Über Seleno- und Telluroarsenite, -antimonite und -bismutite

On Seleno- and Telluroarsenites, -antimonites, and -bismutites The new compounds NaAsSe₂, NaSbSe₂, NaSbTe₂, and NaBiTe₂ have been prepared and their structures determined. NaSbSe₂, NaSbTe₂, and NaBiTe₂ build up the NaCl structure with the following lattice constants: NaSbSe₂: a = 596.6(2) pm, NaSbTe₂: a = 631.7(2) pm, NaBiTe₂: a = 636.6(3) pm. NaAsSe₂ crystallizes orthorhombic with a = 583 ± 1pm, b = 2427 ± 5 pm, c = 1182 ± 2 pm, Pbca. In the structure there are distorted trigonal AsSe₃ pyramids which are connected by corners to chains.     

Cantharidin: Hochzeitsgabe,Schutz‐ und Lockstoff,Blasenzieher und Enzymhemmer

Numerous species of blister beetles use cantharidin in their blood as a protecting and attracting agent. From antiquity to the 20^th century these beetles (and later the substance cantharidin itself) have been utilized as a medicine and an aphrodisiac. The advantages were however very limited, because of cantharidins high toxicity. From the first isolation of the active substance to the unravelling of its structure and the discovery of viable synthetic methods it took 150 years. Cantharidin has recently found growing interest among molecular biologists, pharmacologists and chemists, due to its property of inhibiting enzymes (protein phosphatases) which regulate cellular metabolism.     

Darstellung,Eigenschaften und Molekülstrukturen von Dimethylmetallalkoxiden und ‐amiden des Aluminiums und Galliums

Preparation, Properties, and Molecular Structures of Dimethylmetal Alkoxides and Amides of Aluminium and Gallium Dimethylaluminium‐ ( 1 ) and Dimethylgallium‐o‐methoxyphenyl‐1‐ethoxide ( 2 ) were obtained by reaction of Me₃Al and Me₃Ga respectively with o‐Methoxyphenyl‐1‐ethanol in n‐pentane. Dimethylaluminium‐ ( 3 ) and dimethylgallium‐o‐methoxyphenyl‐2‐ethylamide ( 4 ) were prepared by treatment of Me₂AlCl and Me₂GaCl respectively with Lithium‐o‐methoxyphenyl‐2‐ethylamide. Trimethylgallium‐o‐methoxyphenylmethylamine‐Adduct ( 5 ) was isolated using reaction of Me₃Ga with the corresponding amine. The compounds were characterised by ¹H‐, ¹³C‐, and ²⁷Al n.m.r. spectroscopy. The molecular structures of 2 and 5 were determined by X‐ray diffraction. Compounds 1 – 4 form brigded dimeric molecules. The bond distances of the central Ga₂O₂ ring in 2 correspond to those of compounds of similar structure.     

DySBr und DySI – Synthese,Kristallstruktur und Magnetismus

DySBr and DySI – Synthesis, Crystal Structure, and Magnetism By reaction of Dy₂S₃ with Dy metal and Br₂ (I₂) at 750°C (900°C), single phase crystalline DySBr (DySI) has been synthesized. Crystal structure refinement of DySBr confirms the FeOCl-type structure (R = 0.049; space group Pmmn, Z = 2, lattice parameters (in Å): a = 5.349(2), b = 4.079(2), c = 8.066(2)) which is also ascertained for DySI (R = 0.059; lattice parameters (in Å): a = 5.320(2), b = 4.168(1), c = 9.224(5)). The magnetic susceptibilities (temperature range 3.4 K – 295 K) can be described on the basis of simple models (cubic crystal field, molecular field approximation) above 5 K and 15 K respectively. The deviations at low temperature are assumed to be related essentially to Dy—Dy exchange interactions which are not adequately described with the molecular field approach.     

Dimethylerdmetall‐Heterocyclen als Derivate trimethylsilylierter, ‐germylierter und ‐stannylierter Phosphane und Arsane – Synthesen,Spektren und Strukturen

Dimethyl Earth‐Metal Heterocycles – Derivatives of Trimethyl‐silylated, ‐germylated, and ‐stannylated Phosphanes and Arsanes – Syntheses, Spectra, and Structures The organo earth‐metal heterocycles [Me₂M^III–E(M^IVMe₃)₂]_n with M^III = Al, Ga, In; E = P, As; M^IV = Si, Ge, Sn and n = 2, 3 (Me = CH₃) have been prepared from the dimethyl metal compounds Me₂M^IIIX (X = Me, H, Cl, OMe, OPh) and the pnicogen derivatives H_nE(M^IVMe₃)_3–n (n = 0, 1) according to known preparation methods. The mass, ¹H, ¹³C, ³¹P, ²⁹Si, ¹¹⁹Sn nmr, as well as the ir and Raman spectra have been discussed comparatively; selected representatives are characterized by X‐ray structure analyses. The dimeric species with four‐membered (E–M^III)₂ rings are isotypic and crystallize in the triclinic space group P1, the trimer [Me₂In–P(SnMe₃)₂]₃ with a strongly puckered (In–P)₃‐ring skeleton crystallizes with two formula units per cell in the same centrosymmetric triclinic space group.     

Goldmacherei in Deutschland und Europa. Fürsten,Bürger und Betrüger

The article shows how deceitful alchemists betrayed their victims from the 16th to the 20th century. A number of biographical sketches demonstrate, how they hoodwinked their victims and what tricks they employed with their seemingly successful transmutations. It is also shown, why people again and again where willing to believe the goldmakers' promises of tons of gold.     

