Joachim Pickardt

Darstellung, Eigenschaften und Kristallstruktur von Di-μ-(n-butyrato)-bis[dicarbonyl(tri-t-butylphosphin)ruthenium(I)(RuRu)

Abstract Ru3(CO)12 reacts with tri-t-butylphosphine and butyric acid to form di-μ-(n-butyrato)bis[dicarbonyl(tri-t-butylphosphine)ruthenium(I)](RuRu). The IR- and NMR-spectroscopic data are discussed. The crystal structure has been determined from a single crystal X-ray study. The compound crystallizes with four molecules in the unit cell of symmetry P21/a, with the following parameters: a = 17.250(7), b = 21.978(7), c = 12.017(3) A, β = 108.69(3)°. The complex has a RuRu bond of 2.728(1) A, which is bridged by two butyrato groups. The CO groups are trans to the bridging ligands and form a sawhorse like structure. The long RuP distances of 2.619(3) and 2.627(3) A are caused by steric hindrance of the bulky phosphine ligands.

Organometallic compounds of the lanthanides

Abstract Bis(tetrahydrofuran)lithium dimethylbis(cyclopentadienyl)lutetate( III ) have been shown to react with t-butyl alcohol, t-butyl hydrosulfide, and phenyl hydroselenide in ether at −78°C to give the complexes (C 5 H 5 ) 2 Lu(OC 4 H 9 -t)(THF), (C 5 H 5 ) 2 Lu(SC 4 H 9 -t) 2 Li(THF) 2 , and (C 5 H 5 ) 2 Lu(SeC 6 H 5 ) 2 Li(THF) 2 , respectively. The analogous pentamethylcyclopentadienyl complexes (C 5 Me 5 ) 2 Lu(OC 4 H 9 -t)(THF), and (C 5 Me 5 ) 2 Lu(SC 4 H 9 -t) 2 Li(THF) 2 have been prepared from (C 5 Me 5 ) 2 Lu(μ- CH 3 ) 2 Li(THF) 2 and t-C 4 H 9 OH or t-C 4 H 9 SH, respectively. The new compounds have been characterized by elemental analysis and 1 H and 13 C NMR spectroscopy. The structures of the complexes (C 5 Me 5 ) 2 Lu(SC 4 H 9 -t) 2 Li(THF) 2 ( 7 ) and (C 5 H 5 ) 2 Lu(SeC 6 H 5 ) 2 Li(THF) 2 ( 8 ) have been determined by X-ray diffraction. The crystals of 7 are monoclinic with a 19.016(7), b 17.206(6), c 11.899(4) A, β 101.82(3), space group P 2 1 / n , Z = 4, R = 0.052, and 4228 observed ( I >- 2σ( I )) reflections. The crystals of 8 are monoclinic with a 21.60( 3 ), b 13.98(1), c 11.43(1) A, β 120.68(7)°, space group P 2 1 / a , Z = 4, R = 0.066, and 2615 observed ( I >- 3σ( I )) reflections.

Hirsutinolides, glaucolides and sesquiterpene lactone from Vernonia species

Abstract The investigation of nine Vernonia species afforded in addition to known sesquiterpenes 28 new ones. The structures were elucidated by high field 1 H NMR spectroscopy and the configurations were determined by NOE difference spectroscopy and, in one case, by X-ray analysis. The results indicated that configurations of several previously reported sesquiterpene lactones have had to be revised. In addition to known types two new ones, the jalcaguaianolides and the vernojalcanolides, are described. Furthermore some unusual reaction products are presented which, in part, led to some natural occurring lactones.

Synthesis of chiral tridentate oxazolines with thioether and heteroaryl donor groups and their application in the catalysis of asymmetric Michael reactions

Abstract Four chiral amino alcohols 1 derived from the natural α-amino acids L -cysteine and L -methionine have been converted with 2-thiophene and 2-pyridine carboxylic acid derivatives 2 to give eight tridentate oxazoline ligands 3a-d and 4a-d with a heteroaryl and a thioether donor function. In one case the coordination geometry at copper(II) was established by X-ray single crystal structure analysis. All ligands have been screened with 13 metal compounds 8 with regard to the asymmetric catalysis of the Michael reaction of a β-keto ester 6 with methyl vinyl ketone ( 7 ) to give an optimal result of 19% ee .

