asymmetric induction and nonlinear effects are discussed.     

Adsorption of SO2 on alumina

The adsorption of SO₂ on alumina used in the aluminium industry, the so-called smelter-grade alumina, was studied in the temperature range 15–120°C. It was found that at temperatures lower than 40°C, sulphur dioxide was bonded to alumina reversibly by physical forces, and the adsorption could be described satisfactorily by the Langmuir adsorption isotherm. The heat of adsorption was estimated to be −33 kJ mol⁻¹. At temperatures ranging from 80°C to 120°C, which prevail in dry scrubbers in the aluminium industry, the heat of adsorption was determined to be −56 kJ mol⁻¹. When SO₂ was adsorbed at temperatures higher than 80°C, about 30 % of the SO₂ could not be desorbed even if the samples were heated up to 250°C. In the presence of SO₂ and oxygen, the formation of sulphate was observed at temperatures above 90°C.     

Effect of bacteria growth temperature on the distribution of supercoiled DNA and its thermal stability

Changes in DNA supercoiling might be essential to generate the response of cellular machinery to temperature stress. The heat-induced structural transition for a topoisomer depends on the value of its specific linking difference. We detect only less negatively supercoiled DNA and an abundance of alternative irregular DNA forms at culture temperatures close to the growth limit of Escherichia coli. We show that the irregular forms are derived from regular plasmid DNAs and their population in the cells is temperature-dependent. Here, we show that it is possible to isolate and characterize individual DNA topoisomers directly from cells without a topoisomerase treatment. Temperature gradient gel electrophoresis (TGGE) and atomic force microscopy (AFM) were used to study the effect of bacteria growth temperature on the distribution of supercoiled DNA and its thermal stability.     

Rapid separation of mercury,arsenic, thallium and chromium species

Radiochemical neutron activation analysis is the only method to determine the galactic cosmic ray (GCR) produced radionuclide⁵³Mn (T=3.8·10⁶) in small meteorite samples. A large number of such samples was analyzed using extremely thermalized neutrons of the DIDO reactor at the KFA Jülich. The detection limit of 10^–14 g/g was recently achieved in our laboratory through the improvement of pre- and postirradiation chemistry. The main purpose of our studies of meteorite finds from Antarctica and the Southwestern United States is to establish their exposure ages up to 12·10⁶ a by means of⁵³Mn. Especially in the case of Antarctic meteorites terrestrial ages up to several 10⁵ years have been observed by combining⁵³Mn and²⁶Al (T=7.2·10⁵ a) measurements.     

Cooperative effects in the activation of molecular oxygen by anionic silver clusters

A novel size dependence in the adsorption reaction of multiple O2 molecules onto anionic silver clusters Agn- (n = 1-5) is revealed by gas-phase reaction studies in an rf-ion trap. Ab initio theoretical modeling based on DFT method provides insight into the reaction mechanism and finds cooperative electronic and structural effects to be responsible for the size selective reactivity of Agn- clusters toward one or more O2. In particular, Agn- clusters with odd n have paired electrons and therefore bind one O2 only weakly, but they are simultaneously activated to adsorb a strongly bound second oxygen molecule. For the clusters Ag3O4- and Ag5O4-, this cooperative effect results in a superoxo-like, doubly bound O2 subunit with potentially high activity in catalytic silver cluster oxidation processes.     

Chemie der Seltenerdmetalle, 11. Mitt.: Yttriumtartratkomplexe im sauren Bereich

Zusammenfassung Es wurde ein systematisches Studium des Systems im sauren Bereich durchgeführt. Aus den Ergebnissen der pH-Messungen wurden die Gleichgewichtskonstanten der Komplexe [YH₃ T]²⁺, [YH₂ T]⁺, [Y₂H₂ T]⁴⁺, [Y(H₂ T)₂]^– und HYT bestimmt. Es wurden die Verbindungen Y₂(H₂ T)₃ · 8 H₂O, Y₂(H₂ T)₃ · 5 H₂O und H[Y(H₂ T)₂] · 3 H₂O isoliert. Diese wurden mit Hilfe von Röntgenstreuung, Thermoanalyse und IR-Absorptionsspektren untersucht.

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A systematic investigation of the system in the acidic range was undertaken. The equilibrium constants of the complexes [YH₃ T]²⁺, [YH₂ T]^–, [Y₂H₂ T]⁴⁺, [Y(H₂ T)₂]^– and HYT were determined, making use of the results of p_H-measurements. The compounds Y₂(H₂ T)₃ · 8 H₂O, Y₂(H₂ T)₃ · 5 H₂O and H[Y(H₂ T)₂] · 3 H₂O were isolated. Their X-ray diffraction, thermal analysis and IR spectra were investigated.

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Mit 2 Abbildungen

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Zugleich 24. Mitt. der Reihe: Koordinationsverbindungen von organischen Oxoubstanzen; H₄ T=C₄H₆O₆.