Chemical processing is a prolific field in South Africa’s National Research and Development Strategy and catalysis is central to the chemical industry, being fundamental to the production of value-added materials. With feedstocks such as alkanes and alkenes readily available, there is a need for the design and synthesis of new, more efficient and selective catalysts which will allow for conversion into more useful products and add value to hydrocarbon products. South Africa is also one the largest suppliers of Platinum Group Metals world-wide and there is a drive to find useful, value-added applications for these metals.
However, with the depletion of available PGM resources and the added expense of these metals, PGM recovery and sustainability remains a key issue for researchers. Over the past few years, our group has been involved in immobilising catalysts on polymeric/dendritic supports and in biphasic media. This not only combines the advantages of homogeneous and heterogeneous catalysis but allows for ease of separation of the reaction product from rreaction mixtures, facilitating recycling of the catalysts to avoid environmental toxicity and makes purification of products easier. The multinuclear catalysts may also display enhanced activity over mononuclear analogues. Applications of this work have been extended to various organic transformation reactions, in particular, hydroformylation and carbon-carbon coupling reactions.
Selected Publications
Nicholas C.C. Breckwoldt, Neill J. Goosen, Percy van der Gryp and Gregory S. Smith*
Hydroformylation of the post-metathesis product 7-tetradecene using rhodium(I) Schiff base catalyst precursors
Applied Catalysis A, General, 2019, 573, 49-55
Leah C. Matsinha, Shepherd Siangwata, Gregory S. Smith and Banothile C.E. Makhubela*
Aqueous biphasic hydroformylation of olefins: From classical phosphine-containing systems to emerging strategies based on water-soluble nonphosphine ligands
Catalysis Reviews, 2019, 61, 111-133
Diteboho S. Ramarou, Banothile C.E. Makhubela and Gregory S. Smith*
Synthesis of Rh(I) alkylated-PTA complexes as catalyst precursors in the aqueous-biphasic hydroformylation of 1-octene
Journal of Organometallic Chemistry, 2018, 870, 23-31
Maxime Dauchy, Michel Ferreira, Jerome Leblond, Herve Bricout, Sebastien Tilloy, Gregory Smith and Eric Monflier*
New water-soluble Schiff-base ligands based on ß-cyclodextrin for aqueous biphasic hydroformylation reaction
Pure and Applied Chemistry, 2018, 90, 845-855
Munsaf Ali, Avinash K. Srivastava, Shepherd Siangwata, Gregory S. Smith and, Raj K. Joshi*
Photo induced alkyne hydration reactions mediated by a water soluble, reusable Rhodium(I) catalyst
Catalysis Communications, 2018, 115, 78-81
Cody Williams, Michel Ferreira, Eric Monflier, Selwyn F. Mapolie and Gregory S. Smith*
Synthesis and hydroformylation evaluation of Fréchet-type organometallic dendrons with N,O-salicylaldimine Rh(I) complexes at the focal point
Dalton Transactions, 2018, 47, 9418-9429
Preshendren Govender, Siyabonga Ngubane, Bruno Therrien and Gregory S. Smith*
Monometallic and mixed-valence bimetallic Rh(I/III) complexes: Synthesis, structure, electrochemistry and application in 1-octene hydroformylation
Journal of Organometallic Chemistry, 2017, 848, 281-287
Shepherd Siangwata, Sisaenkosi Chulu, Clive L. Oliver and Gregory S. Smith*
