P NANOPARTICLES · P4 as precursor for metal phosphide nanoparticles and N2 activation and reduction to organic derivatives
FP7 — People (Marie Curie Actions)
- Duration
- 2008-06-02 → 2010-06-01
- EU contribution
- €171,601
- Participants
- 1
- Scheme
- MC-IEF
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Results in brief
P4 as precursor for metal phosphide nanoparticles and N2 activation and reduction to organic derivatives
Two different topics were studied during the two years of the project. The first one involved the use of white phosphorus P4 as a stoichiometric P atom donor for the synthesis of nanocristals of metal-phosphides MxPy. The second topic dealt with the activation of dinitrogen. These projects may appear unrelated, but in fact in the strategy envisioned, they do both rely on the use of transition metals in a reduced form. Two metal phosphides were selected for the first part of the project: Ni2P and InP. Indeed, these two compounds are of primary importance, as Ni2P is an industrial catalyst for the hydrodesulfuration of crude oil, and InP is a semiconductor. It has been shown that nanocristals of semi-conductors possess luminescent properties that depend: a) on the chemical elements; b) on the size of the nanocristal; c) on the shape of the nanocristal; and d) the efficient trapping of the electron / hole pair in the nanocristal. Our purpose was to design the appropriate chemical systems and to understand the mechanisms by which the desired MxPy could be formed. In a preliminary work, we had shown that either monometallic Ni(0) precursor or Ni(0) nanoparticles would be used to generate the corresponding Ni2P upon reaction with stoichiometric amounts of white phosphorus. This work opened the way for the extension of this strategy to In(0) precursors. The In(0) nanoparticles could be generated from the air and water sensitive In(I) precursor, Cp*In (Cp* = pentamethyl cyclopentadienyl). The formation of nanoparticles of InP with excellent dispersion in size could be achieved. The luminescent properties of these nanocristals were not satisfactory since nanoparticles of InP are known to oxidize rapidly in air. The second part of the project dealt with the activation of dinitrogen N2, as well as its functionalisation into amines of the type NR3. This task is of major importance as amines are industrially synthesised from NH3, which is in turn synthesised from N2 under strenuous conditions (Haber Bosch process, heterogeneous catalysis). We have based our work on known Mo(0) complexes which feature N2 as ligand. We focused on the use of Mo(dppe)2(N2)2 to evaluate the possible involvement of radical species R° to generate NR3. R° were chosen as bulky silyl derivatives R'3Si°.
Data: CORDIS, © European Union
Project objective
There are two different aspects in the project: i) the use of P4 in the synthesis of nanocristals of metal-phosphide and ii) fixation and activation of nitrogen and its reduction to organic derivatives. i) Synthesis of nanocrystals MxPy Usually the syntheses of these species imply the thermal decomposition (at high temperature) of a metallic precursor and a P atom donor in the presence of a mixture of a solvent/ligand. Normally P atom donor is TOP ligand. The main objective of our project is the use of more efficient P atom donor like P4. As starting point the synthesis of Ni2P and InP particles would be attempt due the expected properties for them (catalyst for olefine polymerization for Ni2P and optoelectronic and biology for imaging for InP) but the procedure will be extended to other metals like Pd, Pt or Ga. ii) Nitrogen activation The transformation of N2 into nitrogen containing species is a formidable challenge for chemists. The prerequisite for such transformation is the coordination then activation of N2 onto a metal complex. The Haber Bosch process allows the formation of NH3 from N2 an H2 but the conditions employed are quite hard and it is performed on a heterogeneous support. The second part of the project we propose to carry out involves homogeneous metal complexes together with silyl radicals and the use of nanoparticules for N2 activation. We are going to use for homogenous N2 activation a Mo(0) compound stabilized by ligands which would not decompose by the presence of reducing agent. The starting point is the reaction of [Mo(dppe)2(N2)2] with very bulky silyl derivatives to put in evidence the involvement of radicals in the process.
Original text from CORDIS.
Participants
- CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS · ParisCoordinatorFrance
Links
Data: CORDIS, © European Union