Ferrocenyltrithiocarbonates : I. Direct access from α-ferrocenylcarbinols by a SNi mechanism. Absolute x-ray structure determination of (R)-ferrocenylmethylmethane S-methyl-trithiocarbonate

¹⁰³Rh Chemical shifts of a variety of mono- and di-nuclear rhodium carbonyl complexes are reported together with the modifications to the probe and decoupler unit of a JEOL PS-100 PFT spectrometer which enable these ¹⁰³Rh-decoupled ¹³C NMR measurements to be made. These data are discussed in conjunction with ¹³C NMR data on other rhodium carbonyls.     

Formation of nitric acid in the gas-phase HO2 + NO reaction: effects of temperature and water vapor

A high-pressure turbulent flow reactor coupled with a chemical ionization mass spectrometer was used to investigate the minor channel (1b) producing nitric acid, HNO3, in the HO2 + NO reaction for which only one channel (1a) is known so far: HO2 + NO --> OH + NO2 (1a), HO2 + NO --> HNO3 (1b). The reaction has been investigated in the temperature range 223-298 K at a pressure of 200 Torr of N2 carrier gas. The influence of water vapor has been studied at 298 K. The branching ratio, k1b/k1a, was found to increase from (0.18(+0.04/-0.06))% at 298 K to (0.87(+0.05/-0.08))% at 223 K, corresponding to k1b = (1.6 +/- 0.5) x 10(-14) and (10.4 +/- 1.7) x 10(-14) cm3 molecule(-1) s(-1), respectively at 298 and 223 K. The data could be fitted by the Arrhenius expression k1b = 6.4 x 10(-17) exp((1644 +/- 76)/T) cm3 molecule(-1) s(-1) at T = 223-298 K. The yield of HNO3 was found to increase in the presence of water vapor (by 90% at about 3 Torr of H2O). Implications of the obtained results for atmospheric radicals chemistry and chemical amplifiers used to measure peroxy radicals are discussed. The results show in particular that reaction 1b can be a significant loss process for the HO(x) (OH, HO2) radicals in the upper troposphere.     

Organic synthesis with sulphones—XVII: The anti-markownikoff halosulphonylation of olefins via an ionic pathway,and a new method of preparing benzenesulphonyl iodide

Iodine and bromine in the presence of sodium benzenesulphinate react with olefins in acetone solution to give halosulphones resulting from an apparent steric direction of attack at the intermediate halonium ion. A straightforward preparation of benzenesulphonyl iodide from benzenesulphonyl chloride and sodium iodide is also described.     

Developments on carbon dioxide reduction: Their promise,achievements, and challenges

CO₂ reduction processes continue to be developed for electrosynthesis, energy storage applications, and environmental remediation. A number of promising materials have shown high activity and selectivity to target reduction products. However, the progress has been mainly at a small laboratory scale, and the technical challenges of large scale CO₂ reduction have not been considered adequately. This review covers recent advancements in catalyst materials and cell designs. The leading materials for CO₂ reduction to a number of useful products are presented with their corresponding cell and reactor designs. The latest efforts to progress to industrially relevant scales are discussed, along with the challenges that must be met for carbon dioxide reduction to be a viable route for mass scale production.     

Topological degree of a family of convex functions and localization of nash equilibrium points

We define the degree of a family of convex functionsf _x, wherex , and prove that, if this degree is different from zero, one has at least one Nash equilibrium point in . This is a criterion of localization of such equilibrium points.     

Mechanism of formation and decay of the compound nuclei150Gd produced by two entrance channels (16O+134Ba) and (40Ar+110Pd)

Excitation functions have been drawn for evaporation residues issued from¹⁵⁰Gd, a compound nucleus produced either by¹⁶O ions on¹³⁴Ba, or by⁴⁰Ar on¹¹⁰Pd. Absolute cross sections were measured for^145–147Gd,^145–147Eu,^141m Sm,^143m Sm,^140m Pm and^139m Nd. Complete fusion cross sections have been obtained and compared to calculated estimations based, at low energies, on the simple expressionσ _CF=πR _Fuss ² (1?V _Fus/E) whereR _Fus andV _Fus are respectively the distance and the potential for fusion atdV/dr=0. For high energies σ_CF=πR _cr ² (1?V_cr/E) with the model of critical distanceR _cr and critical potentialV _cr. Thresholds energies have been determined with a particular care. The analysis of the shape and the width of excitation functions, particularly for the emission of 4 and 5 neutrons, has been carried out and compared to calculated values. The difference between argon and oxygen induced reactions has been attributed to the difference inl population in the entrance channel.     

