Reaction of carboxamide with Cu2Oisonitrile complex; formation of a new chelated copper(I) complex

Reaction of carboxamides with Cu₂O in the presence of t-butyl isocyanide gave new chelated copper(I) complexes, which probably are formed by the insertion of t-butyl isocyanide into the coppernitrogen bond of copper(I) amide isonitrile complexes, which were initially produced from the carboxamides and Cu₂Ot-butyl isocyanide complex. The same chelated copper(I) complexes were prepared more readily by the reaction of the corresponding N-trimethylsilyl-carboxamides with Cu₂Ot-butyl isocyanide complex. Reactions of the copper(I) complexes thus obtained with alkylating agents, such as alkyl halides, alkyl tosylates and triethyloxonium tetrafluoroborate, also were described.     

Rapid computer simulation of ESR spectra. Conventional ESR of axially symmetric 14N-nitroxide spin labels

A computer algorithm is presented for the simulation of the effect of molecular tumbling on ESR spectra, and is applied to simulation of the conventional ESR signal (the absorption signal detected at the first harmonic of the modulation frequency and in-phase with the modulation frequency, in the limit of low microwave and modulation power) of axially symmetric ¹⁴N-nitroxide spin labels. The algorithm is extremely fast and is economical in terms of computer memory requirements.     

The vibrational spectra and normal coordinate analysis of tetracyclopropyllead

All the fundamental frequencies observed in IR and Raman spectra have been assigned to the normal modes of the molecule (C₃H₅)₄Pb (C₃H₅ = cyclopropyl). The calculated force field is compared to that of (C₃H₅)₂Hg and the Cmetal stretching force constants are discussed along with those of Me₄Pb and Me₂Hg; The similarity of the spectra of cyclopropyllead and cyclopropyl-mercury proves that the vibrations of cyclopropyl structural units are isolated in both molecules.     

量子化学奠基人之一——查尔斯.阿尔弗雷德.库尔森

查尔斯·阿尔弗雷德·库尔森是量子化学领域的杰出研究者,也是“英国量子化学学派”的领导者。他将分子轨道理论应用于化学键、分子电子结构和分数价概念,并发展了许多数学技术来解决化学和物理问题;他的著作《原子价》被认为是用于量子化学教学的杰作。库尔森无疑为提升量子化学在当今化学中的作用做出了巨大贡献。本文就库尔森的生平、求学经历及其对量子化学的贡献进行了论述。     

Alfred Nier and the sector field mass spectrometer

Science and technology are intimately related, and advances in science often become possible with the availability of new instrumentation. This has certainly been the case in mass spectrometry, which is used in so many scientific disciplines. Originally developed as an instrument for research in physics it was used in the discovery of isotopes, their recognition as the fundamental species comprising the elements, and the investigation of elemental isotopic composition. Isotope ratio mass spectrometry is a metrological technique of the highest order, and has been widely used in chemical, biochemical, cosmochemical, environmental, geological, physical, and nuclear research. Mass spectrometry presently plays a key role not only in scientific research, but also in industrial operations. This paper highlights the role that Alfred Otto Carl Nier played in bringing mass spectrometry into the mainstream of science. Nier's career spanned a remarkable period in science, and he made crucial contributions to atomic weights, geochronology, isotope geochemistry, nuclear physics, and space science. He is widely viewed as the 'father of modern mass spectrometry', because of his genius with instrumentation, his innovations, and the generosity with which he shared his ideas and designs. It is timely to remember his fundamental work in mass spectrometry, particularly the development of the sector field mass spectrometer, which is still the instrument of choice for many isotope scientists some 66 years after its first appearance in 1940.     

“Are the genre and the Geschlecht one and the same number?” An inquiry into Alfred Clebsch's Geschlecht

This article is aimed at throwing new light on the history of the notion of genus, whose paternity is usually attributed to Bernhard Riemann while its original name Geschlecht is often credited to Alfred Clebsch. By comparing the approaches of the two mathematicians, we show that Clebsch's act of naming was rooted in a projective geometric reinterpretation of Riemann's research, and that his Geschlecht was actually a different notion than that of Riemann. We also prove that until the beginning of the 1880s, mathematicians clearly distinguished between the notions of Clebsch and Riemann, the former being mainly associated with algebraic curves, and the latter with surfaces and Riemann surfaces. In the concluding remarks, we discuss the historiographic issues raised by the use of phrases like “the genus of a Riemann surface”—which began to appear in some works of Felix Klein at the very end of the 1870s—to describe Riemann's original research.     

Syntheses of metal carbonyls: XVII. Formation of a heteronuclear organometallic cluster containing ruthenium and rhodium; crystal and molecular structure of {[Rh(η-C5Me5)]3Ru(CO)3](μ3-CO)2}

Ru(C₆Me₆)(C₂H₄)₂ reacts with Rh(C₅Me₅)(CO)₂ to give the known dinuclear complex [Rh(C₅Me₅)(CO)]₂ and the new heteronuclear cluster complex {[Rh(C₅Me₅)]₃[Ru(CO)₃](μ₃-CO)₂} which has been fully characterized by a single crystal X-ray diffraction study.     

Sesquiterpenes from termite soldiers. Structure of amiteol,a new 5β, 7β, 10β-eudesmane from amitermesexcellens

The defense secretions of termite soldiers in the genera $\text{Amitermes}$, $\text{Noditermes}$, and $\text{Prorhinotermes}$ contain sesqueterpene hydrocarbons, alcohols and ethers. Three new eudesmanes possessing the hitherto unknown 5β, 7β, 10β configuration were identified from $\text{Amitermes}$$\text{excellens}$.     

Preparation and properties of the formamidino complexes [M(π-C5H5){HC(NR)2}(CO)2] (M = molybdenum or tungsten; R = aryl or alkyl)

The preparation and properties of the complexes [M(π-C₅H₅){HC(NR)₂}CO)₂] (M = Mo, W; R = aryl or alkyl) are reported. The complex [Mo(π-C₅H₅){HC(N-p-tolyl)₂}(CO)₂] could be prepared by (a) reaction of MoCp(CO)₃Cl with M′{HC(N-p-tolyl)₂} (M′ = K, Ag or Cu); (b) irradiation of MoCp(CO)₃Cl with HC(HN-p-tolyl)N-p-tolyl); and (c) reaction of [MoCp(CO)₃]₂ with M′{HC(N-p-tolyl)₂} (M′ = Ag or Cu). The several routes to this complex give indications of the mechanisms of formation. The structure of these complexes and the bonding nature of the metal with the formamidino group is discussed on basis of the ¹H and ¹³C NMR and IR spectra.Reaction of N,N′-dimethyl formamidine with MCp(CO)₃Cl gave the complex [M(π-C₅H₅){HC(NMe)N(CO)Me}(CO)₂], containing a carbonyl inserted between the metal and the formamidino group. Irradiation of this carbamoyl complex caused decarbonylation, yielding the complex [M(π-C₅H₅){HC(NMe)₂}CO)₂].