Showing papers by "Eberhardt Herdtweck published in 1999"
TL;DR: In this article, density functional calculations reveal that the increased efficiency of these complexes as catalysts for olefin epoxidation originates from their stability and from the moderate energies of the corresponding transition states.
Abstract: Pyrazole and pyridine adducts of methyltrioxorhenium(VII) form bisperoxo complexes with excess H2O2 (see picture). Density functional calculations reveal that the increased efficiency of these complexes as catalysts for olefin epoxidation originates from their stability and from the moderate energies of the corresponding transition states. Nonaromatic nitrogen-base ligands reduce the catalytic performance of the adducts, in agreement with the computational results.
110 citations
TL;DR: "Bidentate" ligand behavior is shown by (2,6-dimethylphenyl)diphenylphosphane in the title compound, and NMR investigation and an X-ray analysis reveal that the methyl groups act as weak donors to form two strong agostic Ru⋅ⓂC-H interactions.
Abstract: "Bidentate" ligand behavior is shown by (2,6-dimethylphenyl)diphenylphosphane in the title compound: In the nearly octahedral environment of the ruthenium atom two coordination sites are occupied by methyl groups of the two xylyl substituents. NMR investigation and an X-ray analysis (see picture) reveal that the methyl groups act as weak donors to form two strong agostic Ru⋅⋅⋅C-H interactions.
82 citations
TL;DR: The reaction of 1,1' -fc(BMe2)2 (2) with pyrazine gives a novel poly(ferrocene) [2·pyz]n, which has been structurally characterized by X-ray crystallography as mentioned in this paper.
81 citations
TL;DR: In this article, the preparation and spectroscopic properties of complexes of the general formula MoBr2O2Ln with L=NCCH3 (n=2), NCC(CH3)3 (NCC6H5)
65 citations
21 citations
TL;DR: In this article, axially substituted axial substituted complexes of formula trans-[Mo2(µ-OAc)2(dppma) 2(NCCH3)n][BF4]n were characterized by 1H-, 13C-, and 31P{1H}-NMR, IR, Raman, and UV/Vis spectroscopy, elemental analyses and cyclic voltammetry, and four of these complexes were additionally examined by single crystal X-ray analysis.
Abstract: Reaction of trans-[Mo2(µ-OAc)2(dppma)2(NCCH3)n][BF4]2 (n = 0–2, dppma = bis(diphenylphosphino)methylamine) with a variety of ligands containing a nitrile group leads to axially substituted complexes of formula trans-[Mo2(µ-OAc)2(dppma)2(RCN)2][BF4]n (n = 0, 2), R can be both an organic and an organometallic moiety The obtained complexes are characterized by 1H-, 13C-, and 31P{1H}-NMR, IR, Raman, and UV/Vis spectroscopy, elemental analyses and cyclic voltammetry Four of these complexes are additionally examined by single crystal X-ray analysis The applied methods show that the axial ligands influence the spectroscopic and crystallographic data of the central moiety only slightly However, while X-ray crystallography shows the MoMo quadruple bond length not to be significantly influenced by axial ligands, Raman spectroscopy gives a more detailed insight: organic ligands of the type NCR (R = CH3, t-Bu, C6H5etc) in axial positions weaken the MoMo interaction less than organometallic ligands of the type [NC–M(CO)5]– (M = Cr, Mo, W) and NCFe(CO)2Cp UV/Vis examination indicates charge transfer from the organometallic axial ligands to the MoMo moiety
20 citations
TL;DR: The transition metal substituted gallanes (CO)5MnGaEt2(NC7H13) as discussed by the authors is a transition metal substitute for the gallium-chloriden gallane.
Abstract: Die ubergangsmetallsubsituierten Gallane [(CO)5MnGaEt2(NC7H13)] (1), [(PMe3)(CO)3CoGaCl2 · (NMe3)] (2), [(CO)4CoGaEt2(NC7H13)] (3) und [(CO)4CoGaCl3]K (4) wurden durch Reaktion der Carbonylmetallate [(CO)nM] (Na/K) mit den Galliumchloriden ClGaEt2(NC7H13), Cl3Ga(NMe3) bzw. GaCl3 erhalten. Die Einkristallstrukturbestimmungen ergaben fur 1: Raumgruppe P21/c (I.T.-Nr.: 14); Z = 4; a = 1425,4(2) pm, b = 1007,4(1) pm, c = 1429,9(3) pm; β = 113,92(1)°; 2: Raumgruppe P21/m (I.T.-Nr.: 11); Z = 2; a = 746,1(1) pm, b = 1131,2(1) pm, c = 1061,5(1) pm; β = 101,87(1)°; 3: Raumgruppe P21/c (I.T.-Nr.: 14); Z = 8; a = 1405,9(2) pm, b = 1786.2(2) pm, c = 1430,9(2) pm; β = 91,47(1)°; 4: Raumgruppe P21/c; Z = 4; a = 1185,7(1) pm, b = 895,4(1) pm, c = 1144,7(3) pm; β = 106,47(2)°. Anhand der Modellverbindungen [{L′(CO)3Co}GaX2L] (L′ = CO, PH3; L = NH3, X = H, Cl) wurden die polaren σ(Co–Ga)-Bindungen und die Substituenteneffekte auf die Bindungslange auf der Basis quantenchemischer Dichtefunktionalrechnungen (DFT) charakterisiert.
Transition Metal substituted Gallanes: Synthesis and X-Ray Structures of [(CO)4CoGaEt2(NC7H13)], [(PMe3)(CO)3CoGaCl2(NMe3)], [(CO)4CoGaCl3]K, and [(CO)5MnGaEt2(NC7H13)]
The transition metal substituted gallanes [(CO)5MnGaEt2(NC7H13)] (1), [(PMe3)(CO)3CoGaCl2 · (NMe3)] (2), [(CO)4CoGaEt2(NC7H13)] (3), and [(CO)4CoGaCl3]K (4) were obtained by the reaction of the potassium/sodium salts of the manganese- and cobaltcarbonylmetallates with the chlorogallium species ClGaEt2(NC7H13), Cl3Ga(NMe3), and GaCl3. The structures were established by single crystal X-ray analysis 1: space group P21/c (I.T.-No.: 14); Z = 4; a = 1425.4(2) pm, b = 1007.4(1) pm, c = 1429.9(3) pm; β = 113.92(1)°; 2: space group P21/m (I.T.-No.: 11); Z = 2; a = 746.1(1) pm, b = 1131.2(1) pm, c = 1061.5(1) pm; β = 101.87(1)°; 3: space group P21/c (I.T.-No.: 14); Z = 8; a = 1405.9(2) pm, b = 1786.2(2) pm, c = 1430.9(2) pm; β = 91.47(1)°; 4: space group P21/c; Z = 4; a = 1185.7(1) pm, b = 895.4(1) pm, c = 1144.7(3) pm; β = 106.47(2)°. The model compounds [{L′(CO)3Co}GaX2L] (L′ = CO, PH3; L = NH3, X = H, Cl) with polar σ(Co–Ga) bonds and the effect of the substituent on the bond length are characterized with DFT-calculations.
19 citations
TL;DR: IndWCl 3 (CO) as discussed by the authors is a bis-indenyl analog of tungstenocene, which is synthesized by the reaction of IndW(η 3 -C 3 H 5 )(CO) 2 with HCl gas in dichloromethane.
12 citations