Crystal growth and structure refinement of NaCuO2 by X-ray and neutron diffraction

Abstract Single crystals of sodium oxocuprate(III) NaCuO2 with up to 5 mm length have been prepared from sodium hydroxide/peroxide melts. The structure has been refined by single crystal X-ray and neutron powder data. The Laue symmetry has been determined now unambiguously to be 2 m , resulting in a monoclinic Bravais lattice.

Metallorganische verbindungen der lanthanoiden: XVIII. Synthese und struktur von tris[(1,2-dimethoxyethan)lithium]hexamethyllutetat(III)☆

Abstract The reaction of lutetium trichloride with methyllithium in diethyl ether in the presence of 1,2-dimethoxyethane gives [Li(dme)] 3 [Lu(CH 3 ) 6 ], its crystal structure shows an octahedral Lu(CH 3 ) 6 arrangement with methyl bridges to the lithium atoms of three tetrahedra, coordinated dme ligands. The complex crystallizes in the monoclinic space group Cc with a 1390(2), b 1083(2), c 1839(4) pm, and β 94.08(13)°.

Die kristallstruktur von tetracarbonyl(tri-t-butylphosphin)eisen

The crystal structure of tetracarbonyl(tri-t-butylphosphine)iron has been determined from a single crystal X-ray study. The compound crystallizes with four molecules in an unit cell of symmetry P 212121-D42, with the following parameters: orthorhombic system, a = 18.842(7), b = 10.062(4), c = 9.790(2) A. The structure shows a trigonal bipyramide with the phosphine ligand in an axial position and a FeP bond length of 2.364(1) A.

Metallorganische verbindungen der lanthanoide: XXXV. Bis(tetramethylethylendiamin)lithium tetrakis-t-butylluteta(III): synthese, molekülstruktur und reatives verhalten gegenüber α,β-ungesättigten carbonylverbindungen

Abstract LuCl3 reacts with t-butyllithium in the presence of ether and tetramethylethylene diamine (tmed) to form [Li(tmed)2][Lu(t-C4H9)4], the structure of which has been elucidated through complete X-ray analysis. The crystals are orthorhombic with a 20.995(9), b 18.310(7), c 9.527(2) A, space group P21ab, Z = 4, D(calcd) 1.17 g cm−3, R = 0.035, and 2471 observed reflections. The compound undergoes 1,2-addition to cinnamic aldehyde, benzalacetone, 1-phenylbutene-2-methyl-3-one, 2-methylbutene-3-one and cyclohexanone, respectively, to give after hydrolysis of the reaction mixture α-t-butyl-substituted enoles. The reaction products were identified by means of GC/MS methods.

Synthese und struktur von dicyclopentadienyl(trimethylsilyl)titanchlorid

Abstract Dicyclopentadienyl(trimethylsilyl)titanium chloride, a stable trimethylsilyltitanium compound, is synthesized by reaction of dicyclopentadienyltitanium dichloride and tris(trimethylsilyl)aluminium, coordinated with diethyl ether, or lithium tetarakis(trimethylsilyl)aluminate. The IR and NMR spectra are reported. The crystal structure of the title compound has been determined. It shows a distorted tetrahedral surrounding of the titanium atom; the Ti–Si distance is 267 pm.

Metallorganische Verbindungen der Lanthanoide: XLV. Synthese und Röntgenstrukturanalyse von [Li(DME)3][((C5H5)3Sm)2(μ-N3)]☆

Abstract C5H5)3Sm(THF) reacts with lithium azide in dimethoxyethane(dme) to give [Li(DME)3][(C5H5)3SmNNNSm(C5H5)3], the structure of which has been elucidated by X-ray crystallography. The crystals are orthorhombic with a 1929.5(10), b 1542.0(4), c 1471.7(4) pm, space group P212121, Z = 4, R = 0.055, and 3404 observed reflections.