Search results for "element"

p-Di-(1-phenylvinyl)-Benzol und seine reaktion mit elektronenüberträgern

1972

p-Di-(1-phenylvinyl)-benzol (I) wurde, ausgehend von p-Diacetylbenzol und Phenylmagnesiumbromid, in hoher Reinheit und guter Ausbeute dargestellt und charakterisiert. I setzt sich spontan mit Elektronenubertragern (Natrium, Naphthalin-Natrium) unter Ausbildung einer tief violetten Farbung um. Es entstehen die Oligomeren bis zum Dekameren, wobei die geradzahligen Homologen in hoherer Konzentration vorliegen als die jeweils benachbarten ungeradzahligen. Die Ergebnisse werden diskutiert. p-Di-(1-phenylvinyl) benzene (I) was prepared from diacetyl benzene and phenyl magnesium bromide in high purity and with good yield. It was identified by IR, NMR, and elemental analysis. I reacts immediately w…

Wurtz Syntheses with Naphthalene-sodium

1962

ChemInform Abstract: Reactivity and Selectivity of ortho-Metalated Rhodium(II) Complexes in C-H Insertion Reactions of α-Diazo Compounds.

2010

Regioselective intramolecular C−H insertion reactions of α-diazo β-keto esters and α-diazo ketones are mediated by Rh2[OOCR]4-x[PC]x (x = 1, 2; PC = ortho-metalated phosphine; R = CH3, C3F7). In particular, the intramolecular transformation of 1-diazo-5-methyl-3-propyl-2-hexanone catalyzed by Rh2[OOCCH3]2[PC]2 (PC = (C6H4)P(C6H5)2, head-to-tail (H−T) configuration) afforded only the tertiary C−H insertion product. By comparison, no C−H insertion reaction was promoted by doubly metalated complexes with a head-to-head (H−H) configuration. Rh2[OOCR]3[PC] compounds were found to be less suited for these type of reactions.

Ultrasound assisted reductive cleavage of sesquiterpene γ-enonelactones

1995

Abstract Ultrasound enhances the rate of reductive cleavage of the C 6 -oxygen bond of several cis - and trans - sesquiterpene γ-enonelactones. Interestingly ultrasound overrides the stereoelectronic requirements for the reductive cleavage of the most usually occurring sesquiterpene trans -lactones.

Synthesis of Chlorinated Biphenyls by Suzuki Cross-Coupling Using Diamine or Diimine-Palladium Complexes

2008

Several novel diimines (Salen-type ligands) 2a–2i and their reduced diamine counterparts 3b,3d–3g and 3i form complexes 4a–4i, 5b,5d–5g, and 5i with PdCl2 in DMF or methanol. Using 1 mol-% of the isolated complexes 4e and 5f many polychlorinated biphenyls (PCBs) can be prepared in moderate to excellent yields according to the Suzuki crosscoupling protocol with contact to air. Several 4-acetylbiphen

ChemInform Abstract: Polycondensed Nitrogen Heterocycles. Part 24. Pyrrolo(3,4-c) isoquinolinone by Thermal Rearrangement of a Pyrrolylbenzotriazinon…

2010

Rearrangement under acidic conditions of the pyrrolylbenzotriazinone 7 afforded the pyrrolylbenzamides 10 and 11. By thermal rearrangement instead, the first fully aromatic derivative of the pyrrolo[3,4-c]isoquinoline ring system 9 was obtained.

Sensing of Oxygen by Bacteria

2009

Palladium–Polypyrrole Nanoparticles-Catalyzed Sonogashira Coupling

2012

Abstract Palladium nanoparticles were encapsulated into polypyrrole globules via one-step one-pot redox reaction between tetraamminepal- ladium(ii) dichloride and pyrrole in water. Such a material is an active catalyst for the Sonogashira coupling of iodo- and bromo- arenes.

Gold assisted oxygen dissociation on a molybdenum-doped CaO(001) surface

2016

Using density functional theory (DFT) calculations, we address the adsorption of O2 and the coadsorption of gold species and oxygen molecules on a Mo-doped CaO(001) surface with 1.25% impurity concentration. With the help of the Born–Haber thermodynamic cycle, the enhanced binding of an oxygen molecule on Ca(Mo)O is attributed to energy gain owing to simultaneous electron transfer from the dopant to the molecule and lattice relaxations. We consider three coadsorption structures for an Au atom and O2 molecule with different Au–O2 distances. The calculations demonstrate that the coadsorption structures take one electron from the dopant and the O–Au–O chain structure is thermodynamically more …

Uranium( iv ) cyclobutadienyl sandwich compounds: synthesis, structure and chemical bonding

2019

The 1 : 1 reactions of uranium(IV) tetrakis(borohydride) with the sodium and potassium salts of the cyclobutadienyl anion [C4(SiMe3)4]2− (Cb′′′′) produce the half-sandwich complexes [Na(12-crown-4)2][U(η4-Cb′′′′)(BH4)3] and [U(η4-Cb′′′′)(μ-BH4)3{K(THF)2}]2. In the 1 : 2 reaction of U(BH4)4 with Na2Cb′′′′, formation of [U(η4-Cb′′′′)(η3-C4H(SiMe3)3-κ-(CH2SiMe2)(BH4))]− reveals that a Cb′′′′ ligand undergoes an intramolecular deprotonation, resulting in an allyl/tuck-in bonding mode. A computational study reveals that the uranium–Cb′′′′ bonding has an appreciable covalent component with contributions from the uranium 5f and 6d orbitals. peerReviewed