Rhodium-ferrocenyl complexes supported on phosphine-capped silicon wafers for heterogeneous catalysis applications
Mametsi Sebitlo
University of the Free State
Mametsi Rahab Sebitlo was born and bred in Parys, South Africa, on 16 March 1988. She received her secondary education in 2005 and enrolled for an undergraduate degree in Chemistry at the University of the Free State (UFS). She furthered her studies until obtaining her Doctoral degree in Chemistry. Her research was based on rhodium(I) complexes supported on two-dimensional silicon support for catalytic applications. She currently works as a Post-doctoral fellow at the UFS working on three-dimensional structured bi metal cyanometallate complexes
Abstract
Introduction: Heterogeneous catalysts have major advantages over homogeneous catalyst such as catalyst reusability and recyclability from the reaction media. However to understand their nanoscale surface dynamics by means of... [ view full abstract ]
Introduction:
Heterogeneous catalysts have major advantages over homogeneous catalyst such as catalyst reusability and recyclability from the reaction media. However to understand their nanoscale surface dynamics by means of suitable surface science techniques is a challenge due to the porous nature of their supports. To overcome this challenge, heterogeneous catalysts are studied on flat model support systems. For this reason, we have grafted well-defined rhodium phosphine complexes onto a silanol-activated two-dimensional silicon wafer surface,1 characterised the surface with XPS and studied oxidative addition reactions involving the rhodium(I) nucleous.
Method:
Rhodium complexes were anchored to modified silicon flat surfaces in two ways. First, [Rh(FcCOCHCOR)(CO)2] complexes2 with R = CF3, CH3, Ph and Fc (ferrocenyl) were grafted onto diphenylphosphine-functionalised3 silicon wafer surfaces. Secondly, preformed rhodium phosphine complexes [Rh(FcCOCHCOR)(CO)(PPh2-(CH2)3-Si(OEt)3))] were grafted directly to a silanol-functionalised silicon wafer surface. Surface changes during grafting were monitored by XPS and ATR-FTIR.
Results:
Silicon wafer-immobilised rhodium phosphine complexes were prepared and characterised. X-ray Photoelectron Spectroscopy (XPS) revealed the presence of Rh(I) (specie b) and an unexpected Rh(III) (species d & f) surface species in varying amounts as well as the dissociated RhI(CO)2 (specie c) and FcCOCH2COR (specie e) molecular fragments (as shown in figure). The [Rh(FcCOCHCOR)(CO)(PPh2-(CH2)3-Si(OEt)3))]-capped silicon surfaces underwent successful oxidative addition with gaseous methyl iodide with pseudo-first order rate constant k = 0.83 days-1.
References:
1. Thüne P. C., Verhagen C. P. J., van den Boer M. J. G and Niemantsverdriet J. W., J. Phys. Chem. B, 1997, 101, 8559.
2. Conradie J., Lamprecht G.J., Otto S. and Swarts J.C., Inorg. Chim. Acta., 2002, 328, 191.
3. Capka M., Syn. React. Inorg. Metal-Org. Chem., 1977, 7, 347.
Authors
-
Mametsi Sebitlo
(University of the Free State)
-
Jannie C. Swarts
(University of the Free State)
-
Elizabeth Erasmus
(University of the Free State)
Topic Areas
P - Catalysis processes & applications , P - General aspects of inorganic chemistry , Si - Materials science: polymers, thin films, nanopowders, ceramics, crystals, composites , Si - Advanced synthesis and characterization , Si - General aspects of inorganic chemistry
Session
OS2a-217b » Materials science: polymers, thin films, nanopowders, ceramics, crystals, composites etc. (13:30 - Tuesday, 4th July, 217b)
Presentation Files
The presenter has not uploaded any presentation files.
