Vinesh A. Bhirud

A Site-Isolated Rhodium-Diethylene Complex Supported on Highly Dealuminated Y Zeolite: Synthesis and Characterization

The reaction of Rh(C2H4)2(acac) with the partially dehydroxylated surface of dealuminated zeolite Y (calcined at 773 K) and treatments of the resultant surface species in various atmospheres (He, CO, H2, and D2) were investigated with infrared (IR), extended X-ray absorption fine structure (EXAFS), and 13C NMR spectroscopies. The IR spectra show that Rh(C2H4)2(acac) reacted readily with surface OH groups of the zeolite, leading to loss of acac ligands from the Rh(C2H4)2(acac) and formation of supported mononuclear rhodium complexes, confirmed by the lack of Rh-Rh contributions in the EXAFS spectra; each Rh atom was bonded on average to two oxygen atoms of the zeolite surface with a Rh-O distance of 2.19 A. IR, EXAFS, and 13C NMR spectra show that the ethylene ligands remained bonded to the Rh center in the supported complex. Treatment of the sample in CO led to the formation of site-isolated Rh(CO)2 complexes bonded to the zeolite. The sharpness of the nu(CO) bands in the IR spectrum gives evidence of a nearly uniform supported Rh(CO)2 complex and, by inference, the near uniformity of the mononuclear rhodium complex with ethylene ligands from which it was formed. The supported complex with ethylene ligands reacted with H2 to give ethane, and it also catalyzed ethylene hydrogenation at 294 K.

A highly active catalyst for CO oxidation at 298 K: mononuclear AuIII complexes anchored to La2O3 nanoparticles

Mononuclear La2O3-supported AuIII complexes synthesised from AuIII(CH3)2(C5H7O2) and characterised by X-ray absorption spectroscopy are highly active, stable CO oxidation catalysts at room temperature, demonstrating the importance of the support in stabilizing catalytically active gold species, which need not include zerovalent gold for high activity.