Sökning: "carbenes"

Visar resultat 1 - 5 av 9 avhandlingar innehållade ordet carbenes.

1. 1. Carbenes: The Gathering : Photophysics of Transition Metal Carbene Complexes

   Författare :Nidhi Kaul; Leif Hammarström; James K. McCusker; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; photophysics; time-resolved spectroscopy; transition-metal complexes; Kemi med inriktning mot kemisk fysik; Chemistry with specialization in Chemical Physics;

   Sammanfattning : This thesis explores the photophysics of some transition-metal complexes (TMCs) which utilize N-heterocyclic carbenes as ligands. After a historical interlude which traces the development of the broader field of transition metal complexes and their photophysical investigations, there is an overview of theoretical concepts and the spectroscopic methods employed. LÄS MER

3. 2. C–H and Si–H functionalization using redox-active diazo compounds and decarboxylative coupling

   Författare :Rajdip Chowdhury; Abraham Mendoza; Darren Dixon; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbenes; radicals; redox-active esters; indoles; carboxylic acids; silanes; photochemistry; Organic Chemistry; organisk kemi;

   Sammanfattning : The work presented in this thesis is based on two basic organic chemistry concepts: carbene catalysis and radical coupling reactions. Diazo compounds in the presence of transition-metal catalysts are known to be excellent reagents for the construction of C–X bonds (X = C, Si, N, O, etc.) under mild conditions. LÄS MER

4. 3. Asymmetric Synthesis using Redox-Active Diazocompounds as Chiral Carbon Atom Precursors

   Författare :Matteo Costantini; Abraham Mendoza; Armido Studer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; redox-active carbenes; mechanistic investigation; cyclopropanes; asymmetric catalysis; photochemistry; organisk kemi; Organic Chemistry;

   Sammanfattning : This thesis summarizes the development of general and efficient methods to synthesize enantiomerically enriched cyclopropane compounds. The works reported herein exploit the opportunity presented by redox-active esters to explore the orthogonality between asymmetric carbene-transfer and geminal radical generation. LÄS MER

5. 4. C-H Activation Reactions Mediated by Pd Based Heterogeneous Catalysts : Regioselective Formation of C-O and C-X Bonds

   Författare :Maitham Majeed; Centrum för analys och syntes; []
   Nyckelord :C-H Activation; N-heterocyclic carbenes; palladium; polymer supported Pd II ; undirected acetoxylation; directed halogenation; continuous flow; reduced graphene oxide supported Pd II ;

   Sammanfattning : New classes of N-heterocyclic carbene-palladium(II) complexes containing either a vinyl group in different positions or an anthracene tag in the backbone of the N-heterocycle were synthesized and fully characterized. The vinyl based complexes were copolymerized with divinylbenzene to fabricate robust polymer-supported NHC-Pd(II) systems, while the anthracene based complexes were π-stacked onto the surface of reduced graphene oxide (rGO) producing immobilized catalysts with interesting features. LÄS MER

7. 5. Organocatalytic Transformations with N-Heterocyclic Carbenes - An Investigation of Ionic Liquids as NHC Precatalysts and Aerobic Oxidative Esterifications

   Författare :Linda Ta; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; N-heterocyclic carbene; ionic liquid; multi-component reaction; aerobic oxidation; OTHO; Organocatalysis; green chemistry;

   Sammanfattning : The call for more sustainable processes in the chemical society has led to the development of the field of green chemistry. The Twelve Principles of Green Chemistry serve as guidelines for the design of processes. LÄS MER