Chemie und Science Fiction

Modern Science Fiction has developed to a mirror of progress in science and technics. At the same time, this literal form leads to undesirable developments, frequently in the drug scene, and lapses into the areas of fantasy and satire. Will Science Fiction be able, now and in future, to make young people enthusiastic about studies of chemistry?     

Diselenadiphosphetandiselenide und Triselenadiphospholandiselenide – Synthese und Charakterisierung mittels 31P‐ und 77Se‐Festkörper‐NMRSpektroskopie

Diselenadiphosphetane Diselenides and Triselenadiphospholane Diselenides – Synthesis and Characterization by ³¹P and ⁷⁷Se Solid‐State NMR Spectroscopy 1,3‐Diselena‐2,4‐diphosphetane‐2,4‐diselenides (RPSe₂)₂ with R = Me, Et, t‐Bu, Ph, 4‐Me₂NC₆H₄, 4‐MeOC₆H₄ have been synthesized by different methods. The insoluble compounds were investigated by ³¹P and ⁷⁷Se solid‐state NMR and the purity of the compounds has been checked by their CP MAS sideband NMR spectra. The structure of the investigated compounds has been confirmed by the isotropic and anisotropic values of the chemical shifts and the ¹J_P–Se coupling constants. In addition, two new 1,2,4‐triselena‐3,5‐diphospholane‐3,5‐diselenides, (RPSe₂)₂Se (R = Me, Et), formed under similar synthesis conditions, were investigated. Their structure was derived from the ⁷⁷Se satellites of ³¹P solution spectra and from solid‐state spectra. For (t‐BuPSe₂)₂ the experimentally obtained principal values of phosphorus and selenium shielding tensors are compared with values from IGLO calculations (HF und SOS DFPT). The calculated orientations of the principal axes are discussed.     

Doping und Dopinganalytik: Wirkstoffe und Methoden

Since 1997, alterations regarding the anti‐doping rules of sport federations have led to the prohibition of new classes of substances such as plasma volume expanders, anti‐estrogens, aromatase inhibitors and artificial oxygen carriers (e.g. perfluorocarbons, cross‐linked hemoglobins) besides the classical doping agents including stimulants, narcotics, anabolic agents, diuretics and peptide hormones. The determination of doping substances, which has been based mainly on GC‐MS procedures, is more and more performed employing LC‐MS and LC‐MS/MS instruments. For instance, the classes of betablockers, diuretics, corticosteroids and newly proteins such as the cross‐linked hemoglobin 'Hemopure' are effectively detected utilizing LC‐MS(/MS) systems. The urinary identification of erythropoietin (EPO)‐doping is accomplished by means of an assay composed by isoelectric focusing with subsequent visualisation of characteristic EPO bands with monoclonal EPO antibodies (double blotting).     

Reinigen mit Licht und Regen

After the discovery of the lotus‐effect in the 1970s the attention concerning the field of self‐cleaning surfaces increased rapidly. Besides hydrophobic surfaces which are designed following the example of the lotus flower, superhydrophilic and photocatalytic active coatings play an important role. These coatings are using sunlight to oxidize pollutants and remove residues by rinsing with water. Coatings based on the lotus‐effect suffer from their weak mechanical durability, but are able to work without light. On the other hand, photocatalytic layers are mechanically stable, but they need to be illuminated to become self‐cleaning.     

Darstellung und Kristallstruktur von Rb4Br2O und Rb6Br4O

Syntheses and Crystal Structures of Rb₄Br₂O and Rb₆Br₄O In the quasi‐binary system RbBr/Rb₂O, the addition compounds Rb₄Br₂O and Rb₆Br₄O are obtained by solid state reaction of the boundary components RbBr and Rb₂O. Crystals of red‐orange Rb₄Br₂O as well as of orange Rb₆Br₄O decompose immediately when exposed to air. Rb₄Br₂O (Pearson code tI14, I4/mmm, a = 544.4(6) pm, c = 1725(2) pm, Z = 2, 175 symmetry independent reflections with I_o > 2σ(I), R₁= 0.0618) crystallizes in the anti K₂NiF₄ structure type; Rb₆Br₄O (Pearson code hR22, R3c, a = 1307.8(3) pm, c = 1646.6(5) pm, Z = 6, 630 symmetry independent reflections with I_o > 2σ(I), R₁ = 0.0759) in the anti K₄CdCl₆ structure type. Both structures contain characteristic ORb₆‐octahedra and can be understood as expanded perovskites, following the general systematics of alkaline metal oxide halides.     

Synthese und Kristallstrukturen neuer phosphorverbrückter bimetallischer Cluster der Elemente Quecksilber und Eisen

Synthesis and Crystal Structures of New Phosphorus‐bridged Bimetallic Clusters of the Elements Mercury and Iron The reaction of [Fe(CO)₄(HgX)₂] (X = Cl, Br) with P(SiMe₃)₂^tBu in the presence of tertiary phosphines and phosphinium salts leads to the ionic compounds [PPh₄]₂[Hg₁₂{Fe(CO)₄}₈(P^tBu)₄X₂] (X = Cl, Br) ( 1 , 2 ). If [Fe(CO)₄(HgX)₂] reacts with P(SiMe₃)₂^tBu the polymeric polynuclear complex [Hg₁₅{Fe(CO)₄}₃(P^tBu)₈Br₈]n ( 3 ) as well as the twenty mercury‐ and eight iron‐atoms containing [Hg₂₀{Fe(CO)₄}₈(P^tBu)₁₀X₄]‐clusters (X = Br, Cl) ( 4 , 5 ) are formed. The reaction of [Fe(CO)₄(HgX)₂] with LiPPh₂ yields to the phosphanido‐bridged [Hg₄{Fe(CO)₄}₂(PPh₂)₂Cl₂] ( 6 ), where as the use of LiP(SiMe₃)Ph leads to the diphosphinidene‐bridged cluster [Li(thf)₄]₂[Hg₁₀{Fe(CO)₄}₆(P₂Ph₂)₂Br₆] ( 7 ). The structures of the compounds 1–7 were characterized by X‐ray single crystal structure analysis.