Elemental speciation by chromatographic separation with inductively coupled plasma mass spectrometry detection

Separation techniques coupled to inductively coupled plasma mass spectrometry (ICP-MS) is reviewed. ICP-MS technique is described briefly. Coupling of the different separation techniques are described, together with the most common applications used for each technique that has been described in the literature. An overview for the future of separation techniques coupled to ICP-MS with regard to elemental speciation is discussed.     

Reaktive E = C(p-p)π-Systeme. XLII [1]. Neue Koordinationsverbindungen des 2-(Diisopropylamino)-1-phosphaethins: [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}], [(Ph3P)2Pt{η2-(iPr2NCP)}] und [Co2(CO)6{η2-η2-(iPr2NCP)}]

Reactive E = C(pp)π-Systems. XLII [1]. Novel Coordination Compounds of 2-(Diisopropylamino)-1-phosphaethyne: [{η⁴-(iPr₂NCP)₂}Ni{η²-(iPr₂NCP)}], [(Ph₃P)₂Pt{η²-(iPr₂NCP)}], and [Co₂(CO)₆{η²-μ²-(iPr₂NCP)}] 2-(Diisopropylamino)-phosphaethyne iPr₂N? C?P ( 2 ) reacts with the Ni(0)-complexes [Ni(1,5-cyclooctadiene)₂] and [Ni(CO)₃(1-azabicyclo[2.2.2]octane)], respectively, to give the novel complex [{η⁴-(iPr₂NCP)₂}Ni{η²-(iPr₂NCP)}] ( 5 ), with the 1,3-diphosphacyclobutadiene derivative and 2 (side-on) as π-ligands. The molecular structure of 5 determined by X-ray diffraction on single crystals proves the spin systems and rotational barriers deduced from NMR-data (¹H, ¹³C-, ³¹P). The PC distances of the four-membered ring of 1.817(2) and 1.818(2) Å – as expected – are considerably longer than the PC bond of the η²-coordinated phosphaalkyne 2 [1.671(2) Å]. – In the reactions of 2 with [(Ph₃P)₂Pt(C₂H₄)] or [Co₂(CO)₈] the ligand properties of 2 resemble those of alkynes affording the complexes [(Ph₃P)₂Pt{η²-(iPr₂NCP)}] ( 7 ) with side-on coordinated 2 and [Co₂(CO)₆{η²-μ²-(iPr₂NCP)}] with 2 acting as a 4e donor bridge in quantitative yield. In attempts to prepare copper(I) complexes of the aminophosphaalkyne 2 by reaction with CuCl or CuI the only isolable product formed in reasonable amounts under the influence of air and moisture is the 1 λ³, 3 λ⁵-diphosphetene (iPr₂N) ( 10 ) (isolated yield: ca. 20%). The crystal structure analysis of 10 indicates a strong structural relationship to the diamino-2-phosphaallyl cation [Me(iPr₂N)]⁺ ( 12 ), the 1,3-diphosphacyclobutadiene ligand (iPr₂NCP)₂ in the binuclear complex [{η¹, μ²-(iPr₂NCP)₂}Ni₂(CO)₆] ( 3a ) as well as to the heterocycles (dme)₂LiOE₂′ (E′ = S, 11a ; E′ = Se, 11b ) prepared by Becker et al. [11b, 35].     

Evaluation of Ptitsyn-Eizner λ parameter in dilute solutions of poly(N-vinylcarbazole) and its variation in conformational transitions of poly(methyl methacrylate)

The Ptitsyn-Eizner λ flexibility parameter for poly(N-vinylcarbozole) solutions under theta conditions has been found to be 6.31, demonstrating the rigidity imparted to the polymer chain by the carbazole group. A study has been made of the variation of this parameter with solvent and temperature. A study has been made of the variation of λ in a conformational transition of poly(methyl methacrylate).