@article{SteeplesKellingSchildeetal.2016, author = {Steeples, Elliot and Kelling, Alexandra and Schilde, Uwe and Esposito, Davide}, title = {Amino acid-derived N-heterocyclic carbene palladium complexes for aqueous phase Suzuki-Miyaura couplings}, series = {New journal of chemistry}, volume = {40}, journal = {New journal of chemistry}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1144-0546}, doi = {10.1039/c5nj03337c}, pages = {4922 -- 4930}, year = {2016}, abstract = {In this work, three ligands produced from amino acids were synthesized and used to produce five bis- and PEPPSI-type palladium-NHC complexes using a novel synthesis route from sustainable starting materials. Three of these complexes were used as precatalysts in the aqueous-phase Suzuki-Miyaura coupling of various substrates displaying high activity. TEM and mercury poisoning experiments provide evidence for Pd-nanoparticle formation stabilized in water.}, language = {en} } @misc{SteeplesKellingSchildeetal.2016, author = {Steeples, Elliot and Kelling, Alexandra and Schilde, Uwe and Esposito, Davide}, title = {Amino acid-derived N-heterocyclic carbene palladium complexes for aqueous phase Suzuki-Miyaura couplings}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394488}, pages = {4922 -- 4930}, year = {2016}, abstract = {In this work, three ligands produced from amino acids were synthesized and used to produce five bis- and PEPPSI-type palladium-NHC complexes using a novel synthesis route from sustainable starting materials. Three of these complexes were used as precatalysts in the aqueous-phase Suzuki-Miyaura coupling of various substrates displaying high activity. TEM and mercury poisoning experiments provide evidence for Pd-nanoparticle formation stabilized in water.}, language = {en} } @phdthesis{Steeples2016, author = {Steeples, Elliot}, title = {Amino acid-derived imidazolium salts: platform molecules for N-Heterocyclic carbene metal complexes and organosilica materials}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-101861}, school = {Universit{\"a}t Potsdam}, pages = {139}, year = {2016}, abstract = {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.}, language = {en} }