Neue Pyridiniumchlorometallatverbindungen der Seltenerdelemente

Summary Reaction of the rare earth chlorides with pyridinium chloride in tetrahydrofuran (THF) under anhydrous conditions gave nearly insoluble precipitates of the composition (pyH)₃ RECl₆·THF (RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, and Lu). They were characterized by chemical analysis and IR spectroscopy; decompositionin vacuo was studied, yielding the hithero unknown complexes (pyH)₃ RECl₆ (RE=La, Ce, Pr, Sm, Tb, Ho, Y, Tm, and Lu).

     

H2O‐Catalyzed Route to Early Lanthanide Tribromide THF and DME Solvates from Oxides

A convenient one‐pot synthetic protocol towards THF and DME solvates of lanthanum and other early lanthanide tribromides was developed using the water‐catalyzed reaction of lanthanide(III) oxides with highly reactive Me₃SiBr in situ formed from commercially available disilane Si₂Me₆ and Br₂. This practical route allows to obtain the target lanthanum tribromide solvates [LaBr₃(thf)₄] ( 1a ) and [LaBr₃(dme)₂]₂ ( 1b ) as well as analogous early lanthanide molecular tribromide solvates [NdBr₃(thf)₄] ( 2a ), [NdBr₃(dme)₂] ( 2b ), [SmBr₃(thf)₂] ( 3a ), and [SmBr₃(dme)₂] ( 3b ) difficult to prepare by other solution‐based procedures. The molecular structure of 1b· 2CH₂Cl₂ was determined by an XRD study.     

Identification and Kinetics Study on the Transformation of Mevinolin in Acidic Alcohol Solution by High-performance Liquid Chromatography with Photodiode Array Detector or Mass Spectrometry

IntroductionIncreased levels of cholesterol and triglycerides areknown to be the risk factors for developing coronary ar-tery disease. Lipid lowering agents that inhibit theHMG coenzyme A( HMG-CoA) reductase are nowprominent among the drugs for treating h…     

Tetrakis(acetonitrile)‐dibromo‐nickel(II)‐di‐acetonitrile, [Ni(CH3CN)4Br2]·2CH3CN

[Tetrakis(acetonitrile)‐dibromo‐nickel(II)]‐di‐acetonitrile was obtained from a solution of nickel(II) dibromide in acetonitrile at 258 K. The crystal structure [monoclinic, P2₁/n (no.14), a = 1005.5(5), b = 831.3(5) , c = 1131.7(5) pm, β = 106.263(5)°, V = 908.1(8)·10⁶ pm³, Z = 2, R₁ for 1580 reflections with I₀>2σ(I₀): 0.0505] contains sixfold coordinated Ni^II atoms. Two trans coordinating bromide anions and four equatorial acetonitrile molecules form an elongated octahedron around the central Ni^II atom. [Ni(CH₃CN)₄Br₂] octahedra are connected via hydrogen bonds to neighboring octahedra as well as to solvate acetonitrile molecules.     

Binary systems of C60 with positional isomers 1,2- and 1,3-C6H4Br2

Thermodynamic properties of binary systems of C₆₀ with 1,2- and 1,3-dibromobenzenes have been studied by means of differential scanning calorimetry (DSC). Solid solvates with the compositions C₆₀3(1,2-C₆H₄Br₂); C₆₀2(1,3-C₆H₄Br₂) and C₆₀0.6(1,3-C₆H₄Br₂) have been found. The solvates have been characterised by their enthalpies and temperatures of incongruent melting transition and in part by X-ray powder data. It has been shown that positional isomers 1,2- and 1,3- of the substituted benzenes formed two series of “typical” phase diagrams. Solubility behaviour of C₆₀ in positional isomers has been discussed.     

Structures of cabergoline anhydrate form II and novel cabergoline solvates

Crystal forms of N-[3-(dimethylamino)propyl]-N-(ethylcarbamoyl)-6-allyl-ergoline-8β-carboxamide (cabergoline) originating from various solvents have been examined by X-ray diffraction at 298 or 150 K. Crystal structures of cabergoline anhydrate, (form II, P2₁2₁2₁) and solvates (all P2₁2₁2₁) with tert-butyl methyl ether (form VIII), cyclohexane (form XV), toluene (form IX), p-xylene (form XVI), and 1,2,4-trimethylbenzene (form XVII) are described. Conformation of cabergoline in these forms was compared with crystal structures of forms I and VII of cabergoline (P2₁) described in the literature. Despite a high degree of molecular conformational freedom, cabergoline possesses similar conformation in forms I, II, VIII, IX, XV, XVI, and XVII. Molecular conformations, crystal packing and the effect of the solvent on the former two properties are examined.