Molecular and Crystal Structures of Cp2YbX(THF) (X = Cl,Br)

Cp₂YbCl(THF) crystallizes in the orthorhombic space group Pnma (Z = 4, a = 13.109(5), b = 11.851(4), c = 9.377(3) Å, R1 = 0.0412, wR2 = 0.0482), while Cp₂YbBr(THF) is monoclinic (P2₁/n, Z = 4, a = 8.149(2), b = 12.997(2), c = 14.388(3) Å, β = 105.73(2)°, R1 = 0.0425, wR2 = 0.0436). The ligand arrangements around the formally eight coordinate Yb atoms are pseudo tetrahedral. These two determinations complete the first series of [Cp₂LnX(L)] (X = F, Cl, Br, I) structures covering all halogens for one lanthanoid and cyclopentadienyl group.     

P‐bis(trifluoromethyl) ylides: Synthesis and reactions

Bis(trifluoromethyl)phosphines RP(CF₃)₂ (R = Me, NEt₂) were methylated by MeOSO₂CF₃, yielding the respective phosphonium salts [RP(CF₃)₂Me]⁺ and CF₃SO₃⁻. Deprotonation using MeNP(NEt₂)₃ led to the phosphorus ylides RP(CF₃)₂CH₂, stable in solution at ambient temperature, which could be converted into 1,2λ⁵σ⁵‐oxaphosphetanes by adding hexafluoroacetone. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:650–653, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10061     

Synthesis and Crystal Structure of {(NH4)xCo((3–x)/2)}(H2O)2[BP2O8] · (1 – x) H2O (x ≈ 0.5)

A borophosphate hydrate with general composition {(NH₄)_xCo_((3–x)/2)}(H₂O)₂[BP₂O₈] · (1 – x) H₂O (x ≈ 0.5) was prepared under mild hydrothermal conditions (T = 170 °C). The crystal structure of the purple title compound was refined in space group P6₅ (no. 170) as a merohedric twin (a = 949.14 pm, c = 1558.25 pm, R₁ = 0.037, wR₂ = 0.092 for all data). According to preliminary X‐ray investigations, vis‐spectra, and magnetic susceptibility measurements, a second blue coloured variant exhibits a superstructure of the title compound with a change in coordination numbers around cobalt from six and five to six and four. Both phases show reversible de‐/rehydration properties.     

Two Dieneplatinum Synthetic Reagents,Pt(C6H2F3‐2,4,6)2(cod) and Pt(C6HF4‐2,3,4,5)2(cod)

Reactions of PtCl₂(cod) (cod = cycloocta‐1,5‐diene) with 2,4,6‐trifluoro‐ and 2,3,4,5‐tetrafluoro‐phenyllithium in diethyl ether gives Pt(C₆H₂F₃‐2,4,6)₂(cod) ( 1 ) (monoclinic, P2₁/n, Z = 4, a = 7.141(1), b = 15.002(2), c = 17.071(3) Å, β = 91.37(2)°) and Pt(C₆HF₄‐2,3,4,5)₂(cod) ( 2 ) (triclinic, P 1, Z = 2, a = 10.150(2), b = 10.762(2), c = 10.812(2) Å, α = 63.606(3), β = 63.327(3), γ = 76.496(3)°) respectively, which have two ipso carbon atoms and two double bond midpoint centres in a square planar arrangement, and aromatic rings angled near perpendicular to the coordination plane.     

Ein neues Chloropalladat(II): BaPdCl4

A New Chloropalladate(II): BaPdCl₄ BaPdCl₄ was prepared through reaction of barium chloride and palladium dichloride (molar ratio 2:1) with the aid of the Bridgman technique. According to a X‐ray single crystal investigation, BaPdCl₄ crystallizes with the orthorhombic crystal system (space group Pbcn (No. 60), Z = 4, a = 686.7(1), b = 1258.8(2) pm, c = 750.2(2), R_all = 0.0383). The crystal structure is built up from square planar [PdCl₄] units which are linked together by Ba²⁺ ions in an eightfold coordination.     

[Ag(NH3)2]ClO4: Kristallstrukturen,Phasenumwandlung, Schwingungsspektren

[Ag(NH₃)₂]ClO₄: Crystal Structures, Phase Transition, and Vibrational Spectra [Ag(NH₃)₂](ClO₄) is obtained from a solution of AgClO₄ in conc. ammonia as colourless single crystals (orthorhombic, Pnmn, Z = 4, a = 795.2(1) pm, b = 617.7(1) pm, c = 1298.2(2) pm, R_all = 0.0494). The structure consists of linearly coordinated cations, [Ag(NH₃)₂]⁺, stacked in a staggered conformation and of tetrahedral (ClO₄)^‐ anions. A first order phase transition was observed between 210 and 200 K and the crystal structure of the low‐temperature modification (monoclinic, P2/m, Z = 4, a = 789.9(5) pm, b = 604.1(5) pm, c = 1290.4(5) pm, β = 97.436(5)°, at 170 K, R_all = 0.0636) has also been solved. Spectroscopic investigations (IR/Raman) have been carried out and the assignment of the spectra is discussed.     

Modeling laboratory data from clinical trials

Laboratory data from clinical trials are considered precursors of potential organ dysfunctions. The routine analysis of these data focusses on the occurrence of extremely high or low values relative to normal ranges, the change of these incidences compared to baseline, or the worst values from each individual patient. However, only rarely is an attempt made to model the dynamics of the measurements over time. In this paper we propose to model laboratory measurements by stochastic processes, specifically by Ornstein-Uhlenbeck processes. The aim is to estimate parameters of these processes in order to characterize a potential effect of drugs or other medical treatments. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)