Rhodium-catalysed hydroformylation of 1-octene using aryl and ferrocenyl Schiff base-derived ligands
Applied Organometallic Chemistry, 2017, 31, e3593
Danielle Aucamp, Tim Witteler, Fabian Dielmann, Shepherd Siangwata, David C. Liles, Gregory S. Smith and Daniela I. Bezuidenhout*
A triarylated 1,2,3-triazol-5-ylidene ligand with a redox active ferrocenyl substituent for rhodium(I)-catalysed hydroformylation of 1-octene
European Journal of Inorganic Chemistry, 2017, 1227-1236
Shepherd Siangwata, Nadia Baartzes, Banothile C.E. Makhubela and Gregory S. Smith
Synthesis, characterization and reactivity of water-soluble ferrocenylimine-Rh(I) complexes as aqueous-biphasic hydroformylation catalyst precursors
Journal of Organometallic Chemistry, 2015, 796, 26-32
Leah C. Matsinha, Jincheng Mao, Selwyn F. Mapolie and Gregory S. Smith
Water-Soluble Palladium(II) Sulfhonated Thiosemicarbazone Complexes: Facile Synthesis and Preliminary Catalytic Studies in the Suzuki-Miyaura Cross-Coupling Reaction in Water
European Journal of Inorganic Chemistry, 2015, 4088-4094
Latisa Maqeda, Banothile C.E. Makhubela and Gregory S. Smith
Synthesis, characterization and evaluation of fluorocarbon-containing rhodium(I) complexes for biphasic hydroformylation reactions
Leah C. Matsinha, Selwyn F. Mapolie and Gregory S. Smith
Recoverable and Recyclable Water-Soluble Sulphonated Salicylaldimine Rh(I) Complexes for 1-Octene Hydroformylation in Aqueous Biphasic Media
Dalton Transactions, 2015, 44, 1240-1248 (Open Access)
Linhua Lu, Prinessa Chellan, Gregory Smith*, Xiang Zhang, Hong yan and Jincheng Mao*
Thiosemicarbazone salicylaldiminato palladium(II)-catalysed alkynylation couplings between arylboronic acids and alkynes or alkynyl carboxylic acids
Tetrahedron, 2014, 70, 5980-5985
Leah C. Matsinha, Peter Malatji, Alan T. Hutton, Gerhard A. Venter, Selwyn F. Mapolie and Gregory S. Smith
Water-Soluble Half-Sandwich Ru-Arene complexes: Synthesis, Structure, Electrochemistry, DFT Studies, and Aqueous Phase Hydroformylation of 1-Octene
European Journal of Inorganic Chemistry, 2013, 4318-4328
Hong yan, Prinessa Chellan, Tingyi Li, Jincheng Mao, Kelly Chibale and Gregory Smith
Cyclometallated Pd(II) thiosemicarbazone complexes: new catalyst precursors for Suzuki-coupling reactions
Tetrahedron Letters, 2013, 54, 154-157
Emma B. Hager, Banothile C.E. Makhubela and Gregory S. Smith*
Aqueous-phase Hydroformylation of 1-octene using hydrophilic sulfonate salicylaldimine dendrimers
Dalton Transactions, 2012, 41, 13927-13935
Banothile C.E. Makhubela, Anwar M. Jardine, Gunnar Westman and Gregory S. Smith
Hydroformylation of 1-octene using low-generation Rh(I) Metallodendritic Catalysts based on a Tris-2-(2-pyridyliminoehtyl)amine scaffold
Dalton Transactions, 2012, 41, 10715-10723
Banothile C.E. Makhubela, Anwar Jardine and Gregory S. Smith
Rh(I) Complexes Supported on a Biopolymer as Recyclable and Selective Hydroformylation Catalysts
Green Chemistry, 2012, 14, 338-347
Banothile C.E. Makhubela, Anwar Jardine and Gregory S. Smith.
Pd Nanosized Particles Supported on Chitosan and 6-Deoxy-6-Amino Chitosan as Recyclable Catalysts for Suzuki-Miyaura and Heck Cross-coupling Reactions.
Applied Catalysis A: General, 2011, 393, 231-241
Guanlei Xie, Prinessa Chellan, Jincheng Mao, Kelly Chibale and Gregory S. Smith
Thiosemicarbazone Salicylaldiminato-Palladium(II)-Catalyzed Mizoroki-Heck Reactions