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.