Heinz-Peter Klein

Ein organotitankomplex mit zwei koordinativ gebundenen wassermolekülen: [(π-C5H5)2Ti(H2O)2](ClO4)2 · 3 C4H8O

Abstract (π-C 5 H 5 ) 2 Ti(ClO 4 ) 2 and H 2 O react in tetrahydrofuran to form the diaquo complex [(π-C 5 H 5 ) 2 Ti(H 2 O) 2 ](ClO 4 ) 2 · 3 C 4 H 8 O. X-ray analysis shows the titanium atom to be nearly tetrahedrally coordinated. Mean values of distances: TiO 2.01 A, TiZ 2.03 A (Z = center of ring); angles: OTiO 90.4°, ZTiZ 133.3°. The complex crystallizes in the monoclinic space group P 2 1 / c with Z = 4 and lattice parameters at 100°C a 15.324(5), c 18.325(5) A, and β 110.75(3)°.

Bis(benzoato)-bis(π-cyclopentadienyl)-titan(IV): Darstellung in wässriger lösung und struktur einer neuen modifikation

Abstract The reaction of titanocene dichloride with sodium benzoate in aqueous solution gives titanocene dibenzoate in high yield. Crystals of a modification different from the one described recently by Hoffman et al. can be obtained by recrystallization from chloroform: orthorhombic, space group P212121, Z = 4 and lattice constants at − 120°C a 21.154(4), b 12.529(4), c 7.574(2) A. Whereas the TiO bond for one of the benzoate groups is a normal σ-bond, the other one seems to have a considerable additional π-bond character.

Fragmentierung des schwefeldiimidsystems in tBu2PN=S=NPtBu2 an dreikernigen osmiumclustern. Synthese, feströrperstruktur und dynamische eigenschaften von Os3(CO)11[PtBu2(NH2)] und HOs3(CO)9PtBu2N(H)S]

Abstract The phosphino-substituted sulphur diimide, S(NP t Bu 2 ) 2 , reacts with the trinuclear osmium clusters Os 3 (CO) 11 (NCMe) and H 2 Os 3 (CO) 10 with cleavage of one of the NS bonds to give the cluster compounds Os 3 (CO) 11 [P t Bu 2 (NH 2 )] (I) and HOs 3 (CO) 9 [P t Bu 2 N(H)S] (II), respectively. In the solid state, I contains a closed Os 3 triangle with the phosphine ligand bonded equatorially to an osmium atom through the phosphorus. In solution intramolecular dynamic processes are observed which are explained by carbonyl migration and pseudoration mechanisms. The osmium cluster II, in the solid state, forms an irregular Os 3 triangle which is bridged by a [P t Bu 2 N(H)S] system, and the longest edge of which is bridged by a μ 2 -hydride. In contrast to I, molecule II is relatively rigid in solution; only pseudorotations are observed as dynamic phenomena.

Darstellung, struktur und eigenschaften des dreikernigen titankomplexes (π-C2H5)2TiClOTi(π-C5H5)ClOTiCl(π-C5H5)2·CHCl3

Abstract The trinuclear titanium(IV) complex (π-C5H5)2TiClOTi(π-C5H5)ClOTiCl(π-C5H5)2 · CHCl3 is formed by hydrolysis of (π-C5H5)2TiCl2 at pH > 3.5 and can be isolated in the crystalline state from the reaction of (π-C5H5)2TiCl2 with Ag2O and water in chloroform. Its structure is determined by X-ray analysis.

Darstellung und eigenschaften von bis(μ-fumarato)bis[di(π-cyclopentadienyl)titan(IV)]; strukturuntersuchungen der reinen und der kristall-chloroform enthaltenden phase

Abstract The reaction of titanocene dichloride with disodium fumarate in the two-phase system H2O/CHCl3 yields bis(μ-fumarato)bis[di(π-cyclopentadienyl)titamum(IV)]. Crystal data for the pure compound (IIIa): monoclinic, P21/n, a 18.558(5), b 9.076(5), c 7.559(2) A, β 101.69(2)°; Z = 2. Crystal data for a phase containing chloroform of crystallization (CHCl3/Ti = 1 1 ) (IIIb): triclinic, P 1 , a 20.439(11), b 10.269(5), c 8.858(3) A, α 112.18(3), β 93.93(5), γ 91.63(7)°; Z = 2 × 1. The three independent [(π-C5H5)2TiOCOCHHOCO]2 molecules differ in the puckering of their 14-membered rings and the geometry of their TiOC units.

