Synthesis and Characterization of [Hg(sulfamethoxazolato)2]·2DMSO and[Cu2(μ‐CH3CO2)4(sulfamethoxazole)2]

[Hg(sulfamethoxazolato)₂]·2DMSO ( 1 ) and [Cu₂(CH₃COO)₄(sulfa‐methoxazole)₂] ( 2 ) can be obtained by the reaction of sulfamethoxazole with mercury acetate or copper acetate in methanol. The structures of the two complexes were characterized by single crystal X—ray diffractometry. Compound 1 consists of sulfamethoxazolato ligands bridging the metal ions building an unidimensional chain. Two solvent dimethylsulfoxide molecules are involved via N‐H···O hydrogen bridges. The mercury atom shows a linear primary coordination arrangement formed by two trans deprotonated sulfonamidic nitrogen atoms. The overall coordination around the metal atom may be regarded as a strongly distorted octahedron when the interactions of mercury with four sulfonamidic oxygen atoms [bond distances of 2.761(4) Å—2.971(4) Å] are also considered to build an equatorial plane and the N1 and N1′ atoms [bond distance of 2.037(5) Å] occupy the apical positions. Compound 2 is a dinuclear complex in which the copper ions are bridged by four syn‐syn acetate ligands which are related by a symmetry centre located in the centre of the complex. Each copper atom presents a nearly octahedral coordination where the equatorial plane is formed by four oxygen atoms and an isoxazolic nitrogen atom and the second copper atom occupy the apical positions.     

X-ray determination of the mean amplitudes of vibration and debye temperatures of some rare earth monochalcogenides

The x-ray diffraction intensities of Bragg reflections have been measured at room temperature for thulium selenide, samarium sulphide, samarium selenide and samarium telluride. On the basis of a common amplitude approximation, the Debye-Waller factor, the mean amplitude of vibration and the Debye temperature have been evaluated. The values of the Debye temperatures and mean amplitudes of vibration are 176±16°K, 0·185 ± 0·017 Å (TmSe), 155 ± 7°K, 0·244 ± 0·012 Å (SmS), 153 ± 14°K, 0·221 ± 0·020 Å (SmSe) and 151 ± 20°K, 0·204 ± 0·027 Å (SmTe).     

A bi-logistic growth model for conference registration with an early bird deadline

The recent interest in human dynamics has led researchers to investigate the processes that explain human behaviour within different contexts. Here we are concerned in modelling the human response to a deadline, and in particular we look at the process of conference registration with an early bird deadline. We provide empirical evidence from a six-year conference registration data set that the bi-logistic growth function, with the interpretation as registration with an early bird deadline, can be viewed as a social mechanism.     

Metal-free direct arylations of indoles and pyrroles with diaryliodonium salts

Direct arylations of indoles and pyrroles with differently substituted diaryliodonium salts were shown to efficiently proceed in the absence of metal catalysts.     

Über Sulfide der vierten Hauptgruppe vom Typ AIIBIVS3 und die Kristallstruktur des SnGeS31)

Inhaltsübersicht. Die Elemente der vierten Hauptgruppe bilden vier Sulfide vom Typ A^IIB^IVS₃: SnGeS₃, PbGeS₃, SnSnS₃, PbSnS₃. Die Verbindungen lassen sich durch Reaktion der Elemente sowie der binären Sulfide darstellen. Es können gute Einkristalle erhalten werden. Auf Grund chemischer, physikalischer und struktureller Eigenschaften lassen sich die Sulfide in zwei Gruppen einteilen. Bestimmend hierfür ist das Element in der Oxydationsstufe +IV. Die Struktur der isotypen Verbindungen SnGeS₃ und PbGeS₃ wurde durch eine vollständige Röntgenstrukturanalyse des SnGeS₃ bestimmt. Cherakteristisch für die Struktur sind Ketten aus eckenverknüpften GeS₄-Tetraedern, die über Sn-Atome zu stark gewellten Schichten vernetzt sind. Type A^IIB^IVS₃ Sulfides of the Fourth Main Group and the Crystal Structure of SnGeS₃ Abstract. The group IV elements form sulfides of the type A^IIB^IVS₃: SnGeS₃, PbGeS₃, SnSnS₃, PbSnS₃. The compounds are formed through the reaction of the elements and of the binary sulfides. Good single crystals are obtained. The sulfides can be sorted into two groups due to their physical, chemical and structural properties. The element in the oxidation state +IV determines these properties. The structure of the isotypic compounds SnGeS₃ and PbGeS₃ was determined by a complete x-ray structure analysis of SnGeS₃. Characteristic for the structure are chains of GeS₄ tetrahedra sharing to vertices each. The chains are linked into corrugated layers by the Sn atoms.     

Hamiltonian cycles in random regular graphs

The existence of Hamiltonian cycles in random vertex-labelled regular graphs is investigated. It is proved that there exists r₀≤796 such that for r≥r₀ almost all vertex-labelled r-regular graphs with n vertices have Hamiltonian cycles as n → ∞.     

Measurement of e+e−→τ+τ− at high energy and properties of the τ lepton

The e⁺e^?→τ⁺τ^? process has been measured using the CELLO detector at a mean total centre of mass energy of 34.2 GeV using essentially all the decay channels of the τ lepton. The measured cross section yields R_τ=1.03±0.05 (stat)±0.07 (syst). Topological branching fraction are given for τ → 1, 3 or 5 charged tracks. The angular distribution shows a clear 1 + cos²θ dependance with a forward-backward asymmetry of -0.103 ± 0.052 corresponding to an axial-vector coupling a_τ of the τ to the weak neutral current given by a_τ=?1.12 ± 0.57.