Trimethylsilyl- und Trimethylstannylester der Trithiophosphonsäuren; Darstellung,Protolyse und weitere Reaktionen

Trimethylsilyl and Trimethylstannyl Esters of the Trithiophosphonic Acids; Preparation, Protolysis, and Further Reactions The organotrithiophosphonic acid bis(trimethylsilyl) esters RP(S)(SSiMe₃)₂, R = Ph ( 1a ), R = t-Bu ( 1b ) and R = Me ( 1c ) are formed in high yield from the organo-bis(trimethylsilyl)-phosphanes RP(SiMe₃)₂ by the addition of three sulfur atoms (3/8 S₈) in toluene solution. 1b has also been prepared by reacting disodium tert-butyltrithiophosphonate, Na₂t-BuP(S)S₂ ( 2 ) with SiMe₃Cl. Analogous reactions can be used for the preparation of the stannyl esters RP(S)(SSnMe₃)₂, R = t-Bu ( 5a ) and R = Me ( 5b ). More favorable, however, these compounds are synthesized from the corresponding silyl esters 1b, c and SnMe₃Cl or, as has been shown in the case of 5a , by reacting dithiophosphonic acid anhydrides (RP(S)S)₂ with (SnMe₃)₂S. Low temperature solvolysis of the silyl esters 1b, c with water or methanol results in the free organotrithiophosphonic acids RP(S)(SH)₂, R = t-Bu ( 6a ) and R = Me ( 6b ), which can be isolated as white solids at —30°C. Contrary to the sodium salt 2 and the stannyl esters 5a, b , the acids 6a, b , and, to a smaller extent, the silyl esters 1a—c are thermally not stable towards decomposition into the thioanhydrides (RP(S)S)₂. The silyl and stannyl esters 1a—c and 5a, b , respectively, are capable of cleaving the ether linkage of tetrahydrofuran, which in the case of 1b leads to the quantitative formation of t-BuP(S)[S(CH₂)₄OSiMe₃]₂ ( 9 ). 1b, c and 5a, b react with Cl₂ and Br₂ forming the 3,6-diorgano-3,6-dithio-1,2,4,5,3,6-tetrathiadiphosphorinanes (RP(S)S₂)₂, R = t-Bu ( 7a ) and R = Me ( 7b ).     

Zur Kenntnis des Calciumbromats und - iodats,Kristallstruktur, röntgenographische,IR- und Raman-spektroskopische und thermoanalytische Untersuchungen

On Calcium Bromated and Iodates – Crystal Structure, X-Ray, IR and Raman Spectroscopical and Thermoanalytical Investigations The phase relationships (and both decomposition and disproportionation)of bromates and iodates of alkaline earth metals are studied by means of thermal analyses (DTA, DSC, TG) and (high-temperature) X-Ray, IR-, and (high-temperature) Raman spectroscopic measurements. The following compounds have been established: Ca(IO₃)₂ · 6 H₂O oF 216, the isotypic Ca(BrO₃)₂ · H₂O and Ca(IO₃)₂ · H₂O mP 48, Ca(IO₃)₂ I (Lautarit) mP 36, Ca(IO₃)₂ II and Ca(BrO₃)₂. The Crystal structure of Ca(IO₃)₂ · H₂O (brüggenite) (space group P2₁/c, Z = 4) has been determined by single crystal X-ray diffraction (MoKα). The final R value for 3888 reflections with I_o > 3σ₁ is 0.0487. The structures of bromates and iodates of alkaline earth metals known so far are discussed with respect to the energetic (mode frequencies) and geometric (bond lengths) distortion of the XO₃–ions as well as the strengths of H-bonds present in the respective hydrates.     

Hydrothermalsynthese und Kristallstruktur der Münzmetall‐Quecksilber‐Chalkogenidhalogenide CuHgSeBr,AgHgSBr und AgHgSI

Hydrothermal Synthesis and Crystal Structure of the Coinage Metal Mercury Chalcogenide Halides CuHgSeBr, AgHgSBr, and AgHgSI The hydrothermal reaction of CuBr and HgSe in concentrated aqueous HBr as solvent at 285 °C yields red crystals of CuHgSeBr, the hydrothermal reaction of AgX (X = Br, I) and HgS in half‐concentrated aqueous HX (X = Br, I) as solvent at 300/400 °C yields yellow crystals of AgHgSBr and AgHgSI. The compounds crystallize isotypically (orthorhombic, Pmma, a = 1020.1(3) pm, b = 431.2(1) pm, c = 925.6(3) pm for CuHgSeBr, a = 964.8(8) pm, b = 466.1(4) pm, c = 942.6(6) pm for AgHgSBr und a = 1015.9(2) pm, b = 464.77(5) pm, c = 984.9(2) pm for AgHgSI, Z = 4). The structures consist of plane folded Hg–Y chains connected by pairs of distorted Y₂X₂ terahedra sharing the X–X‐edge (M = Cu, Ag; X = Br, I; Y = S, Se). Atoms of the monovalent metals M have a strongly distorted tetrahedral coordination of two halogen and two chalcogen atoms. The new structure type shows distinct differences in the arrangement of the Hg–Y chains in comparision to the already known CuHgSeCl, but represents the superposition structure of the order‐disorder phase γ‐Hg₃S₂Cl₂.