Darstellung, struktur und eigenschaften on bis(cyclopentadienyl)oxalatotitan(IV) und bis(cyclopentadienyl)bis(hydrogenmaleinato)titan(IV)

Abstract The reaction of (π-C5H5)2TiCl2 with oxalic acid or maleic acid in aqueous solution yields dicyclopentadienyloxalatotitanium(IV) or dicyclopentadienylbis(hydrogenmaleato)titanium(IV), respectively. X-ray analyses show that both compounds are monomeric. The oxalate group acts as bidentate chelating ligand and each of the hydrogenmaleate groups is bonded via one oxygen atom to the titanium atom.

Hinweise auf reversibles öffnen und schliessen einer metallmetall-bindung in dem trimethylsilylnitren-sulfido-cluster Os3(CO)9(μ3-S)(μ-3NSiMe3)

Abstract The thermal reaction of Os3(CO)12 with S(NSiMe3)2 yields the cluster compound Os3(CO)9(μ3-S(μ3-NSiMe3. The structure of the molecule was solved by a single crystal X-ray structure analysis. In the solid state the osmium atoms define an “open” isosceles triangle which is bridged by both a sulphur and a trimethylslylnitrene ligand. The distance between the osmium atoms at the long edge of the triangle (3.498(2) A compared to 2.774(2) and 2.777(2) A for the short edges) suggests that these two Os atoms are not in bonding contract. A variable-temperature 13C NMR study reveals the structure of the molecule to be dynamic in solution; the spectra are indicative of the existence of two different structures at elevated temperatures. We interprete our findings as reconcilable with the assumption that a reversible closing and opening process of the Os-Os bonds can occur in solution.

Festkörperstruktur, dynamische struktureffekte und elektrochemische charakteristika des clusteranions [HRu3(CO)10(SiEt3)2]−

Abstract The cluster anion [HRu3(CO)10(SiEt3)2]− has been studied by X-ray crystallographic, NMR spectroscopic, and electrochemical methods. In the solid state, the three ruthenium atoms form a triangle, the longest edge of which is bridged by the μ2-hydride; the triethylsilyl groups occupy equatorial positions at the two bridge-head Ru atoms. In solution, only the four carbonyl groups at the unbridged Ru atom are fluxional; the hydride bridge presumably undergoes a rocking movement perpendicular to the Ru3 plane. At a platinum electrode the anion is oxidized to give a neutral species, the lifetime of which is sufficient in dichloromethane to observe reversibility at a scan rate of 1 Vs S−1

Gezielter Aufbau und Röntgenstrukturanalyse von (μ2-H)Os3SW(η5-C5H5)(CO)11: ein Cluster mit einem pyramidalen Os3SW-Gerüst

Abstract By reaction of (η-C 5 H 5 )W(CO) 3 SH with Os 3 (CO) 11 (NCCH 3 ) the (η 5 -C 5 H 5 )W(CO) 3 S unit is introduced into the trinuclear osmium cluster through the sulfur atom. The primary reaction product (μ 2 -H)Os 3 (CO) 10 [μ 2 -SW(η 5 -C 5 H 5 )(CO) 3 ] can be converted thermally into the pyramidal Os 3 SW cluster (η 5 -C 5 H 5 )(CO) 11 , whose structure was solved by a single crystal X-ray structure analysis. The molecule has a pyramidal Os 3 SW skeleton with, in a first approximation a planar Os 3 S basis. Only two of the three Os Os distances are in accordance with chemical bonds.

Strukturchemie titan-organischer verbindungen: Die struktur von π-C5H5Ti(NO3)3

Abstract The reaction of (π-C5H5)2Ti(CF3SO3)2 with [(C2H5)3NH]N03 in Tetrahydrofuran yields crystals of (π-C5H5)2Ti(N03)2 (A). An X-ray analysis of A shows that the nitrate groups are bonded covalently via O to the Ti atom. As in other (π-C5H5)2TiX2 compounds the ligands are arranged in a nearly tetrahedral way around the Ti center. The OTiO angle of 69.5° is surprisingly small and the TiO bond length of 2.15 A is rather long.