Rh 2 P nanoparticles (NPs) have been identified as suitable mimics of [Rh I (Ph 3 P) 3 ] + , the benchmark of homogeneous catalysts in liquid-phase hydroformylation. For this reason, a fitted synthetic strategy is required to develop catalysts based exclusively on Rh 2 P NPs. To attain this, two synthetic pathways have been devised. In the first one, two separate sources of Rh and P were used. In the second one, the Wilkinson complex was employed as a unique source of Rh and P to probe the positive influence of the well-defined molecular organization on the preparation of dispersed and controlled Rh 2 P nanoparticles, stabilized by carbon patches formed during the pyrolysis treatment from PPh 3 . In addition, metallic Rh nanoparticles were also synthesized to be used as reference. All catalysts have been compared by means of: transmission electron microscopy, Xray diffraction, and X-ray adsorption spectroscopy. The application of XAS to the study of Rh 2 P NPs is unusual and has been essential in the discussion of the results. Starting with a well-defined metal precursor leads to the exclusive formation of Rh 2 P NPs with excellent catalytic activity for the liquid-phase hydroformylation. The role of P is to modulate the particle size and the electronic configuration of Rh species, resulting in the improvement of the catalytic performance and the obtention of turnover frequencies of 5236 h −1 at 60 °C and 17,788 h −1 at 100 °C.
The reaction of 1-((2-(pyridin-2-yl)ethyl)amino)anthraquinone with either Fe(HMDS)2 or Li(HMDS)/FeCl2 allowed the preparation of a new anthraquinoid-based iron(ii) complex active in the hydrosilylations of carbonyls. The new complex Fe(2)2 was characterized by single-crystal X-ray diffraction, infrared spectroscopy, NMR, and high resolution mass spectrometry (electrospray ionization). Superconducting quantum interference device (SQUID) magnetometry established no spin crossover behavior with an S = 2 state at room temperature. This complex was determined to be an effective catalyst for the hydrosilylation of aldehydes and ketones, exhibiting turnover frequencies of up to 63 min-1 with a broad functional group tolerance by just using 0.25 mol% of the catalyst at room temperature, and even under solvent-free conditions. The aldehyde hydrosilylation makes it one of the most efficient first-row transition metal catalysts for this transformation. Kinetic studies have proven first-order dependences with respect to acetophenone and Ph2SiH2 and a fractional order in the case of the catalyst.
Alcohol oxidation is among the most important industrial organic reactions. Traditionally, the best-suited catalysts are Pd, Pt and Au supported nanoparticles. The research community has recently started drawing-up strategies to...
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