Method for preparing an organic-compatible and water-compatible composition of metal nanocrystals, and resulting composition

A method for preparing a composition of metal nanocrystals from at least one organometallic precursor, comprising:

• preparing a liquid solution of at least one organometallic precursor in a solvent medium in the presence of at least one PEG ligand, wherein said PEG ligand has at least one carbon chain, at least one end of which is functionalized by a coordination group comprising at least one hetero atom, and is soluble in said solvent medium;
• and
• allowing at least one reducing agent with regard to each organometallic precursor to act on said liquid solution under reaction conditions suitable for direct formation of metal nanocrystals,
• wherein:
• said at least one PEG ligand is selected from the group of organic ligands that are soluble in water and include at least one carbon chain comprising at least one polyoxyethylene group [—OCH2CH2]n, n being an integer greater than 1,
• at least one end of the ligand is functionalized by a coordination group selected from the group consisting of a primary amine —R3NH2;
• a carboxyl group —R4COOH;
• a thiol group —R5SH;
• a phosphine group —R6P(Ph)2, Ph representing phenyl;
• and a phosphonate group chosen from —PO(OR7)(OR8), —PO(O−)2 and —PO(O−)(OH);
• R3, R4, R5, and R6 each independently represent at least one aliphatic chain;
• R7 and R8 each independently are a hydrogen atom or a group comprising at least one aliphatic chain;
• and
• each PEG ligand is soluble in the solvent medium, and wherein a water-compatible and organic-compatible composition of metal nanocrystals is obtained directly in one stage.