One-Pot Synthesis of Au11(PPh2Py)7Br3 for the Highly Chemoselective Hydrogenation of Nitrobenzaldehyde
Citations Over TimeTop 10% of 2015 papers
Abstract
In this study, the gold clusters Au11(PPh3)7Cl3 and Au11(PPh2Py)7Br3 (PPh2Py = diphenyl-2-pyridylphosphine) are synthesized via a one-pot procedure based on the wet chemical reduction method. The Au11(PPh3)7Cl3 cluster is found to be active in the chemoselective hydrogenation of 4-nitrobenzaldehyde in the presence of hydrogen (H2) and a base (e.g., pyridine). Interestingly, the cluster with the functional ligand PPh2Py shows similar activity without losing catalytic efficiency in the absence of the base. The structure of the gold clusters and reaction pathway of the catalytic hydrogenation are investigated at the atomic/molecular level via UV–vis spectroscopy, electrospray ionization (ESI) mass spectrometry, and density functional theory (DFT) calculations. It is found that one ligand (PPh3 or PPh2Py) removal is the first step to expose the core of the gold clusters to reactants, providing an active site for the catalytic reaction. Then, the H–H bond of the H2 molecule becomes activated with the aid of either free amine (base) or ligand PPh2Py which is attached to the gold clusters. This work demonstrates the promise of the functional ligand PPh2Py in the catalytic hydrogenation to reduce the amount of materials (free base: e.g., pyridine) that ultimately enter the waste stream, thereby providing a more environmentally friendly reaction medium.
Related Papers
- → Reactivity of highly Lewis acidic diborane(4) towards pyridine and isocyanide: formation of boraalkene–pyridine complex and ortho-functionalized pyridine derivatives(2017)49 cited
- → THE VIBRATIONAL SPECTRA OF PYRIDINE, PYRIDINE-4-d, PYRIDINE-2,6-d2, AND PYRIDINE-3,5-d2(1957)146 cited
- → Adsorption of pyridine onto the metal organic framework MIL-101(2011)37 cited
- → The reactivity of pyridine towards sulphuric acid at elevated temperatures(1958)21 cited
- → Craig 2‐Bromo‐Pyridine Synthesis(2010)