Sökning: "Hammett study"

Hittade 5 avhandlingar innehållade orden Hammett study.

1. 1. Iron or Copper? - Method Development and Mechanistic Studies on Cross-Coupling Reactions

   Författare :Per-Fredrik Larsson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Iron; Copper; Transition metal; Cross-coupling; Reaction mechanism; Kinetic investigation; Hammett study; Sustainable catalysis; Trace-metal; Mass-transfer; Ligand development; Ligand scope;

   Sammanfattning : The area of catalysis has had an immeasurable impact on modern society. This has been acknowledged through several Nobel prizes during the 20th century ranging from Haber (1918) for the synthesis of ammonia to Richard F. Heck, Ei-ichi Negishi, and Akira Suzuki (2010) for palladium-catalyzed cross-coupling reactions. LÄS MER

3. 2. Homogeneous and heterogeneous Cp*Ir(III) catalytic systems : Mechanistic studies of redox processes catalyzed by bifunctional iridium complexes, and synthesis of iridium-functionalized MOFs

   Författare :Greco González Miera; Belén Martín-Matute; Matt Clarke; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; catalysis; bifunctional; metal-ligand cooperation; amine alkylation; Hammett; kinetics; acceptorless alcohol dehydrogenation; MOF; transition metal; synchrotron; organisk kemi; Organic Chemistry;

   Sammanfattning : The purpose of this doctoral thesis is to investigate and develop catalytic processes mediated by iridium(III) complexes. By understanding the mechanisms, the weaknesses of the designed catalysts can be identified and be overcome in the following generation. LÄS MER

4. 3. Iron catalyzed C-C coupling reactions - mechanistic investigations

   Författare :Anna Hedström; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; iron; homogenous catalysis; cross coupling; C-C bond formation; reaction mechanisms; kinetic investigations; competitive Hammett study; density functional theory;

   Sammanfattning : The mechanism of the iron catalyzed cross coupling of aryl electrophiles with alkyl Grignard reagents was studied. The reaction proceeds via a rate-limiting oxidative addition of the aryl halide to an Fe(I) complex generated in situ. A transmetalation from an aryl Grignard reagent occurs either before or after the oxidative addition. LÄS MER

5. 4. Concerted or Stepwise? : β-Elimination, Nucleophilic Substitution, Copper Catalysed Aziridination and Ruthenium Catalysed Transfer Hydrogenation Studied by Kinetic Isotope Effects and Linear Free-Energy Relationships

   Författare :Per Ryberg; Heinz F. Koch; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Kinetic isotope effect; linear free energy relationship; elimination; substitution; aziridination; transfer hydrogenation; Organisk kemi; Organic chemistry; Organisk kemi; organisk kemi; Organic Chemistry;

   Sammanfattning : This thesis describes the use of kinetic isotope effects, linear free energy relationships and stereochamical studies to distinguish between different mechanistic alternatives and to obtain information about transition state structure.In the first part fluorine and deuterium kinetic isotope effects were determined for the base promoted HF elimination from 4-fluoro-4-(4’-nitrophenyl)butane-2-on. LÄS MER

7. 5. Manganese(salen) catalyzed epoxidation of alkenes

   Författare :Christian Linde; KTH; []
   Nyckelord :;

   Sammanfattning : This thesis deals the with steric and electronic effects inthe manganese(salen) catalyzed epoxidation of alkenes.Different methods were employed in the mechanisticinvestigations; molecular modelling, radical trapping, Hammettstudies on linear free-energy relationships and densityfunctional methods. LÄS MER