Amino acid-derived imidazolium salts: platform molecules for N-Heterocyclic carbene metal complexes and organosilica materials

In the interest of producing functional catalysts from sustainable building-blocks, 1, 3-dicarboxylate imidazolium salts derived from amino acids were successfully modified to be suitable as N-Heterocyclic carbene (NHC) ligands within metal complexes. Complexes of Ag(I), Pd(II), and Ir(I) were successfully produced using known procedures using ligands derived from glycine, alanine, β-alanine and phenylalanine. The complexes were characterized in solid state using X-Ray crystallography, which allowed for the steric and electronic comparison of these ligands to well-known NHC ligands within analogous metal complexes. The palladium complexes were tested as catalysts for aqueous-phase Suzuki-Miyaura cross-coupling. Water-solubility could be induced via ester hydrolysis of the N-bound groups in the presence of base. The mono-NHC–Pd complexes were seen to be highly active in the coupling of aryl bromides with phenylboronic acid; the active catalyst of which was determined to be mostly Pd(0) nanoparticles. Kinetic studies determined that reaction proceeds quickly in the coupling of bromoacetophenone, for both pre-hydrolyzed and in-situ hydrolysis catalyst dissolution. The catalyst could also be recycled for an extra run by simply re-using the aqueous layer. The imidazolium salts were also used to produce organosilica hybrid materials. This was attempted via two methods: by post-grafting onto a commercial organosilica, and co-condensation of the corresponding organosilane. The co-condensation technique harbours potential for the production of solid-support catalysts.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Potsdam

Year

2016

Author dc:creator

• Steeples, Elliot

Contributors dc:contributor

• Antonietti, Markus

• synthesis
• Synthese
• sustainable chemistry
• nachhaltige Chemie
• organometallics
• Metallorganischen
• water
• Wasser

Statement dc:rights

• CC-BY-NC-ND - Namensnennung, nicht kommerziell, keine Bearbeitungen 4.0 International

Repository record source_url

https://publishup.uni-potsdam.de/frontdoor/index/index/docId/10186

OAI identifier oai:identifier

oai:kobv.de-opus4-uni-potsdam:10186